There are two main residential solar technologies, and a third option for large-scale power generation. Photovoltaic solar power systems convert solar power into electricity. Thermal solar systems are a simpler, older technology for using solar power to heat water. Concentrating solar power systems are a hybrid of the two concepts.
Concentrating solar systems collect solar power with an array of mirrors. Like asatellite dish, they reflect the power into a central concentrator that boils water. The steam is converted to electric solar power. Concentrating solar power has been used mainly for industrial applications and large-scale electric generation. Concentrating solar power is too expensive and generates too much power for residential use.
For homeowners, photovoltaic solar power systems remain the best option for producing renewable electricity. Most photovoltaic solar power systems have a series of thin silicon semiconductor cells embedded between layers of glass. Light energy from the sun dislodges silicon electrons, which is the first step in creating direct-current electricity. Each cell only produces one or two watts of power, but they are combined into photovoltaic solar power systems that produce more than 1,000 watts, or a megawatt, which is enough to power a small, energy-efficient home.
Photovoltaic solar power systems also may contain cadmium-telluride, copper-indium-diselenide or gallium-arsenide in the semiconductors, each of which may offer some cost and production advantages.
The other components in photovoltaic solar power systems may include devices that point solar cells toward the sun, batteries for electric storage and converters to turn the direct current into alternating current that flows through the wires in the house.
The first photovoltaic solar power systems were developed in the 1950s. They have since become cheaper, more efficient and more advanced. Experts suggest that photovoltaic solar power systems will continue to drop in cost. By 2016, photovoltaic solar power systems are projected to reach a cost per megawatt comparable to coal-fired power plants, which are by far the most common power source in the United States.
There also are federal, state and local rebates and tax credits for homeowners installing photovoltaic solar power systems. Another new option in some areas is leasing photovoltaic solar power systems. Some companies promise that the savings on electric bills for anenergy-efficient home can equal the monthly lease.
Photovoltaic solar power systems differ significantly from solar thermal systems and concentrating solar power systems, and they are the best option for residential solar electric generation.
Author Steve Graham is an expert on green building who writes for several homeimprovement publications. He's full of great, practical home improvement answers, and incidentally, he's pretty funny - so send him a message.