Renewable energy sources are those energy sources which are not destroyed when their energy is harnessed. Renewable energy sources are distinct from fossil fuels, which must be consumed to release energy. Use of renewable energy requires technologies that harness natural phenomena, such as sunlight, wind, waves, water flow, biological processes and geothermal heat.

Traditional uses of wind, water, and solar power are already widespread; but the mass production of electricity using renewable energy sources has become popular recently, due to major threats of global warming, concerns about the exhaustion of fossil fuels and the environmental, social and political risks of extensive use of fossil fuels.