Photovoltaic systems and renewable energy

GTMO Gardening

2011-10-01T12:32:00.007-05:00

My primary goal is to grow tomatoes. However, this time of year the ground temperature is too warm. In an effort to trick mother nature I'm shading the ground, and pumping cool water around my tomato plants.

Notice that the basil and cilantro are doing well, but tomatoes not-so-much.

My container plants have the same problem; too warm here this time of year.

Tropical plants, like this pineapple, are doing well.

I was hoping for fresh bananna's, but this seems to be a plantain plant. I'll take what I can get.

We enjoy fresh Mango's, when in season.

I've never seen a Banyon tree before coming to GTMO. These can be freeky and huge.

I'll probably have to wait for cooler weather before I can successfully grow tomatoes again. Meanwhile, I'll enjoy the beach.

John

Range Anxiety

2010-10-20T18:23:00.003-05:00

As I think about what I’ll look for in my first electric car, one of my primary concerns is range. I didn’t invent the term “Range Anxiety”, but that is precisely what I am feeling. I think about the driving I’ll do, and how I’ll be limited by lack of range. When I want to visit my daughter, 95 miles away, I realize that the round-trip will not be possible with most electric cars in my price range. I know that charging stations will be popping up everywhere, but will I find one when I need one? When I get to one, will I have to wait in line? My “Range Anxiety” is likely to be replaced by “Charging Station Anxiety”, once I actually own an electric car.

It seems that GM considered “Range Anxiety” when they decided to put a gas-engine in their Volt. If it delivers as promised, it will be an excellent choice. On the other hand Nisson just doesn’t seem to get it. Their Leif car not only doesn’t have a gas-engine, it also requires a special charger, and that charger is not portable. Trips to visit my daughter in a Leaf are out. I won’t be able to recharge for the trip back home. The Leif would be great for my daily work commute, but I would have to own a second car for longer trips.

The Plug-in Prius, expected to be available in 2012, will be a wise choice for some. For those who drive less than 13 miles per day, as many commuters do, it will do that without using a drop of gas. After the initial 13 miles, it becomes an efficient gas-powered car, getting up to 50 miles per gallon. Like the Volt, there will be no range anxiety with a Plug-in Prius. And with it's smaller battery pack, the Plug-in Prius should cost less than the Volt. The Plug-in Prius can be charged in 3 hours or less, using a standard 110 volt outlet. For those who can charge while at work, electric-only round-trip (work commute) range will be 26 miles.

It’s not hard to predict how we’ll drive in the future. The Volt and the Plug-in Prius will be excellent cross-over cars, until technology catches up and solves the range problem with the early electric-only cars. It’s bound to happen. With tens of thousands of batteries in production, prices will drop and performance will improve. This is precisely what has happened with televisions, computers, and just about everything else in mass-production. And keep in mind that the total cost of ownership includes more than just the purchase price. Televisions, for example, once had tubes in them. Those TV’s quickly disappeared when they became too expensive to maintain. And like televisions, VCR’s were once large and expensive. Now we get the same results with a smaller and much less expensive device. Electric cars will be much less expensive to fuel, repair and maintain.

Nisson is not the only car company that “doesn’t get it”. Many manufacturers think we’ll settle for “Clown Cars”. (That’s what they look like to me). Not only do I not want to be seen in such a car, I wouldn’t dare drive it on an expressway. I would be better off with a golf cart for neighborhood-only driving.

Making safe electric cars will be a big challenge. A lighter car will deliver greater range per charge, but will probably be less safe in an accident than a heavier car. On the other hand, I can’t imagine anything more dangerous than sitting a few feet from 15 gallons of gasoline and a hot engine. Battery-powered cars will have devices designed to cut power in the event of a crash.

How much will it cost to drive a Plug-in Prius?

According to the Plug-in Prius webpage, it will take 1000 watts for 3 hours (3kwh) to charge the Plug-in Prius, and you’ll be able to drive 13 miles on a full charge.

If electricity costs 10 cents per kwh, 13 miles of driving in a Plug-in Prius will cost 30 cents in electricity.

If gasoline costs $3.00 per gallon, and you drive a car that gets 26 miles per gallon, it will cost $1.50 in gas to drive 13 miles.

In some locations, electric rates vary, depending on the time of day. In fact, I pay less than 3 cents per kwh late at night. At that rate, my cost to drive a Plug-in Prius, for the first 13 miles, will be less than 9 cents. Now 13 miles doesn’t sound like a lot, but my work commute (before I moved to GTMO) was about 13 miles. With the Plug-in Prius, I will trade $30.00 in gasoline for $1.80 in electricity each month. After the first 13 miles, Plug-in Prius gas range is expected to be about 50mpg, or about twice as good as the car I currently drive.

Someday soon, owning a gas-powered car will be like owning a television from the 60’s. Unless it’s a “Show Car”, it just won’t make sense. It might be fun to keep one around to tinker with, but it will not be practical as a source of transportation. Some will have trouble leaving the memories behind, like the sound of a well-tuned V8 engine, but I can live without it. I can live without the grease, pollution, and noise. If I have to have high-performance, I’ll save up for a Tesla Roadster.

Range anxiety is likely to be a household term soon, but we’ll quickly forget about that, just as we’ve forgotten about all of those VCR’s that constantly flashed 12:00. The Volt and the Plug-in Prius will soon be thought of as a sensible forms of transportation, but years from now we’ll think of them as quaint.

John

Just Say No to Oil

2010-05-24T19:32:00.003-05:00

I could jump on the bandwagon and blame BP, the president, or congress for the recent disaster in the Gulf, but I won’t. I think we need to look at ourselves instead. As long as we keep using oil, someone will drill for it and accidents will happen. If we stop using oil there would be no need for off-shore drilling.

I do understand that we’re not going to stop using oil overnight. Paul Roberts, author of the book “The End of Oil” claims that the U.S. is decades away from shedding its reliance on oil. I disagree. Cutting back would be a good start, and that’s something we can begin to do today. We can start by avoiding unnecessary driving. Motor-bikes, scooters, or even bicycles are practical alternatives to cars for some, while others can use mass-transit. When it’s time to replace the vehicle (that you absolutely can’t live without), consider an efficient one, perhaps a hybrid. Plug-in-electric vehicles will soon be available, so plan accordingly. These are only a few things we can all do. With a little effort, we could reduce oil consumption by 50% in one year. Imagine how we would all benefit from that!

If you’re reading this, you are probably someone who is concerned about the envoronment. That’s great, but we need to bring others on-board. We need to lead by example. Leading by example is far more effective than ranting and raving like an environmentalist kook. The car you drive speaks volumes about your intentions. And while few will notice your energy-efficient lighting or appliances, solar panels on your roof would be hard to ignore. Start small if you must, at least replacing some of the fossil fuel you would otherwise use in your home with electricity from solar panels. Others will follow your lead eventually, and we’ll all benefit.

Sadly, many people still think that conservation, and implementing renewable energy solutions, will somehow result in a lower quality of life. This is simply not true, and we need to spread the word. When done right, quality of life can be enhanced. CFL or LED lighting provide the same amount of light as incandescent bulbs, while reducing electricity use significantly. Imagine that; you’ll be doing something positive for the environment, and enhancing your quality of life via lower electric bills.

And speaking of enhancing your quality of life; a plug-in-hybrid car can be recharged at night, when electric rates are low. You might be able to replace the four dollars a day you are currently spending for gasoline with less than one dollar for electricity. For more about this, click here: http://solarjohn.blogspot.com/2007/12/driving-phev-is-like-buying-gasoline-at.html

Everything we currently do that involves oil can be done another way, and often in a much better way. The transition to renewable energy will open up new career opportunities. Technically savvy folks will find interesting work in energy production, construction, service, and transportation. Those who are the quickest to accept post-oil technologies will be the most successful.

We can’t just stop using oil overnight, but the idea of waiting decades is a concept that we shouldn’t accept. When the oil spill in the gulf becomes old news, we must remain committed to cutting back. Each time we purchase a vehicle, an appliance, or even a light bulb, we should shop with energy-efficiency as our top priority.

If you need another reason to implement and promote alternative energy, perhaps the best one is that not a single soldier will need to give his life to keep renewable energy flowing.

Please, just say no to oil.

John

Solar Panels at Gitmo

2010-03-17T19:57:00.004-05:00

Does anyone know what the plastic rods on top of the solar panels are for? My guess is that their purpose is to keep birds from perching there.

Gitmo has windmills too...

GITMO

2009-11-21T20:58:00.003-06:00

My renewable energy projects have been placed on hold, for now, because I'm on assignment at GITMO. Fortunately, my off-grid system is running on automatic pilot. Too bad I didn't make provisions for monitoring it via the Internet. For anyone who might be interested, here's a little information from where I am at the present time. Check back later for my report on renewable energy at GITMO.

GITMO is an incredibly interesting place to explore. There are some great bike trails. Here's a view of a section of the base from up on a hill. The second picture is a section of Caribbean Shoreline. The cliffs are acutally rock and fossilized corral. I've never seen anything like it. The final picture is of the base Hospital.

The Smart Grid and You

2009-08-04T20:18:00.002-05:00

If you’re reading this you’re probably someone who takes responsibility for your own future, instead of waiting for the government or someone else to do things for you. Perhaps you’ve already installed solar panels, instead of waiting for substantial rebates or subsidies. You don’t get excited when you hear about a breakthrough, and you’re not waiting for a dramatic price reduction of solar panels. You may not be able to justify the high cost based on the electricity your system produces, but you have no regrets. You have a system that provides an emergency source of electricity to serve when the grid fails, and you have some protection from the inevitable rate increases. And, should you experience a total melt-down of society, you’re better equipped to live a self-sufficient lifestyle than those who don’t have these systems.

As content as you might be with your own efforts, it’s good to see environmentally-beneficial government-supported projects when they do occur. The Smart Grid is a project that recently received significant funding from the Obama Administration, and those of us who already have solar- or wind-power systems will benefit to a greater extent than those who don’t.

The Smart Grid, when implemented, will be a modernization of the current electrical generation and distribution system. The Smart Grid will be an automated network, with a two-way flow of electricity and information. Extensive monitoring will result in a much more efficient system, benefiting electricity providers, as well as consumers. Providers will be better equipped to reduce generation and transmission costs, and consumers will be better prepared to make decisions affecting their use of electricity and control cost. The Smart Grid will have a positive environmental benefit as well.

Monitoring and control will extend beyond the generation and transmission infrastructure. In-home monitoring and control is another characteristic of the Smart Grid. Consumers will have real-time cost information, helping them to manage electricity use in order to save money. Additionally, smart appliances in the home will use this information to automatically reduce energy usage. Use of the cost-saving features built into smart appliances will be voluntary, not mandatory. Users will have the ability to override these cost-saving features if they so desire.

Other characteristics of the Smart Grid are its ability to accept power from solar and wind systems, and to utilize energy storage devices. This should be particularly interesting to those who have solar or wind systems, and to those who plan to purchase an electric vehicle. You may be an electricity provider someday, and you’ll be paid for it.

While some will simply ignore the available information concerning the cost of electricity, others will minimize their use when the cost is high. Doing laundry, running the dishwasher, and vacuuming are all chores that can be done when rates are low. If you have a solar electric system or a wind turbine, you have an additional option; use energy from your system when grid-supplied electricity is expensive, and use grid-supplied electricity when the cost is low. That, of course, is intuitive and many are already doing that. However, there are other strategies that may result in additional savings. For example; consider charging batteries when electric rates are low, and use the stored energy when rates are high. The battery charger could be controlled by a timer, set to be powered-up when rates are low, and to switch off when rates are high. Better yet, the battery charger could be switched on and off via a “Smart Controller”. A Smart Controller would be a device that can switch power to an outlet on and off based on preset electricity rate thresholds. I’m not aware that such a device exists, but it soon will. You’ll need a battery charger, (like the one described here), that will not overcharge your batteries.

Those who’ll benefit most from the Smart Grid will be, no doubt, those who drive Plug-in-Electric-Vehicles (PHEV’s). Most will be charged at night, when electric rates are low. Consider for a moment that you’ll pay about twenty cents per kwh for electricity during periods of peak demand, and less than two cents per kwh when demand is low. (These figures are based on my actual cost for electricity as a participant in a program offered by my provider). While your cost to top off the battery during the day might be as much as 3 dollars, the cost at night could be less than 30 cents. Replacing gasoline with electricity for transportation could result in a savings of $1000.00 each year. At 3 dollars per gallon, cutting gasoline use by one gallon a day would accomplish that. Those who need to charge their PHEV’s during the day, night-shift workers for example, would benefit by installing a PV system.

Some PHEV’s will be connected to the grid during the day, returning excess power to the grid during periods of peak demand. This concept, known as Vehicle-to-Grid (V2G) technology, is another example of an innovation made possible by a Smart Grid implementation that will benefit providers and users of electricity. Theoretically, you could earn money by connecting a PHEV to the grid. If you recharge at night when rates are low, and return power to the grid when rates are high, you might find that the power company owes you money at the end of the month. You’ll not only eliminate your use of gasoline, you could fuel your car at no cost at all. Your actual results will depend on the number of miles you drive each day.

“Ask not what the grid
can do for you. Ask what you can do for the grid – and
prepare to get paid for it!”

Your contribution to the grid, as small as it might be, will be an important part of the Smart Grid. Solar, wind, and V2G systems will increase the number of electricity providers dramatically. The result will be a broad distribution system that is less vulnerable to natural disasters and terrorist attacks. Utilities will have better control of resources, reducing the need to add power plants simply to meet peak demands.

Whether you’re an electricity provider, consumer, or both, you need to be able to measure the flow of electricity to be able to control it. The Smart Grid will provide that capability, and pave the way for the development of tools to better manage electricity. Pilot projects have already shown that Smart Grid technology not only enhances electric grid reliability and reduces outages, but also creates smaller electricity bills for consumers and could alleviate the need for additional infrastructure. The Smart Grid connects consumers to the grid in a way that is beneficial to both. This is the dawn of some pretty interesting innovations.

John

Survival in the 21st Century (Part 2)

2009-07-29T19:44:00.001-05:00

Recently I asked you to consider what would happen to you and your family in the event of a pandemic, natural disaster, or major terrorist attack. I ask you to imagine a scenario in which you find empty grocery store shelves, no running water or electricity, and no natural gas service. I find that most people have given some thought to this, and have made preparations, at least for the first few days following an emergency. Putting together an emergency kit is easy. However, preparations for long-term survival are not so easy. To make matters worse, people tend to believe that they’re ready, when in fact they are not. A plan, by itself, is not enough. It’s easy to say “I’ll plant a garden”, but do you have the tools and skills? Could you install a solar photovoltaic (PV) system and make it work? Do you have a plan to keep your home warm if you find yourself without utility-supplied heating fuel? Remember, in an emergency many of your neighbors will be looking for the same equipment and supplies that you’ll be looking for. The time to prepare is BEFORE an emergency.

If you have no previous gardening experience you’re likely to be disappointed with the results of your first attempt. In fact, it may take several seasons to become a good gardener. Even experienced gardeners continue to learn from season to season. Are you confident that you can grow a crop big enough to get you and your family through the winter? Do you have seeds? Can you keep insects and pests from ruining your crops? If you do manage to grow something, will you be able to preserve it for later consumption? Do you have the items needed for canning and preserving?

Solar panels, batteries, and the other components needed to build a solar electric system might be hard to find in an emergency. And, even if you can find the items you need, will you be able to build a system and use it efficiently? Unless you have previous experience, it’s unlikely that you’ll get the most out of this equipment. Beginner’s mistakes might result in damaged equipment and a system malfunction just when it’s needed the most.

I suspect that most of us are woefully unprepared for long-term survival and sustainable living, but fortunately we can do something about that. Here are a few suggestions:

Learn how to grow things now, don’t wait until spring. You’ll find plenty of information on-line. Consider plants that you can grow indoors, with limited space requirements. These might include herbs, wheat-grass, and dwarf tomato plants. Start a compost pile/bin. You’ll use the finished compost (humus), later to improve the soil. Plan your outdoor garden, and begin working the soil early in the spring. Save seeds from your successful crops. Saved seeds, from crops grown in your own backyard, will be better suited to your area than those bought from an out-of-the-area supplier. By the end of the season you’ll have plenty of ideas for doing things better next year.

If you have an acre or more of land, you might consider growing your own heating fuel. You can grow enough corn to heat your home for an entire winter on just one acre of land, but land alone is not enough. You’ll need equipment for planting, growing, and processing the corn as well as a way to securely store it for later use. You’ll have to protect your crop from insects and animals. This can be a monumental task, and perhaps overwhelming without the appropriate equipment. You might consider heating your home with wood if you can count on an abundant supply. Whichever method you choose, learn to use your stove or alternative heater efficiently and safely, and stock up on the appropriate fuel. Keep in mind that with an ordinary fireplace the heat goes up the chimney. The only warm spot in the home is directly in front of the fireplace. You’ll need a better strategy than that. If you’ve installed a heat exchanger, and if you have a dependable supply of electricity to power the blower, you’re in business.

Install and use an off-grid solar photovoltaic (PV) system. Monitor daily electricity production, and use. Shut down service from the power grid once in a while to check your system’s performance in a simulated grid power failure. You’ll learn from these simulations, you’ll adjust, and you’ll be better prepared for an actual emergency. Since your system probably won’t be big enough to supply all of your household needs for electricity, you’ll find ways to conserve. You’ll change to power-sipping compact fluorescent bulbs (cfl’s), for example. As you become more and more self-sufficient, you’ll be cutting your utility bills at the same time, a win-win situation.

Sustainable living skills need to be learned and practiced BEFORE an emergency. Unless you prepare in advance you probably won’t have the equipment, supplies, and skills needed for survival in the event of an emergency. Remember, you’re not preparing for the end of the world, you’re preparing for the future of the unknown. I hope you’ll take advantage of the information provided in this blog’s archives as you prepare. As always, I look forward to your comments and suggestions as I become more self-sufficient.

John

Survival in the 21st Century

2009-07-23T19:15:00.003-05:00

What would happen to you and your family if a pandemic, natural disaster or a major terrorist attack were to occur? Imagine empty grocery store shelves, no gasoline, no running water, no electricity, and no natural gas service. You may have enough food and water to last for a few days, but what do you do after that?

You can live 3 minutes without air.
You can live 3 days without water.
You can live 3 weeks without food.

A good survival plan should begin with preparations to deal with an emergency within the first few minutes, and end with strategies for long-term survival.

In the event of an explosion, fire, or crash you may need to deal with broken glass and sharp metal objects and hot objects. Imagine how handy gloves would be. You should also be prepared to handle physical injuries you may sustain, as well as those of family members and others nearby. A knife is a necessity, as is a well-equipped first aid kit.

Survival preparations for the first few days after the emergency should include a supply of food and water, of course, but you’ll also need shelter and perhaps the ability to stay warm and dry. Help may be slow in coming in the event of a large-scale disaster. Many New Orleans residents learned this the hard way after Hurricane Katrina.

Survival becomes something else after the first few days. Your need for water and food is an ongoing one, and your stockpile may be running low. Perhaps you’ve banded together with neighbors, and pooled your resources. That’s a good thing. Each member of the group has his or her own unique talents, many of which can help to ensure the survival of your group. Skills such as hunting, trapping, and fishing will certainly come in handy, as will the ability to identify edible plants.

Whether you live in a city, or in a rural area, the importance of urban gardening and small-scale farming cannot be overemphasized. And, of course, you’ll need to know how to preserve and store food. Improperly stored food may rot, or be ruined by insects or rodents. It should be obvious that these skills need to be learned BEFORE an emergency. The people most likely to survive are those who’ve already incorporated elements of sustainable living into their everyday lives. Some have moved out of heavily populated areas, realizing that in the event of a disaster it will be difficult to get food when a million of their neighbors are also looking for it. They’re learning and practicing the skills that their great grandparents knew well. Some are making their own electricity with solar panels, windmills, and micro-hydro systems. Life in a rural area presents an abundance of opportunities for sustainable living, many of which are not available in the city.

Electricity may seem like a luxury, and some may believe that solar panels, windmills, and micro-hydro systems shouldn’t be included in a survival discussion. I disagree. Electricity can be an important aspect of survival in several ways. When used to power a refrigerator or freezer, electricity becomes a big part of a food preservation strategy. Additionally, refrigeration is often needed to keep medications from spoiling. Having electricity means that you’ll have good lighting, an important security consideration, and it helps to prevent accidental injuries around the home. Without electricity, you might have to boil water over a fire to make it safe for drinking. A renewable supply of electricity can keep a radio or TV operating, providing critical information as well as entertainment. When you think of all the electrically-operated appliances that you would otherwise have to do without, it’s obvious that electricity can make life comfortable in an otherwise unbearable situation.

Some will have you believe that you’ll need to spend tens of thousands of dollars for a practical solar electric system, but that’s simply not true. A system to meet your basic needs can be built for under $1000.00. You won’t have central air-conditioning with a small system, but you will have lighting, communications, and perhaps a limited amount of electricity for cooking and refrigeration. In the absence of grid power, you’ll be thankful for the small amount of electricity your system provides. You’ll learn techniques for getting by with less. A chest freezer, for example, can meet your refrigeration needs with much less energy consumption than a refrigerator.

You may think that these gloom-and-doom scenarios are unrealistic and choose to do nothing, but if you believe that that things could get ugly you should prepare as soon as you can. If you wait until things get bad, it will be too late. You’ll be forced to use the resources you have available, not the systems you planned to install someday. Surviving a disaster will be a challenge, so being in good physical condition is important. Don’t abuse alcohol, tobacco, or other drugs. You may have the additional task of caring for very young or very old family members. Make regular exercise a part of your plan. Don’t be overwhelmed, the important thing is to get started. Eat healthy and get plenty of rest.

“The thing about being a survivalist kook and stockpiling gold, guns, and food is that there’s no downside. Even if you’re wrong, you’ve still got gold, guns, and food.” W.C. Verson

Being a “survivalist” today means more than simply providing for your own comfort. Today, survival of the planet is an important consideration as well. In the absence of a healthy planet, even the most carefully laid out personal plans will be of no value.

About 50% of the electricity produced in the United States comes from coal-fired power plants. Mining, transporting, and burning coal has terrible environmental consequences. Additionally, oil reserves are running low (peak oil). It should be obvious that we’re on the brink of a radical lifestyle change. The good news is that we can do a lot, with very little sacrifice. Our lifestyles include a lot of waste, and therefore we have numerous opportunities to make changes that will benefit not only ourselves, but all of mankind and the planet.

By incorporating elements of self-sufficient living into your lifestyle, you’ll benefit from a better quality of food, more exercise, and better air quality. Anyone who’s ever compared a store-bought tomato to one grown in a backyard garden knows what I mean. Tomatoes that have to be shipped a long distance are picked green, and “gassed” to turn them red by the time they show up in the supermarket. They’re rock-hard, and have little flavor. I can only guess that the nutritional and cancer-fighting properties are not what they should be either. And it’s wise to remember that the recent salmonella outbreak linked to tomatoes was a result of industrial agriculture. Shipping fewer vegetables not only means better food, it also means fewer trucks on the road, which reduces fossil fuel use and improves air quality.

In the words of Charles Darwin, "It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.” Problems related to global warming and the decline of oil are among the most significant changes this generation will face. Many believe that global warming is responsible for climate change, including extreme weather, such as storms of greater intensity. Some believe that global warming is a natural phenomenon, while others believe that it is caused by our actions. Perhaps it’s some of both. Regardless of the cause, our response needs to be a thoughtful plan, not simply a knee-jerk reaction to the latest crisis.

Someday we’ll have a leader who will actually work with us to solve problems, instead of telling us we’re “addicted to oil”, but for now we’re just going to have to rely on our own efforts. Mass acceptance of renewable energy systems by the general public will show our elected officials, and the rest of the world, that we want to do the right thing. We can do it. We should do it. Future generations will appreciate our efforts.

John

OAR, SAIC, and The Green Dream

2009-06-14T18:39:00.008-05:00

Being so involved with recycling, conservation, and renewable energy in my personal life, I was happy to volunteer to assist in a recycling booth last week. Rock Band OAR and corporate sponsor SAIC teamed up recently to encourage recycling and conservation. OAR calls this their “Green Dream Tour.”

For my efforts I received a souvenir T-shirt, an opportunity to meet the band, and free admission to the concert. More importantly, I had the opportunity to spread the word about the importance of recycling and conservation. The band, my co-volunteers, and everyone else involved was fun to work with. This was an enjoyable evening. Here are a few pictures…..

The band, and SAIC volunteers.

The fabulous Fox Theater in St. Louis.

Setting up.

OAR on stage.

Great show! The packed house really seemed to enjoy it.

John

My Off-Grid Photovoltaic System and This Blog

2009-05-30T23:32:00.002-05:00

You might have noticed a decline in the number of posts to this blog since the first of this year. The decline is primarily due to the fact that my off-grid system hasn’t changed much over the past 6 months. I’ve slowed down because I now pretty much have what I want; a system that can meet my basic needs for electricity during a grid power failure, and one that provides enough energy to significantly lower my electric bill. I’ve also added automation to my system, providing additional protection for my batteries while optimizing power output.

I’ll probably never have enough PV-provided electricity to meet all of my needs, but I can get by pretty comfortably most of the time with the system I now have. It’s important to mention that my need for electricity during a grid-power failure varies with each season. Lengthy periods of cold weather provide the greatest challenge. In addition to the electricity needed for lighting, refrigeration, cooking, and communications, I’ll need electricity to keep my home warm. I can easily use up all of my stored energy during extended periods of cloud cover. With that in mind, I plan to add another PV panel this year, and one or more next year. Other than that, I have no other significant upgrade plans. I’ll maintain this slow but steady progress unless I see a dramatic increase in the cost of grid-supplied electricity, or a dramatic decrease in the cost of solar panels. I hope to drive an electric car within the next two years, and I would love to power it with solar. This is not practical now, with PV panels costing $5.00 per watt.

Here is an overview of my system:

Type: Off-grid
PV: 7 X 85, or 595 watts
Batteries: GC2’s wired for 12 volts, 900ah.
Spare Battery Bank: Marine Deep Cycle, 420ah.
Controller: TriStar 60 with meter and remote temperature probe
Inverter: Exeltec 12-volt, 1100-watt pure sine wave
Automation: Morningstar Relay Driver programmed to enable/disable the inverter and an Iota Transfer Switch

When I started installing solar PV, my primary goal was to become more self-sufficient, especially in the event of a major disaster. From time to time I need to remind myself that water and food are much more important than electric lights in the event of such a disaster. That’s why you’ll find so many articles about growing and preserving food in this blogs archives. You’ll also find articles concerning alternative heating, another necessity for surviving in the event of a loss of natural gas and grid-supplied electricity.

I hope that you’ll browse my archives now and then for ideas, and comment. Let’s learn from each other.

John

Grow Your Own Medicine

2009-04-17T21:45:00.003-05:00

Last week I provided strategies for growing your own vegetables. If you choose to do that you’ll not only be eating fresher and healthier food, you’ll avoid harmful chemicals and pesticides. This is more important today than ever before for a couple of reasons: Much of the food we consume comes from bioengineered plants, and those plants are much more dependent upon chemicals than the plants they’ve replaced. As a result, we’re exposed to chemicals to a much greater extent than we were in the past. Additionally, much of the food we consume today comes from foreign suppliers, including China, where regulations and inspections are not as thorough as they should be. And unfortunately, only a small percentage of food imports are inspected as they enter the United States.

While your garden might include great-tasting tomatoes, peppers, lettuce, and so on, you might also consider growing medicinal crops. Many people have already switched to alternative medicine due to the high cost of conventional medicine, while others choose alternatives when conventional medicine fails. The possibility of a dramatic cure, improved quality of life, and increased life expectancy are a few more reasons some people choose alternatives.

Of the medicinal crops that you might consider, Bitter Melon is one that can be used to treat a variety of disorders, including diabetes and HIV. Bitter Melon is a green, cucumber shaped fruit, with gourd-like bumps. While all parts of the plant have been used, the fruit is the safest and most prevalent part of the plant used medicinally. Rich in iron, bitter melon has twice the beta carotene of broccoli, twice the calcium of spinach, twice the potassium of bananas, and contains vitamins C and B 1 to 3, phosphorus and good dietary fiber. It is believed to be good for the liver and has been proven by western scientists to contain insulin, act as an anti-tumor agent, and inhibit HIV-1 infection. Multiple clinical studies have clearly established the role of Bitter Melon in people with diabetes. Practitioners of Chinese medicine have been using it for hundreds of years with good results. In the Philippines, Bitter Melon (known as Ampalaya) is also used to treat infections, fevers, and rheumatism.

Bitter Melon contains an insulin-like principle, known as plant-insulin, which has been found effective in lowering blood and urine sugar levels. The diabetic should take the juice of about four or five fruits every morning on an empty stomach. Bitter Melon seeds can be added to food in a powdered form. Fresh juice from the leaves of Bitter Melon can be used to treat a variety of disorders. To prepare a Bitter Melon extract:

Wash and finely chop the leaves.
Add 6 tablespoons of the chopped leaves in 2 glasses of water.
Boil it for 15 min. in an uncovered pot.
Cool down and strain.
Drink 1/3 cup of it 3x a day.

Although research supports the use of Bitter Melon as a treatment for many conditions, it is not clear what dose is safe and effective. Bitter Melon should be used cautiously, with close monitoring by your health care provider.

Need seeds? Let me know.

Link:

Check out Garden Web, Asian Vegetables section, for information about growing Bitter Melon. As you search for additional information, keep in mind that Bitter Melon is also known as Ampalaya and Bitter Gourd.

http://forums.gardenweb.com/forums/asianveg/

Other Links:

http://bittermelon.org/

http://holisticonline.com/Herbal-Med/_Herbs/h31.htm

http://www.sciencedaily.com/releases/2008/03/080327091255.htm

John

Strategies for Eating Healthy

2009-04-09T20:26:00.010-05:00

“Eat your vegetables and you’ll grow up strong and healthy”, we were told as children, but things are different today. Today, much of our food comes from overseas, and hardly a week goes by without news of a tainted food product, usually from China. China’s agricultural exports to the United States surged last year, and I expect to see many more disturbing articles in the future. And sadly, we can’t rely on product labels for healthy eating. Some farmers in China are taking advantage of confusing rules to falsely label food. Chinese authorities have vowed to fix the problems, but the disasters keep coming.

Since the United States subjects only a small fraction of its food imports to inspection, it’s up to each of us to see that our families are eating healthy. With these things in mind, here are my suggestions:

1. Grow your own food. Preserve some of it for off-season consumption.

Canning, freezing, and storing food in a root-cellar are a few of strategies you might consider.

2. Buy locally-grown organic food when it is in season.

You can often find bargains, and will benefit by preserving some of those crops for off-season consumption.

3. Learn to grow food in the winter.

If you have a sunroom, or even a south-facing windowsill, you can grow your own vegetables and herbs year-round. Since full-sized plants might present a space problem, investigate dwarf plants instead. Red Robin, for example, is a tomato plant that grows to a height of only 16 inches, and produces bunches of great-tasting cherry tomatoes.

If you decide to grow your own vegetables indoors you’ll need to provide the right conditions for plant growth. This can be a little tricky, since each type of plant will have somewhat different needs. The small plant stand shown here includes a heater, and a shop light with fluorescent tubes. Upper and lower levels contribute to an efficient use of space.

Here are some things you'll need to know in order to grow dwarf tomato plants:

Temperature:

Seeds germinate best at about 70 to 80 degrees F.

The ideal temperature for new seedlings is about 60 to 65 degrees.

Mature plants need warmer temperatures for setting fruit (70 to 85 degrees).

Plants can tolerate night-time temperature drops, but avoid going below 50 degrees.

Avoid temperatures above 90 degrees. Extreme temperature variations will affect production.

Light:

Provide at least 6 hours of sunlight per day for seeds that have sprouted. More sunlight, up to 16 hours per day, will produce better tasting fruit. If potted plants will be getting light from a closed window, place the plants as close to the window as possible. If necessary, supplement natural sunlight with the light from a cool-white fluorescent bulb. For this to be effective, the light must be placed within a few inches of the top of the plants.

Soil:

Use a good quality seed starting soil. Repot, when necessary, in a good quality potting soil. Provide good drainage and avoid compaction of the soil. The bottom of the pot should have holes to allow excess water to drain. Red Robin will do well in an 8” diameter container, but you can try a smaller one if your space is limited. If the plant cannot support the weight of the fruit, stake it with a ¼” stick or dowel. Tie the main stem to the stake with cotton or nylon cloth. Do not use string or thread.

Water and feeding:

Use an organic fertilizer formulated specifically for tomatoes according to the instructions on the package. Don’t use fertilizer heavy in Nitrogen. That will result in lush plants with very little fruit. Occasionally, use water with 1 tablespoon per gallon Epsom salts. This provides additional magnesium for the plants.

Avoid watering from the top. Too much dampness at the base of the plant can result in a fungal problem. It is best to water from the bottom, allowing the potting soil to soak it up. Do not add more water than can be soaked up by the plant.

Air:

Plants breathe. Use a fan to circulate air through the leaves or open a window (weather permitting). A strong breeze not only helps with respiration, it helps stalks and stems grow sturdy. Remember that roots need air also. Avoid watering too much, and soil compaction.

Pollination:

Once a day, shake or tap plants that have produced flowers. This allows the plants to pollinate, and therefore, set fruit. A gentle breeze also helps with pollination.

Saving Seeds:

Cut a ripe tomato in half, scoop out the seeds and pulp, and place in a jar with a little water and cover with plastic wrap. Stir the seeds a few times a day for the next 2 or 3 days. During the fermentation process, the good seeds will separate from the gelatinous covering and sink to the bottom after which time you can pour off the liquid and junk. Rinse the seeds with cool, clean water. A fine mesh strainer or even coffee filters work. Dry seeds thoroughly before storing.

Additional Information:

Gardening, indoor or outdoor, not only reduces your exposure to harmful pesticides, you’ll enjoy fresher and tastier food and cut your grocery bill. Exercise and fresh-air are a couple more benefits you’ll experience as a gardener. But, there’s more! Have you ever considered growing medicinal crops? Check back next week for more information on that subject.

Links:

Here is a good source of seeds and information:

http://www.containerseeds.com/index.html

Garden Web is one of the best informational sites I’ve found:

http://www.gardenweb.com

Washington Post article about tainted milk from China:

http://www.washingtonpost.com/wp-dyn/content/article/2007/04/24/AR2007042402539_pf.html

More bad news from China:

http://www.manufacturing.net/News-Pesticides-Found-In-Frozen-Beans-From-China.aspx?menuid

John

GeoBulb (LED) vs CFL (Compact Fluorescent)

2009-04-01T21:18:00.007-05:00

I’m always on the lookout for products that reduce my carbon footprint while saving me money, and I don’t mind paying a premium price for a product if I can expect to benefit in the long run. At first glance the C.Crane GeoBulb seems to be such a product, so I’ve decided to take a closer look.

My first task was to get as much information about the GeoBulb as possible. I would have liked to try it out before writing a review, but since it sells for a whopping $119.95, I decided to rely on whatever data I could find instead. Fortunately, the C.Crane website not only lists specifications, it also provides a chart comparing the GeoBulb to incandescent bulbs and CFL’s. Since I’m not interested in incandescent bulbs, I’ll limit this discussion to CFL’s and the GeoBulb bulb only. My comparison assumes that the GeoBulb provides about the same amount of light as a 13-watt CFL bulb. Here is my line-by-line evaluation:

Life Span:

C.Crane claims that CFL’s last up to 2,500 hours, and the GeoBulb lasts up to 30,000 hours. Interesting data from C.Crane, since Sylvania claims that the average rated life of their CFL’s is 10,000 hours. This skews the results significantly.

Bulb Cost:

C.Crane claims that the cost of a CFL bulb is $5.00. Absurd! I’ve found 13-watt CFL’s from $1.65 to $2.49. I can buy more than 50 CFL’s for the same price as one GeoBulb!

Cost of Electricity:

It's easy to calculate the cost of electricity. My calculations are based on 13-watts for the CFL, and 7.5-watts for the GeoBulb. C.Crane lists the cost of electricity for 30,000 hours of operation at $44.73 for CFL’s, and $25.81 for the GeoBulb. Those calculations are based on electricity at 11.47 cents per kwh. Although my electric rates are somewhat lower than that, I won’t argue with C.Crane’s cost of electricity data.

Total Cost:

C.Crane claims that the total cost (bulb + electricity) for CFL’s is $104.76, while the total cost for the GeoBulb is $145.76. My calculations are based on longer CFL life and lower CFL cost:

Total Cost for CFL’s (3 bulbs plus electricity): $49.68
Total Cost for GeoBulb (1 bulb plus electricity): $145.76

Hazardous Material:

C.Crane correctly states that CFL bulbs contain mercury, a hazardous material, while stating that the GeoBulb has no hazardous materials. While it is true that CFL’s contain mercury, it is a very small amount, and it’s sealed within the bulb. Recycled CFL bulbs are not harmful to people or the environment.

Cost to Run:

C.Crane claims that the cost to run a CFL for 12 hours a day for one year is $6.53, while the cost to run the GeoBulb for the same amount of time is $3.77. C.Crane offers no additional explanation of how it arrived at the $6.53 for the GeoBulb, and I find that data hard to believe. Roughly calculated, at 30,000 hour lifespan, the cost would be about $17.00 per year for the bulb, and another 50 cents for electricity. On the other hand, one CFL should last about 2 years under similar conditions, and would use about $1.00 worth of electricity. Here are my figures:

CFL cost to run: $1.82
GeoBulb cost to run: $17.50

Other Considerations:

The GeoBulb and the CFL share some common benefits as well as limitations. Both will cut electricity use when compared to ordinary incandescent bulbs. However, heat build-up can shorten the lifespan of both, and neither type should be used outdoors. The GeoBulb, as well as most CFL's, can't be used with a dimmer switch.

Summary:

It didn’t take long for me to decide not to buy the GeoBulb. Information from the C.Crane website, a few web searches, and some simple calculations provided enough information. I need not look into other issues, such as the quality of light from the GeoBulb, or whether the claim of 30,000 hours is accurate. CFL’s just make more sense at the present time. I find it disturbing that the C.Crane Corporation chooses to post incorrect, or outdated at best, information on their website. The public will not embrace energy-efficient products if they can’t trust the claims of those who sell them.

Here is a link to the C.Crane website:

http://www.ccrane.com/lights/led-light-bulbs/geobulb/

John

Earth Hour - Will You Participate?

2009-03-21T22:48:00.001-05:00

Participation is easy; simply switch off your lights for one hour from 8:30 until 9:30pm, local time, on March 28th.

Earth Hour began in Sydney Australia in 2007, when 2.2 million homes and businesses switched off their lights for one hour. The goal this year is to have 1 billion people switch off their lights for one hour as part of a global vote. Also known as Vote Earth, this is a global call to action for every individual, every business, and every community. It’s a call to stand up and take control over the future of our planet. Your light switch is your vote. Results will be presented to world leaders at the Global Climate Change Conference in Copenhagen later this year. That meeting will determine official government policies to take action against global warming, which will replace the Kyoto Protocol. By taking part in Earth Hour 2009, you’ll send a message that we must act now to slow climate change.

Your participation in Earth Hour does more than just send a message; it’s an opportunity to think about your impact on the environment. As you sit in the dark for one hour, perhaps you’ll think about the ways you can reduce your carbon footprint. Consider an ongoing effort to conserve electricity and natural resources. Think about switching to energy-efficient lighting, appliances, and transportation. Try to make a difference everyday, not just one hour each year. Your grandchildren will thank you.

To sign up, or to learn more about Earth Hour, visit:

www.earthhourUS.org

John

Green, User-Friendly, and High-Tech

2009-01-15T21:50:00.002-06:00

Solar panels and wind generators are two examples of green technology, but cleaning products and disposable diapers can also be called green products if they’re made to be environmentally friendly. Perhaps any device that reduces pollution, or cuts fossil fuel consumption can be considered a green product. A cell-phone, for example, has potential but I wouldn’t add it to my list.

I despise modern cell-phones. They tend to offer so many features that basic functions, like making a call, can be difficult. The poor design of cell-phones extends beyond a crazy menu system; the physical layout is absurd. I usually activate the “Speakerphone” function when I pick up my wife’s cell-phone because the button for that function is on the side of the phone. How, I wonder, am I supposed to pick it up? Developers could, if they wanted to, offer advanced features without making the device unnecessarily difficult to operate. Basic functions should be easily accomplished with a minimum of keystrokes, and advanced features could be accessed via a hierarchical menu system. The number of switches could be minimized. A cell-phone might save the user time and money, but I’m disappointed with most I’ve seen because they’re not user-friendly. Can a high-tech device be “Green” and “User-Friendly” at the same time?

My idea of a great high-tech device is one that makes life easier, and saves the user time or money. A really great high-tech device does those things, but also works right out of the box without a long learning curve. I bought such a device recently. It’s called a “Personal Travel Assistant”, or PTA. They’re also known by their brand names. Garmin, Magellon, and Tom Tom are a few you might recognize.

I must confess that I felt guilty for buying it at first. It seemed that I was wasting money on something that wouldn’t be of any real value to me. But to my surprise the device actually started saving me money on the second day. I’ll explain in a moment, but first let me tell you how it works. There are two basic modes of operation. Normally, the device shows your direction of travel and nearby roads. You’ll see the names of upcoming intersections and side streets before you get to them. However, if you pre-program a destination address the device will plot a route for you. It tells you in a pleasant voice when a turn is coming up. As a test of my new device I programmed in the address of a destination I occasionally travel to. As I drove toward the destination, I was surprised when I was given a shorter route than the one I usually follow. Eureka! I saved gas and time. It looks as though I’ll save even more time and burn less gas as I use other features. The device can help me locate restaurants and gas stations anywhere I happen to be, and I’ll avoid getting lost as I travel to unfamiliar destinations. I’ll no longer need to print out MapQuest directions, or to pull over and read a map.

I’ve changed jobs recently, and my new employer asked if I would be willing to spend 4 to 6 weeks working in Tampa Florida. Knowing that I would be leaving sub-freezing weather for a more favorable climate, accepting the assignment was an easy choice. I’ve never been to the Tampa area, and my new PTA has been extremely helpful.

Since my ultimate goal is to cut fossil fuel consumption, my “Personal Travel Assistant” is as important as my solar panels and my bio-fueled stove. Reducing my carbon footprint is something I want to do, primarily for the benefit of my grandchildren, and I’ll take advantage of every opportunity to do so. If I can have a little fun while doing it, that’s OK too.

John

What have you done for the earth today?

2008-12-15T19:30:00.009-06:00

Within a century most of the CO2 presently trapped in oil, coal, and underground sources of natural gas will be burned and released into the atmosphere. All of this "extra" CO2 is creating a serious problem, and it's not going to go away without a serious effort by all of us. Since each of us contribute to the problem, we should all do what we can to resolve it. Even a very small commitment can make a big difference if enough people do it.

If you've already replaced incandescent light bulbs with compact fluorescent types you've reduced your cabon footprint, and that's great, but don't stop there. Reducing your carbon footprint should be an ongoing effort.

Did you replace all of your incandescent bulbs? I neglected to replace bulbs in a large chandelier because its bulbs are not the standard screw-in type. Bulbs with a small screw-in base were not available at the time I replaced the other bulbs in my home. I also neglected to replace incandescent bulbs in a light fixture that's controlled by a dimmer. Now that small base screw-in and dimmable CFL's are available, I have no excuse for not replacing the rest of the bulbs in my house.

By the same token you might have replaced weather stripping last year, but have you checked your doors and windows this year? You may have added insulation, but could you benefit by adding a little more? And what about your appliances? Is it time to replace that old refrigerator? If your refrigerator is old, replacing it with an energy-efficient model will not only help the planet, it will result in a significant reduction on your electric bill.

Perhaps you measure progress by comparing this year's energy bills with those from last year. You've probably seen a reduction. Continue to make energy-efficiency improvements to ensure a reduction next year as well. Stroll through your local hardware store and see if you spot anything else that might help. Tell your neighbors about your progress, and encourage them to do the same. Show them your energy bills. Give them CFL bulbs as a Christmas present. Send them the URL to this blog, and tell them that I have many more ideas in my archives. Spread good will, and help Mother Earth at the same time.

Happy Holidays!
John

Smart Appliances and the ZigBee Alliance

2008-12-08T16:15:00.010-06:00

Imagine a vending machine that dispenses candy at a low price in the morning, but charges more for the same product in the afternoon. You would tend to make purchases in the morning, wouldn’t you? For those of us who pay for electricity based on demand, the grid is like that vending machine. We take advantage of the price differences by doing laundry, running the dishwasher, and using other appliances during those hours when electric rates are low. We ease up on heating and cooling when electric rates are high.

Although we make an effort to use electricity as efficiently as possible, our appliances don’t always cooperate. My refrigerator, for example, tends to go through its “defrost” cycle when electric rates are high. The energy consumption of my refrigerator while in defrost cycle is three times as high as when the refrigerator is running normally. Short of rewiring my refrigerator for manual defrost, there doesn’t seem to be much I can do about it, but that may soon change. Soon we’ll be able to buy “Smart” appliances. My refrigerator, for example, will no longer switch to “defrost” mode when electricity is expensive. Additionally, temperature settings could be adjusted upward slightly when electric rates are high, and lowered when rates go down. Because these changes will be small, you’ll save money without jeopardizing the contents of your fridge. Signals from the utility company will trigger the setting changes.

Smart appliances do more than cut your electric bill, they also benefit electricity providers. They reduce the peak demand, resulting in less strain on the power grid. With widespread use of smart appliances, slight adjustments to each one would result in a significant demand reduction system wide without a noticeable change at your home.

Most people, I suspect, won’t rush out to buy new appliances just to take advantage of this technology. You’ll probably wait to replace your refrigerator, dishwasher, washing machine, dryer, air-conditioner, and other appliances until a product failure creates a need. The first smart product you might buy, and perhaps the most useful of all, is an “In-Home Display”. This device receives real-time rate and consumption data from your electric meter. Not only will you know the exact cost of electricity at any time of the day, a quick glance at the color-coded display tells you if rates are low, medium, or high. With this device, you’ll know the best time to run the dishwasher and other appliances. You’ll know when it’s advantageous to cut back on the air conditioning a bit.

As useful as the “In-Home Display” shown here is, it lacks one important feature. It doesn’t have the ability to control other devices. If it included that feature you might use the device to perform one or more of the following functions:

Enable a battery charger when electric rates are low.
Enable supplemental heating when electric rates are low.
Pump water when electric rates are low.
Disable non-critical electrical devices when electric rates are high.

Charging batteries while rates are low would provide you with stored energy that could be used when rates are high. Supplemental heating could lower overall heating costs by limiting the amount of time the primary heater runs when rates are high. Water pumping could be enabled when rates are low, minimizing the need to pump water when rates are high.

Smart products, like the ones described here, are built around “ZigBee” technology. ZigBee is a wireless control technology that offers product manufacturers and developers the ability to build reliable, cost effective, low-power wireless control products. The ZigBee Smart Energy Profile was completed in January of 2008. A product achieves ZigBee Certified Product status after successfully passing certification testing. In addition to display units, ZigBee Smart Energy Thermostats are available at the time of this writing, and smart appliances should be available sometime next year. It is important to note that for Smart Energy products to work, you must also have a “smart” electric meter. My meter was installed when I enrolled in Ameren’s Power Smart Pricing program.

This technology will not be limited to communications and appliance control. V2G is another application of ZigBee technology that will someday benefit the consumer as well as the utility provider.

John

About Power Smart Pricing: http://www.powersmartpricing.org/

About the InHomeDisplay: http://www.comverge.com/products/ihd.cfm

Another Display Product: http://www.lsr.com/smartenergy/

A list of ZigBee Smart Energy products currently available: http://electronics.ihs.com/news/2008/zigbee-certifies-smart-energy.htm

About the ZigBee Smart Energy Profile: http://www.industrial-embedded.com/news/db/?10035

A Note to the President Elect

2008-11-20T14:52:00.002-06:00

Since off-grid solar systems and bio-fuel home heating are not exactly mainstream, I often use on-line forums as an opportunity to learn from others. I contribute to those forums when I think that others can benefit from my experiences. On one such forum I noted that I’ve reduced my fossil fuel use by nearly 50% over the past three years, and I mentioned that if everyone would do that the impact would be tremendous. Someone followed my comments with the comment “You should tell the president about that.” I believe the follow-up comment was meant to be sarcastic, but then again it sounded like a good idea. Here is my message to Barak Obama, via his website, change.gov

Dear Mr. President Elect;

Under your leadership I’m confident that our nation is about to experience a period of unprecedented technological growth, and that we will finally begin to address the energy crisis and the climate crisis. The purpose of this message is to suggest ideas that if implemented, will lead to success. First of all, let me tell you about my own work:

My goal is to stop using fossil fuels and to help others do the same. I’ll not use fossil fuel for transportation or home heating, and I’ll stop using electricity generated by coal-fired power plants. I’ll generate my own electricity, and grow my own bio-fuel using farming techniques that do not rely on fossil fuel. I’ll drive electric vehicles. I’ll do all of these things without sacrificing comfort or my quality of life.

I’ve been working toward this goal for nearly three years, and I’ve already cut my fossil fuel use by almost 50%. I share what I learn with others, via my blog: http://solarjohn.blogspot.com My accomplishments have been due to conservation, energy-efficiency improvements, the implementation of solar photovoltaics, and home heating via bio-fuel. If everyone would do what I’ve already done, the impact on the economy and the environment would be staggering. I’ve done these things on a modest budget, and without financial help of any kind. That brings me to my suggestions.

Although grants are available in some states for putting solar panels on public buildings, and organizations like the National Renewable Energy Lab (NREL) in Colorado receive federal funds, I have been unable to find any source of financial assistance for the important work I am doing. While putting solar panels on a few buildings may result in a good photo opportunity, it does little to help reduce our dependence on foreign oil. State and Federal Government spend too little on renewable energy projects, and money is not spent wisely. Please make money available to people like me who are working on worthwhile projects. I’ve accomplished a lot, but just imagine how much more I could do with funding.

Secondly, I respectfully ask that you put engineers and scientists in charge once again. Engineers and scientists gave us an industrial revolution and put a man on the moon, but things are much different today, now that lobbyists and money managers are in charge. We now have a financial crisis on top of other problems. It’s time for new leadership in important government positions.

And finally, make it easier to buy electric cars and make solar panels and other alternative energy products more affordable. With your help, ordinary people like me will show the skeptics that alternative energy can eliminate our dependence on foreign oil. For many of us this is an effort to build a better future for our grandchildren. We are dedicated, and with your help we will succeed. With your help, eliminating oil imports during your administration is possible.

John

Look to Engineers for a Change We Can Believe In

2008-11-05T13:24:00.003-06:00

How can the new administration fix the problems we face today? Putting engineers in charge would be a good start.

Engineers and scientists gave us an industrial revolution and put a man on the moon, but technology seems to have stalled now that politicians and money managers are in charge. While engineers do things that lead to real productivity, politicians and money managers don’t do anything productive, they just manipulate money. It seems that they’re not even good at that, as we now have a financial crisis on top of an energy crisis and a climate crisis. And, as everyone knows, money managers want the rest of us to bail them out. It’s time to put engineers back in charge. If we’re ever going to replace fossil fuel or solve the climate crisis, it will be because of the efforts of engineers.

Until engineers are in charge once again I doubt that we’ll see substantial progress. Politicians lack vision when it comes to renewable energy projects. You might find a grant for putting solar panels on a library, but nothing for an engineer working to make solar systems more efficient and affordable to the public. While they could be generating excitement about moving away from fossil fuels, instead they solarize a few buildings. It makes a great photo opportunity, but doesn’t really do much good beyond that. We need more money for renewable energy projects, and we need to use the available funds wisely. We need to investigate renewable energy solutions in actual homes, in all corners of the country, not just at the National Renewable Energy Laboratory (NREL) in Colorado.

Don’t wait for wealthy industrialists like Richard Branson or T. Boone Pickens to solve the problems. Both claim to care about the environment, and both have projects in the works. Branson seems to love the spotlight, but it remains to be seen if he’ll make good on any of his promises. Boone hopes to recruit others to do his bidding, and it remains to be seen how much he’ll accomplish. I’ve written to both gentlemen about my work. It seems that if they truly care about the environment, they would be interested in what I’ve been able to do. I’ve cut my own use of electricity and natural gas by almost 50%, on a small budget, and without sacrificing my quality of life. It should be obvious that with funding, my work could be duplicated in households across the country, resulting in a large reduction of fossil fuel use and a tremendous environmental impact. This should be of interest to anyone genuinely interested in the environment, but I haven’t heard from either Branson or Pickins. I doubt that I’ll hear from the new president either.

So I’ll keep plugging away at my own projects, with my own personal funds, as will many other engineers and ordinary people who hope to make a difference. Maybe our grandchildren will have a better future because of our efforts, maybe not. At least I’ll go to bed at night, knowing that I did the best I could.

John

I've Installed Off-Grid Solar - Why Didn't my Electric Bill go Down?

2008-10-24T08:13:00.015-05:00

It’s interesting to talk about alternative electricity with those who live in areas where electric rates are high. They tend to know all about energy-efficient lighting and appliances. They know how to conserve, and they understand the benefits of energy efficiency-related home improvements. They’ve either installed a small photovoltaic (PV) system, or they’re planning to install one in the near future. They understand how PV systems work, and they’re tired of articles telling them to keep the panels clean and avoid shading. Those things are intuitive. What they’re really looking for is a way to reduce their electric bill.

My approach is simple; I use as much free energy from the sun as my system can supply, and switch to grid-supplied electricity only when necessary. This strategy may seem odd to those who are conditioned to think of a battery-based system as a backup to the grid. It’s counterintuitive. The first step is to get comfortable with the concept of using the power grid as a backup system.

When both sources of electricity are available, make sure that no one in the house uses grid power. Design the system to switch automatically, with battery power as the default. Switch to grid power ONLY when batteries are depleted. Many inverters have this capability built-in, but you can purchase an Automatic Transfer Switch if yours does not. By transferring all lights and electrical outlets in your home to battery power, no one has access to grid power, and therefore no one will be running up your electric bill by accident or without your knowledge. If your PV system is small, high-power items will have to be excluded. Your central air conditioner, for example, will probably not be switched to battery power. Once your batteries become discharged, late at night perhaps, lights and outlets in your home will be switched to grid power. Fortunately, this is the time when electricity use will be at its lowest level for most households.

Inverters draw energy from the batteries until battery voltage drops to a point where the inverter can no longer function. Typically, the cut-off point is about 10.5 volts (for a 12 volt inverter). Unfortunately, allowing batteries to discharge that much can be harmful to them. You’ll need another way to switch your inverter off. And, once the batteries are drained to that level, they should be recharged fully before reconnecting loads. Reconnecting batteries to the load too soon could result in chronic undercharging, which would shorten the life of the batteries. Some charge controllers allow you to configure disconnect and reconnect set points, or they have that functionality available as an option. Look for that feature in the equipment you’ll purchase. With these things in mind, let’s review system functionality:

The sun rises in the morning, and batteries become fully charged.

Selected AC loads are switched to battery power via the inverter.

The sun sets in the evening and battery voltage declines.

When battery voltage falls to a preset level, AC loads are switched to grid power.

The cycle repeats each day.

The concept I’ve described here is simple, but effective. It eliminates the waste that would occur if you were to switch manually. After all, you’re not setting at the controls 24/7 watching for the ideal time to switch, are you? By switching automatically you might save hundreds of dollars each year on your electric bill. If your PV system is small, start with one or two rooms and add rooms as you add solar panels and batteries to your system. An electrician can easily wire in additional circuits as your system grows.

I use this strategy in my home, with a chest freezer and refrigerator as the only loads. Instead of tying into my existing house wiring, I’ve added separate wiring to those appliances. Because I didn’t tie in to the existing house wiring, I saved myself the cost of having an electrician do the wiring. I’ve observed that my system switches to battery power on sunny days at about 10:30am. It switches back to grid-supplied AC at about midnight. It’s easy to see that I could use more batteries and solar panels. I plan to expand, and I hope that by the end of next year I’ll be able to add to the existing loads. By making sure that the size of the load exceeds the capacity of the PV system I know that I’m getting as much power as the system is capable of producing.

The system as described should cut your electric bill considerably, but you can cut it even more if you watch for opportunities. A properly designed system should include enough PV capacity to fully charge your battery bank each day, and excess energy is often wasted. Watch for opportunities to use that otherwise wasted energy. For maximum efficiency, use appliances mid-day with power coming directly from the solar panels.

The way to get the most from any Off-Grid PV system is not to let any solar-generated electricity go to waste.

An automatic transfer switch should be installed by a properly trained and licensed electrician.

John

Smart Transportation

2008-10-18T18:17:00.010-05:00

Finding a car that is gentle on the environment, and fuel-efficient may be easy in Southern California, but choices are limited here in Southern Illinois. Ask about an electric car here, and dealers are likely to point to the golf-cart they use to transport customers around the lot. The 2005 Smart-ForTwo shown here seems to be way over priced at a local dealership.

They tell me there's a waiting list for these cars. I think I'll wait instead for a plug-in-electric. GM, Ford, and Toyota plan to offer plug-in-hybrid cars by 2010.

Can't wait for an electric car? You could buy a Prius now, and spend another $10,000 to have it converted to plug-in, but that seems a bit pricey to me. No, I think I'll wait instead to choose from the available 2010 models.

System Automation for a Spare Battery Bank

2008-10-07T09:46:00.004-05:00

Having recently replaced my PV system’s battery bank, I had to decide what to do with the still-good older batteries. Connecting batteries of different types and ages together is not a good idea; it shortens the life of the newer batteries. My choice was to install a switch, allowing me to add and remove the old bank from the charge controller/inverter circuit. When I want to charge the old bank, I can simply switch it in. I can also switch it in when I need extra amp-hours, during a grid power failure for example. I can switch it out the rest of the time, keeping it from dragging down the new battery bank.

My plan worked fine for awhile, but then I neglected to check the batteries for a few days. To my horror, I found that the battery voltage dropped below 10 volts. Allowing batteries to deeply discharge, and remain in that state for an extended period of time, can ruin them. I knew I had to do something else. I wanted to use energy from the sun to keep both battery banks charged, but I wanted the main battery bank to have top priority. Here’s what I did:

The problem was easily solved by adding a relay to an unused channel of my Morningstar Relay Driver. I’ve programmed the relay driver to monitor the main battery bank voltage. When the main battery bank is nearly fully charged, I divert excess current to the older battery bank. Programming voltage thresholds is done by temporarily connecting a computer to the relay driver and running a simple configuration program. Here are my settings for the spare battery bank relay:

Turn on relay when main battery voltage > 14.40 volts.

This establishes the main battery bank as the top charging priority. Power will be diverted to the spare battery bank ONLY when the main battery bank is nearly fully charged.

Turn off relay when main battery voltage < 14.00 volts.

Turning off the relay disconnects the spare battery bank from the inverter and charge controller, preventing it from discharging through the load.

The main battery bank provides power to the loads day and night, cutting my electric bill. I’ve programmed the relay driver to remove the load from the main bank when its state-of-charge (SOC) drops below 80%. This happens at night, or when it’s cloudy, leaving me with little surplus power to use in the event of a grid power failure. However, by keeping the spare battery bank fully charged I now have the best of both worlds, lower electric bills and reserve energy to serve in the event of an emergency. A simplified diagram of my system is shown below. Relay 1 switches the inverter on and off, while relay 2 switches the spare battery bank in and out of the circuit.

John

Big Performance from a Small Off-Grid System

2008-09-26T08:20:00.029-05:00

Gasoline prices have soared over the past couple of years, and some believe that electricity rates will soon follow. When that happens, alternatives like PV (photovoltaic) systems will become an attractive option. The surge in demand for solar panels will result in higher prices, and only the well-to-do will be able to install systems large enough to meet the needs of an entire household. The average home owner will be forced to pay the high utility rates, or to learn to get by with a small PV system. The good news is that you can get by with a smaller PV system than you might have imagined, but it’s going to take some “out-of-the-box” thinking.

Much has been written about the benefits of home improvements such as adding insulation, replacing windows and doors, efficient lighting and appliances, the elimination of phantom loads, and passive solar improvements. Alternatives to electric heating and cooling are also important. These are logical, and often necessary, prerequisites to PV system implementation, and especially important to anyone wanting to get by with a small system. Since those topics have been discussed at length elsewhere, this discussion will be limited to getting the most from a small PV system.

The daily capacity of a PV system can be calculated by multiplying the capacity of the PV array, in watts, by the number of hours of peak sunlight. A PV panel array consisting of five one hundred watt panels, for example, can produce 2000 watt-hours in a four-hour period. That’s 500 watts times 4 hours. It is widely accepted as fact that an off-grid PV system with batteries will be 65% efficient, lowering the expected daily production in this case from 2000 watt-hours to just 1300 watt-hours. Now that you know the basics, let’s explore some ideas for getting most from a small PV system:

1. Load shifting

An off-grid system is least efficient when it is used to charge batteries. The inefficiencies associated with converting energy, storing it, and converting the stored energy back to electricity results in a huge energy loss. The obvious solution therefore is to use electricity directly from the solar panels as it is produced, instead of storing it in batteries for use at a later time. Doing the laundry, running a vacuum cleaner, and cooking are some of the obvious tasks you can do in the daytime, but other strategies are not so obvious.

A well-insulated chest freezer will keep things frozen for many hours in the event of a power loss. Consider putting your chest freezer on a timer, limiting its operating hours to daytime. This will require a little experimentation, as you don’t want food to partially thaw each night.

To improve its efficiency, move your chest freezer to the coolest part of the house, perhaps the basement. Allow plenty of room for air circulation near the condenser to improve operating efficiency, don't limit it to the two or three inches that the manual suggests.

2. Eliminate unnecessary appliances

Could you get by without a refrigerator? You certainly could if you had to, and you’ll reduce the load on your PV system by 1000 to 3000 watt-hours each day. You’ll be able to eliminate a dozen or more solar panels from your array, saving a small fortune. I spoke to a friend recently who, after his refrigerator failed, continued to use it to keep items cold by using ice from his chest freezer. He used his chest freezer to produce ice, and placed that ice in his refrigerator. Milk jugs provided a convenient way to do it, and he cycled three, one gallon jugs, from his freezer to his refrigerator each day.

Perhaps you’re not quite ready to shut down your refrigerator full-time. Instead, why not put it on a timer? Shutting it down for a few hours each night will reduce the system load significantly.

Converting a chest freezer to a super-efficient refrigerator is another strategy you might consider. A thermostat mounted inside the freezer switches AC power to the freezer on and off as needed. No significant modifications to the chest freezer are necessary.

3. Add diversion load control to your PV system

If you monitor your PV system during the day you probably find that once the batteries are fully charged, you have a lot of excess energy available that doesn’t get used. Putting this previously wasted energy to use can significantly increase the usefulness of a small PV system. Adding diversion load control to your system is one way to tap into that extra energy. Some charge controllers can be used as diversion load controllers, but you can also use a PLC (Programmable Logic Controller) for the task. I use a Morningstar Relay Driver, a much less expensive option.

Often, systems are designed to use the extra energy to pre-heat water, but that’s probably the least-efficient way to use it. Using the sun to heat water directly makes more sense. If your home uses a cistern for its water supply, using this excess energy to pump water is a much better idea. It is far better to use excess energy for this task than to have to pump water at night, due to demand, using energy from batteries.

You could also use the excess energy to charge a spare battery bank. The spare battery bank might be used to power some DC loads, 12-volt dc lights for example. Using this surplus power for DC loads eliminates the conversion loss that you would otherwise experience by running a DC to AC inverter. This might allow you to turn off your inverter, perhaps all night long, saving yourself the power it consumes when idling.

4. Make Peukert’s Law work to your advantage

According to Peukert, a lightly loaded battery bank operates at higher efficiency than a heavily loaded battery bank. Looking at this another way; if you increase the size of the battery bank, without increasing the load, efficiency improves. Take advantage of this phenomenon by making your battery bank larger than necessary. As a bonus, your batteries will last longer because they’ll be stressed less.

Avoid using two or more high-power appliances at the same time. Making toast, while using the microwave oven, is an example of this. Heavy current from the battery bank results in lower efficiency, according to Peukert.

Conclusion

Anyone who’s ever struggled to get through an extended grid power failure knows that electricity is more than simply a matter of comfort and convenience. While it’s a necessity for some, it would be hard for any of us to get by without it. Imagine doing without lights on a long winter evening, or not having the ability to keep food refrigerated. Imagine doing without air conditioning, and not even having an electric fan to circulate fresh air.

Use these strategies to the extent that you can. You might start by adding the ability to log system data. The ability to log data will help you determine if system improvements and modifications are beneficial. Adding automation to your system is the logical next step. This allows you to shift loads and divert power when it is beneficial to do so. And most importantly, be on the lookout for other ways to lighten the load and improve system performance. Please share your ideas with the rest of us, in the form of a comment, so that we can all learn from each other.

John

Off-grid Systems and Off-grid People

2008-09-19T15:30:00.002-05:00

“To acquire knowledge, one must study; but to acquire wisdom, one must observe”. Marilyn vos Savant

Some off-grid systems and the people who use them:

I have an off-grid photovoltaic (PV) system, but since I’m connected to the electrical grid I can’t honestly say that I know what off-grid living is like. My system powers some loads on a daily basis, and serves as an emergency backup system, but I rely on the power grid for most of my everyday electricity needs. The closest I’ve come to real off-grid living has been during those times when my grid power failed. To understand what off-grid living is really like it’s helpful to peek into the lives of those who actually live off-grid on a full-time basis.

An off-grid lifestyle can range from primitive to luxurious, depending upon the size of the system. While some are happy with a minimalist lifestyle, it’s common to find others who after attempting to live off-grid, have become disillusioned upon realizing just how much work is involved. Some give up, and others enlarge their systems until they achieve an acceptable comfort level. On the other end of the spectrum are off-gridders who want all of the conveniences that their well-connected counterparts in the city enjoy. This group includes the well-to-do who choose to live in an area where utility services are unavailable. Most off-gridders, I suppose, fall somewhere in-between primitive and luxurious.

With these things in mind, let’s look into the lives of some off-grid people and their systems:

#1. Can you guess which country has the most residential solar PV systems installed? It’s Kenya. PV systems are replacing kerosene lamps in remote villages, greatly improving the quality of life of the residents. Typically, these small systems are only able to provide a few hours of light each night, but the importance of the elimination of fire hazards and indoor air quality improvements cannot be overstated. Because children can study longer into the evening with the extra light, these small systems also have an educational benefit.

#2. Here in the United States, Ward’s solar PV system was built for less than $700.00. It provides all of the electrical needs of this bachelor in his remote cabin, including lights, TV, VCR, and a boombox. Ward uses a wood-burning stove for heat, and a propane refrigerator. He has no indoor plumbing. His system includes a 75-watt solar panel, four batteries, a charge controller, and a 350-watt inverter.

#3. It would be a disservice to Karen to limit this discussion to her PV system. Karen transformed a 5-acre site in the Mojave desert to a comfortable homestead. Among her accomplishments Karen installed a septic system and a 4000 gallon water tank. She renovated an old cabin, including a passive solar system of her own design. Karen uses a wood stove for heat, and propane for cooking and refrigeration. And yes, she put in a solar PV system. Her system includes 400-watts of PV, 880ah of battery capacity, a charge controller, and a 3500-watt inverter. A system of this size can be built for less than $3000.00. Because Karen’s system is larger than Wards, she can do much more. Her capabilities include pumping water, running a vacuum cleaner, and using kitchen appliances.

Although Ward and Karen may be satisfied with what they have, a typical family would probably struggle to get by with such limitations. Some might opt for the prepackaged 2000 watt off-grid PV system described below. The cost of the entire system, including batteries and wiring, is in the neighborhood of $20,000.00. A system of this size will allow the use of a washer and dryer, and almost any electrical device imaginable. In spite of the size of this system, the average family of four may experience shortages of electricity from time to time. Energy efficient construction, efficient heating and cooling systems and efficient appliances will help, but some homeowners will opt for a generator to make up for periods of extended cloud cover.

System Specifications:

PV: 2000 Watts
Batteries: 6000ah
Pre-Wired Power Center with 4,400 Watts 120/240VAC

Need even more electricity? Obviously you can have as much as your budget and space will allow. Your decision to live off-grid means that you’ll have to maintain your own power systems, but it’s really not that difficult. You’ll have sophisticated equipment that automates some of the maintenance tasks and alerts you to small problems before they become big ones. You’ll know the status of your batteries, and the amount of stored power at a glance. If you choose to install a generator as a backup, it can be set to start up automatically in the event that it’s needed.

Ward and Karen may be thought of as being on the fringe of society now, but that notion will change someday. Declining fossil fuels and an increased awareness of the harm we’re doing to our environment will someday make a change to renewable technologies a necessity, not just a good idea. Folks like Ward and Karen will be typical, not the exception. We’ll all be better off when that happens.

For more off-grid systems and people, click on this link: http://offgrid.homestead.com/OffGridersPage.html

Here’s another site that showcases off-grid systems and people: http://gallery.altenergystore.com/main.php?g2_page=1

John

Are Electric Cars More Harmful to the Environment than Gasoline-Powered Cars?

2008-09-05T08:13:00.003-05:00

Because we’re likely to see a massive shift to personal electric transportation in the next few years, this is an important question. Ideally we should reduce our carbon footprint in the transition, not increase it, but here are the facts:

• Burning a gallon of gasoline releases 19.6 pounds of CO2 into the atmosphere.

• A gallon of gasoline has as much energy as 33kwh of electricity.

• For every kwh of electricity that a coal-fired power plant produces, 2.2 pounds of CO2 is released into the atmosphere.

These statistics seem to indicate that it is better to burn a gallon of gasoline and release 19.6 pounds of CO2 than to use an equivalent amount of electricity and release 72.6 pounds (33kwh X 2.2 pounds), into the atmosphere. It seems that driving an electric car will be much more harmful to the environment than driving a gasoline-powered car. Could this be true?

These statistics suggest that an electric car, starting with a fully charged 33kwh battery pack, would travel as far as a similarly-sized gasoline powered car could go on a single gallon of gasoline. However, the Chevy Volt is expected to be able to travel 40 miles on a fully-charged 16kwh battery pack. What gives? The discrepancy is due primarily to the fact that electric motors are 90 to 95% efficient, while gasoline engines are only 20 to 30% efficient. In reality, driving an electric car will produce about the same amount of pollution as driving a gasoline-powered car, it just moves the source of the pollution from the tailpipe to the power plant.

The net result, it seems, is that we accomplish nothing by switching to electric cars, but that’s not entirely true either. It’s easier to stop pollution at a few power plants, than it is to stop it at the tailpipes of millions of cars. Electric cars also give us the opportunity to use electricity from clean sources, such as solar PV panels or hydro-electric plants. So instead of releasing millions of tons of pollution each year, we’ll soon have an opportunity to drive our personal automobiles without releasing any CO2 into the atmosphere. That’s something we’ll never be able to do with gasoline-powered cars.

The millions of electric cars we’ll see on the road within a few years will all need to be recharged each night. It’s clear that our priority as a nation should be to clean-up or eliminate coal-fired power plants. Expensive schemes, such as carbon sequestration, are not the best use of federal funds. Promoting solar-, wind-, and hydro-power would be better. Energy from a modestly-sized solar-electric (PV) array on a single residential rooftop can offset 2000 pounds of CO2 each day, so just imagine how beneficial a million solar roofs would be. That’s 2 billion pounds of CO2 each day!

Concerned about electric car performance? Don’t be. Electric cars can be built to be both highly efficient and very quick. Tesla Motors has already proven that. Increasing the size of an electric motor improves both horsepower and efficiency. On the other hand, a big motor is needed to make a gasoline-powered car quick, but gas mileage suffers as a result.

Driving a personal automobile doesn’t have to be an environmental disaster. The switch to electric transportation can have a positive effect on the environment. All that we need now is intelligent leadership and an aggressive plan. Maybe if we can get our politicians to stop taking money from coal and oil interests, we might just get legislation that is good for the environment for a change.

John

Sources:

Carbon Dioxide Information Analysis Center:
http://cdiac.ornl.gov/pns/faq.html

Chevy Volt Site:
http://gm-volt.com/

Tesla Paper:
http://www.stanford.edu/group/greendorm/participate/cee124/TeslaReading.pdf

Design and Build an Off-Grid Solar Electric System

2008-08-27T15:39:00.018-05:00

Anyone with a basic understanding of electricity and good mechanical skills can design and build a solar photovoltaic (PV) system. Here, condensed into a few easy steps, is what you need to know.

Overview

There are two basic types of solar PV systems, off-grid and grid-tied. An off-grid system uses batteries, while batteries are optional in a grid-tied system. In this article we’ll be discussing off-grid systems. An off-grid system uses solar photovoltaic (PV) panels to turn sunlight into electricity, and stores that electricity in batteries for later use. Battery charging must be done in a controlled manner to protect them from damage, and for efficiency and safety. The stored energy must be converted to AC voltage in order to power ordinary household appliances.

Building a system large enough to meet your daily needs for electricity can be an expensive project. For most people, reducing the load by improving energy efficiency will be more cost effective than building a system big enough to handle a heavy load. Replacing incandescent lights with compact fluorescent (CFL’s), and upgrading to energy-efficient appliances are a couple of things you can do that will pay off in the long run. Having done that, you’re ready to start the design phase.

Step 1. Determine your daily needs.

List the electrical requirements of each device that you plan to power with the PV system. Example:

A 13-watt bulb in use for 5 hours each day (average) uses 13 watts times 5 hours, or 65 watt/hours per day.

Enter the information for each device into a chart as shown below:

Your total energy needs are the sum of the individual requirements of all devices, or 4985 watt/hours per day in this example. You may choose to build a system to meet all of your needs, or choose instead to build a system to meet a portion of your needs.

Tip: If you don’t know the electrical requirements of a particular appliance or device, an inexpensive Kill-A-Watt meter can help you find out. Click (HERE) for more information.

Step 2. Determine the amount of PV needed.

PV panels are rated in watts. One 100-watt panel produces the same amount of power as two 50-watt panels. If you get 4 hours of sunlight each day, a 100-watt panel is capable of producing 4 times 100, or 400-watt/hours of power daily. The example above lists your needs at almost 5000 watt/hours per day. Dividing 5000 by 400 shows that you’ll need twelve and a half 100-watt panels to meet your daily needs. To make up for system losses, and because you’ll probably want all panels to be the same size, you should go at least 20% bigger, opting for 15 panels. You might want even more panels to compensate for extended periods of cloud cover.

Step 3. Planning your battery bank.

Batteries are rated in amp/hours. Begin by converting watt/hours to amp/hours by dividing watt/hours by 12 (the battery voltage). In this example, the 4985 watt/hours that you need divided by 12 equals about 415 amp/hours. Since discharging batteries beyond 50% of their capacity will shorten their life, you’ll need a battery bank rated at no less than 830 amp/hours (in this example). Additionally, you’ll have to increase the size of your battery bank by about 20% to compensate for conversion losses. Having done that, you should have enough battery capacity to get you by for one full day. Ten 100 amp/hour batteries connected in parallel will do the job in this example, but if you want to compensate for extended periods of cloud cover you’ll need more. In addition to keeping your equipment running in the event of extended cloud cover, over-sizing the battery bank helps to extend the life of the batteries as a result of less-aggressive use.

As you shop for batteries, be sure to select those designed for deep cycle applications, not automotive batteries. Batteries designed for golf-carts, floor scrubbers, and forklifts are all good choices. The most expensive batteries tend to have the longest lifespan. Your bank of batteries will be wired to provide 12, 24, or 48 volts. More about that later.

Step 4. Select an inverter.

An inverter converts the low DC voltage from your battery bank to 120-volts AC. To determine the size of the inverter needed, add up the power requirements of all of the loads that you intend to run simultaneously. The total load in Step 1 was just under 5000-watts, but it’s unlikely that you’ll ever use all of those devices at the same time. You might, however, use the microwave oven and toaster at the same time, a total of 1900 watts. You might also have a few lights on at the same time. In this example, an inverter rated at 2000-watts would just meet your needs.

There are two basic types of inverters, modified sine wave and true sine wave. Modified sine wave inverters are much less expensive, but some equipment may not work well with modified sine waves. Motors may overheat and run at the wrong speed, and sensitive electronic equipment can be damaged. For best results, I highly recommend a true sine wave inverter.

The choice of an inverter will also influence another important design decision. Inverters typically accept an input voltage of 12, 24, or 48 volts. Generally speaking, a 12-volt inverter would be the best choice for a small system, while a 24 or 48 volt inverter would be better for a large system.

Step 5. Select a Charge Controller.

A charge controller efficiently controls the battery charging voltage and current, and keeps the batteries from overcharging. If you choose to build a small system, you need not get an expensive charge controller. A single PV panel can produce no more than 5 to 10 amps of current, and just about any charge controller will be able to handle that. A large PV system may require you to use more than one charge controller, splitting the PV panels into two or more sections. Your charge controller should include a battery temperature probe. The charge controller cannot efficiently charge batteries unless it has a way to compensate for battery temperature.

Unless you have a separate device for monitoring system parameters, you should opt for a charge controller with a digital meter. Most importantly, you’ll want to monitor battery voltage. The ability to monitor PV panel voltage and current is also helpful. Reduced output may alert you to the need to clean the panels, for instance.

The best available charge controllers (suitable for large systems), are able to convert voltage to lower or higher levels. Your PV array, for example, could be wired to provide 48 volts to the charge controller, which is converted to 24 volts in order to match the voltage requirements of the inverter. Operating at voltages greater than 12-volts can cut system losses due to the resistance of the wiring. By increasing voltage you can use thinner, less expensive wire, and cut costs.

Choose a charge controller that best matches the size of your system. For small systems, the charge controller should consume very little current for its operation. Typically, these are PWM (Pulse Width Modulation) controllers. PWM types provide pulses, instead of a steady DC voltage, to the batteries. For large systems the charge controller should have the ability to track PV panel output and adjust to provide the most efficient charging. This is called MPPT, or Maximum Power Point Tracking.

Step 6. Mounting the Solar Panels.

Keep in mind that cool panels operate much more efficiently than hot panels. Mount the panels in a way that allows good air circulation under them. Check my blog of 2/15/2007 for mounting ideas, and information you’ll need to determine the ideal panel orientation for your geographical location. If panels are to be mounted on a pole or roof, a lightning protection device is a good idea. Install that in accordance with the manufacturer’s instructions.

Step 7. Wiring and Safety Considerations.

Be sure to use wire that is large enough to handle the maximum current that will flow through it. Typically, a set of wires from each solar panel terminates in a combiner box or breaker box, and a thicker wire connects the solar panel array to the charge controller. Since the output of each solar panel is usually less than 10 amps, 10 gauge wires can be used from each panel to the combiner box. Battery interconnections and battery-to-inverter wires will need to be much thicker, since the current flow there can be very high. Fuses, breakers, and disconnect switches should be included in your design for safety.

Check with an electrician for the correct type and size of wiring if you’re not sure, and to make sure everything gets done according to code.

The drawing below is a typical wiring scheme for a small off-grid system. Be sure to include safety devices (not shown here):

Adding Functionality

Perhaps you’ve decided to build a system to lower your electric bills, or to serve as an emergency supply of electricity. The system described here will certainly do those things, but it also has its limitations. You may want your system to kick-in automatically in the event of a power failure, perhaps to prevent frozen food from spoiling when you’re not home. The addition of an “Automatic Transfer Switch” will provide that functionality.

You might want to automatically disconnect batteries from the load, perhaps switching to another source of power, when batteries reach a predetermined state of discharge. Check out my blog entry of 2/25/2008 for more information on that topic.

Be sure to consult with a licensed electrician before connecting to your house wiring.

Conclusion

Don’t let a lack of technical training or experience discourage you from building your own PV system. It’s not that complicated. You can build a safe, efficient system with off-the-shelf equipment from numerous sources. Learn as much as you can before you begin, to avoid altering your plans after you’ve purchased equipment. Be especially careful to take good care of your batteries, as they can be easily damaged by abuse. If you plan to start small and add to your system over time, develop a plan that will allow you to do that with as little waste as possible. Since this post has been primarily an overview, check other websites for in-depth information as needed.

Don’t let the cost of system components discourage you from building your own PV system. Start small if you must, but start. The world is changing, and we cannot continue to burn fossil fuels as we currently do. Future generations deserve more from us, and it seems that we cannot rely on politicians to do the right thing. In the words of Charles Darwin:

“It is not the strongest of the species that survives, not the most intelligent, but the one most responsive to change.”

John

Sizing Your Off-Grid Solar Electric System

2008-08-15T16:18:00.002-05:00

The average US home consumes about 940kwh of electricity each month. For many, electricity use could be cut in half with a serious conservation effort. But if you had to rely on a small photovoltaic (PV) system could you get by on 120kwh per month?

To get by on less you’ll first need to make sure you’re using electricity as efficiently as possible. Replacing incandescent light bulbs with compact fluorescent (CFL’s) is a good start. You’ll also benefit by eliminating phantom loads and replacing inefficient appliances. I’ve listed many more things you can do in previous posts, so I won’t repeat them here. Check this blog’s archives for that information.

Living (comfortably) off-grid on less than 120kwh of electricity per month (about 4kwh per day) may sound impossible, but you just might be able to do it. Here’s how:

Of the 20 or so 13 watt CFL lights in your home, you might use each (on the average) 1 hour per day. So, 13 times 20 times 1 = 260 watt/hours. Shown below is the total for lights, and a list of other ways you might use this limited supply of electricity.

Lights: 13 watts X 20 hours = 260 watt/hours
Refrigerator: 50 watts (average) X 24 hours = 1200 watt/hours
TV and Cable box: 125 watts X 3 hours = 375 watt/hours
Radio: 5 watts X 6 hours = 30 watt/hours
Fans: 35 watts X 16 hours = 560 watt/hours
Computer and monitor: 120 watts X 2 hours = 240 watt/hours
Microwave oven: 1000 watts X 0.5 hours = 500 watt/hours
Toaster: 900 watts X 0.1 hours = 90 watt/hours
Vacuum Cleaner: 750 watts X .2 hours = 150 watt/hours
Cell Phone Battery Charger: 25 watts X 2 hours = 50 watt/hours
Washing Machine: 500 watts X .25 hours = 125 watt/hours
Iron: 1000 watts X .25 hours = 250 watt/hours

Total: 3930 watt/hours per day

How you use the available electricity will not exactly match my list of course. This is simply an example to show how you might get by on much less electricity than you’re currently using. Off-grid doesn’t have to mean living like a caveman. A small PV system can meet most of your electrical needs, including a limited amount of cooking and climate control. As long as you have other systems in place for heating, cooling, and other high-energy devices, you could live quite comfortably on much less than you currently use.

Why is this important?

Most of us purchase electricity from our local utility company for less than 2% of our household income. Because grid-supplied electricity is inexpensive and convenient, few people have any interest in alternatives at this time. But just as gasoline prices have skyrocketed in the last two years, we’ll soon see the cost of electricity increase dramatically. Most consumers will deal with this by cutting back, but some will choose to disconnect from the grid. A PV system large enough to meet your current electricity requirements may cost 25 to 35 thousand dollars. For most, reducing usage and installing a smaller PV system will be easier and less costly than installing a system big enough to meet current demands for electricity.

What would this smaller PV system cost?

First of all it’s important to understand that a system capable of providing 4kwh of electricity a day will not provide 4kwh on a cloudy/rainy day. Typically, a lack of sunshine prompts the user to either cut back on electricity use that day, or to use another source of electricity during those times, typically a generator. It is also important to understand that we’re discussing an off-grid system, not a grid-tied system. An off-grid system includes the extra expense of batteries, and is not as efficient as a grid-tied system. Your system design might include a battery bank large enough to compensate for a day or two of cloudy conditions.

PV panels produce electricity when the sun strikes them, but are most productive during hours of peak-sunlight, or stated another way, when the sun is almost directly overhead. We’ll do our calculations based on an average of 4 hours of sunlight each day. A 100 watt solar panel can produce 400 watts/hours (100 watts times 4 hours) of power each day. It follows then that to get 4000 watt/hours (4kwh)from the panels each day, you’ll need 1000 watts of PV panels. To make up for system inefficiencies, you should shoot for at least 1200 watts of PV. That would be 12 one hundred watt panels for example. If you shop around, you’ll find solar panels for less than $4.50 per watt, so you’ll spend about $5400.00 for PV panels alone. You’ll also need a charge controller, batteries, an inverter, panel mounting hardware, wire, and safety components. These items can be bought for $2600.00 if you shop around. If you’re not able to do the installation yourself, you might spend another $3000.00 for that, making your total cost about $11,000.00. If this sounds expensive, don’t forget that it eliminates your electric bill. The system could pay for itself in 5 years, or less as electricity prices increase. And since solar panels can be expected to last in excess of 20 years, you’ll be getting many years of low-cost electricity after that.

Using your system:

Your small system may not always keep up with your needs, but you’ll learn techniques to maximize efficiency. Using energy from the sun as it’s generated (instead of storing it in batteries for later use), increases system efficiency greatly. By using the vacuum cleaner, washing machine, and other appliances during peak-sunlight hours you eliminate losses associated with converting, storing, and retrieving energy. Your goal should be to use electricity wisely, ensuring a surplus. That surplus will come in handy when it’s cloudy.

Conclusion:

Having your own power plant means that you’ll not be affected by outages and brown-outs that grid-connected customers often experience. News reports about rate increases will no longer concern you. You’ll feel good knowing that by disconnecting from the grid you’re not contributing to the environmental problems associated with mining and burning coal to produce electricity. By installing your own PV system you’ll be taking an important step toward personal electric transportation, or as a politician might say eliminating your “addiction to oil”. Declining oil supplies will soon usher in the age of electric cars, and it’s not unreasonable to think that someday you’ll be able to drive on free energy from the sun. That’s something to get excited about!

John

Hollywood Green vs. Real Green

2008-08-06T08:19:00.005-05:00

Although alternative technologies are often mentioned in the media, the details remain esoteric. Hollywood gives us a vague overview with programs that attempt to show what green living is all about, but they’re obviously trying harder to entertain than to teach. I’m somewhat impressed by “Living With Ed”, a program that attempts to teach and entertain at the same time, but the trend seems to be to move away from substance. Les (Survivorman) Stroud’s journal of his off-grid living project was interesting, but woefully short on details. Les admits that photovoltaic (PV) technology is not his strong point, and as a casual viewer I spotted several mistakes.

The worst I’ve seen so far is the Tommy Lee vs. Ludicris competition called Battleground Earth on the Science Channel. Here we have two people who don’t have a clue, competing with each other to see who can be more green. What a joke! The contestants and their teams compete to solve riddles and to assemble pre-fabricated projects. It’s like watching someone put together a small jigsaw puzzle, and with the same educational value. This so-called “reality” program is laughable, and the Science Channel should be embarrassed for showing it. The producers believe that these two “big stars” will inspire others to go green. I doubt it. The goal of the first challenge was to see who could be the first to use solar power to illuminate a large sign with their name on it. Someone should remind the Science Channel that solar power can also help reduce our dependence on oil, while helping to clean up the environment. There are so many things wrong with this program that I won’t even begin to list them here.

Programs like those listed above may have some entertainment value, but you’ll need details if you want to accomplish anything. I suggest that you:

Subscribe to Home Power Magazine: www.homepower.com

Visit discussion sites, like: www.wind-sun.com/ForumVB

And keep reading this blog.

John

PV System Performance Update

2008-07-29T12:43:00.004-05:00

People sometimes ask me how much I save on my electric bill since installing solar panels. I have some difficulty answering that question. While my grid-supplied electricity usage is about 50% less than it was two years ago, much of that is due to energy efficiency improvements I’ve made. Replacing my refrigerator and switching to CFL lights contributed in a big way to cutting electricity usage. Still, my PV system has made a significant contribution and it’s good to evaluate performance now and then.

About my system:

My system can be considered small. If this were my only source of electricity I would be quite limited in the appliances I could use. Although some folks rely on PV systems much smaller than mine to meet all of their needs for electricity, my family prefers not to live with such limitations. I’ll continue to use electricity from the power grid, and continue to enlarge my system as my budget allows. I plan to add 1 or 2 more solar panels before the end of this year, and perhaps 2 more next year. I would like to be able to use wind or hydro, but those options are not practical for my location. Solar fits nicely into my budget, unlike more elaborate solutions such as hydrogen generation.

System specifications and capabilities:

I have 425-watts of PV panels on my roof.
My main battery bank is rated at 630ah.
My spare battery bank is rated at 420ah.
The typical load is a chest freezer, and a refrigerator.
When neither compressor is running, the load can be as low as 5 watts.
The maximum load sometimes exceeds 525 watts.
The system is automated. The load switches to grid-supplied power when batteries are low.

With about 4 hours of sunlight per day, I expect 1700 watt/hours of electricity production.

At 65% efficiency, I should get 1100 watt/hours from the system each sunny day.

My refrigerator and freezer need about 3.6 kilowatt/hours per day for their operation, much more than the PV system can generate. I could have provided a smaller load, but by connecting a load greater than the system can handle I’m not wasting any of the power that the system is capable of producing.

Measured results:

For the month of June, my solar panels delivered 42kwh to the batteries and load, an average of 1.4kwh per day.

My data also shows that I’m sending about 2kwh to the loads each day, more than the solar panels produce. The apparent discrepancy is due to the fact that I top off the charge on my batteries at night with a battery charger. My utility-provided electricity has been very inexpensive at night, and I take advantage of that by storing the low-cost energy for use during the day when rates are higher. This opportunity will end in the fall, when daytime rates go down, and nighttime rates increase. You can learn more about this plan at www.powersmartpricing.org.

When the grid fails:

My day-to-day strategy is to use as much of the solar-generated power as I can for household use, cutting my electric bill. My strategy changes dramatically when grid power fails. Since I don’t have enough capacity to keep my big refrigerator running, I unplug it. I place all of my frozen food in the chest freezer. I place items from my refrigerator in ice-chests, and use ice that I’ve previously stored in the chest freezer. My PV system can keep the chest freezer running continuously, as long as I have plenty of sunshine. I use CFL’s for light, watch TV and listen to the radio, use the microwave oven, charge the cell phone battery, and do most of the other things I would normally do with grid-supplied power. I just have to use this limited supply of power more conservatively.

Winter is the worst possible time to suffer from an extended grid power outage. To conserve electricity, I heat only a portion of my home using my corn-burning stove. Eventually I’ll have a solar PV system big enough to keep the stove running 24/7, but I’m not quite there yet. My system is big enough to meet my summertime needs, but using central air-conditioning is not possible. I have plenty of energy during mild weather grid-power outages, and I’m very comfortable in my home when that happens. It’s a joy to have plenty of light, to be able to use a TV and appliances, and to prepare food while many of my neighbors are using candles. I must admit that I still have a small gasoline-powered generator, but I’ll phase it out as my PV system grows.

Conclusion:

I’ll soon be installing another solar panel, and I have a couple of system modifications in mind that I expect will improve overall system efficiency. Starting small has been a rewarding experience for me, and I would highly recommend it to others. You might be surprised by how much you can benefit by implementing a small PV system, and you’ll certainly learn a lot. Each system upgrade makes you more independent, and improves your comfort level in the event of a grid power failure. Producing your own electricity will lead to using less gasoline. By using less gasoline you’ll be sending less money to those who want to kill you or convert you to Islam against your will. For each kwh of grid-supplied power that you don’t use, about 2.2 pounds of carbon dioxide is kept out of the atmosphere, not to mention other pollutants emitted from coal-fired power plants. If many of us do a little, it will help a lot.

John

Future USA

2008-07-22T14:01:00.001-05:00

George W has a horrible environmental record as president, but his Texas ranch is off-grid with a variety of renewable energy systems. Although he’s done little to prepare the country for the effects of declining fossil fuel, he hasn’t neglected his own needs. Does he know something about the future that the rest of us don’t? We see skyrocketing gasoline and food prices, but we tend to plan for the future as if we expect things to be pretty much the same as they are today. Are we in a state of denial about our future?

Perhaps we’re all in a state of denial, even large corporations. GM spends an enormous amount of money promoting big cars and trucks, while closing several of its assembly plants due to lack of sales. Shouldn’t they have seen this coming? Why did they let Toyota and Honda take the lead with their fuel-efficient vehicles? GM continues to push it's gas-guzzlers by offering discounts and rebates, even offering to pay a portion of your gas bill. They use slogans like “Let’s Refuel America”. It seems that they’re determined to use up all of the remaining fossil fuel as quickly as possible!

Banks are in trouble, and I wonder why so many of them have been willing to make loans to people who probably won’t be able to keep up with the payments. Again, shouldn’t they have seen this coming? We shouldn’t be shocked when we find ourselves in a society that is much different than the one we live in today. Unlike some car manufacturers and banks, we should see this coming and prepare for it. We already drive less today because of the high cost of gasoline, but we still drive. We’re learning to economize as food prices go up, but we still buy food of course. Today most of us can compensate for rising food and gasoline prices by cutting back here and there, but what will we do if things get worse?

While another terrorist attack could trigger a sudden collapse of our economy, we might suffer more from a gradual decline. If your cost of living outpaces your income long enough, you’re in trouble. You may think that these gloom-and-doom scenarios are unrealistic and choose to do nothing, but if you believe that the worst is yet to come you should prepare as soon as you can. If you wait until things get worse, it will be too late. You’ll be forced to use the renewable energy systems you have in place, not the systems you planned to install someday.

Once you’ve decided to prepare, the next question is “How do I prepare?” How you prepare depends on how you want to live, and on your budget. You might choose to prepare for a total melt-down of society by considering your basic needs, or you might opt for a strategy that attempts to maintain your lifestyle as it was before the melt-down. A reasonable approach would be somewhere in between. Since everyone’s goals and budgets are different, this article is not a one-size-fits-all design guide. Instead, these are some ideas to help you formulate your own plan.

You can probably live as comfortably as you do now, and use half of the resources that you’re currently using, if you’ll simply cut waste. Start by eliminating phantom loads. Put your TV’s, and other items that continue to use power when turned off, on power strips. Get used to powering these items on and off with the power strips on/off switch. Get rid of unnecessary items like hand-lotion warmers. When possible, replace electrical items with mechanical items that serve the same purpose. Alarm clocks, can openers, and doorbells are a few examples. If you haven’t done so already, replace your incandescent light bulbs with compact fluorescents (CFL’s). Replace old and inefficient appliances, especially your refrigerator. Consider energy-saving home improvements, such as adding insulation and replacing inefficient windows and doors. These things not only help to cut your energy costs, they are a logical prerequisite to implementing alternative energy systems in your home. Having done those things you can get by with a smaller photovoltaic (PV) system, but you’re still not fully prepared to deal with a serious energy crisis. Let’s go beyond the basics.

Do you heat and cool your entire house 24/7? You could cut your heating and cooling costs dramatically if you were to heat and cool only the area’s that you’re using. Is a 14’ by 14’ bedroom really necessary? Couldn’t you sleep just as well in a climate-controlled 6’ by 9’ space? Providing climate control to a much smaller space requires less energy, making it possible to get by with a smaller photovoltaic (PV) system. If you have an unused room in your home, perhaps an unfinished basement with a window, you can easily create a living environment that requires little energy. You can be just as comfortable in a small well insulated space, perhaps with the aid of a window air conditioner or an electric blanket, as you are now in your big bedroom. If you’ll make the necessary adjustments you’ll be able to meet your energy needs with a small PV array, instead of covering your entire south-facing roof and spending $25,000.00. I’ve determined that I can meet my own basic needs with as little as 800 watts of PV panels, and a total investment of less than $6000.00. With 4 hours of sunshine, a system that size can generate 3200 watt/hours each day (not taking into account system losses and inefficiencies). A big portion of the energy I produce will be used to keep a small chest freezer running. I’ll also use cfl’s, radio and tv, cell phone charger, microwave oven, and fans. I’ll have limited use of my corn-burning stove or a window air conditioner. I can summarize my minimum needs as shown below:

Mild Weather Energy Requirements: 1220 watt/hours per day

Hot Weather Energy Requirements: 2530 watt/hours per day

Cold Weather Energy Requirements: 2990 watt/hours per day

If I build a system that barely meets my cold weather requirements, I’ll have shortages on cloudy days. I’ll need to cut back at times. But a system designed to meet my cold weather requirements will give me a surplus of electricity during mild and warm weather, allowing me to use other appliances to a greater extent. I’ve learned techniques that help me get the most from a small system. For example; if I place my chest freezer in the coolest portion of the house, it uses less energy for its operation while providing some heat to that area. I don’t run my refrigerator when the power fails; I use an ice-chest instead. My freezer, which is powered by my PV system, provides the ice.

As you make your plans, don’t neglect your basic needs. You’ll need fresh water on an ongoing basis of course. You might want to visit one of the many survivalist websites for information and ideas along those lines.

Since your need for food is an ongoing one, knowing how to grow and preserve vegetables and fruits is a skill that will serve you well. If you’re already a gardener, enlarge your garden. Tomatoes and other veggies are easy to grow, and easy to preserve. By canning your vegetables, you’ll have a supply of food that doesn’t require refrigeration. It’s a good feeling to know that an extended power failure (or a failure of your PV system), won’t ruin a big portion of your emergency food supply.

“Perhaps the day will come when the United States is no longer addicted to imported oil; but that day is still many years off. For now, the reason for America's rapt attention to the security of the Persian Gulf is what it has always been. It's about the oil.” Ted Koppel

Fighting for control of every last drop of oil is the foundation of this administration’s energy policy, and it will not end well. To the extent that we can, let’s not support this policy. Mass acceptance of renewable energy systems by the general public will show our elected officials, and the rest of the world, that we want to do the right thing. We can do it. We should do it. Future generations will appreciate our efforts.

John

My Renewable Energy Projects, an Update

2008-07-14T10:01:00.012-05:00

Solar Water Heater:

My solar swimming pool water heating project is still a work in progress. I now circulate water through 200 feet of pvc tubing mounted in the attic of my storage shed. I pump cool water from the pool, circulate it through the pvc heat exchanger, and return the heated water back into the pool.

The system heats the water nicely, but I seem to have too much pool for the small amount of hot water I’m producing. I’m using an ordinary garden hose for the water input, and it has a tendency to collapse under the vacuum that the pump creates. This restriction lowers the output of the system. I may put this project on hold, since heating the pool water is not necessary this time of year. I suppose I'll work on it again this fall, or next spring.

Home Heating with Corn:

My corn stove saw limited use last winter due to the high cost of corn. Corn was about $2.50 per bushel when I installed the stove, but it’s currently about $7.00 per bushel. The sharp increase was due to the huge demand for corn by the ethanol industry. I expect the cost of corn to decline as cellulosic ethanol plants come on line, and I’ll once again be able to economically use the stove.

If the price of corn remains high, I might try growing it myself (again). I've recently purchased my first piece of equipment to help with the process, an old corn sheller. I found the sheller at an antique store. This should be well worth the 20 dollars I paid for it.

My PV System Automation and Battery Charging:

Summer has arrived, and hot weather has resulted in an increased demand for electricity. My utility rate plan has me paying for electricity based on demand, and the rate has exceeded .17 per kwh a few times. However, my nighttime rates have been surprisingly low, sometimes below .01 per kwh. To take advantage of this large discrepancy, I sometimes charge my batteries at night and use the stored energy to run my refrigerator and freezer during the day when utility rates are high. It seems that switching to a variable electricity rate plan has paid off, and that my load shifting plan is working. Here are some statistics:

My cost for the electricity I used in June of 2008 was $65.38.
My cost for the electricity I used in June of 2007 was $116.31.

I used 625kwh of electricity in June of 2008.
I used 1127kwh of electricity in June of 2007.

Other PV System Statistics:

I currently have 5 – 85 watt PV panels on my roof. I’ve not yet adjusted the angle for the summer sun, so they’re not pointed at an optimal angle. I waited a little too long to do this, and now I want to avoid walking on the roof while the shingles are hot. Later this year I’ll add another PV panel, and I’ll adjust the angle at that time.

In addition to the inefficiency caused by a less-than-ideal angle, I’ve noticed the effect of temperature on the PV panels. I seldom see PV panel current exceed 22 amps. I’ve seen panel current exceed 25 amps during cold weather.

System output averages a little more than 2kwh per day, or about 10% of my total household usage, but that is with a boost from the battery charger. I’m pretty happy with this free, and low-cost, electricity.

Summary:

Some say that unless utility rates are exceptionally high, and renewable energy incentives are exceptionally good, the payback for a solar PV system might be in excess of 25 years. But for those of us who do most of the labor ourselves, and explore ways to improve efficiency, payback can be much quicker. At the same time we benefit from a system that shelters us from utility failures. We can stay comfortably in our homes at a time when others need to abandon theirs. We can keep our refrigerators and freezers running, protecting our food from spoiling. We can keep our communications and entertainment equipment working, and protect our property and belongings. I don’t dwell on the payback period. My system has already paid for itself as far as I’m concerned. My systems can keep me comfortable in my home regardless of outside weather, or disruptions of any of my utilities. My systems are far from complete, but are improving with time. In the not-to-distant future I’ll be able to cut my transportation expenses thanks to my PV system. Perhaps one of these days I’ll be able to pull the plug on all outside services.

John

Transportation Alternatives That Make Sense

2008-07-07T13:41:00.002-05:00

Most of us can’t afford ocean-front property, so we take vacations. Most of us can’t afford a luxury yacht, so we charter cruises instead. Most of us can’t afford to own an airplane, so we book flights with commercial airline companies. We tend to use common sense for most of our travel, but many of us drive vehicles that greatly exceed our needs. While our day-to-day needs might call for a vehicle that is capable of taking one person on a 20-mile round-trip work commute, we often end up with a much larger vehicle. We buy these larger vehicles because we sometimes need the extra capacity. We need the extra capacity to haul hardware or appliances, to take the family on a camping trip, or maybe to tow a trailer or boat. We may only need the extra capacity 1% of the time, but we end up using a vehicle that burns an excessive amount of gasoline every day. This excessive use of gasoline is not only expensive, it’s bad for the environment and a waste of natural resources that are already in short supply. Excessive use of gasoline feeds the greediness of oil companies, causing gasoline to be even more expensive for all of us.

Do you drive a gas-guzzler?
At today’s prices you could be
spending $40.00 for 400 miles
of driving, instead of $140.00
to go the same distance.

The automobile industry thought it could address the problem by making large vehicles more fuel-efficient, but had to reconsider when people stopped buying large vehicles. Consumers understand that while a fuel-efficient SUV might get 20mpg instead of 10, they are better off driving a smaller vehicle at 35mpg or more. Many of us would be better off using a gas-efficient vehicle for our daily commute, and renting a larger vehicle when extra capacity is needed. A fuel-efficient vehicle might save the owner $2000.00 or more in gasoline per year, more than enough to pay for the rental of a larger vehicle for those times when it’s needed. A hardware-store in my neighborhood has truck rentals at a cost of $20.00 for 90 minutes.

If you need to haul small loads often, frequent large vehicle rentals might not be the best strategy for you. A small utility trailer might be your best choice. Even the smallest of cars can tow a lightly-loaded trailer easily. You’ll need to install a trailer hitch, add a connector for lights, and you’ll need to license the trailer, but you’ll save in the long run.

My strategy is to avoid using the family mini-van as much as possible, but I could do better. I would much rather co-own a mini-van or truck. If several families owned a large vehicle, each of them could use it for a few days each month. The purchase cost, as well as the cost for licensing and insurance, would be much less if those costs were divided among several owners. Many of us don’t need a large vehicle for more than a few days each month anyway.

This co-ownership plan could be easily expanded to include more than one vehicle, helping to ensure that plan participants would get the type of vehicle needed, when they need it. For example; 16 families could co-own 2 vehicles. One could be a pickup truck, and one could be a mini-van. Scheduling could be done via the Internet, and all participants would have instant access to vehicle availability information. Payment plans could be tailored to meet the needs of each participant, ensuring a fair deal for each member of the group. Some two-car families could benefit from this plan by becoming one-car families.

I’ve thought about my own needs, and my ideal plan would include the use of a mini-van for about three weeks each year. This would allow me to take my family on a two-week vacation, and a couple of weekend get-a-way trips. I’ll also need a pickup truck about 21 times each year to haul building materials, garden and landscaping supplies, appliances and furniture, and corn for my stove. If everyone in the plan has equal access, each of the 16 participating families will have just over 42 days of vehicle availability each year. A potential drawback of the plan is that participants would tend to want the vehicles on weekends, and not so much during the week. This problem might be minimized by careful selection of plan participants. A retired couple might be happy to use one of the available vehicles during the week for shopping, leaving it free on the weekends for family outings. Such arrangements could be specified by plan clauses.

There are many ways a co-ownership plan could be implemented. Several families could co-own an old beat-up pickup truck for example. After purchasing an inexpensive vehicle outright, insurance and maintenance would be the only ongoing cost. This would be a dirt-cheap solution for each family involved.

Co-ownership may sound like a radical idea, and the car rental agencies are going to hate it, but it’s an idea whose time has come. The best implementation would be on a neighborhood-by-neighborhood basis, providing quick and easy access to vehicles with little advance planning.

John

Living a Better Life - Post Oil

2008-06-23T14:59:00.005-05:00

Did your parents ever scold you for wasting energy? Did they complain when you didn’t close a door or turn off the light when you left a room? I suspect that most of us were chastised on occasion. Some of us might recall a parent saying; “when you’re paying the electric bill, you can leave the lights on as much as you want”.

By contrast, children of the future might be chastised for NOT using electricity. That may sound odd, so let me explain. Photovoltaic (PV) panels generate electricity as long as the sun hits them, but they’re most productive during “peak” sunlight hours. Most of the United States gets peak sunlight, and therefore maximum output from solar panels, for 3 to 5 hours per day. A grid-tied system feeds this energy back into the grid, and it offsets power used at night. On the other hand, the energy produced by an off-grid system is usually stored in batteries. For several reasons, this process is far less efficient than a grid-tied system. However, if the off-grid system output is used to directly power a load, instead of storing and retrieving it, system efficiency increases dramatically. We get the most from an off-grid system by using it during peak sunlight hours, and we should exploit that whenever we can. Chores like washing and drying clothes, pumping water, and preparing food should be done during the day. Using appliances and machinery during the day, and avoiding their use at night, will be common practice in the future. The child who forgets to do his chores during peak sunlight hours may be in for a scolding.

For the past 100 years we’ve gotten used to paying for the electricity we use. It may be hard for some of us to grasp the concept of free electricity, but PV-produced electricity is indeed free. Once we’ve used all we need for charging batteries and powering devices, the rest can be considered free. We can leave lights or appliances on at no cost (except for the wear and tear on the lights and appliances).

Some people believe that civilization will decline as fossil fuels become more expensive, but I believe that we’ll adjust. Learning new habits will be part of that adjustment. The way we use electricity will not be the only change. We’ll still have transportation, but the vehicles that take us from place to place will change dramatically. We’ll still have comfortable homes, but our HVAC systems will be radically different than they are today. The equipment and systems will still be automatic and thermostatically controlled, and we’ll continue to make adjustments to ensure optimization. In other words; our equipment will be different but we’ll use it pretty much the same way we use the equipment of today.

More of us will have gardens in the future, and those who already have gardens will have bigger ones. Gardens not only help offset the rising cost of food, they can be part of our heating and cooling systems. Some already heat their homes with biofuels, and some use “green roofs” to help keep their homes cool.

You might argue that the ideas I’ve presented here represent a more labor-intensive lifestyle than we’re used to, indicating a decline in the quality of life, but I would disagree. While many of these strategies do indeed require more effort, they’ll also keep us more fit and in better health. We’ll benefit from a better quality of food, more exercise, and better air quality. Anyone who’s ever compared a store-bought tomato to one grown in a backyard garden knows what I mean. Tomatoes that have to be shipped a long distance are picked green, and “gassed” to turn them red by the time they show up in the supermarket. They’re rock-hard, and have little flavor. I can only guess that the nutritional and cancer-fighting properties are not what they should be either. And it’s wise to remember that the recent salmonella outbreak linked to tomatoes was a result of industrial agriculture. Shipping fewer vegetables not only means better food, it also means fewer trucks on the road, which reduces fossil fuel use and improves air quality.

When it comes to the future, there are three kinds of people: those who let it happen, those who make it happen, and those who wonder what happened.

John M. Richardson, Jr.

There will be bumps in the road to oil independence. We’ve overreacted to the rapid rise in the price of oil by making ethanol from corn (kernels), when we should be making it from agricultural waste (cellulosic ethanol). But we’ll adjust, and we’ll eventually be living a far better life than we do today. We’ll replace our dirty gasoline-powered cars with non-polluting electric ones. We’ll develop better ways to keep warm in the winter and cool in the summer. We’ll find better ways to heat water. We’ll generate at least a portion of our own electricity. We’ll build communities that allow us to walk or bike to the grocery store and to work. Additional chores will instill a greater sense of responsibility in our children, resulting in far fewer social problems than we have today.

What we need now is for governments to stop making war, stop promoting fossil fuels, and to begin supporting alternative energy in a substantial way and with well thought out plans. Beyond that, we need little help from them. If they’ll just get out of our way and let us use what God has given us, we’ll be fine.

John

Unbelievably Low Electricity Rates

2008-06-16T09:39:00.008-05:00

Here’s something you’re not going to believe - electric rates below 1 cent per kilowatt hour (kwh). My electricity provider, Ameren, must have lost its mind! For most of the United States, electric rates are about ten cents per kwh, with many areas paying much more than that.

As a participant in the “PowerSmart Pricing” plan, my electricity rate fluctuates from hour to hour, depending on the demand at the time. Shown below are the rates for June 11th, 2008. Notice that from 2:00am until 4:00am electric rates are below 1 cent, and then slightly more than 1 cent per kwh from 4:00am until 6:00am. The highest cost for the day was just over 11 cents per kwh at 3:00pm.

Date * * * * * * * Hour * * * * Price
2008-06-11 * * * 00 - 01 * * * 0.015520
2008-06-11 * * * 01 - 02 * * * 0.012190
2008-06-11 * * * 02 - 03 * * * 0.009200
2008-06-11 * * * 03 - 04 * * * 0.009380
2008-06-11 * * * 04 - 05 * * * 0.012560
2008-06-11 * * * 05 - 06 * * * 0.013790
2008-06-11 * * * 06 - 07 * * * 0.020730
2008-06-11 * * * 07 - 08 * * * 0.030550
2008-06-11 * * * 08 - 09 * * * 0.042160
2008-06-11 * * * 09 - 10 * * * 0.060670
2008-06-11 * * * 10 - 11 * * * 0.077770
2008-06-11 * * * 11 - 12 * * * 0.091420
2008-06-11 * * * 12 - 13 * * * 0.100440
2008-06-11 * * * 13 - 14 * * * 0.108230
2008-06-11 * * * 14 - 15 * * * 0.111300
2008-06-11 * * * 15 - 16 * * * 0.111880
2008-06-11 * * * 16 - 17 * * * 0.104470
2008-06-11 * * * 17 - 18 * * * 0.095140
2008-06-11 * * * 18 - 19 * * * 0.084570
2008-06-11 * * * 19 - 20 * * * 0.070230
2008-06-11 * * * 20 - 21 * * * 0.084700
2008-06-11 * * * 21 - 22 * * * 0.073010
2008-06-11 * * * 22 - 23 * * * 0.042210
2008-06-11 * * * 23 - 24 * * * 0.027310

As unbelievable as these rates are, I was even more surprised on June 16th when my 3:00am rate dropped to .00207 (two tenths of a cent per kwh).

These low rates won’t last forever. When plug-in electric cars become available, most will be charged at night. This increased demand for electricity will drive up the rates. But for now I’m taking advantage of these exceptionally low nighttime rates by topping off the charge on my batteries while rates are at their lowest, and using the stored energy when rates are higher. My battery charger is on a timer, set to power it up from 1:00am until 5:00am. Load switching is automatic. I’ve also switched most of my laundry chores to late-night. See my previous post for additional details, or my March 15th post.

For information about the Ameren plan, visit the PowerSmart Website.

John

Adjusting to New Batteries and Higher Electric Rates

2008-06-09T18:51:00.007-05:00

Every PV system upgrade has had a noticeable effect on performance, and my recent battery upgrade was no exception. The larger battery bank takes longer to charge on a sunny day, but it also powers loads for longer periods at night. Because of the battery bank upgrade, I decided that it would be wise to review system settings. My goals are:

• Prevent battery overcharging.
• Prevent battery under-charging.
• Prevent batteries from discharging too deeply.
• Get as much energy from the system as possible, reducing my electric bill.
• Maintain safety.

A charge controller prevents batteries from overcharging, and mine is adjustable via internal switches. Since my old batteries were sealed, and my new batteries have removable watering caps, I’ve readjusted charging parameters to accommodate the new batteries. I’ve adjusted the battery voltage upward a little. Some “gassing” shouldn’t be a problem, since I’ll be checking battery fluid level on a regular basis.

My batteries are in a windowed sunroom, and therefore I’ve set “Equalization” to manual instead of using the automatic equalization setting. I’ll open the windows when I equalize the batteries, allowing hydrogen gas to escape. My charge controller keeps track of the days between equalization, so I’ll know when it’s time to do it.

My automation settings help me get the most from my system, while protecting the batteries, by performing two basic functions:

• Wait until batteries are nearly fully charged before switching on loads.
• When battery voltage declines to a preset value, remove the loads.

The automation settings turn the inverter on and off, and therefore control the loads. I’ve adjusted the settings as posted below:

• Battery High Voltage Threshold = 13.85 volts (Turn inverter on)
• Battery Low Voltage Threshold = 12.25 volts (Turn inverter off)

I have a Transfer Switch, which is nothing more than a relay, wired to use AC from the inverter as the default. It switches to utility-supplied AC when the inverter is off. With this setup I can be pretty sure that my refrigerator and freezer will always be powered up.

Since I’ve just spent a great deal of money on the new batteries I’ve decided to be more conservative with the settings in order to prolong their life. I’ve adjusted the Battery Low Voltage Threshold upward, minimizing the depth of discharge. This adjustment not only prolongs the life of the battery, it means that I’ll have more reserve energy available in the event of a grid power failure. I’ve adjusted the Battery High Voltage Threshold upward, providing a little more assurance that the batteries will be fully recharged each day.

Even with these conservative settings I’ve observed a significant performance increase with the new batteries. I’ve also learned that it is beneficial to keep the load relatively high. A heavy load reduces the amount of time that the charge controller spends in the “absorption” and “float” states. In other words; more of the available sun’s energy is used to power the loads and therefore less of the sun’s energy is unused.

Adjusting to “PowerSmart Pricing”

My electricity rates vary on an hourly basis, depending on the demand at the time. I might pay as little as 1.5 cents per kwh when demand is low, and more than 17 cents per kwh when demand is high. Now that summer is here, and demand is greater, electric rates tend to be highest from about 10:00am until about 8:00pm. This has caused me to adjust my strategy somewhat. I want to make sure that I’m using electricity from the PV system as much as possible during times when rates are highest. In addition to using as much energy from the sun as possible I can take advantage of this large price differential by charging my batteries at night when rates are low, and use the stored energy during the day when rates are high.

In other words:

I sometimes buy electricity for less than 2 cents per kwh (to charge batteries), and use that stored energy when utility rates exceed 17 cents per kwh. Even with system losses considered, I suspect that I’ll come out ahead. I shift loads to the PV system when electric rates are highest, hoping to have enough energy from the sun and stored energy to last until rates drop.

To avoid manually switching things on and off in the early morning hours I use a timer. Here's a picture of my timer, charger, and battery bank.

And here's a simplified diagram of my system with the charger and timer:

I’ll have to compare this summer’s electric bill to that of last summer to see if my efforts have paid off. If so, I don’t think I’ll have any problem convincing the wife that we can benefit from a couple more panels by the end of the year.

John

Second Anniversary Message

2008-05-31T20:54:00.005-05:00

I began my first anniversary message with a rejection of the notion that “America is Addicted to Oil”. Today I’m proud to be among a growing number of people who are actually doing something about it. We have different strategies, and different kinds of projects underway, but similar goals. We’re fortunate to live in a time when it is easy to share information, and to learn from each other. At the rate gasoline prices have been rising, we all need to avoid mistakes and to work as efficiently as possible.

In addition to individual efforts, it’s good to see corporate projects. We’re closer to having practical electric vehicles than we were on this date last year. The GM Volt seems to be progressing on schedule, and the Norwegian Th!nk City car should arrive in the United States sometime next year. Both will have Lithium Ion batteries, and that technology seems to be progressing nicely. Because of the rapid progress, I’m no longer sure if my first electric car will be a plug-in-hybrid-electric, or an electric-only vehicle. As long as I have enough range to meet my daily driving requirements, an electric-only car will meet my needs. I’ll continue to enlarge my PV system so that at least a portion of my driving will be via free energy from the sun.

Another winter has passed, and my corn-burning stove once again supplemented my home heating system. I’m happy to have replaced fossil-fuel heating with corn, but I didn’t really save money this year due to the high cost of corn. I hope someday to own enough land to not only grow my own food, but also to grow corn to be used for home heating. I’ve been told that I can meet all of my home heating needs with just one acre of corn. I know that this will be an ambitious project, so I may hold off until I’m ready to retire from my day job.

In addition to my solar electric and bio-fuel projects, I’m now experimenting with solar water heating. Besides cutting my use of fossil fuels, this project has the potential for cutting my natural gas bill. Check back later for a progress report.

As we go forward we follow different paths, but diverse strategies are good. There will be no single solution to the problems we’ll face as oil declines. Short-term solutions, like hoarding gasoline, will be of little value. Let’s continue to share information as we face the challenges of the future, including our successes and failures, for the benefit of all. As we make the transition to alternative sources of energy, let's enjoy the journey. I appreciate blog comments, and hope to see more of them as I enter the third year of this blog.

John

My Solar Water Heating Project

2008-05-16T15:59:00.005-05:00

My interest in renewable energy has led to experiments with solar electricity and to home heating with bio-fuels, so I guess it’s only natural that I would want to experiment with solar water heating as well. My latest project is an attempt to build a solar-powered water heater for my above-ground swimming pool. I’m not concerned with storing hot water, so I won’t need a tank. I just want to be able to raise the water temperature in the pool during the day.

I started with a plan to pump water from the pool, circulate it through tubing where it would be heated by the sun, and return the heated water back into the pool. I planned to mount PVC tubing to the side of a storage shed, and to paint the tubing black to increase its ability to absorb the sun’s heat. As the experiment progressed, family members hinted that the backyard was beginning to look like a wastewater treatment plant. I had to admit that they were right, and I decided to change my approach. Since the storage shed has an insulated ceiling, I decided to take advantage of the heat that builds up in the attic. Instead of mounting the tubing on the side of the shed, I’ve mounted it to the inside of the roof. I currently have 120 feet of 1” PVC pipe installed, and I’ll add as much as 200 feet more if necessary. The cost for the tubing is $2.42 per 10 foot section. I’ve purchased a small pump, and it seems to be able to circulate the water. I won’t know how well the system works until I can test it on a hot day. I’m currently using a 55 gallon plastic drum as a substitute for the pool.

Mounting the tubing in the attic means that it will be out of sight and out of mind during the winter. I won’t have to clean around and under the pipe array. I’ll just have to make sure that the pipes are drained, and gravity will help with that. In addition to its use as a pool water heater, I also have the option of using it as a solar-heated shower. I can make that conversion by connecting a garden hose to the pipe array, instead of pumping water from the pool. Regulating the amount of flow should also regulate the water temperature. The entire project will cost less than $300.00, and it should last for years. I’ll post additional details later, but here are some pictures of the project as it stands today.

Many thanks to Solar Gary for ideas and advice on solar water heating strategies. Anyone considering a related project should check out his website for ideas: http://www.builditsolar.com/

John

Another Grid Power Failure

2008-05-08T15:58:00.003-05:00

And another test of my off-grid solar electric system:

With each grid power failure I learn new things, and Wednesday’s power failure was no exception. This power failure occurred early in the afternoon while I was at work. It was a gloomy day, and batteries were not fully charged at the time of the failure, making it necessary to switch the system on manually. This would have been easy for me to do, had I been home at the time, but not so easy for a family member. The simple system I once had is now an automated system with several components and switches. Explaining over the phone how to switch the system on is not as simple as it was in the past. It went something like this:

Me: Flip the Inverter toggle switch on.
Family Member: Which one is the inverter?
Me: The black box that says Exeltech on it.
Family Member: Where is the on/off switch?
Me: It is under the Kill-A-Watt meter.
Family Member: Which one is the Kill-A-Watt meter?
Me: It’s the grey thing that’s plugged in to the inverter.
Family Member: I don’t see a switch under the Kill-A-Watt meter.
Me: The switch isn’t on the Kill-A-Watt meter, it’s on the front of the Inverter.
Family Member: OK. I’ve switched it on and I see a green light.
Me: That’s what you should see. The system is now on.

From this experience I’ve learned that I need to better educate family members so they’ll be prepared for the next grid power failure. To help with this, I’ve created a visual aid. The name of each device is listed next to its picture, along with a brief description. Basic operating instructions are also provided. The challenge is to provide enough information, but not too much. Too much information could be confusing.

First of all, family members need to understand the system configuration. There are two common system configurations:

Configuration #1: In the event of a grid-power failure, the inverter switches on, and the loads are automatically switched from grid power to battery power.

Configuration #2: Loads are powered by battery power until battery voltage drops to a preset level. Loads are then automatically switched to grid power.

My system is wired for Configuration #2. The system doesn’t automatically switch on when a power failure occurs; it switches on when batteries are fully charged. The refrigerator, freezer, and anything else plugged into the system’s AC outlet will automatically switch to grid power when the inverter switches off, but a grid power failure does not automatically switch the loads to battery power.

Because it is sometimes necessary to switch the system on manually, it must also be switched off manually, and users also need to know when to do that. Users need to monitor battery voltage, and must avoid letting battery voltage drop too far. This can be a little tricky too, since battery voltage is influenced by the size of the load. And so, without supplying too much information, I need to set a low-battery-voltage limit for them to follow.

To complicate things just a little, I’ve also provided information about the back-up battery bank, and how to switch it into the circuit. As with the main battery bank, battery voltage must be monitored and voltage must not be allowed to fall below a predetermined low-voltage limit.

Wednesday’s grid power failure was brief, about 2 hours, but it was a valuable learning experience. With the visual aid I’ve created, and a little instruction, we’re better prepared for the next power failure. We’ve been having a lot of storms lately, so we may not have to wait long to find out.

John

My Latest Off-Grid PV System Upgrade

2008-05-03T22:28:00.003-05:00

Because of a recent system upgrade I now have better control over the amount of power I use, and the amount of power I keep in reserve. While I want to benefit from as much power as the system is capable of providing on a day-to-day basis, I find myself cutting back, knowing that I’ll need stored energy in the event of a grid power failure. I need to strike a balance between the amount of power I use, and the amount of power I keep in reserve, but I find myself wanting more of both.

Since my solar panels have the ability to fully charge the existing battery bank by noon on a sunny day, it’s obvious that I have the capacity to charge a larger battery bank. It seems that a battery bank upgrade will allow me to get more from the system on a daily basis while at the same time increasing the amount of stored energy. For that reason, I’ve just replaced my old battery bank, increasing the amp-hour capacity from 420 to 675.

I’ve known that I could greatly improve system performance with a bigger battery bank for some time, but I’ve been holding off because my old batteries are still in good shape. Since batteries of different sizes, types, and ages shouldn’t be included in the same battery bank, I was confronted with the problem of what to do with the old batteries. I decided to isolate the two battery banks from each other, and to use a switch to connect or disconnect the old battery bank as needed. The diagram below shows how I did that:

The new ones are 6-volt batteries, most commonly used in golf carts. I series wired three pairs of these to create the equivalent of three 12-volt batteries at 225ah each, and paralleled the three pairs for 675ah at 12-volts. I’ve installed a heavy-duty switch, allowing me to switch in bank 1, bank 2, or both banks at the same time. I’ll switch in the new battery bank for day-to-day operation, only switching to the old bank once in awhile to keep it fully charged. In the event of a power failure, when I’ll need the extra capacity, I’ll switch in both battery banks. With both battery banks connected, I’ll have one large battery bank with an awesome 1095 amp-hour capacity.

Understanding that batteries should not be allowed to fall to more than 50% of their capacity, I now have a useable capacity of 547 amp-hours, a significant upgrade from the previous 210 amp-hour useable capacity I previously had. After monitoring the new battery bank for a few days I observed that:

· It does indeed take more time to fully charge the bank.
· Loads are powered for a longer period of time each evening, after the sun goes down.

In the event of an extended power failure I’ll have light, refrigeration, communications, the ability to prepare food. I’ll be able to use my bio-fueled stove for heat, and fans to circulate fresh air. I’ll be able to watch TV or listen to the radio. I’ve had these capabilities previously, but not to the extent that I have them now. This will serve me well in the event of an extended power failure. I’ll need to continue upgrading the system if I expect to use it to charge the electric vehicle I hope to purchase within the next two years, but I’m getting there. I’ll be doing some capacity tests soon, and I’ll record the results on this blog. Check back later.

For information concerning my recent system automation upgrade, check my February 25th post: http://solarjohn.blogspot.com/2008/02/ive-automated-my-off-grid-pv-system.html

John

Think Th!nk - Please Help Me Get One

2008-04-27T17:55:00.004-05:00

Due to the skyrocketing cost of gasoline it is inevitable that Americans will soon be driving a radically different kind of car. We already have the Prius, and other hybrids, and we’ll have plug-in hybrids within a few years, but all of these have one thing in common; they still use gasoline. They all have an internal combustion engine, adding to the weight, cost, and complexity of the car. The gas engine is necessary to extend the range of the vehicle. Without it the car is impractical for long trips.

I had pretty much decided to wait until 2011 or 2012 for a Chevy Volt (plug-in-hybrid) until I learned that the “Th!nk” is coming to the USA sometime next year. The Th!nk is a plug-in-electric car that can get up to 110 miles on an overnight charge, and can reach speeds of 65 mph. It doesn’t have an internal combustion engine, so long trips are impractical, but it’s perfect for my daily work commute of 64 miles. Since the wife and I both work outside of the home, we’re a two-car family by necessity. Our other car can be used for long trips.

I understand that the Th!nk will first be offered to fleets, and then to consumers in California. I’ve recently sent several email inquiries asking how I might be able to be among the first in the USA to own or evaluate a Th!nk. I expressed a desire to test the Th!nk here in the Mid-West where we have an extreme range of temperatures and driving conditions. I explained that I want to use the Th!nk for my daily work commute, evaluate it’s performance, and publish the results on my blog. I mentioned that I intend to enlarge my PV system to the extent that I’ll be able to drive entirely off of free energy from the sun.

The only response I’ve received so far was a form letter. My questions went unanswered. For that reason I’m turning to you, my readers, for help. I’m asking that you write or email those involved with Th!nk in North America on my behalf. I’m just one person, easily ignored, but I doubt that they’ll ignore a large number of requests from all parts of the globe. To make this as easy as possible, I’ve composed a sample message, and I’ve listed the email addresses of those who might be able to make this happen. Just copy and paste the email addresses into the “To” line of your “New Message” window. I’ve included my own email address so that I’ll know how many messages have been sent. Next, copy and paste the suggested subject into the “Subject” line, and then copy and paste the message into the “Message” area.

In case you prefer to contact Th!nk by mail or phone, Vicki Northrup is the North American Operations Manager. Here is the information for her:

Vicki Northrup, Operations Manager
Th!nk North America
2750 Sand Hill Road
Menlo Park, CA 94205
Direct: +1 650 561 0243
Cell: +1 650 892 5068

Let’s let them know that we’re serious about eliminating our use of fossil fuels, and we want to do it now. Thank you very much for your help.

John

Please send the message to the following email accounts:

ila@think.no; willums@online.no; rayl@kpcb.com; info@thinkna.com; jdallas@charter.net

Suggested Subject:

Th!nk testing in the Mid-Western USA

Suggested Message:

To Whom It May Concern:

I am a regular reader of Solar John’s blog (http://solarjohn.blogspot.com/), and am writing at John’s request. I’ve learned that the Th!nk City car is coming to California next year, and John would like to be among the first to test it in the Mid-Western United States. Unlike Southern California, the Mid-West offers a wide range of weather extremes and road conditions, making this an ideal venue for an extended test and evaluation of the Th!nk. John’s test would include using the car for his daily 64-mile round trip work commute. Additionally, John plans to use his solar photovoltaic (PV) system to charge the car, perhaps driving it entirely off of free energy from the sun, and to publish the results on his blog. John is not involved in the Alternative Energy industry, or the Automobile industry, and therefore I expect unbiased reporting from him.

John is not asking for a hand-out, he’s willing to pay full retail price for the car if necessary. He simply wants to be among the first in North America to have the opportunity to evaluate the Th!nk. Sadly, John’s inquiries have gone unanswered. Can you please help? You need not respond to this message, but please work directly with John. You may contact him at this email address: Jdallas@Charter.net

Thank you in advance,

(Your Name)
(Your City, State, Country)

The Energy 12-Step Program

2008-04-15T21:19:00.002-05:00

When President Kennedy made it America’s goal to put a man on the moon, it happened within ten years. But America is in a technology “funk” today. We have a president who tells us we’re addicted to oil, while at the same time underfunding projects that would help to solve the oil crisis. Instead of developing solutions, our president implies that the American people need a 12-Step program. With that in mind, let’s examine the 12-steps:

Step 1. Admit that we are powerless over oil, and that our lives have become unmanageable.

Absurd! If you believe that you’re powerless over oil, and that you can’t manage your own life, you’ll never accomplish anything.

Step 2. Come to believe that a power greater than yourself can restore you to sanity.

Ridiculous! You’re not insane.

Step 3. Make a decision to turn your will and your life over to the care of God.

Bolderdash! Don’t expect God to solve your problems. Solve problems with the help of God.

Step 4. Make a searching and moral inventory of yourself.

Finally, some good advice! Applying your knowledge and skills to this problem is morally appropriate.

Step 5. Admit to God, to yourself, and to another human being the exact nature of your wrongs.

Silly! You did nothing wrong in the context of oil use. It was wrong of our president to tell us we’re addicted to oil.

Step 6. We’re entirely ready to have God remove all these defects of character.

Asinine! Your use of oil does not represent a defect of character.

Step 7. Humbly ask God to remove your shortcomings.

Good advice, but remember that your use of oil is not a shortcoming.

Step 8. Make a list of all persons you’ve harmed, and become willing to make amends to them all.

Don’t feel guilty for your past use of oil, it was thrust upon you.

Step 9. Make amends to such people whenever possible.

You harmed no one, and therefore need not make amends.

Step 10. Continue to take personal inventory, and admit when you’re wrong.

Good advice, but don’t list your use of oil as a wrong.

Step 11. Improve your conscious contact with God.

Good advice, but remember that God doesn’t solve your problems; you do that with God’s help.

Step 12. Practice these principles in your affairs.

You’re not addicted to oil no matter who says you are, and you don’t need a twelve-step program. Use your time and talents to make better use of the resources you have, and don’t expect God or anyone else to do it for you. Someday we’ll have leaders who will actually work with us to solve problems, instead of calling us “addicts”, but for now we’re just going to have to rely on our own efforts. God bless you, keep up the good work, and don’t listen to those who say you’re an addict. God gave us a limited supply of oil, and we could have used it more responsibly. More than anyone else, this was the fault of our leaders. If we’re “addicts” in our president’s mind, then he’s the “dealer”. He himself may need a 12-Step program, but we don’t.

John

You'll Buy an Electric Car Someday - You'll Charge it!

2008-04-07T08:13:00.002-05:00

Has anyone else noticed how expensive gasoline is these days? Ten years ago a gallon of gas could be bought for under $1.00. Gasoline hit the $2.00 mark in 2004, and we were paying $3.00 per gallon in 2006. Now it looks like gas might hit $4.00 per gallon before the end of this year. If this trend continues, we’ll be paying $6.00 per gallon in 2012. Car manufactures are taking notice of this, and several have electric cars in the works.

Since the days of cheap gasoline seem to be gone forever, a sudden shift to electric cars is inevitable. With the automotive industry already working on electric cars, and battery manufacturers competing to see who can make the best batteries, we’re well on our way. The first generation of electric cars will be equipped with a small gasoline engine, included to extend the range of the car. These are called plug-in-hybrid-electric-vehicles, or PHEV’s. And while the PHEV is a great intermediate step, the gasoline engine will eventually be eliminated altogether. Quick charging batteries, and the emergence of battery charging stations, will make that possible.

It looks as if the transition to electric cars will be more of a landslide than a trickle, a scenario that will create some problems. The electric grid, which is already strained in some parts of the country, may not be able to handle the additional load of charging all of these vehicles. Fortunately, most of these electric cars will be charged at night, when other demands on the grid are low. V2G technology (cars that supply power to the grid during the day), will help, but infrastructure upgrades are needed before that can happen. We’ll pay for improvements, and for the upgrades needed for the implementation of V2G technology, through higher electric rates.

Another problem created by a sudden shift to electric cars is that there will be less money available for highway maintenance. Federal and state taxes on gasoline pay for road improvements, bridges, and maintenance. A sudden switch to electric transportation will reduce gasoline tax revenue, and it’s likely that we’ll be required to pay our share of road-usage taxes in some other way. If you use 25 gallons of gas per month, enough to drive about 500 miles, you’re paying about $150.00 per year in road-use taxes. Many of us are paying much more than that. To make up for the loss, we might see additional taxes on our electric bill, but that isn’t the best solution. There is no easy way of determining how much electricity is used for charging our car(s), and how much is ordinary household use. It’s likely that we’ll calculate our share of road-use tax via our state and federal income tax forms. Tax forms will include questions designed to determine how much electricity we use for charging our electric car(s).

The sudden need for more electricity does more than just strain the electrical grid, it means that coal-fired power plants will burn more coal. This will drive up the cost of coal, and you’ll pay for that on your electric bill. Any way you look at it you’re going to have to pay for electricity at an ever-increasing rate, and you’ll soon be taxed for the electricity you use at a much higher rate than you’re paying now. Just as gasoline prices have skyrocketed in recent times, the days of cheap electricity will end as well.

What can you do about it? I’m glad you asked!

Most of the country pays about ten cents per kilowatt hour for electricity now, making it possible to charge an electric vehicle for less than $1.00 per night. You’ll be able to drive 40 miles or more on an overnight charge, instead of burning five to eight dollars worth gasoline at today’s prices. What a deal! But with the likelihood that electric rates will soon mimic the steep increase of gasoline prices, it would be wise to consider other options. For many, a solar electric (PV) system is a great way to deal with the expense of, and problems related to, a sudden switch to electric transportation. It seems that those who already drive electric cars are aware of this, since 50% of them also use solar electric systems.

Off-grid or Grid-tied?

A grid-tied PV system may be the best choice for those served by a robust electrical grid. Electricity is fed into the grid during the day, offsetting electricity pulled from the grid at night. With a large enough system, the user contributes more than he withdraws, and therefore pays nothing for electricity. An off-grid PV system may be the best choice for those with marginal electric service, but system inefficiencies and the added cost of batteries will result in a much higher system cost.

Size matters:

While it’s alright to start out small, it’s going to take a substantial PV system to charge an electric car’s battery bank. GM’s Volt PHEV can be charged via a 110 volt standard home outlet, and a full charge will take 6 ½ hours. I suspect that the charge current will exceed 10 amps, or about 1100 watts, representing a pretty hefty load on a PV system. A 2kw grid-tied system will produce enough electricity (on sunny days) to offset the charging power supplied by the grid at night, but an off-grid system will need to be substantially larger than that in order to compensate for system inefficiencies. If you opt for an off-grid system, and if you’re able to charge your PHEV during the day, you’ll achieve efficiencies similar to those who implement a grid-tied system. An off-grid PV system operates much more efficiently when power flows directly from the solar panels to the load, instead of temporarily storing that power in PV system batteries and retrieving it later. Another thing to consider is that a two-car family will need a PV system twice as large as a one-car family. Still, you can start out with a small system that will generate a portion of your needs, and upgrade later.

PV system cost vs. savings:

As you do your homework you might be shocked by the high cost of a PV system, but don’t forget to do the math. By switching from a gas-powered car to electric, you might be eliminating $3600.00 worth of gasoline per year from your budget. If you apply those savings toward the purchase of a PV system, the payback period will be 2 to 5 years. And better yet, you’ll be driving on FREE power from the sun once your solar equipment is paid for. Any economist, I suspect, would call that a good investment.

Something else to consider:

Once your PV system is in place, you’ll use it as much as possible to charge your PHEV. During times when the sun doesn’t shine, you’ll need to charge your PHEV in some other way. For most people, that other way will be the power grid. This will be the best option as long as electric rates remain reasonable. Charging can be done by wind power, micro hydro, or even a bio-fueled generator after that.

A bonus:

If you don’t drive much on the weekends, you’ll have a surplus of electricity for household use at a time when you’ll need it most.

Conclusion

Like the invention of radio, TV, and the personal computer, the plug-in electric car appears to be the next great invention that will change the way we live. The sudden switch from gas to electricity will trigger an increase in the price we pay for electricity, but those who use PV for some or all of their needs will suffer the least. The surge in the cost of electricity will result in a greater demand for solar panels and equipment, leading to shortages and price increases. To avoid dealing with those shortages and price increases, now is the time to install solar electric panels and systems. And as an added bonus, the massive shift away from internal combustion engines, combined with an increased use of solar panels, will have a positive affect on the quality of our air. You gotta love that!

How will you charge your electric car?

With a credit card of course.

John

Small-Scale Solar PV for Your Home

2008-03-29T23:11:00.007-05:00

Not ready to spend thousands on a solar electric system to power your home? Consider powering a portion of your home with solar instead.

A few years ago this probably wouldn’t have been a good idea, since small home-based PV systems tend to be underused. After all, if you try to run your refrigerator with a small system you might return home from work some cloudy day and find a lot of spoiled food. Since most of us work or go to school during the day, power from a small system is typically used to charge batteries. That stored energy might be used for a few hours of TV viewing or to run a computer in the evening. But energy from the sun during peak sunlight hours could be more efficiently used to power a load. Better yet, mid-day power from the solar panels could power a load and charge batteries simultaneously.

You can easily build a system that will use power from the panels and batteries to run the load until battery voltage drops to a preset level. The load will then be automatically switched to AC from the power grid. A few years ago it would have taken a computer guru, or an electronics engineer to make that happen, but not today. Today the components you'll need are available at a reasonable cost, and it doesn’t take a scientist to hook things up.

By adding automation to a simple off-grid PV system you’ll be using as much of the free energy from the sun as your system is capable of processing, making the most of your renewable energy investment. You’ll be cutting your electric bill as much as possible, instead of under-using your solar panels and equipment. You can use a refrigerator and freezer as the load without worrying about food spoiling, and your batteries will be protected from over charging and from over discharging, extending their life.

The system is expandable. You can start on a small budget, and add to your system as funds become available. Once you see how well this works, and how little maintenance is required, you’ll want to make it bigger.

Does this idea appeal to you? Check out my blog archives for system design details, especially this one:

"I've automated my off-grid pv system"

You need not use the same system parts or configuration. My approach represents one of many ways to do it. You might discover other ways as you look at the capabilities of different brands and types of system components.

I’ll be happy to answer your questions. Just leave a comment.

John

Cutting your Electric Bill

2008-03-26T13:49:00.008-05:00

Most of us know about, and have implemented a number of strategies to cut electricity usage. We’ve replaced incandescent bulbs with CFL types, installed a set-back thermostat, and added insulation. It is inevitable that at some point we’ll ask ourselves “is there nothing left I can do?” Here are some energy-saving ideas that you may not have thought of. Take the time to consider these strategies, and let me know if I’ve overlooked anything.

1. We all know to change our furnace filters regularly, but how often do you clean the squirrel-cage blower inside your furnace? A clean blower assembly turns more freely and moves more air. Additionally, lubricate the bearings or bushings in accordance with the manufacturer’s instructions.

2. When a family member came down with a cold recently, I did something that I’ve always done in the past; I got out the portable humidifier. Out of curiosity I plugged it into my Kill-A-Watt meter. I was surprised by the readings. I found that it draws 285 watts, or nearly as much as five, 60-Watt light bulbs. This type of humidifier produces steam by passing water between two electrodes. Knowing that I could be using a cool-mist humidifier, which probably uses less than 35 watts, I was appalled by how much energy my humidifier wastes. It will cost about $6.00 per month in electricity if I use it for 8 hours each night, but a cool-mist unit will run for the same amount of time at a cost of less than one dollar per month. Purchase a Kill-A-Watt meter and test every electrical item in your home. You may be surprised by the results, and you’ll discover ways to cut back as I did.

3. Consider creative uses for timers. Timers shouldn’t be limited to controlling night lights; there are other ways to use timers to save money. If you seldom watch TV from midnight to 7:00am, you can use a timer to turn off your cable box during those hours. Not only does your cable box use electricity when it’s turned on, it uses it even when it’s turned off (a phantom load). By switching it off for seven hours each day, you’ll save a considerable amount of electricity.

4. Consider creative uses for motion sensors. My kids have their own TV and gaming room. They often fall asleep, or leave the room without turning things off. A motion sensor, connected to the TV’s power strip, would be useful here. The motion sensor below replaces a wall switch.

5. Apply energy-saving settings to your computer. For a Windows-based computer, open the “Control Panel”, and click on “Power Options”. Configure the settings to turn off the monitor and hard-drive after 15 minutes of inactivity. Set your computer to go into standby, or hibernate, after 30 minutes of inactivity. Additionally, use a surge protector/power strip to turn power on and off, eliminating a phantom load.

6. Replace energy-wasting appliances with mechanical ones that serve the same purpose. This includes doorbells, can openers, and alarm clocks. Don’t use frivolous items, like hand-lotion warmers and plug-in air-fresheners. They may use only a small amount of electricity, but it adds up.

7. Use an electric blanket in the winter. You probably already turn your thermostat down at night, but you can turn it down even more and still be comfortable if you use an electric blanket.

8. If you currently have low-voltage outdoor lighting, consider replacing those lights with solar-powered outdoor lighting instead. If your outdoor lights are on a timer, consider burning them for fewer hours each night. Likewise, operate outdoor fountains and waterfalls for fewer hours each day.

9. Consider a bio-fuel stove (pellet or corn-burning), to supplement your furnace. These are available as free-standing units, or as fireplace inserts. They are easy to install and maintain. I use mine to supplement the heat from my furnace, and have cut hundreds of dollars off of my heating bill. Since I’m on budget billing, I enjoy those savings every month of the year.

10. When it’s time to replace your refrigerator, don’t buy one that is too small for the size of your family. Frequent trips to the grocery store will outpace any energy savings you might realize by going with a smaller unit. Look at the energy-star tags as you shop for a refrigerator, and get the most energy-efficient model you can find. If you do, your savings will be significant over the lifetime of the device.

I look forward to your comments, and other energy-saving strategies I’ve missed.

John

Carpe diem

2008-03-15T22:58:00.010-05:00

Carpe diem, or “seize the moment”, is a good way to describe my latest effort to get the most from my off-grid solar electric system. Because electric rates are lowest during the early morning hours, I’ve implemented a plan to shift my electricity usage to that period of time. And no, my plan doesn’t involve staying up all night to do laundry or to cook meals.

My Variable Electric Rates

Although my actual rate varies from day to day, the chart below is typical of my rates for any given day. Notice that I pay about 2 ½ cents per kwh for electricity during the first five hours of the day, and much more than that at any other time of the day.

Building on the system I already have, I’ve added a sophisticated battery charger and a timer. The premise is simple: Charge batteries at night, when rates are low, and use the stored energy in the early morning hours when electric rates are higher. Shortly after that, the loads are powered by the sun. The diagram below is of my system, including the timer and battery charger.

Here is a picture of the charger and timer. Actually, I had to replace the timer. This one wasn’t “heavy-duty” enough.

Theory of Operation

The AC loads are powered by the batteries when battery SOC (state of charge) is high, and by the utility grid when battery SOC is low. That part of the system automation was explained in a previous article, and so I’ll not repeat it here.

The timer is set to apply AC to the battery charger between the hours of 1:00am and 5:00am every day. The battery charger is a three-stage charger, meaning that it will not overcharge. It switches to “float” mode when it senses full batteries, and it does not represent a discharge path when it is switched off.

Due to the evening loads, battery voltage is low just before 1:00am. When the timer applies AC to the battery charger, battery voltage rises rapidly. Once the batteries reach a predetermined SOC, the loads are switched from grid-supplied AC to AC from the system. At that point the charger continues to charge the batteries, and it also provides the power necessary to run the AC loads. At 5:00am the timer disconnects AC from the charger, and the loads are powered with the energy stored in the batteries. Soon after that, the sun comes up. On a sunny day, the solar panels keep the batteries charged and provide power to the loads. When the sun sets, the loads are once again powered by the energy stored in the batteries, and battery voltage declines. When battery SOC drops to a preset level, the loads are transferred to grid-supplied power. This cycle repeats every day.

Initial Test

The data logger was set to take battery voltage readings every 30 minutes. The sharp voltage increases (look just to the right of the vertical grid lines) show that AC voltage was applied to the charger. The vertical grid lines indicate midnight. Battery voltage stabilizes somewhat, and then sharply falls off when AC to the charter is removed. The batteries continue to power the load for awhile after that, resulting in a gradual decline of battery voltage. Then, the sun shines on the panels and battery voltage increases once again.

Except for the first day of the test, batteries were not fully charged. This is disturbing, since chronically undercharging batteries can shorten their life. For the duration of this test the load consisted of a refrigerator, a freezer, a TV, and a cable box. To correct the problem, I’ve reduced the load by removing the TV and cable box.

I initially set the timer to apply power to the charger for three hours each night. I determined that this was not enough, and increased the charger on-time to four hours.

The jagged lines on the graph are the result of devices switching on and off.

Conclusion

It looks as though I’ve managed to cut my use of utility-provided electricity just before the sun comes up, accomplishing my goal. But wildly fluctuating electric rates, and the inefficiencies of storing and retrieving utility-provided electricity, make it difficult to estimate any savings I might realize as a result of this plan. This has been an interesting experiment, but I don’t think I’ll continue it. I’ll be better off with a bigger battery bank, eliminating the need to use this timer/charger arrangement. Still, I can think of two benefits of this plan:

1. Batteries will tend to be kept at a higher SOC, extending their life.

2. This process is similar to the experience of those who actually live off-grid. Those who live off-grid usually have a secondary source of electricity, a generator perhaps. When lack of sunshine necessitates the use of the generator, using it for brief periods to charge batteries is the best strategy. In my case, I’ve substituted grid-supplied power for generator-derived power. Living off-grid is my ultimate goal, and this experience helps me learn more about that.

John

Off-Grid PV System Performance Data

2008-03-10T08:24:00.005-05:00

The graph shown below is the result of battery voltage readings taken every 30 minutes for 5 days and nights. Battery voltage increases during the day, even on cloudy days, as a result of charge current from the solar panels. Battery voltage decreases at night, due to the load. These voltage differences can be seen as hills and valleys on the graph. The first day was partly sunny, and battery voltage climbed to about 14 volts. The next two days were overcast, followed by two partly sunny days.

Listed below are the highest and lowest battery voltage readings for each of the 5 days. A reading in excess of 14 volts indicates that the batteries were fully charged that day. Fully recharging batteries everyday is the goal, but bad weather interfered with that. A failure to fully recharge the batteries on a regular basis can be considered chronic undercharging, and can damage the batteries.

Battery Voltage -- Day 1 - Day 2 - Day 3 - Day 4 - Day 5

Highest Voltage -- 14.05 - 12.80 - 13.30 - 14.40 - 14.15
Lowest Voltage --- 11.90 - 12.45 - 12.55 - 11.90 - 11.85

It’s interesting to note that on day 2 and 3, battery voltage did not reach the high voltage threshold. (See my previous two articles for more information about the system automation). As a result the relay did not energize, and the load was not applied to the batteries. The system automation worked well. In this case, it helped to prevent chronic under-charging. The load was applied only after the batteries were fully charged. This occurred on day 1, 3, and 5. Once the relay energizes, it does not deenergize until battery voltage dips below 12 volts. This is seen as three sharp dips on the graph.

It is also interesting to note that once the battery voltage dips below 12 volts, and the load is removed, battery voltage rises somewhat. This is a normal battery characteristic. Battery voltage then stabilized at about 12.5 volts, which means that the battery was about 80% charged at that time. Allowing the battery to discharge beyond that will shorten its life.

John

PV System Automation Test

2008-03-05T09:43:00.010-06:00

It was the best of times, it was the worst of times…

Those words from a Charles Dickens novel came to mind as I reviewed the data from my PV system automation test. The test was conducted during the last week in February, and sunlight on the solar panels was a rare occurrence here in Illinois. While it would have been great to see loads powered by the sun during the day, and batteries fully charged before sunset, that hasn’t happened much lately. The past few weeks have seen rain, snow, sleet, and mostly overcast skies. This was the worst of times for sunlight, resulting in the lowest PV system electricity production of the year.

Ironically, the bad weather makes this one of the best times to test the PV system. It is important to know how the system responds to these, the worst-case conditions. It will be equally important to see how the system responds to best-case conditions, a sunny summer day.

Without proper care, batteries can be ruined or weakened. The Charge Controller prevents over-charging, but does nothing to protect the batteries from over-discharging or chronic under-charging. The automation described here is an attempt to do just that. With the new automation, system loads are applied and removed depending on the battery state of charge (SOC). On a typical day, the sun shines on the panels and battery voltage rises as the batteries are charged. Once the battery voltage reaches a preset “high voltage threshold”, a relay closes. This relay connects the system to an electrical load, such as a refrigerator or freezer. The PV panels power the load, and can charge the batteries at the same time if the load is not too large. When the solar panels are unable to meet the demands of the load, at night for instance, the batteries must supply power to the load instead, causing battery voltage to decline. Once the battery voltage drops to match the “low voltage threshold” setting, the relay opens and the load is removed. Because the load is removed, the batteries do not discharge any further. To maximize battery longevity, the depth of discharge (DOD) should not exceed 20%. The automation described here amounts to little more than the low and high battery voltage threshold settings.

Using a data logger, battery voltage readings were taken every 30 minutes for several days. Battery voltage increases during the day, even on cloudy days, as a result of charge current from the solar panels. Battery voltage decreases at night, due to the loads. When charted, these voltage differences are seen as hills and valleys on the graph. For this test, a refrigerator and a freezer were used as the load. Since those devices have compressors that switch on and off at random times, the load was not constant throughout the duration of the test. When one or both of the compressors turn on, the heavy electrical load causes battery voltage to sag a little. This is followed by a voltage increase when one or both of the compressors turn off. The resulting voltage dips and peaks result in jagged lines on the graph.

Interpreting the data and making adjustments:

Data from the first set of tests suggests that battery damage could occur as a result of chronic undercharging. Although this was the result of a lack of sunshine, raising the high voltage threshold setting will help to ensure that the batteries are not chronically undercharged.

A high motor-starting current might result in a temporary voltage sag that can cause the relay to deenergize prematurely. Setting a high to low threshold delay will prevent this from occurring.

Although there was no evidence of false-triggering, a voltage spike could cause the relay to energize prematurely. This can be prevented by setting a low to high threshold delay.

It seems that the best strategy will be to apply different settings for summer and winter. Specifically, the high voltage threshold setting may be lowered in the summer, since more sunlight is expected. More sunlight will reduce the chance of chronic undercharging.

For now, the automation settings will be changed as indicated below:

Name and Purpose of Setting -- -- -- -- -- Present Setting -- New
H. Voltage Threshold - Energize relay --- 13.65 volts ----- 13.85 v
L. Voltage Threshold - Deenergize relay - 12.00 volts ----- 12.00 v
High to low threshold delay -- -- -- -- -- -- - Not set ------- 10 sec.
Low to high threshold delay -- -- -- -- -- -- - Not set ------- 2 sec.

This was the first of a series of tests that will be conducted throughout the year. I’ll continue to gather data and adjust the automation settings as necessary. Once I have sufficient data, I’ll list the setting changes I’ve deemed appropriate for the different seasons. Up to this point, the data I’ve gathered has been during a period of unusually bad weather.

It’s interesting to note that before automating the system, the average daily output was less than 0.5kwh. The system was capable of producing more, but I wasn't there to turn it on and off. Since I’ve automated the system I frequently get more than 1.2kwh from it. Unused energy from the sun is wasted energy, and I’m pleased with the results of this upgrade. I’ll post additional performance data as I get it. Check back later.

The settings described here are applied to the Morningstar Relay Driver, using MSView software. More information can be found on the Morningstar website: http://www.morningstarcorp.com

John

I've Automated my Off-Grid PV System

2008-02-25T15:27:00.010-06:00

Because over-discharging batteries can ruin them, I only connect loads to my photovoltaic (PV) system on weekends and evenings, and only when I’m home and awake so that I can carefully monitor battery voltage. I’ve been getting 10 to 12kwh of production out of my system each month, but knowing that it’s capable of producing 45kwh or more, I’ve been looking forward to this upgrade.

When the solar panels don’t provide enough power to satisfy the AC load, energy stored in the batteries is used instead. This will occur at night, of course, but also when it’s cloudy during the day. Under these conditions battery voltage will continue to decline, and eventually the inverter will stop working. My inverter stops functioning at about 11.6 volts. Allowing the voltage to dip that low can damage the batteries, and the risk is even greater if the batteries are not recharged quickly.

Shown below is a simplified diagram of my system before the upgrade.

This is my system after the upgrade.

I’ve programmed the voltage-controlled-switch to close a relay when battery voltage is above 13.75 volts. Closing the relay switches the DC to AC inverter on. The AC transfer switch is wired to use AC from the inverter as the default, only switching to grid-supplied AC when the inverter is switched off. The voltage-controlled-switch opens the relay when battery voltage drops to 11.95 volts. When the relay opens, the inverter is switched off and the AC transfer switch connects the load to grid-supplied AC. Once the load is removed, battery voltage will gradually rise. However, the voltage-controlled-switch will not close the relay until battery voltage once again reaches 13.75 volts.

I currently have a data logger connected to measure battery voltage. If I find that the battery does not fully recharge during the day, I’ll reprogram the voltage-controlled-switch. Likewise, I may need to reprogram the low-voltage threshold for better efficiency or battery protection. I’ll determine the appropriate settings after reviewing a few days worth of data logger readings.

Shown below is the complete system, with the new components.

The voltage-controlled-switch is the device at the top-left of the picture. It’s called a “Relay Driver”, and it can be programmed for four independent functions. It gets its information (battery voltage in this case), from the TriStar Charge Controller. Mounted just to the right of the relay driver is the automatic AC transfer switch. AC from the inverter, and AC from the power grid feed in to this device, and the selected AC source is applied to the AC outlet just below the transfer switch.

The off-white aluminum box mounted just below the relay driver contains the relay. For convenience, relay inputs and outputs are wired to the terminal blocks. A relay-override switch is mounted near the bottom of the relay box. To facilitate future expansion, I’ve installed two additional relays, and an LED (barely visible on the top of the box). I’ve wired one of the relays for AC. I have some expansion ideas that I’m kicking around, and I have some ideas to improve efficiency.

I’ll post additional details after I’ve had a chance to see how the system performs. Check back for an update.

John

Dealing with the Energy Crisis

2008-02-15T14:51:00.004-06:00

Alternative energy research tends to produce interesting, but useless information. Do you really care how much of the sun’s energy falls on one square meter of land on any given day? Do you benefit by knowing how much electricity is needed to power Chicago? David MacKay, University of Cambridge Physics Professor, is one source of information of this nature. For the most part it’s interesting, but not really helpful. David did get my attention with a couple of statements: “…the people of the developed world are living immorally, and a huge crisis is upon us, unless we change our lifestyle.” I don’t know if we’re living immorally, but it’s hard to deny that an energy crisis exists, and that it’s getting worse.

How did we get into this mess?

Most of the electricity produced in the United States comes from coal-fired power plants. Since coal has always been plentiful and inexpensive, electric rates have been reasonable. Most people spend less than 2% of their household income on electricity, and as a result of its low cost, we tend to waste a lot of it. We use electric doorbells when we could be using mechanical ones. We have electric can openers, hand-lotion warmers, air-fresheners, and many other unnecessary items. In addition to the wasteful items we use by choice, many wasteful items are forced upon us because of a lack of availability of energy-efficient alternatives. Many of our electrical devices use energy even when they’re turned off. These are known as “phantom loads”, and they’re more wasteful than most people realize. Because a device appears to be off, we’re not always aware that it is wasting energy.

How do we correct the problem?

Because our lifestyle includes so many wasteful gadgets, there are many corrective actions we can take. Begin with an energy audit of your home. You’re likely to find some no-cost energy-saving measures you can take that will not adversely affect the quality of your life. Do you really need that plug-in air freshener or hand-lotion warmer? You probably already have surge protectors on your TV’s and stereo equipment. If you use the switch on the surge protector, instead of the remote-control unit for on/off control of your TV, you’ll eliminate a phantom load. Check all of your AC outlets, and remove all unused wall-warts (transformers).

Next, you might want to spend a few dollars on things that will end up costing you nothing by virtue of the savings you’ll see on your electric bill. Replacing incandescent light bulbs with compact fluorescent bulbs is a good example. And why not replace your clock-radio with a wind-up alarm clock? Having done those things, it’s time to move on to larger items. Maybe it’s time to replace that old refrigerator with an energy-star-rated model. You might cut $20.00 per month off of your electric bill if you do. And isn’t it time to replace that big old TV in the den with a new 42” plasma model? In doing so you might go from 300-Watts to 100-Watts. You’ll get three hours of TV viewing for the price of one hour. The savings really add up at the end of the month.

After doing all of those things, you might consider geothermal heating and cooling, and solar hot water heating. I use a corn-burning stove to supplement my natural gas heating. Burning corn is a little more work, but it reduces my heating bill significantly. Check with a reliable contractor to see if any of these strategies will benefit you.

How much are you willing to sacrifice?

Once you’ve done all you can to reduce consumption, and perhaps made energy-efficiency improvements to your home, you then need to decide just how far you’re willing to cut back. It’s easy to say “I’ll turn my thermostat down” when the weather is mild, but will you really do it when you’re shivering in the coldest winter months? Will you also cut back significantly on air-conditioning? Be honest with yourself. If it seems like too much of a sacrifice, remind yourself of the negative effects of excessive energy consumption. Cutting back benefits you, your children, and the entire planet.

It’s unlikely that you’ll be able to make all of these changes at once. Do some research and come up with a game plan, and a consumption rate to shoot for. Check the energy-star tags on appliances you intend to buy. Look at your electric bill. If you’re currently averaging 900kwh of electricity per month, that’s a lot. Try to cut it in half. If you’re using 500kwh of electricity per month, try to cut it by at least 25%.

As you work on your plan you’re likely to discover energy-saving lifestyle changes that actually enhance the quality of your life instead of detracting from it. I’ve found it much more pleasant to turn my thermostat down and use an electric blanket in a cool bedroom. An inexpensive Kill-A-Watt meter helps me determine how much I’m saving.

Beyond conservation

After you’ve reduced consumption, the cost of a solar photovoltaic, wind, or a hybrid electric system won’t be so daunting. If you’re not ready to disconnect from the grid entirely, you can install a small system that meets a portion of your needs. If you choose to start small, employ a strategy that helps you get the most out of your system. Solar equipment that is unused, or underused, is counterproductive. Everything you’ll need to automate your system for maximum efficiency is available, and at a reasonable cost.

Expensive gasoline – The other part of the energy crisis

Having a solar electric system in place not only contributes to your independence from the power company, it’s the first step toward gasoline independence. Plug-in-hybrid-electric-vehicles (PHEV’s) will start to show up in dealer showrooms in the year 2010. By charging your car with power from your photovoltaic system, you’ll be driving on free power from the sun instead of expensive gasoline. It’s going to take a substantial system to do the charging, so now would be a good time to get started.

Renewables – No War Required

By purchasing less oil from Middle Eastern countries we not only reduce the amount of money that they have available for war, we eliminate our need to be there in the first place. Since the politicians won’t stop it, it’s up to each of us to lead the way.

When the people lead, leaders follow. Let’s roll!

John

Electricity Use - Survey Results

2008-02-08T08:49:00.000-06:00

Good Job!

Looking over the electricity use survey, it’s good to see that so many of us are at the low-end of the scale. While we Americans are often criticized for over-consumption, it’s obvious that many of us don’t deserve it. For the most part it’s our leadership that has failed, not the American people. President Bush’s message “America is addicted to oil” strikes me as a shameful attempt to shift the blame from his inept and corrupt administration to the American people. We should expect our government to recognize problems and provide better solutions, but clearly they’ve let us down. Too much federal money supports oil and coal interests, while little goes to renewable energy projects. I’m tired of politicians who claim to care, but don’t act as if they do.

Your Accomplishment

Your efforts to conserve electricity, and your interest in renewable energy technologies, show that you care. Because of your efforts, the world is less polluted, and what remains of the earth’s fossil fuels will last a little longer. People may notice your PV panels, or your windmill, but they probably don’t give much thought to how much your efforts contribute to the quality of their lives.

Your Reward

The decline of fossil fuels will lead to electricity shortages, which will lead to laws restricting the use of electricity. Energy use restrictions will not apply to those who generate their own. Instead of a shortage, you’re likely to have a surplus of electricity from time to time. If you’re feeding that back into the grid, you’ll be compensated financially. If not, you can use that electricity in any way you wish, and think of it as “guilt-free” electricity.

Why we’re Ignored

We use bio-fueled stoves, windmills, PV panels, solar hot water heaters, and a number of other environmentally friendly systems. We talk about our projects with those doing similar things, but seldom with others. Mostly, we’re just ignored. Some are reluctant to discuss renewable energy because they don’t understand the technology, but others shy away from the topic out of feelings of guilt. After all, they see you and I doing much more than they are doing.

Promoting Renewable Energy

While it might be tempting to flaunt a “greener-than-thou” attitude, it’s important to know that successful movements are not powered by guilt, they’re the result of confidence and passion. Be patient, and nonjudgmental, but don’t expect to convert everyone you see. There will always be those who don’t care about anyone or anything but their own selfish interests, and there will always be those who have discretionary income but no discretion.

Conclusion

Pat yourself on the back, enjoy some guilt-free consumption, and get back to work! The world needs you, and is better off because of you.

sj

Off Grid Solar PV - Measuring Progress

2008-02-01T09:49:00.000-06:00

In a speech at the World Future Energy Summit recently, Department of Energy Secretary Samuel Bodman told the audience “the biggest source of immediately available “new” energy is the energy that we waste every day.” Those words reminded me of my own conservation efforts. My habit of turning off lights and resetting thermostats can almost be called obsessive-compulsive behavior. But my past efforts have not been particularly satisfying because I’ve never measured progress. Because of that, I had no real sense of accomplishment.

To generate interest, I’ve decided to track my electricity use over time. I was able to get records of my electricity use for the past two years from my utility company’s website. I entered that information in a spreadsheet, and could immediately see that past efforts have been worthwhile. My use of electricity was significantly lower in 2007 than it was in 2006, with the greatest reductions being in the most recent months. This was expected, since I’ve recently replaced a refrigerator and a TV with energy-star-rated models. Here is the data for November:

My electricity use in November of 2006 was 747kwh.
My electricity use in November of 2007 was 562kwh.

The 185kwh difference was a huge reduction, and perhaps somewhat of an anomaly. The October 2006 to October 2007 difference was only 22kwh. Still, I’m quite pleased with my overall progress. As my use of utility-provided electricity is going down, my use of solar- (PV)-provided electricity is increasing.

My current average monthly use of PV-generated electricity is about 12kwh. I’ll soon be applying a system upgrade, and expect my average monthly use of PV-generated electricity to be about 45kwh.

If I can continue to use less electricity, and generate more of electricity I use, I’ll eventually be able to meet all of my needs with solar panels. And while my figures seem to show that the date is many years in the future, it may be sooner than expected. In the not-to-distant future my wife and I will become empty-nesters. When the kids leave, electricity use will go way down. Unused rooms will be closed off, and we’ll seldom need to use lights or appliances in those rooms. Our laundry and dishwashing loads will decline. At the same time we’ll continue to replace worn-out appliances with energy-efficient ones. We’ll replace more of our lights with CFL’s, or perhaps with LED lighting.

I look forward to the day when I can finally flip the utility breakers off, and still live comfortably with energy from the sun. Last Sunday I used surplus PV-generated electricity to make toast. My batteries were fully charged at the time, so this was an opportunity to take advantage of solar energy that otherwise would have been wasted. I’ll be watching for more opportunities like this in the future. Energy Secretary Bodman would be pleased if he knew about my efforts, but more importantly, I feel good about what I’m doing.

Sunday Morning Toast - Courtesy of the Sun

Please take the time to answer the survey question; “How much electricity do you use each month?” Provide a monthly average if you can. Look for a line on your electric bill that states “total usage in killawatt hours (kwh).” Keep the information you’ve collected so that you’ll be able to measure progress as you take steps to reduce consumption.

John

Photovoltaic Systems and Politics

2008-01-28T09:27:00.000-06:00

Each of us has his/her own reason for implementing a solar photovoltaic (PV) system. A solar PV system is a practical solution for those not served by a utility company. Some of us implement alternative electric systems because we want to cut our electric bill, or because we like the idea of “green” living. Many of us implement small PV systems because we expect weather-related power outages, or because of an unreliable electric service provider.

Whatever your reason for using alternative energy, you’ve chosen to invest your time and money in a responsible way. As the 2008 election approaches, this would be a good time to consider which of the candidates would be the best choice for those of us who choose to act in such a responsible manner. Maybe the following stories will help you decide:

Ant & the Grasshopper

Two Different Versions! Two different Morals!

OLD VERSION: The ant works hard in the withering heat all summer long, building his house and laying up supplies for the winter.

The grasshopper thinks the ant is a fool and laughs and dances and plays the summer away. Come winter, the ant is warm and well fed.

The grasshopper has no food or shelter, so he dies out in the cold.

MORAL OF THE STORY: Be responsible for yourself!

-------------------------------------------

MODERN VERSION:

The ant works hard in the withering heat all summer long, building his
house and laying up supplies for the winter.

The grasshopper thinks the ant is a fool and laughs and dances and plays the summer away.

Come winter, the shivering grasshopper calls a press conference and demands
to know why the ant should be allowed to be warm and well fed while others are cold and starving.

CBS, NBC, PBS, CNN, and ABC show up to provide pictures of the shivering grasshopper next to a video of the ant in his comfortable home with a table
filled with food. America is stunned by the sharp contrast.

How can this be, that in a country of such wealth, this poor grasshopper is allowed to suffer so ?

Kermit the Frog appears on Oprah with the grasshopper, and everybody cries when they sing, 'It's Not Easy Being green.'

Jesse Jackson stages a demonstration in front of the ant's house where the news stations film the group singing, 'We shall overcome.' Jesse then has the group kneel down to pray to God for the grasshopper's sake.

Nancy Pelosi & John Kerry exclaim in an interview with Larry King that the ant has gotten rich off the back of the grasshopper, and both call for an immediate tax hike on the ant to make him pay his fair share.

Finally, the EEOC drafts the Economic Equity & Anti-Grasshopper Act retroactive to the beginning of the summer.

The ant is fined for failing to hire a proportionate number of green bugs and, having nothing left to pay his retroactive taxes, his home is confiscated by the government.

Hillary gets her old law firm to represent the grasshopper in a defamation suit against the ant, and the case is tried before a panel of federal judges that Bill Clinton appointed from a list of single-parent welfare recipients.

The ant loses the case.

The story ends as we see the grasshopper finishing up the last bits of the ant's food while the government house he is in, which just happens to be
the ant's old house, crumbles around him because he doesn't maintain it.

The ant has disappeared in the snow.

The grasshopper is found dead in a drug related incident and the house, now abandoned, is taken over by a gang of spiders who terrorize the once
peaceful neighborhood.

MORAL OF THE STORY: Be careful how you vote in 2008

- - Thanks JA for this story. sj

Load Switcher Project Update

2008-01-24T14:04:00.000-06:00

My goal is to get as much as I can from my solar photovoltaic system, and at the same time protect my batteries from over-discharging. I want to be able to use battery power as much as possible, and only switch to grid-supplied AC when battery state of charge (SOC) has declined to a preset value. The first step, the installation of a “Transfer Switch”, has already been done. Next, I’ll need a way to switch my inverter on and off, depending upon the battery state of charge (SOC) at any given time. When the inverter is switched on, the load is powered by the batteries. When the inverter is switched off, the transfer switch automatically connects the load to grid-supplied AC power instead.

I’ve considered three ways to accomplish the task, and thought about the pro’s and con’s of each:

1. A simple circuit that allows precise control of low and high voltage threshold settings to open and close a relay.

A considerable amount of time is needed for development and testing. Cost is also an issue. While the finished product may do the job, it may not be as efficient as a commercially available product that can perform the same function. This device will not be easily expandable.

2. A microprocessor-based controller that can easily be reprogrammed to open and close a relay based on battery voltage.

Hardware and software development time will be tremendous, unless I go with a commercially available product, but that will be expensive. However, the result will be a product that performs a simple task at first, but can be easily expanded to include many more functions. A real-time-clock can be included, greatly enhancing control, monitoring, and logging functionality.

3. A commercially available product that can be programmed or configured to connect and disconnect the load based on battery voltage.

The one-time cost will be significant, but the system will be up and running in a short time. Expansion capabilities are considerable, but do not include a real-time-clock (RTC). An RTC would be useful because I will want to take advantage of low night time electric rates to run a battery charger.

I’ve already built a simple device, but it’s going to take more time to get it working as well as I would like. Meanwhile, I’m not making the most of the available energy from the sun right now. Building a microprocessor-based device would take even longer. I want to get things going fairly quickly, and the time I have available for this project is limited. With these things in mind, I’ve decided to go with option number 3. Specifically, I’m considering the Morningstar Relay Driver and MSView software.

Calling the Morningstar product a “Relay Driver” is, in my opinion, a big mistake, and perhaps the reason I overlooked this option earlier. The name implies that its function is simply to turn on and off one or more relays, based on external signals. In reality, it does much more than that. Using the MSView software, the device can be programmed to perform a variety of functions. Most importantly to me, it can control a relay based on high and low battery voltage setpoints. I’ll use that relay to turn my inverter on when batteries are at a high SOC, and switch it off when battery voltage is low, with the transfer switch selecting the appropriate source of AC for the loads. I’ll use just one relay at first, but will add functionality later. The Morningstar Relay Driver can control up to four relays.

Once I get load control set up and tested, I probably want to control a battery charger. I’ll use the Morningstar Relay Driver to close a relay based on battery voltage, and I’ll use a timer to only allow the charger to be powered-up when electric rates are low.

Shown below is my simple circuit in the testing phase. I’ll soon be abandoning this project in favor of the Morningstar Relay Driver.

John

The Need for Automatic Control in Off-Grid Solar PV Systems

2008-01-18T12:55:00.000-06:00

To get as much as I can from my off-grid system I manually connect loads to it, watch as battery voltage declines, and remove the loads before the battery voltage falls to an unacceptably low level. Since I’m not always home, and because I’m not always monitoring voltage while I am at home, I often fail to use the available energy efficiently. I also run the risk of over-discharging the batteries, possibly causing irreversible damage to them. I’ve outlined a plan to automate my system previously, and I’ve made significant progress toward implementing that plan. It’s an ambitious project, but well worth the effort. Read on for additional justification, and a progress report.

I now have a Transfer Switch installed and functioning. When I turn on the inverter, loads attached to the circuit are powered by it. When I switch off the inverter, the loads are automatically switched to grid-supplied power instead. I’m using my refrigerator and a chest freezer as the test loads. Installing the Transfer Switch was “Step 1” of my plan. Automating the switching on and off of the inverter based on battery voltage is the next step.

Recently, I switched on the inverter with the loads attached in the afternoon as I often do. I monitored the battery voltage at regular intervals, intending to switch off the inverter before bedtime. Unfortunately, I fell asleep without switching the inverter off. I woke up at 4:00am to find that my refrigerator and freezer had no power. This wasn’t supposed to happen; the Transfer Switch was supposed to connect the loads to grid-supplied AC if the inverter stopped functioning. I found that battery voltage had dropped to 11.7 volts. The Transfer Switch was “chattering”. Analyzing the situation, this is what I determined: When battery voltage dropped to a point where the inverter could no longer function, the Transfer Switch disconnected the load, connecting it instead to the grid. With no load on the batteries, battery voltage quickly increased to the point where the inverter could once again function. This, in turn, caused the Transfer Switch to reconnect the inverter to the load. This cycle kept repeating at a rapid pace, which resulted in the Transfer Switch chatter. Eventually the breaker for the grid-supplied AC tripped. The tripped breaker didn’t stop the cycle, it just prevented grid-supplied AC from getting to the load. I had to manually intervene by turning off the inverter and resetting the breaker.

The incident described above demonstrates an interesting battery characteristic. When a load is applied, voltage drops. When the load is removed, battery voltage increases, even when the battery is deeply discharged. It is for this reason that I decided to use low and high set-points in my control circuit. And to facilitate differences in battery bank sizes and type of batteries, I’ve decided to make those set-points adjustable. I’ll make them adjustable to one-hundredth of a volt, which is much better control than some commercially available equipment provides. Once batteries are disconnected, they will not reconnect until they’re once again fully charged. After I’ve determined the appropriate settings, I should not experience a problem like the one I experienced recently.

I’ll get many of the parts needed for the project tomorrow (Saturday), and will hopefully have a portion of the circuit built and tested by the end of this weekend. Check in on me later for a progress report.

John

My Solar Electric System and New Year's Resolution

2008-01-01T12:01:00.000-06:00

Plans for my off-grid photovoltaic (PV) system have been pretty much the same for the past two years; enlarge the system and use more of the available power. I’ll continue to do both of these things in 2008, but I’ll also make a major change in the way I use energy from the system. In the past I’ve carefully monitored battery voltage and manually switched loads on and off. By doing this manually I not only miss opportunities to use energy from the sun, I risk damaging the batteries by over discharging them. To resolve these problems, and to relieve myself of the chore of manually switching between power sources, I plan to automate this task.

I’ll automate the switching on and off of loads using ideas from a recent post, “Getting the Most from an Off-grid System”. I’ve decided to use a transfer switch, and a circuit of my own design, to accomplish this task. Refer to the drawing below:

How it works:

The Transfer Switch is configured to use power from the inverter as the primary source of AC power for the load, only switching to grid-supplied AC power when the inverter is switched off. The inverter will be automatically switched on when the battery state of charge (SOC) is high, and switched off when the battery SOC has dropped to a predetermined value.

Thumbwheel switches, precision resistors, and a regulated reference voltage allow precise settings of the “Low Voltage Threshold” and the “High Voltage Threshold”. The thumbwheel switches and resistors create two voltage dividers. The output of the low voltage threshold voltage divider is equal to the low voltage threshold thumbwheel setting, and the output from the high voltage threshold divider is equal to the high voltage threshold thumbwheel setting. These two reference voltages are fed into two comparators.

When the battery voltage falls below the “Low Voltage Threshold” setting, comparator 1 changes state, triggering the Flip Flop, and the inverter is turned off. The Transfer Switch senses the loss of AC voltage from the inverter and switches the load to grid-supplied AC power.

When the battery voltage rises above the “High Voltage Threshold” setting, comparator 2 changes state, resetting the Flip Flop, and the inverter is switched on. The Transfer Switch senses the AC voltage from the inverter, and connects the load to the inverter.

Initially, I’ll set the low voltage threshold voltage to 12.25 volts. That voltage represents an approximate 75% state of charge (SOC). I’ll set the high voltage threshold at 14.75 volts, ensuring that the batteries are fully charged before allowing them to power the load.

It’s interesting to note that the battery voltage will not reach the high voltage threshold setting unless the sun is shining and the batteries have been fully charged. I’ll experiment with other settings in an attempt to improve system efficiency without endangering the batteries.

Benefits:

Since I’m not able to constantly monitor battery voltage, I’ve missed opportunities to use as much of the free power that my solar electric system is capable of providing. Instead, I disconnect the load when I think that the battery SOC may fall below 80%. Once I’ve implemented this plan, I’ll be able to use more of the available power from the system without the fear of damaging the batteries. Additionally, this automation will help to keep the batteries at a high enough SOC to ensure the availability of power in the event of a grid power failure.

With a Twist:

Because of a utility company plan that results in low rates at night, I’m thinking about storing energy in a larger battery bank at night when rates are low, and using that energy to power loads during the day when utility rates are high. And because my PV array is still small, I’m thinking about using a battery charger to supplement the charging that now comes from my PV array. The charger will be turned on via a timer in the early morning hours when rates are lowest, and turned off later in the morning before rates go up. When cloudy conditions limit the amount of charging my PV panels are able to provide, the battery charger will take up the slack and the batteries should be fully charged each morning. Confident that I’ll have plenty of stored energy in the morning, I’ll add more to the daytime battery load, and therefore save money on my electric bill.

With the charger switched on during the early morning hours, it’s likely that the batteries will quickly become fully charged. When that happens, the inverter will once again be used to power the load. Because the charger is still connected, and switched on via the timer, it too will provide power to the load. However, this will occur in the early morning hours when electric rates are low, and I’ll be taking advantage of the lowest rates, cutting my electric bill.

The graph below shows the expected results over a 24 hour period. As a result of charging from the PV panels during the day, and charging from the battery charger at night, the load will be powered by the batteries most of the time.

John

Getting the Most from a Small Off-Grid PV System

2007-12-21T09:06:00.000-06:00

Although my off-grid system is small, I’m proud to say that by using it I’m reducing the amount of CO2 that would otherwise be released into the atmosphere and I’m reducing my electric bill. However, it’s a challenge to use as much solar-generated energy as possible, while still being gentle to the batteries. Allowing too much power to be sucked out of the batteries each night will shorten their life. On the other hand, I don’t want to under-use the system by not using enough of the available energy each day. Unused energy is wasted energy. The purpose of this article is to explore strategies for getting the most from a small off-grid PV system.

Strategy #1

A 100-watt solar panel might produce 500-watt/hours of electricity on a sunny day. But, due to system inefficiencies, it’s likely that only about 300-watt/hours of energy will make it to the load. Using solar-generated energy during peak sunlight hours is one way to improve efficiency. When power from the solar panels goes straight to the inverter, overall efficiency is much greater, since the losses associated with storing and retrieving electrical energy in batteries are eliminated.

The AC load can be plugged into the PV system’s inverter during the day and then to grid-supplied power at night, or switched automatically via a timer as illustrated below. A refrigerator or freezer is an ideal load for this scenario, since the amount of electricity required is about the same from day-to-day. The timer can be adjusted to match the power generated by the PV system to the power required by the load.

Strategy #2

A no-cost way to squeeze every available electron from an off-grid system is to constantly monitor battery voltage, disconnecting the load when the battery falls to a certain level, and reconnecting it when the battery is once again fully charged. Obviously, monitoring the system 24 hours a day is not practical. However, most DC to AC inverters include a low-battery “alarm” feature. The alarm sounds when the battery voltage drops below a certain level, eliminating the need for constant monitoring. Still, listening for an alarm is only a modest improvement over constant monitoring. No one wants to respond to an alarm in the middle of the night. Another drawback of this strategy is that the low-voltage alarm level is usually not adjustable. Typically, the alarm threshold voltage is about 10.6 volts (for a 12-volt inverter), which, depending upon battery type, translates to about a 75% depth of discharge. Most inverters will shut-down when battery voltage falls a little below the alarm threshold. While this strategy will work to a certain extent, you shouldn’t allow your battery state of charge (SOC) to fall that low. Allowing battery voltage to drop to those depths on a frequent basis will shorten the life of the battery. This strategy is not recommended on a day-to-day basis, but could be used in emergency situations, such as a grid power failure.

Strategy #3

To automate the process of disconnecting and reconnecting the load based on battery voltage, a charge controller with built-in low voltage disconnect (LVD) capabilities can be used. An LVD-capable charge controller is a great strategy for unattended systems, such as a weekend cottage. If a load is accidentally left on, the battery will be protected.

Although this is a good solution for applications where power to the load flows through the charge controller, it is not viable in systems where power to the load does not. The input current of an inverter is usually higher that the charge controller can handle, making it necessary to connect the inverter directly to the battery.

The diagram below shows typical wiring for a small, off-grid, PV system. Notice that the inverter is connected directly to the battery, and therefore will not be shut down when the Charge Controller’s low voltage disconnect kicks in. Only the DC output from the Charge Controller will be shut down in this scenario. Battery voltage will continue to decline (because of the AC load), even after the Low Voltage Disconnect kicks in. At some point the inverter will stop functioning. This is not a good strategy unless you’re only using the DC output of the Charge Controller to power a load, or unless you’re carefully monitoring the battery voltage while powering an AC load.

Strategy #4

Some Charge Controllers can be configured as “Load Controllers”, providing another strategy for getting the most from a small system. A Load Controller does not replace a Charge Controller, it is an add-on to the system. An advantage of using a Load Controller is that disconnect and reconnect thresholds can be precisely set. Settings are determined by the type of batteries, and by the size of the load. When properly set, the disconnect set-point prevents the battery from discharging too much, and the reconnect set-point value is high enough to ensure that the battery is not damaged by chronic undercharging. In other words, the disconnect and reconnect settings are optimized. The extra hardware does, of course, add considerable cost to the system.

Shown below is a typical application of a Load Controller. In the example, the Load Controller uses the batteries as the primary source of energy, but switches to a secondary source of energy when the batteries are depleted to a preset level. Once the batteries are recharged, they are again used to power the load. The beauty of this system is that it uses as much “free” energy from the sun as is available, only using a more costly source of energy when necessary.

Strategy #5

Those with electronics skills may consider the solution outlined below. This diagram represents a simple circuit that can replace the “Load Controller” and relay in the diagram above. Disconnect and reconnect voltage levels are set via two potentiometers. The potentiometers could be replaced by thumbwheel switches and precision resistors, providing better control of the threshold voltages. Notice that the relay wiring doesn’t allow AC from the inverter and AC from the power grid to be applied to the load simultaneously. Allowing that to happen would probably result in damage to the inverter.

Strategy #6

The battery-protecting switchover functions described above are also available in equipment designed for larger systems, but that equipment may not be appropriate for small systems. In addition to the high cost, this equipment typically uses more power for its operation than equipment designed for smaller systems. While this power drain may not be significant for a large system, it represents a significant percentage of the overall energy production of a small system.

Conclusion

In compiling this information it has been my intention to demonstrate optimization while holding down the cost. You may benefit from using one or more of the strategies outlined here. I welcome other suggestions for accomplishing the task.

John

Driving a PHEV is Like Buying Gasoline at 20 Cents a Gallon

2007-12-14T08:48:00.000-06:00

While you might think a Plug-in-Hybrid-Electric-Vehicle (PHEV) is simply an ordinary hybrid with a plug added for charging, there is another significant difference between the two. Typical hybrid cars on the road today have a gasoline motor and an electric motor, and either of them can be used to drive the wheels. On the other hand, power to the wheels on the new breed of PHEV’s will come ONLY from the electric motor. The gasoline motor is used to recharge batteries. This design is inherently more fuel-efficient, since the gasoline motor will run at a constant speed. It’s called a “series” hybrid, and the Chevrolet Volt is an example. The plug-in Volt is expected to be available in 2010. It will have a 16kwh lithium-ion battery that will take 6 to 6 ½ hours to charge, and a fully-charged battery can propel the car for the first 40 miles. The gasoline motor kicks-in after that, extending the range of the car. For those who drive less than 40 miles per day, which is most of us, the car will use no gasoline at all.

Based on that information, it’s easy to calculate operating expenses. Assuming that electricity costs ten cents per kwh, the cost to charge the battery should not exceed $1.60, which is ten cents per kwh times 16kwh. In reality, the battery will not be fully drained, and therefore the actual cost will be less than that. But for no more than $1.60 worth of electricity, the car will go 40 miles. It takes $3.00 to $6.00 worth of gasoline to go that far in a typical gasoline-powered car!

Nighttime electric rates are much less than daytime rates in many locations, and I’ve signed up for a plan that gives me rates as low as two cents per kwh in the early morning hours. My rate will change from day to day and hour to hour, but if it averages less than four cents per kwh at night, I’ll be able to charge my Volt for as little as twenty six cents. Needless to say, I can hardly wait to own one. When compared to a car that gets 30 mpg, this is equivalent to gasoline at 20 cents per gallon for the first 40 miles of driving each day!

In reality, state and federal legislators will soon realize that I’m not paying my fair share of road use taxes, and somehow I’ll be forced to make up the difference, but I’ll certainly have some unbelievably inexpensive transportation in the mean time.

Here’s the info from Chevy: http://www.chevrolet.com/pop/electriccar/2007/process_en.jsp

John

Renewable Energy Survey Results

2007-12-10T10:13:00.000-06:00

Money saved by using energy-efficient appliances is often used to buy additional appliances and vehicles, resulting in an even greater use of energy. Respondents to my survey overwhelmingly said that the solution to this problem is generous rebates and incentives for the purchase of hybrid cars and renewable energy systems. And, of the choices listed in the survey, I agree that this was the best one. Some respondents selected “Other”, suggesting that they have even better ideas. I hope those folks will submit comments to this post, telling us what those ideas are. It seems that almost no one wants laws or penalties, but some of us favor higher taxes for those who consume the most.

Tax incentives are great, but that choice is in the hands of politicians. Rebates will help to sell more energy-efficient cars, but that decision is in the hands of auto makers. There’s an even better solution than those listed; each of us can lead by example. And while only a few of us are ready to install windmills or solar panels, every one of us can contribute in some way. The important thing is to just do something. If you do, someone will notice. If millions of people will install just one compact fluorescent bulb, the benefit to the planet will be tremendous. The best solution is for each us to lead by example.

When the people lead, leaders follow

Hopefully we’ll all do more than to just replace light bulbs. When appliances wear out, replace them with energy-efficient ones. Don’t wait for legislation, and don’t wait for your neighbor to lead the way. Start a movement to save the planet and to preserve natural resources for future generations. Global warming, air and water pollution, and peak oil are all problems that won’t go away without action. Don’t wait for solutions, create them. It’s a good feeling to do the right thing.

Once you’ve made a commitment to do your part, you might begin with an energy audit. You can call a professional, but that’s usually not necessary. You probably already know what needs to be done in your own home. If your list is long, attend to the easiest and less costly improvements first, or as Ed Begley Jr. puts it, the “low hanging fruit.”

John

Power Smart Pricing from Ameren

2007-12-04T08:58:00.000-06:00

My electric utility company now has a real-time pricing program and I’ve enrolled. Instead of a paying a flat rate for electricity, my rate will vary by the hour depending upon demand at the time. I'll minimize my electricity use during peak demand times. Tasks like washing and drying clothes can be done late at night when rates are low.

My current electric bill is hard to understand, but from a recent one this is what I’ve been able to determine:

I am charged 0.072 per kwh of electricity of electricity I use.

With taxes, customer charge, distribution charge, and other miscellaneous charges and credits, I am actually paying 0.1016 per kwh.

Based on program information from the utility’s website, I’ll be paying as little as 0.015 per kwh when demand is low, or as much as 0.15 per kwh when demand is high. In addition to the rate information available to me over the Internet, I’ll be alerted when rates are expected to exceed 0.13 per kwh.

A new electric meter was installed on December 3rd, allowing my electricity use to be monitored by time-of-day.

To get the most from this program I’ll run as many daytime loads as possible off of my solar photovoltaic (PV) system. To the extent that my small system can keep up, I’ll run my refrigerator and chest freezer off of it. At night, when rates are low, I’ll run them off of grid-supplied power. Fortunately, the PV system operates most efficiently during the day because energy goes straight to the load, instead of being stored in and retrieved from batteries. As I add solar panels to my existing array, I’ll add electrical items to the daytime load when utility rates are highest.

Perhaps the easiest way to switch between the grid and solar is by way of a simple timer and relay as illustrated below:

The circuit above will work, but for safety and NEC code compliance a transfer switch should be used. The inverter can be switched on and off via a timer as shown below:

The transfer switch can be wired so that it selects the inverter when AC is present, and switches to grid-supplied power when necessary. The timer can be programmed to switch the inverter on during the day, and off at night.

With nightly electricity rates below 0.035 per kwh, I’ll have to reevaluate my Plug-In-Electric-Vehicle (PHEV) recharging strategy. It no longer seems practical to purchase extra solar panels for this. I’ll buy extra panels for the daytime loads instead.

I might also benefit from this plan by using the grid to charge batteries. I'll charge batteries at night when rates are low, and use the stored energy to power household loads during the day when rates are high. I suspect that the losses associated with storing and retrieving energy will be more than offset by the low nighttime electric rates.

As I gain experience, I suspect that I’ll discover other ways to get the most from this plan. I welcome suggestions and comments from others.

For more information about the plan I’ve signed up for, click here: http://www.powersmartpricing.org/

John

Renewable Energy Project Progress Report

2007-11-27T09:37:00.000-06:00

It was approximately on today’s date, two years ago, that I first decided to install solar panels on my roof. This plan evolved into an effort to become more self-sufficient, and then to a mission to eliminate my use of fossil fuels altogether. And although I have a long way to go, I’ve made significant progress toward my goals. The following paragraphs outline my progress:

PV System Upgrades:

As finances allow, I continue to expand my PV system. I now have 4 solar panels on my roof, 420ah of battery capacity, a 60-amp charge controller, and an 1100-watt pure sinewave inverter.

Using the PV System on a Daily Basis:

The PV system is now used to power a chest freezer on a daily basis. The resulting reduction of my grid-supplied energy use eases the load on a coal-fired power plant, reduces my electric bill, and is consistent with my goals to use less fossil fuel and to become more self-sufficient. As I continue to enlarge the PV system, I’ll add additional appliances to the solar-powered load.

The Corn-burning Stove:

I installed and began using a corn-burning stove in 2006. By using the stove I’ve greatly reduced my use of natural gas, cutting my home heating cost at the same time. The money I save on my heating bill is used to help pay for PV system upgrades.

Energy-saving Lights:

I’ve replaced nearly all of the incandescent light bulbs in my home with energy-saving compact fluorescent ones. Having done that, I noticed a reduction of my electric bill.

Home Improvements:

I’ve added insulation and replaced old windows with energy-efficient ones.

Appliances:

I’ve replaced my old refrigerator with an energy-star-rated one. Although my new refrigerator is larger, it uses about 65% less energy than the old one. I've also replaced two televisions with energy-star-rated TV's.

Growing Food and Fuel:

I've significantly enlarged the size of my garden over the past two years, and preserve more of what I grow. I have successfully grown tomatoes indoors, and I've grown a small amount of corn that can be used as fuel in my stove.

My Blog:

I include my blog as an accomplishment for several reasons. I hope to inspire others to do similar work. When they do, everyone benefits. Not only do readers comments show that I’ve helped others, they are also my opportunity to learn from them.

Conclusion:

I’ve made significant progress toward my mission over the past two years, and I now have a good emergency power system as a bonus. When grid-power fails, I have electricity and can generate heat if necessary. I’ve investigated electric vehicle technology, and am preparing to purchase a PHEV when they become available. My work and my research will become even more relevant as gasoline prices continue to climb.

John

I Burn Corn to Heat My Home

2007-11-16T09:52:00.000-06:00

If you visit this blog frequently you know that I supplement my home heat by burning corn. The corn-burning stove is part of an overall strategy to reduce my use of fossil fuels, and to become more self-sufficient. The stove uses electricity for the blowers and an auger motor, and my photovoltaic (PV) system supplies that energy if the grid is down. My stove must be lit manually, and will not relight itself if the fire goes out. While this is somewhat of an inconvenience, it also keeps the power requirements of the stove low, making it possible to get by with fewer solar panels and batteries. And although the stove doesn’t have a thermostat, it does have individual controls for the corn feed rate and for the room air blower motor. When properly set, these controls help to maintain a comfortable indoor temperature regardless of the outside temperature.

I buy shelled corn in 50-pound bags, and use the stove when the outside temperature drops into the 30’s. I usually start the stove in the evening and stop using it mid-day as the outside temperature rises. This is my second season with the stove. Here are some details from last winter:

I purchased (and burned) 2 ½ tons of corn.
My natural gas bill for the heating season was $524.97
My natural gas bill for the same period, one year before getting the stove, was $1140.71
Because I burn corn, I cut my natural gas bill by $615.74
For this period my cost for corn was: $397.45
My net savings was $218.29

People sometimes ask me if the extra work involved in heating with corn is worthwhile. I believe it is. I’ve calculated that corn-handling and stove-related chores take about 10 minutes per 50 pound bag of corn. Or to put it another way, these chores took about 15 hours during the entire heating season. If I divide my time by the money I saved, I conclude that I’ve saved about $15.00 dollars per hour. I call that worthwhile. And, for a variety of reasons, it’s likely that my savings will dramatically increase in the future.

Some say that burning a source of food is immoral. I disagree. Blowing up mountains in order to harvest coal is immoral. Since that coal is used in power plants, purchasing electricity from those power plants is immoral. Any step taken to reduce energy consumption is a step in the right direction. Solar panels, compact fluorescent lighting, energy-saving appliances, recycling, and alternative heating and cooling are a few of the steps you can take to do your part.

Is burning corn immoral? I will ponder that as I sit in front of my stove on a cold winter day.

John

Another Renewable Energy Myth

2007-11-04T20:46:00.000-06:00

I’ve heard it said that it takes more energy to create a solar panel than the panel will produce in its lifetime. That’s absurd! Here are some facts:

A 100 watt solar panel can produce about 400-watt hours on a sunny day.

In one year, that single panel can produce about 146 killowatt hours.

The life expectancy of a solar panel is more than 20 years. In 20 years, that single panel can produce almost 3 thousand kilowatt hours of electricity, enough to prevent 6,600 pounds of CO2 from entering the atmosphere. Source: National Renewable Energy Labs (NREL). Keep in mind however that these figures are for a solar panel that is in service everyday, used to its capacity. An underused panel, one on an RV that is only used a few weeks each year for example, will not measure up over its lifetime.

And, for the benefit of anyone still skeptical, consider this:

It’s better to use fossil fuel to manufacture a solar panel than to just burn it, and still have the problem.

John

Are You Ready for a Winter Emergency?

2007-10-31T15:55:00.001-05:00

Winter is almost here, and that brings back memories of last years extended power failure. It was obvious at the moment the failure occurred that this was going to be a worst-case scenario. With sub-freezing temperatures outside, I knew it wouldn’t be long before it would be unbearably cold inside. Fortunately I had plenty of corn on hand for the corn-burning stove, and electricity available from my small off-grid photovoltaic (PV) system. We survived the first night comfortably, but I knew the PV system would not be able to keep up with the electrical demand of the stove.

That power failure taught me a valuable lesson. When the grid fails, you use the systems you have, not the ones you wish you had. And although that may sound obvious, you’ll understand the significance of that statement once you’ve experienced it for yourself. You’ll find yourself wishing you had installed eight PV panels instead of four, and you’ll wish you had a bigger battery bank. As you make do with what you have, you’ll vow to make the needed upgrades before the next emergency.

My PV system was too small to supply the electrical needs of the stove and the chest freezer last winter, so I purchased a small gasoline-powered generator. I was fortunate in that the electrical outage was spotty, and I only had to drive one mile to find a source of gasoline. With winter approaching once again, this is a good time to assess preparedness.

When last-year’s power failure occurred, I had 2 PV panels (170-watts of PV), while now I have four panels (340-watts of PV). I still have the same amount of batteries, a total of 420ah. In practical terms this means that I can charge my batteries faster, but I have no more storage capacity than I did last winter. Based on my previous experience, I should be able to run the stove for at least 8 hours, but I may be able to fully charge the batteries with only one day of sunshine. Previously, it has taken two days. This means, of course, that I could have as much as eight hours of heat per night, every night, as long as the sun shines during the day. That’s great progress, but I obviously need to do much more.

I’ve recently replaced my 20-amp charge controller with a 60-amp one, paving the way for additional solar panels. I’m very pleased with my 1100-watt sine wave inverter, so no upgrades are needed in that area. My goal before the end of the year is to add at least one more panel, and another 210ah of battery capacity. In addition to the electrical demands of the corn stove, being able to run the chest freezer means that I can keep food from spoiling. Additionally, I’ll need lights, the ability to charge a cell-phone, and the limited use of other household appliances.

Because my system will remain small in the short term, I need to incorporate other strategies in the event of an extended power failure occurring in the winter. Closing off unused rooms is one way I can cut back on heating. I can use an electric blanket, and therefore tolerate cooler indoor temperatures as I sleep. Instead of running a refrigerator, I'll place perishables in an ice-chest, and use an energy-efficient chest freezer. While these inconveniences are annoying, at least I can remain relatively comfortable in my home. Some of my neighbors had to abandon their homes during last-years power outage. With each system upgrade, living through an extended power failure becomes less of an annoyance.

John

PV System Upgrade

2007-10-15T09:07:00.000-05:00

While I’m looking forward to adding PV panels to my array, I’ll first have to replace my 20 amp charge controller with a bigger one. After careful consideration of available products, I’ve selected the Morningstar TriStar-60. I considered the Outback MX-60, but decided that the TriStar would be a better choice for my small system.

The Outback is a maximum power point tracking (MPPT) charge controller, which means that it can convert DC voltage to a higher or lower value. In some cases, this can result in more efficiency, but it probably wouldn’t benefit me much because my PV array is small. The TriStar is a pulse width modulation (PWM) charge controller, and it charges batteries in four stages. The strength of the charging signal is controlled by varying the pulse width. This has proven to be an efficient charging scheme for small systems.

The Outback charge controller can match any common PV array voltage to any common battery voltage. This feature allows the user to economize on wiring, and minimize losses that would otherwise occur. The TriStar can operate at 12, 24, or 48 volts, but cannot convert a high PV panel voltage to a lower battery voltage as the Outback can. While the Outback MX-60 is also a four-stage charge controller, its dc voltage conversion feature would not benefit me greatly, considering the limited wiring options I have with my small system.

The TriStar-60 uses less than 20ma (0.02amp) of current for its operation, much less than the Outback, an important consideration for a small system. More of the solar-generated power will be applied to the load. And the TriStar-60 comes with a 5-year warranty, while the Outback MX-60 controller is only warranted for two years.

Perhaps the most interesting feature of the TriStar-60 is its digital meter (option). I’ll be able to monitor system performance more easily, and I’ll return my digital multimeter to the toolbox where it belongs. In addition to instantaneous readings, the TriStar-60’s meter can display performance over time (data logging), and remote monitoring via the Internet is possible.

Before the year ends I’ll install at least one more solar panel. My ultimate goal is not only to power my home with PV-generated electricity, but to eliminate my use of fossil fuels entirely. I already burn corn to supplement natural gas heating, and I hope to purchase a plug-in car (PHEV) within the next two years. Using cfl lighting and replacing old appliances are other ways that I’m moving closer to my goal. I might just be the first person in my town to accomplish this. How cool is that!

John

Environmentally-Friendly Products - Are They Any Good?

2007-10-09T10:56:00.000-05:00

The energy crunch of the 1970’s resulted in a sudden influx of alternative products, many of which did not perform as advertised. As a result, the public was left with a perception that alternative products were not as good as traditional ones that serve the same purpose. Sadly, it seems that many environmentally-friendly products currently available also fail to live up to their advertised claims, and it’s easy to understand why the general public is slow to accept them. Here are a few examples:

Compact fluorescent lights:

I’ve experienced a high failure rate on the cfl’s used in my bathrooms. Perhaps the frequent on/off cycles shorten their life. I’ve cut my electric bill, but I’m not sure I’m really saving money or helping the environment due to the frequent cfl failures I’m experiencing.

I’ve observed that a cfl takes a minute or two to reach full brightness, but I’m not troubled by this. I use 19- to 25-watt cfl’s in locations where 13-watt cfl’s don’t supply enough light.

Energy-Star-rated appliances:

I suspect that Energy Star ratings are similar to gas mileage ratings on cars. We never achieve the posted gas mileage in real life, and we’ll never achieve the posted killawatt/hour per year figure posted on our Energy Star-rated appliances. I’ve tested my new refrigerator with a Kill-A-Watt meter, and found that it uses nearly twice as much energy as the Energy-Star tag says it should. I suppose that it might approach the posted rating if I seldom opened the refrigerator door, but that certainly isn’t practical. Or perhaps the energy use will be lower this winter, when it’s cooler in the house. While I am pleased that my new refrigerator uses much less energy than my old one, I wish that the ratings were more accurate.

Tankless Water Heaters:

While some people love them, my personal experience was not good. My contractor had little experience with tankless water heaters, and that’s where the problem began. I was willing to accept the high cost of the unit itself, but was unaware of the additional costs that I incurred when the unit was installed. I learned that I couldn’t simply tie-in to the existing furnace flue, I had to run a separate one using expensive stainless steel fittings. Then, I found that the unit would only produce a trickle of hot water. This problem was due to an insufficient supply of natural gas. For safety reasons, increasing the natural gas pressure was not an option. I was going to need a separate gas line from the meter to the water heater. Another option was to use several smaller tankless heaters, each one installed near the point of use. Instead, I decided to send the unit back, and return to a traditional water heater.

Washing Machines:

According to Consumer Reports, the U.S. Department of Energy now requires washers to use 21 percent less energy. Cleaning ability was compromised in order to meet those goals.

TerrorFreeOil.org:

Terror Free Oil is not a product, it’s a company dedicated to purchasing oil only from countries that don’t export terrorism. Unfortunately, this well-intentioned effort will not work. It doesn’t matter where we get our oil from; the amount we use is the problem.

Products that DO work:

My corn-burning stove is one product that I am pleased with. Not only is it good for the environment, I’ve significantly reduced my home heating costs. See previous blog posts on this topic for details.

Since I’m trying to power my home with PV I’ll continue to use cfl’s and energy-efficient appliances to lighten the load. These measures allow me to get by with a smaller PV system, and in that context I am saving money.

Please feel free to comment on my observations, and add to the list based on your own experiences. Maybe this article can be the start of a renewable energy product database. After all, there are many sources of information, but few of them are unbiased.

John

Off-Grid vs. Grid-Tied, My Survey

2007-10-01T18:16:00.000-05:00

By more than a two to one margin, visitors to my blog prefer grid-tied over off-grid. This came as somewhat of a surprise to me. I expected more people to opt for off-grid. I thought that being self-sufficient and having a reliable source of electricity would have steered more folks toward an off-grid system. I chose off-grid because of budget constraints, and because of an unreliable grid. I was able to build a “starter” system on a small budget, and as a result I have a limited amount of power when the grid is down. My goals were; to avoid being in the dark, to have the capability to keep warm in the winter and cool in the summer, to keep food from spoiling, and to have the limited use of other appliances. I’ve already met those goals to a certain extent. My small system can’t keep up during temperature extremes or during extended periods of cloud cover, but its benefits are impressive nevertheless when considering the size of my investment. And it’s always exciting when I upgrade the system and extend its capabilities. (I don’t know how I’d amuse myself if I were rich).

If money were no object, I’d opt for a grid-tied system with batteries. While such a system provides the best of both worlds, it is also the most costly. A grid-tied system with batteries must be able to automatically disconnect from the electrical grid when the power fails. If not, it could be dangerous for utility workers in the area. As a major advantage of such a system, it uses all of the free-power available, only switching to costly grid-supplied power as a last resort. Switching is automatic, based on setup parameters. The system can be set to be very gentle on the batteries, extending their life, or be set to use them to a greater extent, resulting in a lower electric bill. It must be great to have choices like that!

I think it’s reasonable to assume that while grid reliability problems may increase in the future, the grid is never going to disappear completely. As long as it is there part of the time, those attached can take from it and contribute to it. And those who supply power to the grid are paid, or at least credited, for their contributions. So unless electric rates or grid-connection charges are prohibitively high, being grid-tied makes more sense from a financial standpoint than an off-grid system does. And since an off-grid system with batteries efficiently uses the energy generated by the sun, it’s a good “green” choice.

While a batteryless grid-tied system is efficient and cost-effective, it must be embarrassing to have a large PV array, but no power when the grid goes down. What would the neighbors think? Still, this type of system is the best “green” choice, and it requires the least maintenance. On the other hand, I like my independence. If I could disconnect from the grid completely, I’d do it, even though that is not the most economical way to go. Unused power is wasted, so it’s a challenge to use as much of it as possible, while not stressing my batteries. I like the idea of using free energy from the sun, and not from a coal-burning power plant. I’m being kind to the planet, and preserving natural resources for future generations. Perhaps even more importantly, I’m setting a good example. Some things are more important than saving money.

John

Weekend Chores

2007-09-18T08:39:00.000-05:00

Our corn-burning stove is clean, and ready for the upcoming heating season. I’ve cut the top off of a 55-gallon plastic drum, and will be using it as a storage bin for corn. Because the bagged corn contains cob and stem pieces that could clog the stove’s auger, I screen the corn as I fill the bin. I’ll store additional bagged corn in my shed, and screen it into the bin as necessary.

While I once used fire starting blocks to light the stove, I’ve found that alcohol-soaked wood pellets are a much less expensive alternative. The bucket of pellets (below) should last all season.

Check this blog’s archives for more information about our corn-burning stove.

Julie and I finally decided to get a new refrigerator. I’ve tested our old one with a Kill-A-Watt meter and found that it uses over 2000Kwh of electricity per year. We selected an Energy-Star-Rated 25 cubic foot Kenmore model that uses only 499Kwh per year. Not only will this save $$ on our electric bill, I can use the PV system to power it in the event of a grid power failure. And, when I add a few more panels to my array, I’ll be able to run the new refrigerator full-time off of solar power. For additional information, see my blog post of July 27th.

As we go from summer to fall, the sun’s position in the sky is noticeably more southern. I’ve adjusted the tilt of my solar panels to better align them with the sun during the fall and winter months. My blog post of February 15th provides additional details.

I have a few tomato plants started in my sunroom, and I expect to have fresh tomatoes before Christmas. I don’t bother to grow tomatoes indoors during the summer, because my outdoor garden provides an abundance of them. For more information about growing tomatoes indoors all-year-long, see my August 24th blog post.

It’s a little early for leaves to be turning, but Julie and I had a pleasant drive in the country anyway. I’m hoping to find a three to five acre piece of land where I can build a retirement home. An ideal location will have wind and hydro resources, as well as unobstructed sunlight, allowing me to continue toward my goal of sustainable living.

John

Change or Die!

2007-09-14T08:51:00.000-05:00

"It is not the strongest of the species that survives, nor the most
intelligent, but the one most responsive to change."
Charles Darwin

Many believe that global warming is responsible for climate change, including extreme weather, such as storms of greater intensity. If Darwin is right, then the people of New Orleans are among those who should be more responsive to change. Instead, many choose to rebuild again in the same location. While this group is an obvious candidate for change, could it be that the rest of us fail to see the dangers that lie ahead? Is this the time to respond to the changes we see happening today? The answer is yes, absolutely! Just because you don’t live in a costal city doesn’t mean you’re out of harms way. Perhaps costal areas will be the first victims of the effects of global warming, but the rest of the country will surely follow.

Sadly, our government lacks the wisdom needed to formulate an intelligent plan. Its solution is to build bigger levees and help people rebuild in areas where nature doesn’t want them to. Money that could be spent in a sensible relocation effort is instead wasted on projects that are destined to fail. Money that could be spent to develop sustainable energy is instead spent on projects aimed at finding and using what little fossil fuels remain. In the absence of intelligent leadership, it is up to us as individuals to take the necessary actions to enhance our chances for survival. Stockpiling food and water will help to ride out the storm, but we need to plan beyond that. We need to think long-term.

The people most likely to survive are those who’ve already started to adapt. They’re not just moving out of costal areas, they’re moving out of heavily populated areas altogether. They’re growing their own food, and reducing or eliminating their need for public utilities. They realize that, in the event of a major disaster, it will be difficult to get food when a million of their neighbors are also looking for it. They’re learning skills that their great-grandparents knew well, such as growing food, food preservation, raising animals for food, hunting and fishing. And unlike their ancestors, they’re making their own electricity with solar panels, windmills, and micro-hydro systems. Life in a rural area presents an abundance of opportunities for sustainable living, many of which are not available in the city.

Besides our failure to plan for long-term emergencies, and our lack of survival skills, many of us lack the stamina to survive without automobiles and other modern conveniences. If you’re among this group, now would be a good time to get into shape. Walk, or ride a bicycle to work, if possible, or at least get some exercise several times a week. Eat healthy, and get plenty of rest. Don’t abuse alcohol, tobacco, or other drugs.

The idea of becoming self-sufficient might be a bit overwhelming if you haven’t worked at it in the past, but don’t let that stop you. The important thing is to get started. Think about your basic needs, and what you can do to meet those needs if traditional sources are no longer an option. You may have the additional task of taking care of very old or very young family members.

If a sudden change forces you into an emergency survival situation, you’ll enhance your chances for survival if you belong to a group of like-minded folks. You need not be an expert in every aspect of survival, as long as another member of your group is. You should be able to barter for goods and services.

Survival in the event of a major disaster is not the only reason to embrace sustainable living. For example, Les and Jane Oke were simply looking for a better way of life fourteen years ago when they decided to go off-grid. They managed to get out of debt, and replace noise and strife with contentment and a purpose for life. They, of course, understand doomsday scenarios, as indicated by these comments:

“….. the joy is in the fact that we could go on, endure if you will, any major blowout of industrial society.”

Or this one:

“When we run out of fossil fuel we will still be able to feed ourselves and produce our own power – we have achieved a state of sustainability in our life.”

Their website and online magazine offers some interesting insight into the pleasures and the hardships of this kind of lifestyle. You can find it here: http://www.off-grid-living.com/

On the other hand, you may choose to do nothing. If so, have you given any thought to what would happen to you and your family if a pandemic, natural disaster or a major terrorist attack were to occur? Imagine empty grocery store shelves, no gasoline, no running water, no electricity, and no natural gas service. Looting and riots will be common in many cities, and you’ll be afraid to leave your home. You may have enough food and water to last a few days, but what do you do after that?

John

Rethinking Solar Power (PV) for Your Home

2007-08-20T14:03:00.001-05:00

When considering a solar photovoltaic (PV) system for your home, the first step is to reduce your energy needs by making your home more energy efficient. Improvements might include an upgrade to energy efficient windows and doors, the addition of insulation, and the replacement of older appliances and inefficient lighting. Because these improvements reduce your energy needs, you’ll be able to reduce the size of your PV system and save money. Unfortunately, the overall costs of the improvements, when added to the cost of the PV system, may be more than you want to spend. Instead of discarding the idea entirely, why not consider a small to mid-size system. At least make a thoughtful evaluation of the benefits of a scaled-down system versus its cost before making a decision.

Generally speaking, there are three reasons for considering an alternative to the power supplied by your electric company; saving money, environmental concerns, and reliability issues.

The monetary concern is self-explanatory, everyone likes a bargain. Electric service is available at a reasonable rate for most of us, but not for everyone. In areas where electric rates are excessive, alternatives to grid-supplied electricity make financial sense. A grid-tied system is usually the best choice for those wanting to cut their electric bill, but you can also benefit from a small, and therefore less-costly, off-grid system.

Environmental concerns may mean a desire to use a non-polluting source of power, or a passion to preserve natural resources for future generations. Since the majority of the electricity produced in the United States comes from coal-fired power plants, your decision not to use electricity that originates at those power plants goes a long way toward reducing pollution. From the mine to the fire, coal pollutes every step of the way. Subsidence, contamination of ground water, and even the tragic death of mine workers remind us of the true cost of using coal.

Reliability is more important to some of us than it is to others. Most of us can tolerate a few hours, or even days, without power, but an extended loss of power can be life-threatening to some. Just losing the ability to make an emergency phone call can be dangerous. Climate control is not only important for your safety and comfort, temperature extremes can result in damage to your home. And don’t forget about food spoilage when there’s no electricity to run the refrigerator and freezer.

If you’ve decided to install a PV system for the purpose of saving money, first make reasonable energy-saving improvements to your home. Then size the system so that it produces a little more than your total energy needs. If space constraints or your budget won’t allow you to do that, your next best option is to install the largest system possible. If you’re billed for electricity on a tiered rate, perhaps you can install a PV system large enough to keep your grid-supplied electricity usage within the lowest tier. A sophisticated controller switches between alternative power and grid power in a way that optimizes system performance.

If reliability is the reason for installing a PV system, first consider the electrical needs that you can’t live without. If you live in a cold climate, the greatest need will probably be during the winter months. For home heating you might consider a wood-burning stove or fireplace. A heat exchanger, or even a portable fan, will help to distribute heat to other parts of the house. As an alternative to wood, you might consider a pellet or corn-burning stove. Both require electricity for their operation, but those needs can easily be met by a small PV system. Your summer needs might include cooling, but don’t plan to run a central air conditioning system with your small PV system. You might choose a window air conditioner if your PV system is big enough to handle it, or simply use fans for cooling. Your goal should be to keep at least one room comfortable in the event of a power outage.

When sizing your system (with your budget in mind), don’t forget about your other needs. You should consider a system big enough to power a chest freezer to keep food from spoiling, and to power a microwave oven. The microwave oven not only makes it possible to prepare meals, but also to boil water for drinking should that become necessary. Remember, one of your reasons for installing the PV system is to serve as an emergency source of power. Don’t underestimate your needs in the event of a disaster.

An advantage of making your system large enough to supply power during worst-case conditions is that you’ll have an abundance of power at other times. If you’ve sized your system to get you through power outages during harsh weather, power outages during mild weather are no problem at all. You’ll be able to watch TV, make phone calls, prepare meals, keep food from spoiling, etc. Trust me; it’s a good feeling to light up your house at night when your neighbors are using candles. But don’t be cruel; invite them over for a hot meal and to watch TV.

Using alternative power doesn’t mean that you have to be uncomfortable, but it is important to recognize the limits of your system. If family members practice conservation, you may be able to disconnect from the utility grid entirely when the weather is mild. It’s good to see the disk in the electric meter stop turning. Practices like turning off lights and other devices when they’re not in use will help to ensure a steady, uninterrupted source of power. If you’ve chosen to install an undersized system with plans to upgrade in the future, your good conservation habits will be beneficial later, as your system grows. If your children complain about the limited power your system provides, remind them what life would be like without it.

Some say that there are better ways to spend your money. A generator with an ample fuel supply may appear to be a better alternative. A generator is less expensive than even a small PV system. However, the fuel to run the generator needs to be fresh, and enough of it stored to get you through an extended power outage. The cost for fuel to keep the generator running can exceed the cost of a PV system in a short time. Some New Orleans residents reported generator fuel bills exceeding $900.00 per months after the Katrina disaster. A generator is good for a short-term power outage, but you’ll quickly grow tired of the noise, and refueling chores. Remember also that fuel may not be available locally in the event of a disaster. On the other hand, your solar panels provide quiet and steady power which is renewed each day by the sun.

The recommended way to design a PV system is to first calculate your energy needs. Instead of that approach, why not calculate how much energy you can get from a system that falls within your budget. For under $1000.00 you can build a system that will give you light, recharge your cell phone batteries and power a radio, but not much more. For another $1000.00 you can add some TV viewing, a fan, and other low-power appliances for a short duration. For a little more you can keep a small refrigerator or chest freezer running to protect your food from spoiling, use a microwave oven, and keep warm in the winter. You can live comfortably through an extended power outage with a relatively modest system. Start small if you must, and add to the system as additional funds become available. While you’re saving money on your electric bill, you can be proud that your efforts help to reduce pollution and preserve natural resources.

Be sure to check this blog's archives for additonal information.

sj

More BS about Plug In Hybrid-Electric Vehicles

2007-08-02T09:17:00.000-05:00

Plug-in-Electric-Vehicles are in the news again, and I’m a little puzzled by Toyota’s recent test of a plug-in-Prius. The low electric-only operating range, 8 miles, is far below that of the Tesla Roadster’s 200 mile range. The Tesla car shows what can be done when a vehicle is designed from the ground up, and with the best available technology. The main reason for the performance difference is that the Tesla car doesn’t have an internal combustion engine, and that it uses the best currently available batteries. Toyota uses a much smaller battery pack in a vehicle that also has the extra weight and space limitations of an internal combustion engine.

Toyota, GM, or any other car company could easily build a decent plug-in-electric vehicle if they wanted to, so why don’t they? Conspiracy theorists claim that Cobasys, a battery manufacturer that holds patents on batteries that could be used in plug-in vehicles, is partly owned by an oil company and will not allow their battery technology to be used in automobiles. Others believe that the big automakers are purposely creating cars that no one will want so that legislators will not tighten CAFÉ’ standards. After all, car manufacturers make their money on gas guzzlers. Have you seen “Who Killed the Electric Car?”?

Car makers claim that not enough people want them, they’ll be too expensive, and that the best battery technology is not good enough. These claims are false. People do want them, and problems with early versions of Lithium Ion batteries have been resolved. Additionally, an electric motor is less costly than an internal combustion engine and all that comes with it (pollution control components, transmission, muffler, etc.).

I guess we’ll just have to wait and watch as small companies, like Tesla and Phoenix Motor Cars, show the big automakers how it’s done.

Can’t wait for a PHEV? Here’s some info on conversions: http://www.calcars.org/

Recommended Reading: “Plug-in Hybrids – the Cars that Will Recharge America” by Sherry Boschert.

SJ

A Refrigerator-Freezer Strategy for Energy Efficiency, Saving Money, and Eating Healthy

2007-07-27T08:52:00.000-05:00

At first glance it might seem that a small refrigerator is a better “green” choice than a larger one, but for most households this is simply not true. While a small refrigerator probably uses less energy than a larger one, you’ll also find yourself making more trips to the grocery store. You might save a few dollars on your electric bill to operate the smaller fridge, but you’ll spend much more than that on gasoline for the extra trips to the store.

A properly-sized refrigerator and a chest freezer is the best overall strategy for most families. A top-loading freezer is inherently energy-efficient because the cold air doesn’t “fall out” when the door is opened as it does with any freezer that has a side door. Adding to their efficiency, a typical chest freezer doesn’t have other energy-consuming features such as a light or a fan.

Not only does a chest freezer allow you to stock up on long-lasting items from the grocery store, it also allows you to preserve items grown in your garden during the summer months. Growing your own food not only cuts your grocery bill, home-grown foods are usually healthier and tastier than the same items when purchased at the grocery store. Since I’ve started using a freezer, I’ve increased the size of my garden. This ensures that I’ll have plenty of fresh produce and plenty to save in the freezer. And since I save seeds, my home-grown produce is almost free! If you’re not into gardening, you can stock up on locally grown food in the summer by visiting a farmer’s market.

If you’re about to purchase a refrigerator or freezer, be sure to look for those that have earned the “energy star”. If you’re replacing one that is over ten years old, you might save 50% or more on your electric bill. A 21 cubic foot energy star-rated refrigerator might use 430 kWh per year, or about 1.2 kWh per day. At ten cents per kWh, it will cost about $43.00 per year to operate. Actual results depend not only on your electric rate, but also on how you use it and where it’s located in your home. A small energy star-rated chest freezer might require 300 kWh per year, costing you about $30.00 per year to operate. The basement is a better location for the freezer than the garage because it’s cooler there, causing the compressor to run less frequently. The heat that the freezer produces is often desirable in a cool basement.

A small photovoltaic (PV) system can be used to provide backup power in order to prevent your food from spoiling during an extended power outage. I chose a PV system instead of a generator because it is quieter, less expensive to operate, and I don’t have to store fuel. As a bonus, my PV system provides power to the freezer on a continuous basis, cutting my electric bill. Since my PV system is not large enough to power both the freezer and refrigerator, I’ll use the PV-powered freezer to produce ice which can be used to keep refrigerated food from spoiling during an extended power outage. When I’m able to enlarge the PV system, I’ll add the refrigerator to the load. Currently, I have 340-Watts of solar panels, and 420ah of battery capacity. The PV system is able to meet the energy requirements of the freezer, except when cloudy conditions persist for several consecutive days. When that happens, I run the freezer on grid-supplied power until the batteries are recharged by one or two days of sun.

Transitioning into a future where fossil fuels are declining does not necessarily mean that we will have to do without comforts that we’ve become accustomed to, but we’ll have to do things differently. Recent innovations, like compact fluorescent lights and energy efficient appliances, show that we’re able to adjust to these conditions without giving up anything. This trend is likely to continue, radically changing the vehicles we drive and other products we use. Changing your food preservation strategy is a good, healthy way to begin your journey into the future.

My Garden - July 2007

Solar John

Hey GM, Bring Back the Electric Car!

2007-07-23T15:40:00.000-05:00

If GM's EV-1 electric car were to be manufactured today, it would have a battery pack that weighs half as much as it did in the old EV-1. Great strides in battery technology have been realized since the demise of the EV-1, making this possible. Faster recharge time and longer life are additional benefits of the best currently available batteries. The new breed of Plug-In-Electric Vehicles (PHEV's) would include a backup generator to extend the range, but most owners wouldn't use it for day-to-day commutes. In other words, most of the time they wouldn't use any fossil fuel at all, instead using power stored in the vehicle's batteries. And while using grid-supplied power to recharge the vehicle is not truely a "Green" solution, it's better than the millions of gas and diesel-powered cars that pollute our air today.

Unlike today's hybrids, the fuel-powered engine would recharge the batteries, not directly drive the wheels. GM could be a leader in electric vehicle technology, and a profitable company once again. But more importantly, the world would be different. There would be no need for oil wars, and gasoline would be less expensive due to decreased demand.

Critics of the electric car worry that a suden influx of plug-in cars would overload the already-strained electrical grid, and in some parts of the country this is certainly true. Still, it makes more sense to increase electrical generation and distribution capabilities than it does to continue to use fossil fuels, which are declining and non-renewable. For those who can't wait for power infrastructure upgrades, alternative energy such as solar and wind is an option. Although the cost of such systems is high, the savings over fossil fuel-powered alternatives are significant, and the payback is quicker than you might expect.

SJ

Inventions That Change the Way we Live

2007-07-16T12:57:00.000-05:00

It’s easy to name inventions that have changed our lives. The electric light, radio, and television are among the most notable, and the personal computer is among the most recent. It seems that each of these devices appeared suddenly, but they were actually perfected over time. With that in mind, it’s interesting to contemplate life-changing devices on the horizon.

We may eventually look back and realize that the photovoltaic panel (PV) was the life-changing invention of the present time. While solar photovoltaic panels were once only used in the space program, now they can be found almost anywhere around the world. They not only provide power for lights, they provide the energy needed to pump water for people, as well as for cattle, in locations far from power lines. Thanks to PV panels, remote villages and vacation homes can use the same electrical appliances that city-dwellers use. And now, as electric rates are increasing and reliability is an issue in some parts of the country, many grid-connected homeowners are also installing solar panels.

Some utilities have imposed a tiered-rate structure for electrical usage. While the first 300KWH per month is relatively inexpensive, electricity use in excess of 600KWH is billed at a much higher rate. A PV system can be designed to use solar power as the primary source of electricity, only using grid-supplied power when the PV system’s capacity is exceeded. Switching is automatic, and the homeowner may not even be aware that it has happened. Other sophisticated PV system components protect the batteries from over charging or over discharging, and coax the best possible performance from the system.

Fossil fuel supplies are on the decline, resulting in escalating costs to bring electricity into our homes, but there are other factors that are beginning to make PV systems more appealing to the average household. Newer consumer electrical devices require less power than their older counterparts, making it possible to get by with a smaller PV system. From light-bulbs to major appliances, it’s rare to find an increase in electrical consumption in a newer device. The exception to this rule is the plug-in-electric vehicle. If these become popular in the future, we’ll need sufficient capacity to charge them. Still, the cost of PV panels is expected to decline sharply within the next two years, further increasing their popularity.

The PV panel is not like other life-changing inventions, it simply provides power for them. And, unlike other life-changing inventions, we usually keep solar panels out of sight, rather than on display. As we transition to PV systems, our lives may not have been altered per-se, but without PV all of our electrical devices will be useless, or to costly to use.

President Bush said recently “we’re addicted to oil.” The truth is, were addicted not to oil, but to our cars. By the same token we’re not addicted to electricity, but rather to our lights, radios, TV’s, microwave ovens, dishwashers, and other appliances. And it’s hard to imagine how tradesmen would perform without their power tools and equipment. Because a transition to PV will be gradual, we may not recognize it as a life-changing invention until when we think of what life would be like without it.

John

My Backyard Garden

2007-07-09T13:07:00.001-05:00

It’s mid-July, and my garden is in full-swing once again. Here’s a brief tour:

Tomatoes are on the left. Pole beans are in the background. From left to right the raised bed is home to: Sweet Snap Pea’s, Eggplant, Green Pepper, Basil, Dill, Parsley, Carrots, and Honeydew Melon.

More than anything else, I like to grow tomatoes. We eat them fresh, and can them for use all-year-long. Nothing you can buy at the grocery store in the winter compares to the great taste of canned tomatoes.

I grow “heirloom” tomatoes, and they come in a variety of colors, shapes, and sizes. Cherokee Purple (leftmost tomato), is a great tasting variety that grows well in my environment. Shown next to it is a Better Boy.

The ugly-shaped tomato on the right is a French variety, Cuostralee.

My corn crop was ruined by squirrels last year. To deal with the problem I started a “Squirrel Relocation” project. It looks like I’ll be eating sweet corn from my garden this year.

I’ve had good luck with cucumbers this year. Here are some of the dill pickles I made. I also grow the “dill”, used to give the pickles their flavor.

Raspberries were nearly ready for picking when this picture was taken. I'm getting about a pint of raspberries per day, as of July 8th.

The photo on the right is a closer look at a dill plant.

In addition to great taste, it’s good to know that my family is eating food that has not been genetically engineered, and is free of pesticides and preservatives. I save “open-pollinated” seeds from my own crops each year, just to be sure. My post of 9/6/2006 provides additional information about my gardening practices.

John

The Practical and Efficient Use of a Small PV System

2007-06-22T15:01:00.000-05:00

Since the primary role of my small photovoltaic (PV) system has been to serve as an alternate source of electricity during grid power failures, a great deal of power was unused, and therefore wasted. To minimize the waste, I decided to put the system to use on a daily basis. After all, I reasoned, shouldn’t I be using this energy to reduce my electric bill?

My first task was to determine how much energy I could expect from the system. Since I have 340 Watts of PV capacity (4 – 85 Watt Panels), and I can expect about 4 hours of peak sunlight each day, the overall production will be 340 times 4, or 1360 Watt/Hours per day. Because I’ll be storing some of this energy in batteries, and because I’ll be converting DC to AC, system losses must be considered. Clouds will also limit production. With all of these things in mind, I’ll estimate that my daily capacity averages 900 Watt/Hours.

Looking over a list of appliances in my home, I decided to use a chest freezer as the load. The chest freezer is an ideal load for several reasons: It requires about 800 Watt/Hours per day and the energy requirements change very little from day to day. Because it uses a little less energy than the anticipated daily output of the PV system, the freezer could theoretically be powered indefinitely. I decided to carefully monitor system parameters for a few weeks, and log the results with comments. Here are some log excerpts:

May 6, 2007
Power up inverter and connect chest freezer.

May 13, 2007
Observed that in addition to providing power to the chest freezer, the PV array is able to fully charge the battery bank.

May 31, 2007
The past six days have been mostly rainy and overcast. Switch off inverter due to low battery voltage.

I predicted that the PV system would be able to produce more energy than needed to run the freezer, but six days of mostly cloudy weather depleted the battery bank.

June 2, 2007
Sunny weather has returned and batteries are fully charged. Switch on inverter and connect chest freezer.

June 7th, 2007
Severe thunderstorms are predicted. Switch off inverter in order to preserve batteries in the event they are needed in the event of a grid power failure.

No grid power failure occurred, but it was good to know that a fully charged battery bank was available just in case.

June 8th, 2007
Stormy weather has passed. Switch on inverter and reconnect freezer.

June 10th, 2007
Due to mostly overcast conditions, battery voltage has again declined. Switch off inverter and freezer load.

Overall the system performed pretty much as I expected it to. If not for an extended period of cloudy weather, it could have continued to provide enough energy to power the chest freezer for a very long time. I suspect that the short and cloudy days of winter will create the same situation.

Overall efficiency may seem to be optimized in this example, since the load is about equal to the capacity of the PV system, but a significant increase in efficiency is possible. The freezer could be put on a timer, set to allow the freezer to run only during daylight hours. If the compressor runs during the day, when energy comes directly from the solar panels, the losses associated with storing power in batteries and using power from the batteries are eliminated.

Based on the results of this test, I believe I can improve PV system performance by increasing the size of the battery bank. It is important to note that the battery bank must not be enlarged to a point where the existing PV array cannot fully recharge it. Chronic undercharging will shorten the life of the battery bank. It is also important to remember that in addition to charging the batteries, the PV array needs to provide power to the load.

The system continues to serve as an emergency source of electricity, and most days provides power to the freezer therefore reducing my electric bill. Additional opportunities to enhance system efficiency will surface as I enlarge the system. At this point it's good to know that I've reduced the waste.

Here's a picture of the freezer:

Visitors usually ask about the sign, giving me an opportunity to show-off my PV system.

John