Is Home Solar Power Realistic?

Is home solar power a realistic and affordable option in the US?

Photo voltaic cells, which turn light directly into electricity, are now readily available in the USA. You can buy solar panels and install them yourself, or have a professional installer do this for you at a cost. These will generate some electricity during the hours of daylight, even when it's cloudy. The problem is the cost of the panels, and the additional cost of installation if you don't fancy climbing up on your roof to install them yourself. Typical installation costs run to $10,000 for a 2.5KWp system. More if you have them installed by a contractor. The most this will save you is $300 to $500 a year depending on the price of electricity from your utility company and your climate. This gives you a payback period of 20 years assuming no maintenance is required during the first 20 years. If you live in an area with cloud cover for several months of the year then these figures are ever worse.

So on the face of it, solar power doesn't make sense economically. There are plenty of environmental reasons to consider it but I'll cover those in another article. There are, however, two little known factors that will completely turn this around.

1. State Rebates.

If you are lucky enough to live in certain states, either your state government of your local utility company will rebate a part of the cost of a home solar power installation. Several states are giving cash rebates of up to 80% of the cost. Others will give you a low-interest loan. Due to state and federal requirement for power companies to source more green energy, they are also willing to buy back electricity generated from your solar panels. Your electricity meter runs backwards to measure this. Some householders with large installations, or low power consumption, even receive a monthly check from their utility company instead of a bill!

You can find details of the rebates for your state at DSIRE This is a national database of incentives for renewable energy and efficiency and is free to use.

2. Tax Credits

In 2005 congress introduced a tax credit for renewable and energy conservation in residential buildings. Unfortunately this was capped at $2,000. In 2008 congress extended the tax credit on residential solar power installations for a further eight years and also removed the previous $2,000 cap. Most states are also matching the federal credit, so if you are dipping into your own wallet for solar panels this could make a big difference to your tax bill next April. As with all tax matters the situation may be affected by your personal circumstances so be sure to consult a tax professional before making any commitment.

Given the factors for rebates and tax credits you may find that installing solar power is the best financial decision you ever made. You can get more information on rebates and links for the DSIRE database from Home Solar Power at 4solarpower.net.

Home Solar Power in Practice

Here's a great example of a large home solar power system installed on a rooftop in Wisconsin, probably one of the largest home systems in the state. It generates 7.2KWp of electricity. While most of us only aspire to a more modest system it must be nice to receive checks from the utility company each month instead of a bill.

Photo by mjmonty

The Cost of Disposable Batteries

There's a good analysis over at 4solarpower.net about the real cost of energy from AA batteries which may shock you. They are apparantly costing us over $300 per KWh. Another reason to consider solar power!

Home Solar Electricity

To generate electricity from the sun requires the use of photo voltaic (PV) cells. These cells convert sunlight falling on them directly into electricity.

PV cells are usually comprised of two layers semi conducting material - silicon with current production technology. When sunlight shines on the PV cell it creates a differential field across the two layers. This voltage differential flowing produces an electric current which can then be used directly of stored in a battery for later use. The higher the intensity of sunlight, the higher the current.

Are they suitable for home solar power?

Well... yes and no.

Yes they are readily available in both DIY and electronics stores. They will certainly generate electricity during the day. The problem unfortunately is cost. It will typically cost you $10,000 to have a 2.5KW system installed. This may generate a third to half of your annual electricity. Even if you live in an area with high energy prices this will only save you $500 a year. The payback period, assuming no maintenance is 20 years. Unfortunately battery technology can't provide a no maintenance scenario. When was the last time you car battery lasted 20 years?

The initial costs must be reduced for this to be cost-effective. Luckily there are some DIY solutions than can be installed for a few hundred dollars which will reduce this payback period dramatically. I'm going to cover these DIY home solar power projects in a later posts.

Grand Canyon Solar Power

The Grand Canyon visitor center is getting a solar power boost according to The Arizona Republic

The $185,000 system is expected to supply 30% of the center's electricity needs.

Solar Powered Car

Solar powered car seen at the Washington Auto Show.

Notice the furry dice in the windscreen!

Photo by borman818

Hot Water for the Home from Solar Power

Creating your own home hot water by solar power is the easiest and most cost-effective way of using this free energy.

If you decide to heat your water in this way you may need to make some changes to the plumbing systems in your home. If this is the case, then be sure to get professional advice before making either structural or plumbing changes to your home.

There are several different ways to heat your water using solar power. You can even make your own solar water heater from commonly available materials if you have basic DIY skills. The water to be heated runs through a solar panel before it enters your home. This panel is usually mounted on a south facing wall or roof which is warmed by the sun. You will generally need a tank to store the heated water until you need to use it..

A flat plate collector is the most inexpensive and easiest collector. This is a thin rectangular box that has a see through cover, either glass or UV resistant plastic, which carries the water to be heated. Some systems intended for areas of the world that regularly experience freezing temperatures use an antifreeze solution rather than regular water. The water moves through the tubes, usually copper although plastic is sometimes used, to an absorber plate. This plate is painted a mat black to absorb the heat from the sun. As the sun shines on to the plate, it will get hot and heat the fluid that passes through the tubes. If you have a direct water-based system, the solar heated water passes into an insulated storage tank. For a system with anti-freeze the solution passes through a heat-exchanger to warm water.

Solar water heating systems can be divided into two major groups: Active and passive:

An active systems uses a pump to move the water between the solar collector and the hot-water storage tank. Active is the most common because it is the most efficient.

Passive systems rely on the fact that hot water rises to move the heated water from the collector to the storage tank. This may be slow and is not as efficient but it does not need electrical power to run the pump and is sometimes a more logical choice if you are trying to save energy.

Heating water using solar power is more affordable that generating electricity from PV cells and can be installed with DIY skills. Choosing to heat your water using solar power is a great first step towards home solar power.