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

(N/A) The need to harness non-conventional sources of energy arises due to the following reasons:
$(i)$ The demand for energy is continuously increasing due to the improvement in the quality of life and the rapid growth of the human population.
$(ii)$ Conventional sources of energy,such as fossil fuels,are limited in nature and are being depleted at a fast rate,making them unsustainable for the long term.