roof in

Any time the sun is shining, your home's roof is exposed to solar energy. Why not exploit that energy, reduce your electric bill, and do your part to limit the amount of pollution being added to the atmosphere each day? Mounting photo voltaic cells (PVs) on your roof could very well be a smart way to make your home more energy independent.

A solar panel or cell uses the photoelectric effect to produce electricity. These cells are typically constructed of a thin layer of a photosensitive material such as gallium arsenide, crystalline and amorphous silicon, and copper indium diselenide. These materials produce electricity when they absorb sunlight. Light hitting the solar cell raises the energy level of the electrons within, allowing the electrons to escape from their molecules and create an electric current. This is called the photoelectric effect.

Naturally, solar cells exposed to direct sunlight are the most efficient. Solar panels are ideally mounted on your roof in such a way as to have an unobstructed southern exposure. Depending on your latitude and the angle of your roof's pitch, your PV system installer may suggest changing the angle of your solar panels with an adjustable mount so that they can be exposed to more light Be sure your roof can bear the additional weight before considering installation of solar cells.

Solar shingles are a relatively new alternative to traditional solar panels. Photo voltaic cells have been incorporated into these new shingles allowing the home owner to kill two birds with one stone. If your roof needs to be replaced anyhow, solar shingles are possibly the way to go.

PV cells produce direct current, and can be connected in series to increase the output voltage. Although there are specific appliances intended to operate on direct current, most PV systems send electricity through an inverter. The inverter converts the solar cells' DC to standard household alternating current. The AC output from the inverter is then incorporated into the electrical system of the house. Smaller systems will usually just supplement power from the electric company, reducing your overall bill.

If you install a larger system you may actually produce a surplus of electricity. This surplus may either be stored in on-site batteries, or can be routed back to the electric grid. If you feed your surplus back to the grid, the electric company may actually compensate you. This is called "net metering", and is the law in more than thirty-five states.

The initial cost of a roof mounted solar array can range from $6,000 to $30,000 or more. Before jumping in, it would be wise to compare what you are currently paying per kilowatt-hour to an amortized per kilowatt-hour cost for a PV system. According to the U.S. Department of Energy, that cost is about $0.25 per kilowatt-hour. In most places, this is more than what the utilities charge.

The good news is that there are many state-sponsored incentive programs for solar energy. Also, the cost of the electricity your solar panel system produces is exempt from deregulation, rate-hikes, and inflation. Just think, that amortized twenty-five cents per kilowatt-hour cost will still be twenty-five cents thirty years from now. There is no telling what your local electric rate will be. By going solar, you are reducing the amount of fossil fuels burned at power plants, you are reducing the amount of carbon dioxide we pump into the atmosphere, and you are asserting your energy independence. Producing solar electricity is feasible, makes sense, and is within the reach of most homeowners.