Conventional sources of power like coal, petroleum and natural gas are likely to exhaust in near future.
The development of hydel power alone cannot meet the demand of electricity for the future.
Therefore, there is a need to find and develop alternative sources of power.
Sun, wind, tides, biological wastes and hot springs are such sources which can be developed as the alternative sources of power.
They are called the non-conventional sources of energy.
These sources of energy are renewable and pollution free.