Sources of energy are categorised as conventional and non-conventional. Coal, petroleum, natural gas, and electricity (both thermal and hydel) are conventional while solar; wind, tidal, geothermal, atomic energy and biogas are non-conventional sources of energy. Conventional sources of energy have been in use for quite sometime while non-conventional sources are new.
It is produced from water which is a renewable resource. For generating hydro electricity water is released at great force from a high head, and hence dams are constructed across rivers to store water. Other sources of energy namely coal; petroleum and gas are non-renewable resources. Hydro-electricity accounts for 25 per cent of total electricity produced in India. The hydel energy will play a major role in the prosperity of India in future.
The total hydel power potential of India is estimated at 150,000 MW of which only one sixth has been developed so far. The total installed capacity of the hydel power projects of the country is 23,488 MW. Important hydel power producing states are Andhra Pradesh, Karnataka, Kerala, Orissa and Punjab.