With the dawn of industrial era, in India the sources of energy to run giant machines suddenly came into prominence. Wood fuel was confined only to domestic use and that too in the rural area. Coal, which was already in use, became a highly priced commodity. It was then supplemented by natural oil. Likewise, the use of hydroelectricity gained currency in the areas where running water and needed technology was readily available. After the World War II yet another source of energy was added. It was the nuclear energy. It called for a very sophisticated level of technology. All these sources of energy are known as conventional sources of energy.

These sources of energy, like minerals are exhaustible. Hence they need to be used judiciously and conserved for future use. Among the conventional sources, the coal still occupies a prominent position.

Coal:
Apart from being the prime source of energy, coal is also a raw material and is an indispensable part of the steel and chemical industry.

Oil and Natural Gas
India has a very large proportion of tertiary rocks and alluvial deposits particularly in the extra-peninsular India. These sedimentary rocks, which were once under the shallow seas, hold the possibility of harbouring oil and gas deposits. Hence, this oil and natural gas happens to be one of the main power resources in India.

Thermal Power
The modern world is well aware of hydro-electricity. It is derived from a source, which is plentiful and above all renewable and is reckoned as one of the main natural resources of India.

Nuclear Power
India has been a leader in making peaceful use of atomic energy in fields like medicine and agriculture. Quite ideally therefore India is rich in certain atomic or nuclear minerals.

Power Grids
The power generated from every possible source is fed into five regional grids. All the regional grids are expected to be connected into a single national grid to serve all the regions better even in adverse conditions.