PV: Strategies for Starting Small and Expanding Later

I would have liked to set up a PV system large enough to meet all of my household needs, but I quickly learned that a system of that size costs more than I was prepared to spend. Instead of saving money and waiting, I decided to start off small and add to the system over time.

While there are some advantages to building a big system all at once, there are also advantages to starting small. When an ice storm knocked out power to my home for a week, I was glad to have the modest amount of power my small system provided. If the idea of starting small appeals to you, here are two strategies you might consider:

System #1:

The least expensive option consists of one or more solar panels, a charge controller, batteries, and an inverter. Such a system can be built for less than one thousand dollars. If your needs are limited to lighting, and perhaps a radio, TV and computer, this system might be just right. You can always add to the system later, and add a refrigerator, freezer, microwave oven, and other appliances to the load. You’ll have to keep an eye on the system, switching to another power source when your batteries are depleted. For backup power and battery charging when the sun doesn't shine, you might consider a small gasoline-powered generator.

System #2:

Using an intelligent controller, you can build a system that runs your household on battery power until the battery voltage drops to a set point. At that time another source of power takes over. This source of power can be a generator, or the utility grid. If you rarely experience grid power outages, the utility grid might be your best option. If utility-supplied power is unreliable, you might choose a generator instead. Automatic switching between power sources is possible. The beauty of this system is that it uses all of the power your system can generate before switching to more costly power sources. None of the PV-generated power is wasted. As you add solar panels, your savings increase accordingly. Because of the sophisticated equipment required, this option is significantly more expensive than the first one.

At some point in the not-to-distant future I believe that the demand for solar panels and equipment will skyrocket. To avoid supply-and-demand cost increases, I chose to install a small system rather than to wait until I could afford a larger one. I’ve benefited from this system in many ways, and haven’t regretted my decision.

Happy New Year!

John

My First Year Accomplishments

My involvement with renewable energy began one year ago when I installed the first solar photovoltaic panel on my roof. This year I’ve been able to reduce my use of utility-supplied electricity and natural gas, and I’ve benefited from my alternative heat and electricity sources during two lengthy power outages. In addition to lowering my electric and natural gas bills, I also contribute less to global warming. In other words, I’m moving closer to a carbon-neutral lifestyle. It is also good to know that I’m using less of the earth’s irreplaceable natural resources.

This is a summary of my accomplishments in my first year:

• I've replaced most of the incandescent bulbs in my home with compact fluorescent (cf) types.
• I've installed a small off-grid solar photovoltaic system, and have upgraded it several times. While the system offsets only a small portion of the utility-supplied electricity, it also serves as an emergency source of power. Recently, when an ice storm caused an extended power outage, the system was used to help heat my home as well as to supply electricity for lighting, cooking, and communications. It also provided a portion of the electrical requirements for a chest freezer, preventing food from spoiling.
• I've installed a corn-burning stove, and am using it to reduce my use of natural gas for heating. As a result, I've lowered my heating costs, and was able to keep my home warm during a recent extended power outage.
• I've replaced several windows in my home with energy-saving ones.
• I've replaced an older TV with an energy-efficient flat-panel one.
• I've removed many of the phantom loads in my home.
• I've converted an attached garage to a family room. This project included the addition of insulation, and the replacement of a garage door with an energy-efficient bay window. This room is a work-in-progress.

As I continue to add to the PV system, my savings will continue to increase. Because my electricity provider plans large rate increases over the next few years, I expect bigger savings in the future. At some point in the not-too-distant future, everyone will need to reduce their carbon emissions if this planet is to survive. It’s a good feeling to be in the forefront of this effort, and I look forward to continuing this important work. It’s the right thing to do.

Solar John

Ameren Wants to Stick it to You. Here’s What You Can Do

According to a story in the Belleville News Democrat today, owners of homes and businesses that depend upon electric heat can expect to see their power bills soar by 90 percent or more when AmerenIP rolls out its new rate plan on January 2nd. At the same time, owners of gas-heated homes can expect to pay an extra $1.00 per day under the new plan. David Kolata, executive director of the Citizens Utility Board, says “It’s bad for everyone, but it’s really bad for people with electric heat.”

After reading that article, the cost of solar photovoltaic panels and bio-fueled stoves suddenly doesn’t seem so high anymore. Stove-related chores are less of a burden now that the potential for saving money is greater. Interest in alternative sources of electricity and heating is already growing, but I expect a surge as rates begin their steep climb. For that reason, I’ll continue to provide information on this blog for those interested in pursuing an alternative path. Here is an overview of some heating and electrical system alternatives.

Heating your home with corn:

I chose corn as an alternative source of heating for several reasons. Based on market prices at the time, corn was the least expensive heating fuel. Although corn prices have gone up recently, I believe that corn is still the least expensive heating fuel.

Once you’ve decided to heat your home with corn, the next choice will be to choose a particular stove or furnace. I chose a fireplace insert (considered a stove), in part because I don’t have room for a furnace. I chose a 70,000 BTU model because I wanted the ability to heat my entire home. Had I settled for a smaller one, I would have only been able to heat one or two rooms.

Installation was easy, requiring only a small hole in the side of my house for a clothes-dryer-like vent. Corn is available in bags, but it is more economical to buy it in bulk, perhaps a pickup truck load at a time. In addition to hauling and storing the corn, I spend about 15 minutes a day filling the stove’s hopper, and maintaining the stove. A vast amount of information is available at http://www.iburncorn.com/, so I’ll refer you to that site for additional details.

Solar photovoltaic systems:

If you’re considering an alternative to grid-supplied electricity for your home, you’ll first need to decide upon the type of system. Your choices are; off-grid, and grid-tied.

An off-grid system is a stand-alone system that uses batteries to store power generated by the sun’s rays during the day. A grid-tied system also generates power from the sun’s rays, but surplus power is applied to the power grid for credit. The user relies on power from the grid when the sun doesn’t shine, but the surplus power generated by the photovoltaic array offsets the cost of that power. No batteries are necessary in a grid-tied system.

Here is a complete list of the components for an off-grid system:

One or more solar photovoltaic panel(s).
Mounting hardware for the panel(s).
At least one 12-volt battery.
A charge controller.
A 12-volt dc to 120-volt ac inverter.
Wire and wiring accessories.

Next, you’ll need to determine how much power you’ll need from the system. You can cut your needs considerably by replacing inefficient lighting and appliances in your home. This, of course, will allow you to get by with a less expensive system.

If you’re lucky enough to have an unobstructed south-facing roof, you have an excellent spot to mount your solar panels. Panels can also be mounted on a pole, or other ground-based fixture.

Because this is an overview, I’ll stop here. Check for previous posts on this blog for additional information. You’ll find a list of websites that provide in-depth coverage of topics covered here. Be sure to return to this blog often, and I appreciate your comments.

Solar John

How I Survived the Great Ice Storm of 2006

The ice storm of 2006 resulted in the longest electrical power outage that I’ve ever experienced. To make matters worse, this outage came at a time when temperatures often dropped into the single digits. The need to produce heat, coupled with short days, made this a worst-case scenario for my alternative systems.

For 7 days I used my corn-burning stove to heat my home, and my electrical power came from a small gas-powered generator and a solar photovoltaic (PV) system. While many of my neighbors were forced to stay with relatives or in motels, I remained in my home and was comfortable. I was able to watch TV, prepare food, and I had plenty of light. My wired telephone service was out, but I was able to use my cell phone and keep the batteries charged. I didn’t use my energy-hogging refrigerator, but I ran a chest freezer to prevent frozen food from spoiling. Food that needed to be refrigerated was kept in a cooler outside.

Because I kept my home warm, I didn’t have to worry about pipes freezing. I’m not sure if my neighbors were able to avoid that. Some of them used fireplaces for heat, but they were ineffective without power for blowers to circulate the heat throughout the house.
Others used kerosene or propane heaters, but the cost of fuel was outrageous. I burned about 75 pounds of corn per day at a cost of about $6.00. My generator used about 2 gallons of gas a day at a cost of about $4.50. Considering the extreme cold, this is about what it would have cost to heat my home using utility-supplied electricity and natural gas.

This power outage was a great learning experience, and as a result of it I’m planning a major photovoltaic system upgrade for next year. I want to greatly reduce, if not totally eliminate, the need to use a generator. I’ll be glad to get rid of the noise and smell, and also to eliminate the need to go out in the cold to refuel it every 7 hours. Hauling and storing significant quantities of gasoline are additional drawbacks. In addition, the power that it supplies is not clean and steady, causing streaks and a jittery picture on the TV. On the other hand, power from my solar PV system’s inverter was clean and steady.

To put the PV system to use it was only necessary to connect extension cords and flip a switch on the inverter. Family members are reluctant to set up and use the generator when I’m not home, but have no problem using the PV system.

Considering the duration of the power outage, some people must have felt the same frustrations that Hurricane Katrina victims felt. The Katrina disaster should have been a wakeup call, demonstrating that we may have to wait a long time for help in the event of a disaster of this magnitude. We should have learned to take responsibility for our own comfort and safety instead of relying on someone else. PV panels are expensive, but if they prevent big motel bills, broken plumbing, and spoiled food perhaps they’re worth the cost. Generators and kerosene heaters are another option, but if you choose to do that you must make sure you have a fresh supply of fuel. In the event of an extended outage, the cost for fuel will be high. And, in the case of a disaster, it may be difficult to replenish fuel supplies locally. Some generators are tied to the natural gas supply lines, but that does not guarantee an uninterrupted fuel source in the event of a disaster. Solar panels, securly mounted in an area where they are not likely to be damaged by tree limbs, are the best option in most cases. I'm certainly glad to have mine.

John

The Great Ice Storm of 2006

Due to a severe ice storm, this is day five of an electrical power outage at my home. It wouldn't be so bad, except that the outside temperature has been between 9 and 35 degrees. To keep warm, I'm powering my corn-burning stove with my solar PV system part of the time, and a small gasoline-powered generator the rest of the time. I'll post details of this experience later, but for now.......
Gas for the generator: $4.50 per day

Corn for the stove: $6.00 per day

Staying warm when it's 9 degrees outside and the power grid fails: Priceless!

John

A Letter to my Great Great Great Great Grandchildren

Dear great, great, great, great grandchild;

You probably think of my generation as an industrious group. We work hard to maintain a lifestyle that includes big automobiles and mini-mansions. We travel thousands of miles by air or land each year for recreation, and many of us have boats and RV’s. Some of us have personal spas and swimming pools. We’ve consumed most of the world’s supply of oil, coal, and other natural resources, and we’ve destroyed mountains, prairies, rivers, streams, and nearly caused a meltdown of the planet in order to maintain our lifestyle.

My dear grandchildren, some of us try to conserve and protect natural resources, and a few of us are pioneers of what we call alternative energy. Unfortunately, we get very little support. I know it must sound crazy to you, but the biggest subsidies go to oil and coal companies, the worst polluters. It makes no sense until you consider campaign contributions. But I digress.

Please don’t judge us too harshly. Those who profit from oil and coal want us to believe that alternatives offer too little benefit for their high cost. Those of us who work with alternatives know that this is untrue. Many of us are saving money, and reducing our negative impact on the planet at the same time. And we’re doing this now, with technology that must seem crude to you.

The fact that you’re reading this means that the planet has survived peak oil and peak coal. Perhaps some good has come from our selfishness. Because you don’t burn fossil fuels, global warming is less of a problem. Wars are less of an issue now because the little remaining fossil fuels are not worth fighting for.

Of all of our mistakes, I’m sorry for what we’ve done to the mountains most of all. While you’ve done a lot to renew the planet, you’ll never see those mountains in their original splendor.

Your great great great great grandfather, John

PV System Upgraded

My PV system was very useful during the most recent grid power failure, but at the same time I wished that it could have done more. As a result of that experience I decided that the next upgrade would be a better inverter. My present inverter, a 600-Watt modified sinewave type, does a great job running lights, fans, and charging the cell-phone batteries, but has its limitations. Here is a list:

It is not powerful enough to operate my microwave oven and other large appliances.

It doesn’t provide enough starting current to run a small refrigerator.

It causes buzzing in the sound when I run a radio on it.

It causes streaks in the picture of a TV powered with it.

A timer motor runs fast, making it useless as a timer.

I’m afraid to connect expensive devices to it, fearing that it may damage them.

To overcome these limitations, I’ve just ordered an Exeltech 1100-Watt sine wave inverter. I chose the Exeltech because it seems to be more rugged and dependable than others I’ve considered. And, because it’s made in the USA, I suspect that it will be quicker and easier to get it repaired if I do experience a problem. With the Exeltech, I’ll be able to run almost any appliance I can think of.

In choosing an inverter I first had to assess my needs, and then find one that meets those needs while staying within my budget. In the event of an extended grid power outage a typical load on the system will be:

Three compact fluorescent lights 45-Watts
Small chest freezer 90-Watts (When the compressor runs)
Small refrigerator 115-Watts (When the compressor runs)
One fan (medium setting) 30-Watts
A radio 5-Watts
-----------
Total 285-Watts

I’ll also be able to use other appliances, such as a microwave oven or a vacuum cleaner, at the same time. Since the microwave is rated at 750-Watts, the total power supplied by the inverter will be 750 plus 285, or 1035-Watts. The Exeltech inverter can handle up to 2200-watts for a few seconds, so a high motor starting current surge from the freezer or refrigerator should not present a problem.

With the exception of a few high-power devices, I’ll be able to run multiple appliances at the same time. For example; if I want to use the microwave, I’ll have to avoid using a vacuum cleaner. Of course I’d have preferred a bigger inverter, but when considering the cost, I decided to put up with a little inconvenience.

Daily needs can be calculated by multiplying Watts times Hours. My short-term goal is a system capable of supplying 1450 Watt-hours. My fully-charged battery bank can provide that amount of power for a day, but my solar panel array is not big enough to keep the batteries charged in the event of a power outage lasting more than a day. I plan to add solar panels next year to overcome that limitation. Eventually, I’ll add even more panels so that my system can be used for heating or cooling.

John

What is Peukert's Law and Why Should I Care?

A solar photovoltaic, wind, or hydroelectric system consists of just a few different components. With only a basic understanding of electronics, it is easy to grasp every operational aspect of a complete system. Batteries, however, are the only system components that require an in-depth study. In September of 2006 I posted an entry on this blog titled “Understanding Batteries Used in PV Systems”. http://solarjohn.blogspot.com/2006/09/understanding-batteries-used-in-pv.html. While that paper can be considered an introduction to batteries, this one might be considered Part 2 of batteries. In this paper I’ll continue where Part 1 left off, and in the process make you a battery expert.

In part 1 I stated that “The discharge rate affects battery efficiency. As the rate of discharge increases, battery efficiency decreases.” Peukert, a researcher, noticed this phenomenon, and applied a mathematical formula to it. Since I never was good at math, I’ll avoid explaining Peukert’s observations in mathematical terms. I’ll show you how to use this phenomenon to your advantage as you design your solar PV system.

Peukert observed that as the discharge rate of a battery is increased, less power is available from the battery. A lightly loaded battery bank doesn’t actually supply more power that that which is pumped into it, which would be a violation of the laws of physics, it simply operates at a higher efficiency.

Manufacturers assign their batteries an Amp-hour rating based on a specific rate of discharge. For example, the 105-Ah rating for a typical marine deep-cycle battery is based on a 20 Amperes per hour (20-Ah) discharge rate. This means that the battery will produce 20-Amperes per hour for a little over five hours. Twenty amperes times five hours equals 100, nearly the same as the Ah rating. From this information it seems logical that if the discharge rate were lowered to only two amperes per hour, then the battery would last ten times as long, or fifty hours. However, when we apply Peukerts equations to this battery, we conclude that the battery will actually last seventy hours. The extra power is due to the higher efficiency obtained because of the lighter load. The chart below illustrates battery capacity when different loads are applied:

Battery Capacity = 105-Ah
Battery Amp/Hour Rating = 20

Discharge Rate (Ah) - Battery Lasts (Hrs.) - Amp-hours Available
1 - 172 - 172
2 - 70 - 140
20 - 5 - 70
100 - 0.43 - 43

(Sorry, Due to the way blogger formats data, I'm having a little trouble lining up data in this chart).

This chart shows that a lightly-loaded battery exceeds the advertised capacity of the battery, while a heavily-loaded battery does not meet the advertised capacity.

You may be wondering why, if the rated capacity of a battery is 105-Ah at 20-Amperes, does the battery only provide 70-Amp-hours at the 20-Ampere discharge rate. More than anything else, this is an advertising gimmick. While you could in theory continue to draw power from the battery until it was completely dead, doing so would damage the battery.

It is important to note that in typical applications, battery loads are not constant. Lights that are used at night, for example, may not be used during the day. A ten-ampere load for 1 hour is the same as a twenty-ampere load for thirty minutes, if followed by a thirty minute no-load period. In both cases, the drain on the battery is about the same.

Now that you understand the effects of light and heavy battery loads, let’s consider how you can use that information to your advantage.

A 10-amp load on a single 100-Ah battery is a significant load. However, a 10-amp load on a battery bank consisting of ten 100-Ah batteries connected in parallel is a light load. In the case of ten batteries connected in parallel, the load current is equally divided between each battery, or one amp per battery. The size of the load hasn’t changed, but the load on each battery is ten times lighter than it was for a single battery.

Keeping in mind that we shouldn’t completely drain the battery, a single battery under a ten-ampere load can be expected to last 8.12 hours. From this, one might expect a bank of ten batteries to last ten times as long, or 81.2 hours. Actually, according to Peukert’s Law, the ten-battery bank should last 162 hours. This is important to keep in mind as you design your solar photovoltaic system. By increasing the battery bank size by a factor of ten, the energy available increases by twenty times. By over-sizing the battery bank, the efficiency of the system has been greatly increased.

This example is hypothetical, and depending upon your battery type and actual load, your results may not be this good. Still, as long as the efficinecy increase is great enough to offset the cost of the extra batteries, you benefit.

The design of a solar photovoltaic system begins with an assessment of the expected system load. Perhaps you’re designing a system for a cottage that is only used on weekends. The load may be high when the cottage is occupied, but little if any power is used the other five days of the week. A good design for this scenario would be to skimp on solar panels, and to over-size the battery bank. Even though your solar panel(s) may be unable to keep up with the weekend load, the over-sized battery bank should have enough stored power to meet your weekend needs. And while you’re using more power than you generate during the weekends, recharging occurs during the other five days of the week when the load is light. As a bonus, you’ll achieve greater battery efficiency with the over-sized battery bank. The fewer-panels/more-batteries design is cost-effective too, since solar panels are much more expensive than batteries.

An emergency power system is another scenario where fewer panels and more batteries might be a good option. If a typical power failure lasts for twelve hours or less, then you only need to provide emergency power for twelve hours. If you experience less than one power outage a week, it doesn’t matter that it takes a week to fully recharge your battery bank. In this scenario, you would simply add up the power requirements of all of the devices you want to use and purchase a battery bank capable of meeting those requirements. If you’re only using the system during a power outage, then even a one-panel system will charge the batteries eventually. You just need to be careful not to chronically undercharge the battery bank, as that could shorten its life.

After you’ve determined the storage capacity needed, the next step is to decide which brand and type of batteries you want to use. High performance batteries tend to suffer less from the negative effects of partial charging and discharging cycles, and can better handle other forms of abuse. In other words, they’ll last longer. But high performance batteries also have a high price tag. If your budget won’t allow you to get the best available batteries, consider deep-cycle marine batteries instead. However, make sure you’re not buying starting batteries. Starting batteries, like those in your car, were designed to provide a high current for a short period of time. Deep-cycle batteries are designed to provide a modest amount of current over a long period of time, which is just what you need for a solar photovoltaic system.

Solar PV technology is a viable substitute for utility-supplied power, but needs to be properly implemented for optimum results. If you overestimate the capabilities of your battery bank, you’re likely to be disappointed. On the other hand, you can use the information provided here to your advantage, ending up with a system that far exceeds your expectations. Your battery bank can provide more power than it’s rated at, and operate within a range that is conducive to long life. Modern charge controllers include features that help to prolong the life of your batteries as well, and it would be a good idea to investigate those features before making any battery decisions.

Once you’ve calculated the expected load, you can use the spreadsheet calculator that you’ll find here (http://www.smartgauge.co.uk/index.html), to determine the optimum size for your battery bank. You’ll see the often-dramatic effects of over- or under-sizing your battery bank for a given load. In addition to the useful calculator spreadsheet, this site provides in-depth Peukert’s Law information.

The Sandia National Laboratories web site has in-depth battery information that you might find useful. http://www.sandia.gov

Solar John

Oil Company Finds a Way to Meter the Sun!

It’s hard to imagine a better application of solar photovoltaic technology than to bring electricity to remote areas of developing countries. In an effort to do just that in rural South Africa, Shell International Renewables Limited has partnered with South Africa’s national electricity supplier to develop a “plug and play” system. The system was designed so that individual components cannot be used with any other device, and a prepaid token or magnetic card is required. The user pays an installation charge and monthly fee. Purchasing the equipment is not an option. This sounds like a bad deal to me, but then that is about what I’d expect from an oil company.

On the other hand, organizations like the Solar Electric Light Fund (SELF) also bring photovoltaic systems to rural users in developing countries. SELF is supported through donations, but also make it possible for users to purchase equipment via a time-payment plan. Additionally, SELF trains locals to be dealers, installers, and troubleshooters. The SELF plan sounds like a much better deal than what Shell is offering. Read about them here: http://www.self.org/.

Read about the Shell plan here: http://www.tve.org/ho/doc.cfm?aid=557

Solar John

Renewables, No War Required

In a conversation with Rush Limbaugh today, President Bush stated a few reasons for continuing the war in Iraq. He fears that if extremists take control in that part of the world, the price of oil could skyrocket or that oil shipments might be disrupted. His words convey a lack of faith in our ability to implement renewable energy solutions. In reality, everything we currently do with oil can be done in another way, and often in a better way. The technology is already in place, and it will only improve with time. While there are multiple reasons for being at war, we can and should eliminate this one. If I could say just four words to President Bush, I’d paraphrase one of the mantra’s of the wind-power community; “Renewables, No War Required”.

Politics and the Myth of Clean Coal

One of the reasons renewable energy solutions are so important is that they replace energy sources that are harmful to people and the environment. Coal, for example, is particularly harmful.

The burning of coal for the production of electricity is the largest source of carbon dioxide emissions in the United States, contributing in a major way to global warming. But the problems with coal are not limited to the effects of burning it. Mountaintop Removal Mining is destroying mountains in Appalachia at an alarming rate, and is harmful to the residents of the area in many ways. Unfortunately, practitioners of mountaintop removal mining, such as Don Blankenship, CEO of Massey Energy Co., seem to care little about the mountains of Appalachia or the people who live there.

Coal is big-business in this country, and with that comes political pressure that too often results in actions that are in the interest of the coal industry rather than the interest of people and the environment. Blankenship has been known to contribute millions of dollars to political campaigns, including a massive campaign to unseat a Supreme Court judge. As Beth White, a coordinator with West Virginia Consumers for Justice, put it; “It proves that West Virginia Supreme Court seats (are) for sale.”

At the federal level, the three billion dollar Clean Coal Technology Program is a huge waste of taxpayer dollars. Toxic elements are removed from the coal, but they are not eliminated, they just end up somewhere other than the smokestack. Clean Coal Technology does not address the toxic slurry lagoons that result from the washing of coal. These are often placed in locations where they present a danger to those downstream, and they sometimes contaminate drinking water. One such impoundment failed in 1972, sweeping 125 people to their death and left 4000 others homeless.

The Clean Coal Technology Program is part of the Bush Administration’s Advanced Energy Initiative. It’s the bad part. The money spent on the Clean Coal Technology Program could be better used to fund solar, wind, and other renewable energy projects. As a result, the world would move closer to eliminating the need to produce electricity from coal, and the environment would be better off. Our air would be cleaner, and streams would be free of pollutants. There is no dirtier fuel than coal, and it needs to be phased out as soon as possible. Trying to clean it is the wrong approach.

Sadly, instead of being a good steward of the land, President Bush has placed lobbyists and lawyers from the very industries that they are supposed to regulate into important environmental positions. It is unlikely that any meaningful progress will occur until these positions are filled with people who care more about people and the environment, than they do about big corporate profits.

For more information, visit the websites listed below:

http://www.greenpeace.org/seasia/en/asia-energy-revolution/dirty-energy

http://www.energyjustice.net/coal/

http://www.mountainjusticesummer.org/

http://www.alternet.org/

http://www.washingtonpost.com/wp-dyn/content/article/2006/11/02/AR2006110201668_pf.html

http://en.wikipedia.org/wiki/Buffalo_Creek_Flood

http://solarjohn.blogspot.com

I’ve sent a copy of this paper to my representatives. I hope you will do the same.

Solar John

Phantom Loads, Are They Really That Costly?

For those who don’t know, a phantom load is the use of electrical power by a device when it is turned off. TV’s, for example, require a constant source of power for the remote-control sensing circuitry. This wasteful use of electricity can be eliminated by unplugging the offending device from the wall. Off/On switches on power strips and surge protectors offer another convenient way to disconnect devices. The amount of power used by a turned-off device is usually small, and I’ve often wondered if eliminating this feature is worth the inconvenience it causes. For that reason I decided to do some tests to find out.

I suspect that older devices are more wasteful than newer ones, but I decided to test a flat-panel TV that I recently purchased. I used a Kill-A-Watt meter to measure the current with the TV turned off. Having recently read how wasteful phantom loads are, I was surprised to find a current flow of only 30-milliamperes (0.03-Ampere). Then I did some calculations. The phantom load on this TV ends up costing me about $3.00 per year on my electricity bill. Although this isn’t much over the course of a year, I probably have at least 9 more devices that also waste this much power. That brings the total to more than $30.00 per year. And, since older devices are probably more wasteful than newer ones, my actual total is probably in excess of $60.00 annually. While it’s not a lot of money, I like the idea of reducing my monthly bill by five dollars or more.

The increased cost of grid-supplied electricity is not my only concern. I want to be able to power my home with my solar PV system eventually. Reducing waste allows me to do so with a smaller, less expensive, solar PV system. A current flow of 30-milliamperes at 120-Volts AC is the equivalent of 3.6-watts. In a day, the power wasted by my TV is 86-watts. My solar PV array needs to be able to produce this power every day. And, if I have 9 more devices wasting power due to phantom loads, my array needs to generate 860-watts each day. By reducing this load, I can downsize my solar PV array by two to four solar panels. The result is a PV system that costs considerably less than it otherwise would.

In addition to reducing my system cost, I like the fact that my efforts have a positive environmental impact. If a million homes would eliminate their phantom loads as I’m doing, the load on electrical power plants would be reduced by 860 million watts each year. Since burning coal is the primary source of electricity production, this effort would result in a lot less carbon dioxide being pumped into the atmosphere. Let’s do it!

Tips:

• Consider replacing your doorbell and alarm clocks with mechanical devices that serve the same function.
• Don't leave transformers (wall-warts), plugged in when the connected device is not in use.

Solar John

Lower Gasoline Prices Affect Interest in Renewable Energy Projects

Now that gas prices have dropped it’s likely that the interest in renewable energy will decline. We’ve seen it happen before. Renewable energy systems that Jimmy Carter installed at the White House were removed during the Reagan administration. Interest in alternative energy peaked after limited availability resulted in lines at gas stations, and subsided when supplies became plentiful again.

At times like these it is important to remember other reasons for embracing renewable energy:

- Carbon emissions resulting from the burning of coal and oil contribute to global warming, and must be reduced if our planet is to survive. About 40 percent of carbon dioxide emissions in the United States are the result of burning fossil fuels for the purpose of electricity generation. We can help to reverse this trend through conservation, the use of efficient lighting and appliances, and with renewable energy systems.

- Mountaintop Removal Coal Mining is destroying mountains in Appalachia at an alarming rate, and harming the people who live there. Don’t fall for the myth of “clean coal”. Visit www.mountainjusticesummer.org for more information.

The current low gasoline prices may be a good thing for those just now getting involved in renewable energy-related projects. The demand for alternative energy-related equipment is lower, contributing to better availability and lower prices for that equipment. But don’t wait too long. Some believe that gasoline prices will increase after the elections this fall. Additionally, a terrorist attack, or a major natural disaster, could once again create a high demand, and high prices. Take advantage of these relatively good times to make a home improvement or to install a renewable energy system.

It is also important to remember that oil supplies have peaked, or soon will. Not only will this mean higher prices, but we’re using reserves that should be conserved for future generations.

Keep working on renewable energy projects and conservation. And while you’re at it, ask your federal legislators to support HR2719, a bill that reinstates the Clean Water Act that has recently been gutted by President Bush’s destructive environmental programs and laws. Your great-grandchildren will be glad you did.

Solar John

Corn Stove Update

Being the coldest night of the season so far, I decided to run my new corn-burning stove while I slept last night. To circulate heat without using excessive fuel, I adjusted the blower to high and the fuel rate to low. As I expected, the rooms closest to the stove reached 78 degrees or more, while other parts of the house stayed in the low to mid 70’s.

Because it was still cold outside by the time I had to leave for work, I didn’t shut down the stove. Julie got home about an hour after I left, and was pleased that the house was cozy-warm when she arrived. The stove will shut-off automatically when the corn in the hopper runs out, or it can be shut down by flipping a switch. Julie decided to shut it down for the day.

It will be interesting to see how well the stove performs when the outside temperature drops below freezing. To circulate air to all parts of the house I suspect that we’ll need to use our ceiling fans or the furnace blower.

My stove, the Amaizablaze 4100, is not a highly-automated model. It doesn’t have a thermostatic control, and it must be lit manually. While the lack of these features make the stove somewhat less convenient than it could be, it also results in efficient and trouble-free operation. Because the electrical power needed to run the stove is small, my solar photovoltaic system will easily be able to provide enough power to run it. As a result, I have a reliable emergency-heating system to serve in the event of an electrical power failure. And, as long as corn prices remain low, I have a less-expensive alternative to natural gas heating in my home.

Although it would have been less expensive to buy corn in bulk, I bought mine in 50-pound bags. While there is some dust and dirt involved with the handling of corn, it’s much cleaner than handling wood. Some fly-ash is produced in the burning of corn, but little if any of that enters the house. Corn burns clean, so unlike wood-burning stoves, there is no danger of a chimney fire. In fact, it doesn’t even need a chimney. The air intake for combustion and exhaust flows through a vent similar to that of a clothes dryer.

I’m content with my decision to heat my home by burning corn, and with the 4100 stove. It seems that my heating costs will be lower, and I’m helping to protect the environment through lower carbon emissions. I’ll post again on my experience with this stove later in the heating season.

Solar John

Planet Earth Needs Your Help

While I embrace renewable energy for a variety of reasons, I write about it for only one; to encourage others to get involved. As a result of our addiction to oil we're in a useless war, benefitting large corporations that steal our money! Because politicians rely on those same corporations for campaign funding, we can't rely on them to do the right thing. That is why it is so important that ordinary people take action now. Your efforts will not only shield you from high prices and shortages, but will also help to save the planet.

First, let's consider some of the negative effects of burning fossil-fuels:

• The burning of coal for the production of electricity in the United States is responsible for about 40% of carbon dioxide emissions. The fuel we use in our cars and trucks is the next largest contributor. More than anything else, carbon dioxide emissions are blamed for global warming. Scientists believe that if we don't do something about this soon, we'll reach a tipping point from which there will be no return. The movie "An Inconvenient Truth" is an excellent documentary on this subject. Don't miss it! For more information about global warming, click on the following link. http://www.nrdc.org/globalWarming/f101.asp#1
  
• Deforestation is another contributor to global warming. Read about this, and other causes, at the following website. http://www.ecobridge.org/content/g_cse.htm
  
• Mountaintop removal coal mining in Appalachia not only destroys mountains, but also presents a danger to people who live there. 220 children at Marsh Fork Elementary School in West Virginia are not only harmed by mining-related air pollution, but are also in danger from a leaking earthen dam located above the school site that could bury them under 2.8 billion gallons of toxic waste. The full story can be found here: http://www.ilovemountains.org/news
  
• The use of gas and oil results in harmful carbon emissions, but has other consequences as well. Each time we fill our cars with gasoline, we're sending money to countries that export hate and terrorism. I prefer to send them as little as I possibly can.
  
• Coal and oil are finite resources. In other words, someday they'll run out. We're currently burning them up as if there were no tomorrow. How will we explain to future generations that we've saved none for them? If we don't do something, we'll be thought of as a very selfish generation.

Now let's consider ways the average person can help:

• The first step is to become as energy-efficient as possible. One of the easiest ways is to replace all of the incandescent light bulbs in your home with compact fluorescent (cf) types. Cf bulbs produce as much light as ordinary incandescent ones, but use much less electricity. The high cost of cf bulbs is offset by their long life, and savings on your electric bill.
  
• When it's time to replace an appliance in your home, consider only those that have earned the ENERGY STAR. A product earns the ENERGY STAR by meeting strict energy efficiency guidelines. Consider ultra-efficient appliances, such as Sun Frost refrigerators and freezers, if your budget will allow it.
  
• Consider home improvements, such as insulation and energy-efficient window replacements.
  
• When it's time to replace your car, consider the least-polluting means of transportation available.

More ideas can be found at the following website: http://www.ecobridge.org/content/g_wdo.htm

Whatever you decide, it is important that you start now. Start with energy-conservation projects, and then move on to projects that actually replace fossil fuels. Such projects might include a solar photovoltaic system, solar hot water system, or a bio-fueled stove. I'm attempting to take the mystery out of projects such as these by posting information on this blog. Read my previous posts, and check back often for new ones. My posts include links to some of the best alternative energy-related websites I've found.

If I can assist you in any way, don't hesitate to ask. I look forward to your comments.

Solar John

Children-Powered Water Pumping Project

I found this today on Reuters:

The first lady announced the first commitment - US$10 million from the US government to kick-start a US$60 million public/private project to build children's merry-go-rounds in Africa, which pump clean drinking water into a storage tank.

http://www.planetark.com/dailynewsstory.cfm/newsid/38193/story.htm

Is it just me, or doesn't it seem wrong to support a program that uses children to pump drinking water?

I remember how much fun I had on merry-go-rounds as a kid. Because there was little friction, we really got them spinning. But attaching a pump will add friction and the effort required to get the device spinning will make it a chore rather than a fun activity. If it becomes a chore, rather than a choice, then it's definately wrong.

It would be much wiser to use the available funds for solar photovoltaic systems. Such dedicated water-pumping systems are already in use in many parts of the world. Why anyone would want to use kids instead is beyond me.

Solar John

Celebrities and Renewable Energy

I recently had the pleasure of attending a presentation by Michael Gauldin, former press secretary to Bill Clinton. When a man reaches that level of prominence I assume that he must be very smart, so I’ll pay close attention to what he has to say. Speaking to a group of Department of Interior employees, Michael provided tips for producing interesting news stories that people will want to read. One of his bullet points stated that people are always interested in the lives of celebrities. Conflict and opposing views also make for good stories. With these things in mind, here’s my attempt at writing an interesting article.

Daryl Hannah lives in a teepee…..
http://www.off-grid.net/index.php?p=313

Willie Nelson manufactures and sells bio-diesel…..
http://www.wnbiodiesel.com/

Schwarzenegger Backs New Solar Power Plan…..
http://www.forbes.com/facesinthenews/2005/12/14/schwarzenegger-solar-energy-cx_gl_1214autofacescan15.html

Kennedy campaigns against renewable energy project….
http://www.cbsnews.com/stories/2003/08/12/tech/main567925.shtml

Cameron Diaz Saves the World…..
http://www.mediavillage.com/jmentr/2005/04/20/jmer-04-20-05/

Pearl Jam Takes On Global Warming…..
http://www.tmz.com/2006/07/12/pearl-jam-takes-on-global-warming/

Dave Matthews Wants to Lick Global Warming…..
http://www.lickglobalwarming.org/

Rams – Eagles in NFL’s First Climate Neutral Regular Season Game…..
http://www.socialfunds.com/news/release.cgi?sfArticleId=4830

So there you go. News stories that include celebrities, conflict, opposing views, and sensational headlines. At the same time all of these stories are related to alternative energy and saving the planet. This, no doubt, is my finest posting on this blog.

Solar John

Understanding Batteries Used in PV Systems

If you’ve done your homework before purchasing batteries for your solar PV system you’ve likely purchased some sort of a deep-discharge lead-acid type. Your batteries may have been designed for golf-carts, fork-lifts, or perhaps the kind used to run a trolling motor and lights on a fishing boat. If your budget didn’t allow you to buy the best available batteries, you might have chosen batteries with a shorter life expectancy. Whatever the type of lead-acid batteries you’ve chosen, they all have similar characteristics. If you want to know the condition of your batteries at any given time, you need to understand some basic electrical principles and some battery quirks. That is the purpose of this paper.

A battery can be thought of as a storage medium for electrical energy. Just as a glass of water can be nearly full or nearly empty, a battery can be fully charged, fully discharged, or anywhere in-between. If we were to measure the amount of water in a glass with a ruler, it would be easy to determine how full (or empty) the glass is. Since we can’t see electrical energy, we need to use instruments to measure the state of charge in a battery. A hydrometer is the most accurate instrument for state-of-charge measurements, but a voltmeter can also be used.

A hydrometer measures the density of the fluid, known as electrolyte, in a battery. The heavier the fluid, the greater the state of charge. To perform a test, a little of the liquid is drawn from the battery into the hydrometer. A float and a scale within the instrument indicate the specific gravity (density), of the liquid. With that reading, and through the use of a chart, the state-of-charge can be determined. Obviously, a hydrometer test cannot be done on a sealed battery.

Although not as accurate as a hydrometer, a voltmeter can be used to measure the state-of-charge of a lead-acid battery. However, there are a few things you need to know in order to make accurate measurements.

* Batteries have internal resistance.

When a battery is a part of a complete circuit, that is to say one in which current flows, the battery voltage will decrease. The voltage drop caused by the load on the battery will result in an inaccurate state-of-charge determination. Measure battery voltage with no load connected.

* Batteries are charged by applying a voltage greater than the rating of the battery across the terminals.

To charge a 12-volt battery, for example, 14.4-volts dc may be applied to the battery terminals. You cannot determine the state-of-charge of a battery when a charging voltage is applied. Some charge controllers provide pulses instead of a steady voltage, making dc-voltage readings inaccurate.

* The voltage reading across a recently charged battery may be far in excess of the battery’s rated voltage.

This phenomenon is known as a surface charge. To accurately measure the state-of-charge it is necessary to wait until this charge dissipates, or to burn it off by applying a load to the battery for a short time.

Interpreting Battery Voltage Readings:

Intuitively, one might expect the voltage reading of a fully-charged 12-volt battery to be exactly 12-volts. Likewise, one might expect the voltage reading of a half-discharged 12-volt battery to be 6-volts. However, this is not the case. Keeping in mind the information presented above, the chart below can be used to determine the percentage of charge for a 12-volt battery.

Battery Voltage / Percent of Charge

12.70 Volts = 100
12.58 Volts = 90
12.46 Volts = 80
12.36 Volts = 70
12.28 Volts = 60
12.20 Volts = 50
12.12 Volts = 40
12.04 Volts = 30
11.98 Volts = 20
11.94 Volts = 10
11.90 Volts = Discharged

Understanding that overcharging and over-discharging can damage or shorten the life of a battery, this information is very important. Fortunately, your charge controller prevents overcharging. It does so by removing charging current to the battery-bank once it senses that the batteries are fully charged.

Typically, inverters include the ability to turn themselves off when the battery voltage drops to preset level. As a result, the inverter protects the battery from over-discharging. Systems that do not include an inverter should include some method of removing the load when battery voltage drops to a dangerous level. Some charge controllers provide this functionality.

More Battery quirks:

* Battery capacity is affected by temperature.

A cold battery is not able to supply as much power to the load as a warm battery can.

* The discharge rate affects battery efficiency.

As the rate of discharge increases, battery efficiency decreases. An over-sized battery array is more efficient than a smaller-capacity array.

* Battery charging is more efficient at a lower rate of charge.

Just as batteries are more efficient at lower discharge rates, charging efficiency is greater at lower charge rates. In other words, a battery more efficiently stores energy pumped into it when the charge rate is relatively low.

* Batteries are not 100% efficient.

Expect losses in batteries, and other system components for that matter.

* A strange battery quirk.

When connecting a load to a fully charged battery the voltage initially drops as expected, but then begins to increase over time. This phenomenon may be due to the chemical reactions that occur when current flows within a battery.

* Chronically undercharging a battery will result in shorter battery life.

A PV array that does not provide enough charging-power to keep the battery-bank fully charged will result in reduced battery life. If your PV system is unable to maintain a fully-charged battery bank, add solar panels to your array or reduce the load on the battery.

* Allowing a battery to remain in a discharged state for an extended period of time will shorten its life.

Hard crystals of lead sulfate will form on the plates over time, reducing the capacity of the battery. To prevent this, don’t let a battery remain in a discharged state for an extended period of time.

* Avoid battery stratification.

Because battery acid (sulfuric acid) is heavier than water, it tends to settle at the bottom of the battery. This causes a build-up of lead sulfate on the plates near the bottom. This can be prevented by applying an equalizing charge of 14.4 volts to a fully charged battery for a short time, at least once per month. The elevated voltage causes bubbling, mixing the electrolyte. This function is built in to many modern charge controllers.

* Allow a battery-bank to age gracefully.

Do not add batteries to an existing battery-array. If you do, the life-expectancy of the newer batteries will be adversely affected.

* Overcharging can be dangerous.

Batteries produce hydrogen gas when charging. Overcharging, or charging at a high rate, causes an excess of hydrogen gas production. For safety, the battery-bank should be vented to the outside. Since hydrogen gas is lighter than air, an effective system includes a hood above the battery array, and stove-pipe or pvc tubing rising from the highest point.

Unless your batteries are sealed, check fluid levels at least twice per year. Excessive fluid use can be an indication that batteries are being charged excessively. If that’s the case check the rest of your system, particularly the charge controller, to be sure everything is working properly.

Battery bank capacity testing:

The capacity of a battery bank can be measured by conducting a discharge test. At night, when no charging current is present, connect a constant load to the battery bank. Using an accurate digital voltmeter, measure battery bank voltage at regular intervals and record the results. Terminate the test when the battery bank is 50% discharged. The test results can be used as a baseline to be compared with those of future tests. When the capacity of the battery bank falls to an unacceptable lever replace the entire battery bank.

It is also important to note that one defective battery in a battery array can create a load on the rest of the batteries within the array. To locate a defective battery it is necessary to disconnect batteries one at a time from the array and test each battery individually. The defective battery will probably have a significantly lower voltage than the others.

Summary:

The best way to check the state-of-charge of your batteries is through the use of a hydrometer. It is easier to measure the state of charge with a voltmeter, but you need to avoid measurement pitfalls in order to ensure accuracy.

Avoid battery problems by conducting periodic state-of-charge checks, monitoring the fluid levels, and by avoiding stratification through the application of an equalizing charge periodically. In addition, keep the tops of the batteries and battery terminals clean. Make sure that terminal connections are tight.

To design a PV system you’ll need to understand electrical principles beyond those presented in this paper. For the sake of clarity, technical terms and formulas were avoided.

Solar John

My Garden

Although this blog is primarily about renewable energy, it’s also about surviving and living comfortably in the event of a short or long-term disruption of energy or food supplies. While storage is a good solution for a short-term food shortage, growing it is the best solution for a long-term problem. As a bonus, those who grow their own enjoy tastier, healthier, and less costly food.

I begin early each spring by double-digging my garden area. In addition to the main area I prepare a couple of raised-beds by deeply loosening the soil and mixing in compost. I don’t use a tiller because I don’t want to chop up worms and beneficial bacteria, or destroy aeration and drainage. My garden is 100 percent organic and I don’t use pesticides or chemicals on my lawn, shrubs, or trees. This practice allows me to use plant wastes as compost. I find that because of composting, my plants don’t seem to need fertilizer. I avoid composting weeds because I don’t want their seeds to sprout, but all other plant matter is composted. Egg shells and waste such as shrimp peelings add calcium to the soil.

Late in July each year I have enough tomatoes to make canning worthwhile. I also freeze tomatoes and other vegetables, but I prefer canning, since those need not be refrigerated, and a long-term power outage will not result in spoilage.

Not being content with what I can grow in the summer, I’m also experimenting with techniques for growing vegetables indoors during the winter. I’ve found varieties of dwarf tomato plants that do well in cool weather, and with limited sunlight. Dwarf plants allow me to efficiently use the limited space that I have available for indoor growing. Some of the plants grow no bigger than 8 inches tall, yet produce clusters of good-tasting tomatoes. I use “free-power” from my solar photovoltaic system to run grow lights and bottom warmers in my sunroom. My plants seem to like a cycle of warm days and cool nights. I place fluorescent tubes and compact fluorescent bulbs very close to the tops and sides of the plants to supplement natural light from windows. Growing veggies in the winter is an interesting project, and I’ll devote another blog post to that subject in the future.

To take advantage of the limited space available in my backyard, I’ve planted raspberries along a section of fence. Each summer I have raspberries to snack on, and enough to freeze for later use. I’ve made some tasty pies and jelly.

I attempted to grow field corn this year to fuel my corn-burning stove but had some problems with squirrels. I salvaged a few ears to use for next year’s seed and bought a live trap. I’m planning to relocate the squirrels I’m able to catch, and hopefully reduce the squirrel population in my neighborhood.

In order to minimize city-supplied water usage, I bought two fifty-five gallon plastic drums. I’m planning to divert rain water from my garage and home roofs to the drums, and then use the stored water as needed in the garden. At the present time I use soaker hoses, and I suspect that I’ll be able to pump water from the drums through them. I’m also considering a more sophisticated system using drip emitters. In the event of a water-supply disruption, this stored water could be filtered and used in my home. Stay tuned as I report my success or failure in this endeavor.

If you’re new to gardening it’s important to understand the importance of open-pollinated seeds and heirloom varieties. By using open-pollinated types you’ll be able to save seeds from your own successful crops for future use, reducing your gardening expenses. Don’t try that with a hybrid, the results are unpredictable. The amazing thing about open-pollinated seeds is that they are able to mutate and adapt to the local ecosystem, where hybrids cannot. Heirloom varieties are those that have been handed down from generation to generation, and are usually better-tasting than hybrid types.

Genetically altered seeds produce crops that are more suitable for marketing than their natural counterparts, but taste and nutrition usually suffer. Plants such as these may cause harmful reactions in those with allergies or sensitivities. In addition, these plants may have lost their ability to prevent cancer. On the other hand, fruits and vegetables produced from plants that have not been genetically modified taste much better than any you’ll ever buy from a grocery store, and they’re better for you. They make gardening worthwhile for me.

Support biodiversity: Because of standardization, all plants of a specific variety share the same strengths and weaknesses. Since they share the same weaknesses, a single fungus or disease can wipe out an entire crop. Growing heirloom vegetables provides humanity with a hedge against future massive crop failures.

It’s also important to understand the dangers of using chemical fertilizer and pesticides in the garden. For more information, visit: http://www.organicconsumers.org/index.htm If you’re as old as I am you might remember tadpoles and crawdads in creaks and streams. Sadly, because of chemical runoff from products such as Monsanto’s Roundup, you don’t see them anymore. I hope you’ll do your part to reverse this trend, and encourage others to do the same. It is unfortunate that we cannot rely on our government, or on agribusiness, to do the right thing.

Although I’ve been gardening for many years, the gardenweb forums have been extremely helpful, especially when it comes to indoor growing. Check them out at:

http://www.gardenweb.com/

Here are a few sources of seeds, and other supplies for the organic gardener:

http://www.tomatogrowers.com/

http://www.victoryseeds.com/

http://www.seedsofchange.com/

Solar John

Happy to Have Done my Part

About twenty five years ago I was asked to use my electronics skills to develop a device that would not only improve the quality of life of a disabled person, but also to allow him to call for help in the event of an emergency. Over the years I’ve developed several different versions, each one being better than the previous one. The latest allows full control of a telephone, including a memory for up to twenty-four phone numbers, full control of a television and any other device that is normally operated via a remote-control unit, and off-on control of any AC-operated device. With an appropriate speakerphone the system is always functional, even in the event of a power failure. The control device is fully programmable by the disabled user, and all tasks are performed by using only two switches. For a quadriplegic who has no use of his hands, this level of functionality is necessary. A small tube placed close to the users face provides access to the switches. Short puffs into the tube activate the first switch, and a sipping action activates the second switch. The user scrolls through a menu of functions shown on a backlit LCD display by a series of puffs, and performs the selected action by a brief sip.

The user was my brother-in-law Mike, and unfortunately he passed away last week.

As tragic as Mike’s story is, he was blessed with a good family and friends. Each contributed to the improvement of the quality of Mike’s life in his or her own way, and I’m glad that I was able to do my part.

Because a quadriplegic relies on those around him for tasks that the rest of us take for granted, being able to do some of those things unassisted must have been a pleasure. That simple pleasure is what I hope to have brought to Mike’s life for the duration of his disability. Knowing that I had a positive impact on his daily life is my reward.

John

The Best Application of Solar Photovoltaic Technologies

Large-scale energy projects are wonderful in that they can claim to make substantial reductions in carbon emissions, and provide benefits to the owner or community served, but I find small-scale systems much more interesting. While huge arrays are impressive, they simply serve to replace grid-supplied power with power from the sun. I’m not terribly excited by this. On the other hand, small-scale solar photovoltaic (PV) projects provide practical solutions to a variety of problems. Ranchers, for example, use simple PV systems to pump water for cattle in areas where no power lines exist. While windmills were once used for this purpose, their tendency to breakdown makes PV systems a much more practical solution. The PV solution is elegantly simple in that no batteries, charge controllers, or inverters are required. The output of the PV array is connected directly to the pump. Pumps used in this application have been designed to withstand low-power conditions, resulting from of cloud cover for example, without damage.

Where power lines don’t exist, or where it is simply too expensive to run them, small PV systems are often the best power option. Remote cabins and vacation homes are an example. PV systems offer an alternative to noisy, smelly fuel-powered generators. While the initial cost of a PV system is greater than that of a generator, the cost of fuel to run the generator quickly surpasses the cost of a PV system. And, not having to haul fuel is a bonus.

The limitations of my own small off-grid photovoltaic system keep my interest high. Instead of having a system that automatically kicks-in in the event of a grid power failure, I scramble to run extension cords and lights. I monitor the drain on my system, and ration the power used for the duration of the outage so that I don’t run short. When grid-power fails, I’m the energy czar in my home. While I wish that my system were larger, there are advantages to living with these limitations. Members of my household are aware of the power that certain devices require. While we’ve taken electricity usage for granted in the past, now we tend to conserve. We understand the importance of buying energy-efficient appliances, and turning off lights and other devices when they’re not being used. We’ve learned about phantom loads, and we avoid them. Our goal is to keep enlarging our PV system and to keep reducing our electricity usage. Eventually, we'll be able to produce all that we need. This goal will take years to achieve, but then the journey is the interesting part.

Perhaps the most worthwhile PV systems are those installed in rural third-world country residences. Without PV, many rely on kerosene for lighting. This practice results in fires and injuries, as well as health problems resulting from breathing the fumes. While the initial cost of a system is relatively high considering the income of the recipient, the overall cost is lower than the cost of using kerosene. PV power is also used to run radio’s, TV’s, and computers in rural schools, as well as to provide power for refrigeration needed for medicine. Non-profit groups such as the Solar Electric Light Fund (SELF) install systems and provide financing. In addition, SELF establishes local dealerships and trains local residents as installers and technicians.

While the first practical application of solar panel technology was in the space program, it seems ironic that the most worthwhile use for this technology happens to be in the most underdeveloped areas on this planet. I wonder what the recipients of this technology think when they look at the charge controller. I wonder if they know that it not only protects the battery, but optimizes charging as well. Do they appreciate the effort that some engineer put into the design of this product?

It seems to me that providing PV technology to those who need it is a far better way to win hearts and minds than by occupying a country and killing its residents. As a solar PV system researcher I wish I were eligible for grants and subsidies. I can only imagine what I could do with one point four billion dollars, the cost of one week of war in Iraq. If I were president things would be different. While I’m waiting to be elected, I’ll welcome contributions large and small to finance my work. Anyone? Hello?

Solar John

Gloom and Doom

My research in alternative energy has turned up a lot of what I would call “gloom and doom” predictions. Some articles go as far as to predict widespread chaos, and a total collapse of the economy. I guess that some that are looking into alternative energy are doing so in order to protect themselves from a major energy infrastructure breakdown.

Since we’re already seeing gasoline prices rise at an alarming rate, it’s not hard to believe that these predictions have merit. Food will certainly be more expensive in the future due to processing and shipping costs. If this trend continues, we may eventually see only locally-grown items on the shelves.

It’s not hard to imagine gas prices so high that we only drive in emergency situations. High heating costs could force many of us to lower our thermostats and to wear warmer clothing indoors. A major increase in the cost of electricity might prompt us to cool our homes with fans instead of central air conditioning.

Shortages or costly electricity and heating oil need not be a problem for those who prepare in advance. For a modest investment you can generate enough electricity to exceed your basic needs via solar or wind power. It would be wise to consider alternative heating systems that eliminate your dependence upon natural gas pipelines or other utility-supplied energy. Learning to grow and preserve food could also prove to be a valuable skill.

Those who prepare in advance will not have to venture out for solutions in the event of a crisis. At that point, it’s too late anyway. The necessary items will probably not be available. In a serious crisis, those who don’t prepare will need to be rescued. If help comes at all, it will probably come from ordinary citizens, not the government. The aftermath of Hurricane Katrina should have taught us that. Meanwhile, some will become victims of looters and others desperate to help themselves. Those who don’t have to venture out are the ones most likely to survive. Those who live in the suburbs are more likely to survive than those who live in crowded areas where there will be a lot of competition for few resources.

We typically have food in our pantries, and some of us have emergency water and food stored away, but what do we do when these items run out? We’re sometimes told to keep a 72 hour supply, but we’ve seen that in some emergencies it has taken longer than that for help to arrive. In many cases, rescued survivors were dehydrated, exhausted, cold, and tired. This won’t happen, even in an emergency where help is slow to arrive, for those who’ve made self-reliant living their goal.

Those who incorporate elements of self-reliant living into their daily lives are not only better prepared to handle emergencies, they’re also saving money on their utilities everyday. Those who grow their own food are most likely getting more exercise than those who do not, and they’re certainly eating healthier food.

Surviving a long-term emergency requires skills that the average person does not possess, and advance preparations. Given the current state of the world, this is a good time to acquire those skills and the necessary equipment. Hopefully, with enlightened leadership, a crisis of major proportions will be avoided and they won't be needed.

Begin by assessing your basic needs, and then look into the most efficient ways to meet those needs. After satisfying your needs for water and food, next consider shelter, heating and cooling, and electrical power. Don’t skimp on your electrical system since it can help to preserve (refrigerate), and prepare (cook) food. You'll probably need to boil the water you'll use for drinking. Your system needs to be large enough to do these things as well as to provide lighting, air circulation, and to power a radio and other equipment. Test your systems once in awhile by simulating a failure of utility company supplied electricity and fuel. You might find that your emergency equipment can be used to reduce your household expenses, and to preserve natural resources such as coal and oil, a win-win situation.

When Technology Fails, a book by Matthew Stein, is a good source of information.

Solar John

My Solar Photovoltaic System. Past, Present, and Future.

My solar photovoltaic (PV) system started out small, and is periodically upgraded as funds become available. When power outages have compelled me to use the system I’ve been well pleased with its performance, but at the same time I’ve wished that it could do more. With that in mind, I’ll attempt to outline the past, present, and future capabilities of the system.

Initially, my system components included one solar panel, a charge controller, some gel-cell batteries, and a 600-watt modified sinewave inverter. With the appropriate wiring, panel mounting hardware, and miscellaneous items, the total cost of the system was about $600.00. The batteries were throw-a-ways that I got from the IT department where I work. They were not like new, but still had some life in them.

Using a couple of 75-watt light bulbs as a test load, I found that the battery bank would last for just a little over an hour. While the solar panel was capable of producing more than 400-watts of power on a sunny day, the fully-charged batteries were only able to deliver about 150-watts. Clearly, the battery-bank needed to be upgraded.

I replaced the gel-cell battery bank with two marine deep-cycle batteries. The rated capacity of these is 105ah each, for a total of 210ah. Using the 150-watt test load, the battery bank lasted eight hours. Battery capacity jumped from 150-watts to 1200-watts (150-watts times 8-hours). However, since my single solar panel can only produce about 400-watts of power on a sunny day, it will take three days to fully charge a depleted battery bank. Still, the capabilities are much greater than they were before the battery upgrade. I need not worry about running out of power when the load consists of low-power devices such as compact fluorescent (cf) lamps. The cost of the battery upgrade, including wiring, was about $150.00, and was well worth it.

A recent upgrade included another solar panel and two more marine deep cycle batteries. I now have 800-watts (per sunny day) of charging capacity, and the ability to store 2400-watts of power in the battery bank. The system is limited in that it will take three days to fully recharge a depleted battery bank, but I have an abundance of power. During a recent power outage, I ran several cf lights, fans, a radio, and a cell-phone battery charger. I even connected a TV for a short time. The drop in battery voltage by morning was hardly noticeable.

My next goal is to be able to power our small chest freezer in the event of an electrical grid failure. I’ve measured the power consumption of the freezer, and found that it uses about 0.76 Kilowatt hour per day. This is just slightly less than the total daily capacity of the two-panel array that I currently have. Without another system upgrade, I’ll have very little power left over for lights and other things. Still, running the freezer is better than watching food spoil. And, if you consider that my fully-charged battery bank will supply enough power to run the freezer for more than two days, I should be OK for the short term power outages that we typically experience.

The inverter that I’m currently using may not be able to handle the high motor-starting current of the freezer, so my next step will be to purchase a 1000-watt true sinewave inverter. I’ll also install another solar panel so that I won’t have to skimp on lights and other low-power devices in order to use the freezer. This upgrade will also allow me to use a small microwave oven, and other high-power devices for a short period of time. At this point I’ll have just over two thousand dollars invested. The performance of the system in an emergency will be well worth it.

In the event of an electrical grid power failure in the winter, I’ll want the ability to use the system to provide heat for my home. Having installed a corn-burning stove this summer, the PV system will provide electrical power to the stove’s blowers, and auger. To meet the requirements of the stove, I’ll add one or more solar panels, and two more batteries. I’ll measure the actual power requirements of the corn-burning stove on high and on low settings later this year. The only time I’ll need to conserve power is when cold weather forces me to use the stove for an extended period of time. At all other times I’ll have plenty of power for lights and small appliances.

If I had been thinking only in terms of emergency heat I would have opted for something other than a corn-burning stove. I could have installed a wood-burning stove which could have heated my entire home without any electrical power requirements. However, wood burning is more work, dirtier, and not as safe as burning corn. My previously stated goal is to live comfortably in the event of an extended power failure. All of the chores that go along with wood-burning do not meet my definition of living comfortably.

For a little over $3,000.00 I’ll have a system that will meet all of my basic household electrical needs in the event of a grid power failure. Knowing that I could have opted for a generator for about a third of that, I have no regrets. While the initial cost of a generator would have been much less, the cost of fuel to run the generator would quickly surpass the cost of the PV system. And, fuel is not always available in an emergency. My power source, the sun, is free. It recharges the battery bank each sunny day.

Having met my emergency electrical needs, I’ll next focus on upgrades that will help to reduce my grid-powered electrical load on an everyday basis. I already use the system to provide power to my grow-lights for my plants, but it would be a shame to use the system for that alone. I want to replace grid-supplied power with solar-generated power as much as possible. I’ll run the chest freezer on a continuous basis and add wiring to my computer desk. I’m also considering the replacement of our refrigerator with a highly efficient Sun Frost model. I’ll add that to the solar-powered load. With periodic upgrades, I hope to power my entire house eventually.

I like the fact that my electrical and heating systems help to reduce carbon emissions, a leading cause of global warming. Someday, everyone will have to do their part in this effort. If voluntary efforts fail to produce the desired results, conservation will become mandatory, or perhaps electricity will become so expensive that grid-connected consumers are forced to cut back. Either way, I’m glad I have a head-start.

SolarJohn

Renewable Energy to the Rescue (Again)

On April 4th a tornado ripped through my neighborhood resulting in widespread damage, and a prolonged power outage. This event provided me with my first opportunity to put my small-scale photovoltaic (PV) system to practical use. On July 19th, my area was hit with another severe storm, and another extended power outage.

Prior to the latest storm, I prepared an emergency kit. This kit includes three light fixtures with compact fluorescent (cf) bulbs installed, extension cords, power strips, and a radio. When the power goes out, I run the cords to three areas of the house, and connect the light fixtures. Because cf bulbs use so little power, I don’t worry about the drain on the system if the lights are left on.

This most recent power outage occurred during a heat wave. Since our central air conditioning was unavailable, I connected a couple of fans to the PV system. To keep track of the storms progress, I also connected a radio.

Because our telephone service is provided by the cable company, a power outage results in a loss of service. Fortunately, our cell phones continued to work, and the solar PV system provided power to keep their batteries charged.

I tried to use a microwave oven with the system, but the inverter couldn’t handle the power that it requires. It tripped the breaker. I’ll make a note to myself to get a more powerful inverter as funds become available.

Had the power outage lasted longer, I would have connected our chest freezer to the solar PV system. The energy-efficient chest freezer would have prevented frozen food from spoiling, and I could have made ice to use in a cooler in order to protect perishables from our refrigerator. To keep things humming along in the event of an extended power failure, I'll need one or two more solar panels. I've calculated that my battery bank will keep things running for at least 24 hours, but the additional solar panels are needed to keep the batteries fully charged.

My system doesn’t do everything that I want it to do at the present time, but still it is extremely useful. While most of my neighbors have only candlelight or flashlights, we have plenty of light. We have a source of power for a radio, and I’ve even connected a small TV. We can keep somewhat cool with fans, and can keep our cell-phone batteries charged. Our power source is quiet, and inexpensive to operate. One of my neighbors has a noisy, gas-guzzling generator. I wonder how much it cost him to run that now that gas prices are so high.

Eventually, I’ll have enough power to handle the electrical requirements of our corn-burning stove. This will serve as our emergency heating system in the event of a winter weather power outage. Meanwhile, it’s good to observe that when a power outage occurs, life remains fairly normal in our home.

John

Shown here are my batteries and control electronics.

Extension cords and sockets bring light to other parts of my home.

Automating Solar PV System Performance Tracking

After installing my small solar photovoltaic (PV) system, I found myself constantly monitoring array and battery voltages, and performing tests to assess the capabilities of the system. A typical test involves monitoring a voltage over a long period of time. As an example, I might want to know how long a given battery bank will last when connected to a known load. To perform this simple test a voltage reading must be taken every few minutes over a period of several hours. A notation is made when the battery bank voltage falls below a predetermined value. This is just too time-consuming. To automate this task, I purchased a Data Logger.

The range of the Lascar Voltage USB Data Logger is 0 to 32 volts dc, making it ideal for measuring array and battery voltage. Software furnished with the data logger allows the user to set up logging rate, ranging from one reading per second to one reading every 12 hours. Typically, I use the one minute sample rate.

Another handy feature of the Lascar Data Logger is the option to set the start time. I often want voltage readings to begin just before daylight, but I don’t want to wake up early in the morning to start the data logger. I program the data logger the day before, and connect it to the voltage source to be measured. The data logger remains idle until the preset date and time, and then begins measuring voltage at the preprogrammed sample rate.

The software supplied with the data logger runs under Windows 98, 2000 and XP. Software installation is easy, and it’s hard to imagine how the software could be easier to use. After connecting the data logger to a USB port, simply run the software and answer the prompts. You only need to enter a file name for the current test, upload date and time information, start time, and sample rate. Then, remove the data logger from the computer’s USB port and connect its alligator clips to the voltage source to be sampled. A flashing green light tells you that all-is-well. As it takes each voltage reading, the data logger creates a txt file. This is a type of file that can be viewed with any word processing program, or with a text editor, such as Microsoft’s WordPad program. The software also creates a printable graph from the data.

By maintaining a log of battery bank data, I now have a baseline with which to compare performance in the future. Using this information, I’ll know when it’s time to replace my battery bank. In the same way, analyzing PV array voltage over time can alert me to solar panel problems.

Measuring voltage is helpful, but it is also important to know how much power is being supplied by the array or the battery bank. Measuring power with the data logger is not as straightforward as measuring voltage, but it is possible. The first step is to add a resistor in series with the array or battery wiring. This must be a low-resistance, high-power resistor. Next, use the data logger to measure voltage across the resistor. Then, use Ohms Law to calculate current and power. In the example below, I used a one-tenth Ohm resistor, and I measured 1.2 volts across it.

First, calculate current: Current (I) = E/R or:

Voltage (E) = 1.2
Resistance (R) = 0.1
Current (I) = 1.2/0.1
Current (I) = 12 amperes

Then, calculate power: Power (P) = E times I or:

P = 1.2 times 12
P = 14.4 watts
Note: This is the amount of power dissipated by the resistor, not the power that the array produces.

Caution: Batteries and solar panels are capable of supplying a tremendous amount of power. Choose a resistor of sufficient wattage so that it will not heat up excessively. If in doubt, don’t perform these tests unattended. A fire could result.

Shown below are samples from a logging session. The left-most column is the sample number, beginning with the first sample. Next, the date and time are recorded, followed by the PV array voltage reading for that date and time. Notice that as the sun rose, the voltage readings increased. To avoid a long blog entry, I’ve only shown the first hour of here. Notice that the voltage rose sharply at 5:21:01.


1, 05/06/2006 05:00:01, 0.05
2, 05/06/2006 05:01:01, 0.05
3, 05/06/2006 05:02:01, 0.10
4, 05/06/2006 05:03:01, 0.15
5, 05/06/2006 05:04:01, 0.20
6, 05/06/2006 05:05:01, 0.30
7, 05/06/2006 05:06:01, 0.40
8, 05/06/2006 05:07:01, 0.50
9, 05/06/2006 05:08:01, 0.65
10, 05/06/2006 05:09:01, 0.80
11, 05/06/2006 05:10:01, 1.00
12, 05/06/2006 05:11:01, 1.25
13, 05/06/2006 05:12:01, 1.55
14, 05/06/2006 05:13:01, 1.85
15, 05/06/2006 05:14:01, 2.15
16, 05/06/2006 05:15:01, 2.50
17, 05/06/2006 05:16:01, 2.85
18, 05/06/2006 05:17:01, 3.25
19, 05/06/2006 05:18:01, 3.70
20, 05/06/2006 05:19:01, 4.25
21, 05/06/2006 05:20:01, 4.80
22, 05/06/2006 05:21:01, 12.50
23, 05/06/2006 05:22:01, 12.50
24, 05/06/2006 05:23:01, 12.50
25, 05/06/2006 05:24:01, 12.50
26, 05/06/2006 05:25:01, 12.50
27, 05/06/2006 05:26:01, 12.50
28, 05/06/2006 05:27:01, 12.50
29, 05/06/2006 05:28:01, 12.50
30, 05/06/2006 05:29:01, 12.50
31, 05/06/2006 05:30:01, 12.50
32, 05/06/2006 05:31:01, 12.50
33, 05/06/2006 05:32:01, 12.50
34, 05/06/2006 05:33:01, 12.50
35, 05/06/2006 05:34:01, 12.50
36, 05/06/2006 05:35:01, 12.50
37, 05/06/2006 05:36:01, 12.50
38, 05/06/2006 05:37:01, 12.50
39, 05/06/2006 05:38:01, 12.50
40, 05/06/2006 05:39:01, 12.50
41, 05/06/2006 05:40:01, 12.50
42, 05/06/2006 05:41:01, 12.50
43, 05/06/2006 05:42:01, 12.50
44, 05/06/2006 05:43:01, 12.50
45, 05/06/2006 05:44:01, 12.50
46, 05/06/2006 05:45:01, 12.50
47, 05/06/2006 05:46:01, 12.50
48, 05/06/2006 05:47:01, 12.50
49, 05/06/2006 05:48:01, 12.50
50, 05/06/2006 05:49:01, 12.50
51, 05/06/2006 05:50:01, 12.50
52, 05/06/2006 05:51:01, 12.50
53, 05/06/2006 05:52:01, 12.50
54, 05/06/2006 05:53:01, 12.50
55, 05/06/2006 05:54:01, 12.50
56, 05/06/2006 05:55:01, 12.50
57, 05/06/2006 05:56:01, 12.50
58, 05/06/2006 05:57:01, 12.50
59, 05/06/2006 05:58:01, 12.50
60, 05/06/2006 05:59:01, 12.50

Details from this session:

5:00:01 (am) Begin logging voltage at sunrise.
5:21:01 (am) Voltage sharply rises to about 12.5 volts just after sunrise.

Additional details from this session, but not part of the raw data shown above:

5:30 to 11:00 Power from the PV array tops off the battery charge.
11:00 Charge Controller senses a fully charged battery bank and reduces
charging current. Because the load on the PV array is reduced, PV
array voltage rises.
11:00 to 16:30 Clouds and shadows cause voltage fluctuations.
16:30 As the sun sets, PV array voltage drops.
20:30 PV array voltage drops to zero at dusk.

This data not only shows me that the PV array is producing power, but also that the Charge Controller is working properly. This is good to know. A faulty Charge Controller might damage the batteries, or cause them to produce a dangerous amount of hydrogen gas. Fortunately, I have an option to set alarms when programming the data logger. If the alarm feature is used, the data logger produces an audible signal when a preset low or high voltage set point is reached. By responding to the alarm, I can prevent further damage to the equipment, and avoid a buildup of hydrogen gas.

It would be better to monitor PV array and battery bank voltage simultaneously, but that would require a more expensive data logger. I’m pleased with the performance of my single-channel data logger. Over time, I’m compiling a useful log of system performance data. Since the amount of sunlight varies from day to day and season to season, each logging period produces different results. The load on my battery bank also varies over time, and logging voltage over time is the only meaningful way to monitor battery condition and performance. All things considered, the data logger was a very worthwhile investment.


Solar John

Peak Oil: Bring it on! The sooner the better!

Oil is a finite resource, and many believe that the production of oil has peaked or will soon peak. From that point on, higher costs and shortages are to be expected. There are those who believe that the chaos caused by the sharp decline of oil production will result in the end of the world. Books have been written, and websites created, specifically dealing with the effects of peak oil. Sadly, most fail to recognize the positive effects of the end of cheap oil.

If we are to believe what we read, the industrial age is about to end, and we’re on the verge of returning to an agrarian society. So what’s wrong with that? If you’ve ever tasted fresh produce you know that it sure beats what you buy in the grocery store. Highly processed food lacks the nutritional value of the fresh variety, and often contains harmful preservatives and additives. HFCS, an additive in soft drinks and many other food products, is a major contributor to childhood obesity. In addition, genetically modified food products that line the shelves of grocery stores present a health risk. On the other hand, produce that’s grown locally, and perhaps organically, tastes better and is better for you. Organic methods will replace chemical fertilizers and pesticides, and the result will be greater yields and healthier food. As a bonus, the soil will be replenished instead of being used up as it currently is.

If the industrial age is to end abruptly, you may no longer have to commute to work each day. Can you imagine how that will improve your life? No more rush hour traffic. No more road rage. No more breathing exhaust fumes. You’ll have more time to spend with your family.

As less fossil-fuels are burned, the ozone layer will begin to heal, and the global warming trend will start to reverse itself. Some scientists believe that this is already hapenning due to a variety of steps that have already been implemented. The planet is, or will soon be, on-the-mend. However, if we substitute coal for oil, we might just erase all of the gains we've already made. This must not be allowed to happen.

When we stop buying oil, we stop sending money to countries that export hate and terrorism. I can hardly wait for that to happen.

This, of course, is an oversimplification. The transition will be difficult. However, it is possible to live a good life without petroleum-based products. Everything we currently do that involves oil can be done another way, and often in a much better way. The transition will open up new career opportunities, and not just in agriculture. Technically savvy folks will find interesting work in energy production, construction, service, and transportation. Those who are the quickest to accept post-oil technologies will be the most successful.

Cuba made a quick transition from a budding industrial power to an agrarian society when the collapse of the Soviet Union resulted in the loss of oil imports. We can learn a lot from their experience. Perhaps the most important lesson is that every individual needs to prepare, rather than to wait for the government to take care of them. Without food on the table, government programs are useless. Cubans who had never worked in agriculture before learned to grow food crops, and other survival skills.

The sooner we start to look beyond petroleum, the better. And, since our elected leaders don't seem to grasp the urgency of the current siuation, it is up to each individual to prepare for the future. Fortunately, there are those such as Al Gore and Arnold Schwartzanegger who do understand the urgency and are doing something about it now. Hopefully, others will follow. Please remember them at election time.

Solar John

My Solar Photovoltaic (PV) System

A solar photovoltaic (PV) system can be as simple as a single module with the ability to charge the battery of a cell phone, or a huge installation designed to supply the electrical needs of an entire community. My PV system began with one panel and a small battery bank, and continues to grow as my finances will allow.

People often ask “how much money do you save on your electric bill?” They seem surprised when I tell them almost nothing. At that point, I imagine that they’re wondering why I bother with a system of this small size at all, and I feel compelled to explain why I do what I do.

I hope someday that my PV system will be able to supply all of my electrical needs, but I have already benefited in many ways from my modest system.

It’s a learning experience. I can apply what I’ve learned to a full-blown system. As I expand, I’m not overwhelmed by the technology.

I often use my system to supply power to night-lights, and to grow-lights for my plants. I’ve even used it to power the lights on a Christmas tree.

My system served as an emergency power source recently when a tornado caused a power outage. I had plenty of power for lights, cell-phone battery charging, a TV, a radio, and other small appliances. I can use my system to keep a small freezer running to prevent food from spoiling in the event of an extended power failure.

By reducing electrical usage from the grid, I’m reducing the load on a fossil-fueled power plant, and therefore reducing carbon emissions. Carbon emissions, more than anything else, are responsible for global warming.

Considering the ever-increasing cost of fuel, it’s good to have an alternative. It’s hard to predict how much money I’ll save in the future with my system.

As the price of fuel increases, the demand for PV equipment will rise. This is likely to cause supply problems and dramatic price increases. I’m glad that I already have a PV system in place.

Working with a limited power source has taught me to think about energy-efficient lights and appliances. Each time I purchase an energy-efficient device I’m reducing my utility bill and increasing the usefulness of my system.

In an effort to reduce my home heating costs, I’ve recently installed a corn-burning stove. Using this stove, I expect to be able to heat my home for significantly less than it costs to heat it with natural gas. My PV system will provide power for the stove’s fans and auger. However, I’ll need to add PV panels and batteries if I am to have enough electricity to make it through a cold winter night.

John