Solar Energy

Solar technologies use the sun's energy to provide heat, light, water, electricity, and cooling for homes, businesses and industries. Despite the sunlight's considerable potential for the provision of energy, solar energy has less than 1% of U.S. energy needs. This percentage is expected to increase with the development of new and more efficient solar technology.

Different types of solar collectors used to different energy needs. Passive solar building collect the heat of the sun to provide space heating and lighting. Photovoltaic cells convert sunlight directly into electricity. Concentration solar power systems focusing sunlight with mirrors to a high intensity heat source, which then produces steam or mechanical power to run a generator that produces electricity. Collectors flat panels absorb the sun's heat directly into water or other liquids to supply hot water or space heating. Process and solar energy heating and cooling systems use solar collectors and specialized chemical processes to make large-scale hot water and heating and cooling.

Solar energy technologies produce some negative effects on the environment during the collector. However, there are environmental concerns associated with the production of collectors and storage devices. In addition, cost is a major drawback to solar energy. Although sunlight is free, solar cells and the equipment needed to convert direct current to alternating current output for use in a house is expensive. Electricity by solar cells is still more than twice as expensive as electricity from fossil fuels. Part of the problem with the costs is that solar cells can be generated only during daylight hours. In contrast, coal or natural gas plant can around the clock, which means that the cost for building the plant can be for many hours more.

Around the United States, available sunlight varies greatly due to differences in the cloud cover and width, and also varies with the seasons. In summer, more daylight and a higher sun angle more solar power, compared to the winter months when the sun for a few hours and at a lower position in the sky. These differences must be taken into account in the planning of solar collection.