2. Energy Resources

Depending upon its source and utilization, energy can be divided into two major classifications viz. (i) Traditional or non-commercial, and (ii) Commercial Energy. Examples of non-commercial energy resources are firewood, charcoal, cow dung and agricultural wastes. The commercial sources of energy comprise coal, oil, natural gas, hydro-electricity, natural gas, nuclear power as well as wind and solar power.

Another important classification based on the nature of energy is conventional energy source

and non-conventional energy source. Coal, Petroleum, Natural Gas and electricity are the main sources of conventional energy while solar, wind, tidal, geothermal etc are example of non- conventional source of energy.