Solar energy is the energy received by the earth from the sun in the form of solar radiation. Solar power is the generation of electricity from sunlight directly with photovoltaics (PV) or indirectly with concentrating solar power (CSP).
Solar photovoltaics are arrays of cells containing a material that converts solar radiation into direct current electricity. The production cost of silicon-based solar cell module in 2008 was at some point 4-5 times higher than that of thin film modules. The efficiency in practice is from 6% to 9% and research labs are targeting 20% to 40% (Wikipedia: Solar cell).
Wikipedia: Deployment of solar power to energy grids provides information of solar energy use on each continent.
