Energy is the physical quantity, which can manifest itself as heat, as mechanical work, as motion and in the binding of matter by nuclear or chemical forces. According to the modern concept of energy developed following the work of Einstein, mass itself is a manifestation of energy. One Joule (SI unit of energy) is equal to the energy dissipated by an electric current of 1 ampere driven by one volt for one second. Fuels are valued by the thermal energy that yield on complete combustion in terms of Btu units (One Btu = 251 calories = 1050.18 Joules). Energy utilization, irrespective of the energy source, has environmental consequences as its production and utilization results in the release of greenhouse gases (e.g., CO2, N2O etc.) and air pollutants (e.g., SOx, NOx, hydrocarbons etc.). High ash content in Indian coal and inefficient combustion technologies further aggravate the situation. Nuclear energy on the other hand, raises environmental concerns about long-term storage of radioactive waste.
Fundamentally, there are two different forms of energy resources: (a) Renewable energy resources from sources such as sun, wind, water, agricultural residue, firewood, and animal dung which do not exhaust (b) Nonrenewable energy resources include fossil fuels like coal, oil, natural gas etc. all of which are mixtures of compounds containing carbon and hydrogen. But fossil fuels will not last forever.
India is the world’s seventh largest energy consumer. Coal is the primary fuel for energy in India, followed by petroleum, and natural gas. India is the third largest producer of coal in the world. India’s current power capacity falls 30 percent short of demand. Computed data indicate that CO2 emissions per unit of electricity from most power plants range between 0.8 and 1.2 kg/KWH. Similarly, average SO2 emission per unit of electricity from Indian thermal power plants has been found to be 7.4 gm/KWH.
The key energy challenge facing India today is preventing bottlenecks in energy supply from constraining economic growth.