INTRODUCTION :-
Energy is one of the major input for economic development of any country . In case of the development countries, the energy sector assumes a critical importance in view of the ever increasing energy needs required huge investments to meet them .
ENERGY COME IN DIFFERENT FORMS:-
HEAT (THERMAL) , LIGHT , MECHANICLAL , ELECTRICAL , CHEMICAL AND NUCLEAR ENERGY .
ENERGY CAN BE CLASSIFIED INTO SEVERAL TYPES BASED ON THE FOLLOWING CRITERIA :-
- Primary and secondary energy
- commercial and non-commercial energy
- renewable and non-renewable energy
Primary energy source are those that are either found or stored in nature. common primary energy source are coal , oil , natural gas , and biomass (such as wood ).
Other primary sources available includes nuclear energy from radioactive substance , thermal energy stored in earth interior and potential energy due to earth gravity.

