Which is the most commercially viable form of renewable energy ?

Question

Which is the most commercially viable form of renewable energy ?

Answer 1

In rainy mountains, it might be hydroelectric.  In deserts, solar.

It depends on your location.    

Answer 2

Right now hydroelectric is cheapest and most widely used.   Most of the major rivers have already been dammed, so next would be wind.   Solar concentrators (focus sunlight onto a vessel containing liquid and have it boil and turn a turbine) are cheaper than solar cells.   Wave energy isn't advanced enough to tell how cheap or usable it will be.

Answer 3

I would say it is SOLAR ENERGY.