The modern solar industry began with the oil embargo of 1973-1974 and was strengthened with the second embargo in 1979. The growth of the solar industry during this period of fuel shortages and high prices (1974-1984) soared from 45 solar collector manufacturing firms to 225 firms. The solar market was helped during this period by government assistance - both Federal and State. Currently, solar thermal devices do everything from heating swimming pools to creating steam for electricity generation. Solar power remains an expensive source of electricity, and so accounts for just 1% of the nation's energy supply Energy Information Administration (EIA). The federal government is once again working to bring down the cost of solar power, so that it is competitively priced with other energy sources by 2015.
- Photovoltaics (PV): Semiconductor material (often silicon) absorbs the sun's rays and turns it into electricity. Solar panels work even if it is cloudy, and most of the U.S. gets enough sun to make PV a viable option.
- Solar thermal: Solar collectors absorb the sun's energy to provide low-temperature heat used directly for hot water or space heating for residential or commercial buildings.
- Concentrated Solar Power (CSP): CSP systems use reflective materials that concentrate the sun's heat energy to drive a generator that produces electricity.