Technological advances have enabled man to harness energy, convert it into useful forms and put it to several uses. Adequate amounts of energy in affordable forms is essential for economic development. With increase in income and education levels, demand for power and other forms of energy is increasing rapidly. Rapid industrialisation, urbanisation, mechanisation, population growth and changing life styles of people are also leading to increasing energy consumption. All this has led to energy crisis.
Two renewable energy sources are :
(i) Nuclear Energy : The energy contained in the nucleus of an atom, which binds the subatomic particles together is called nuclear energy. This energy can be released in the form of heat or light either by fission or fusion. It can generate huge amount of energy. Nuclear fission releases energy by splitting the huge nuclei of atoms such as uranium. In nuclear fusion, energy is released by fusing together small atoms such as deuterium.
(ii) Wind Energy : The energy which is obtained from air in motion is known as wind energy. Wind can be used to generate mechanical power such as for pumping water, grinding grains and driving sails boats. A large number of windmills are installed over large area called 'wind farm'. The energy produced by all the windmills is coupled together to generate electricity at a large scale. There are about 100 sites in India where wind farms can be developed. The wind power potential of India is estimated to be 20,000 MW.