There are two major sources of energy such as Conventional sources and Non- Conventional sources of energy. Conventional sources of energy are also known as non-renewable sources of energy and are available in limited quantity apart from hydro-electric power. Examples of these are oil, natural gas, firewood, coal, petroleum and so on. Whereas non-conventional sources of energy are renewable in nature. Examples of these are solar energy, bio-energy, tidal energy and wind energy.