Monday, August 20, 2007

Rethinking Solar Power (PV) for Your Home

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

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

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

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

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

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

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

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

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

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

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

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

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



Anonymous said...


Just visited your site for the first time... love it!
In your opinion, if I only have $10k to spend towards an energy/earth -saving purchase, should I invest in solar panels for my 2000 sq ft New England home or upgrade my 2005 Toyota Highlander to an electric/plug-in hybrid? (I drive about 450 mi. a week)


Solar John said...


Applying that $10K to the purchase of a plug-in hybrid will prove to be better for the environment, and will cut your transportation costs at the same time. Using that $10K for solar panels will not help anywhere near as much as switching to an electric car will. Thanks for the kind words. sj

Solar John said...


I just want to add this....

There are a lot of variables that I didn't consider in my first response. A $10k PV system won't be enough to power most homes, but if you do the labor yourself, and take advantage of federal, state, and local incentives you might end up with a substantial system. Still, 450 miles a week is a lot of driving. But since phev's are not available yet, you can't calculate the savings over your Highlander at this time. My gut feeling is that you'll save more with the phev than with the solar panels. sj

tmcco4316 said...

Solar John:
I just came across your site and you offer some very good information. I wanted to make you and your readers aware of a new resource that I have just published entitled "Tired of Making Your Utility Company Rich, A Solar Homeowner Explains When and Why You Need Solar on Your Home".

This eBook is located at and is in downloadable PDF format.

This eBook is also available on CD-ROM. Distributor pricing is available and we are looking for ways to get this information to the general public.

Thank you.

H. Court Young
Geologist, author and publisher
Promoting awareness through the written word
info @