Sources of energy can be broadly classified into two categories-(i) Exhaustible sources and (ii) Inexhaustible sources or renewable sources. Exhaustible sources are also called conventional sources and include mineral coal, fire wood, cow dung, mineral oils, natural gas, hydro-electricity and nuclear energy. Of these only hydro-electricity is renewable because it is based on inexhaustible source i.e. water. Reserves of all other sources are limited and the quantity once used cannot be used again. Under non- conventional sources or renewable sources, as they are called, come the solar energy, wind energy, energy received from tidal waves and the bio-gas energy.
These sources are not in common use and have not been fully exploited hence these are given the name non-conventional. With the ever-increasing demand for energy in order to run our developing industries, railways, automobiles etc. it is certain that our conventional sources, reserves of which are limited, will sooner or later be exhausted and their exhaustion will definitely lead to chaos.
It is, therefore, necessary to exploit the renewable sources of energy. This will not only save our reserves but will also reduce the cost of transportation of energy to the remote country places where non-conventional sources such as cow-during solar heart and wind are in plenty.
Central Government and some state governments are alive to this fact and attention has been given to non-conventional sources of energy by the planning commission also. In the English Five Year Plan provision had been made for the development of these sources and we discuss these here one by one.
(i) Wind energy:
Setting up of wind farms has been taken up in Orissa, Tamil Nadu, Maharashtra and Gujarat. Bharat Heavy Electrical has also developed machines having 200 MW capacities. This technology is being adopted in private sector and it is hoped that it may soon become an indigenous sources of energy. During seventh plan period about 2500 wind machines had been set up. During eighth plan a target of installing 100 MW pumps was fixed.
(ii) Solar energy:
During most of the year we have plenty of bright sunshine in India. Hence potential of solar energy is quite popular day-by-day. It is a very cheap and easily available source of energy. A thermal power plant has already been set up in Rajasthan which is expected to become functional. This will be an important achievement and will go a long way towards rural development.
Source of biogas energy is mainly the cow-dung which is very easily available in the rural areas. Its set up is quite east. It is quite popular in Uttar Pradesh, Andhra Pradesh, Tamil Nadu and Maharastra. It is mostly used for family purposes i.e. cooking. During seventh plan period nearly 15, 00,000 plants of biogas were set up and some 7, 50,000 plants were expected to be set up during 8th plan period.
(iv) Solar photovoltaic cells:
These cells are mainly meant for Electrification of rural areas. Wherever this source of non-conventional energy is easily available, generators up to the capacity of 10 to 100 kw are being manufactured. Bharat Heavy Electrical and central Electrics ltd. Have come forward to manufacture these cells on a large scale.
There exists great potential for the generation of electricity from the tidal waves of the ocean. Efforts are being made to use this source for commercial purposes. Our scientists are busy in search of potential sources of energy of running automobiles. A department for non-coventional sources of energy has been set up at the centre for which a sum of Rs.857 corer was allotted during the Eighth plan period. Efforts are on for generating electricity from urban waste and we hope that many more sources might be available by the end of 20th century.