What is meant by green energy? Which energy sources can be called green energy sources and why? Give examples.

Electricity can be generated from sources such as water reservoir, wind, sunlight, biofuels and so on. The energy sources used in these are perpetual and never ending. These do not cause any environmental issues and so can be considered to be environment friendly. Meanwhile, the energy produced by these processes is known as green energy. Owing to the issue coming up because of electricity generation using fuels such as coal, natural gas and nuclear fuels, the world is now heading towards more environmentally friendly or green energy sources.