The Smart Grid and You

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)

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

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

My Off-Grid Photovoltaic System and This Blog

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

GeoBulb (LED) vs CFL (Compact Fluorescent)

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?

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

Smart Appliances and the ZigBee Alliance

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

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

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

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

System Automation for a Spare Battery Bank

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

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

“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?

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

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

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

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

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

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