Solar energy from the sun can be used to generate electricity; heat water; and heat, cool, and light buildings. Photovoltaic systems use semiconductor materials similar to those used in computer chips to capture the energy in sunlight and to convert it directly into electricity.
The sun's energy can also be harnessed in a concentrating solar power system, which uses the sun's heat to generate electricity. Sunlight is collected and focused with mirrors to create a high intensity heat source that in turn can be used to generate electricity through a steam turbine or a heat engine.
Solar hot water systems use the sun's energy to heat water for domestic or industrial use. The heat from solar collectors can also be used to heat commercial buildings as well as to provide energy for cooling a building.
Certain materials that can absorb solar energy can be built into the floors and walls of buildings that will store heat during the day and slowly release heat at night.
Solar energy accounts for 1 percent of renewable electricity generation and 0.02 percent of total U.S. electricity supply.
For a map of solar insolation resources in the U.S., see page 6-3 in the National Energy Policy report, May 2001.