renewable energy

Renewable energy is energy which comes from natural processes/resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (i.e. naturally [and usually constantly]replenished). Renewable energy is a cleaner and more sustainable alternative to most conventional fuels in four distinct areas: power generation, hot water/ space heating, transport fuels, and rural (off-grid) energy services. Renewable energy 'fuel' sources (e.g. wind, sunlight rays, ocean waves) differ from conventional fuel sources in that they are generally 'cost'free (they are not commodities)and harnessing them has significantly less of a negative impact on the environment and life on Earth. Besides the renewable energy technologies currently available, new and emerging renewable energy technologies are also under development. {Source [adapted]: Wikipedia}