Question

why is there a need to harness non-conventional sources of energy? give two main reasons.

Answer 1

There are various reason relating to need to harness the non-conventional sources of energy
1)  Conventional sources  like fossils fuels take million of years to form so once used can't be replaced this is why these are also the non-renewable sources of energy. Thus non-conventional sources of energy are better choice .
2) The increase use of fossils fuel led the carter the decrease of these resources and in future there could be the shortage of such resources to fulfill the increasing demand. Hence harness of non-conventional resources  becomes necessary for future. 

Moreover fossils fuels causing the environmental damage and polluting the environment so the need for non-conventional sources like solar energy  and wind energy is a better choice in this regard

Answer 2

There is a need to harness non-conventional sources of energy because:

1. The demand for energy is increasing day by day because the population of the world is increasing rapidly. There is a limited amount of fossil fuels such as coal and petroleum which may get exhausted. So there is a need for alternative sources of energy.

2. Pollution is caused by the use of conventional sources of energy like coal and petroleum. It is essential to use non-conventional sources of energy to reduce pollution.