ENERGY
Solar Energy
Solar energy is radiant energy that is produced by the sun. Every day the sun radiates, or sends out, an enormous amount of energy. Sunlight is an energy source that is by far the most abundant of those available on the planet. On average, the earth's surface receives about 1.2 x 1017W of solar power. Most of the other renewable energy also depends on the sun as the primary source. Throughout human history, non-concentrated solar irradiation has been used to produce daylight, heat and to grow food. The energy contained in fossil fuels - coal, oil and natural gas - originate from the sun's energy.
Utilization of solar energy
Solar energy utilization refers primarily to the use of solar radiation for practical ends. However, all renewable energies, other than geothermal and tidal, derive their energy from the sun. Today, people can use solar energy to heat buildings and water and to generate electricity. Solar powered electrical generation relies on photovoltaics and heat engines. A partial list of other solar applications includes space heating and cooling through solar architecture, daylighting, solar hot water, solar cooking, and high temperature process heat for industrial purposes.