Question

What is the main problem with renewable energy sources?

Answer 1

Concentrating solar power, in which mirrors focus light over a large area into a central generator, has seen costs drop to as little as USD $0.14/kWh. Hydropower, currently the world's largest source of renewable energy, today often provides the lowest cost electricity of any generation source.

Answer 2

The capital for these resources will be high priced and less available.
Also a little amount of energy is produced comparing to non renewable resources