Question

why there is a need to harness non-conventional resources

Answer 1

The increase in population, greater use of machines due to industrialisation and limited supply of fossil fuels are the few reasons that’s why we are looking for alternative or non-conventional sources of energy

hope it will help.

Answer 2

conventional resources have many drawbacks which forces the human populations to harness non conventional resources.
like conventional resources make 1)polution2)healthy hazards3)green house effect3)global warming etc.