How many different types of renewable/clean energy sources are there?

Question

I have recently seen a solar thermal plant in mexico which makes me think what other types are there that i dont know of?

Answer 1

solar-will last for atleast 500 million years

wind-will last as the earth exists

geothermal-will last as the earth exists

hydro-how ever we prevent greenhouse effect.

tidal-again as long as earth exists and rotates due to the sun

bio fuel-as long animals excrete.

nuclear fission.but gives out equal amount of pollutants.

Answer 2

Hydro

Wind

Geothermal

Tidal & wave energy (oceans, kinetic)

Ocean thermal energy (oceans, thermal)

Biogas & Biomass gasification (plant and animal output)