Solar Energy

There are a variety of technologies that have been developed to take advantage of solar energy. As the world has become aware of some of the harm that has resulted in the use of nuclear energy, much has developed to try and correct this. NREL performs research to develop and advance all of these technologies which include: photovoltaic (solar cell systems), which Produce electricity directly from sunlight; concentrating solar systems which uses the sun's heat to produce electricity; passive solar heating and day lighting; which uses solar energy to heat and provide light to buildings; solar hot water which is used to heat water; and solar process heat and space, heating and cooling. Solar energy can be used to generate electricity, provide hot water, and to heat, cool, and light buildings. Photovoltaic systems convert sunlight directly into electricity. A solar or PV cell consists of semi-conducting material that directly absorbs the sunlight for its own uses. This is how it works; the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. PV cells are usually combined into modules that hold about 40 cells. About 10 of these modules are mounted in PV arrays. PV arrays can be used to generate electricity

for a single building or, in large numbers, for a power plant. The use of this technology could some day make the need for nuclear power to become obsolete. A power plant can also use a concentrating solar power system, which uses the sun's heat to generate electricity. The sunlight is collected and focused with mirrors to create a high-intensity heat This heat source produces steam or mechanical power to run a generator that creates electricity. Solar water heating systems for buildings have two main parts: a solar collector and a storage tank. For this to work the sun heats an absorber plate in the collector, which, in turn, heats the fluid running through tubes within the collector.