The important commercial sources of energy are discussed below:

1. Coal: It is the most important source of commercial energy. Around 54% of the commercial energy consumed 55% and of total energy consumed has its origin in coal.

The important consumers of coal in India are thermal power stations, steel plants, brick-kilns, railways, cement factory, etc, and Coal India Ltd and Singrani Coal Company are the two main producers of coal in India.
The quality of Indian coal is not good, therefore India also has to import coal from other countries. Also, given the present rate of consumption, it is feared that India will use up its coal reserves in 125 years. Also, it should be remembered that the consumption of coal for commercial purposes has risen while that for non-commercial purposes has fallen.

2. Petroleum: It is also an important source of energy in India. India has to import petrol because its reserves are not enough to meet its ever increasing demand. About 30% of India's imports account for petroleum and petroleum products.
3. Natural Gas: It is another important source of conventional energy. It is used as cooking gas in households (LPG) and as a raw material in fertilisers and petroleum products. Now-a-days, it is also used as a fuel (CNG) in cars and three-wheelers.
4. Electricity: This is the most important source of commercial energy.