Oil is cool and all but i believe that in the future we will mostly use gas and nuclear power.
Why?
Well because methane exists everywhere, not just on earth. Theoretically one could extract methane from Titan which would solve any possible energy crisis on earth or in the solar system forever.
Additionally one could come up with a way to extract gases from the gas giants which just sit there waiting to be exploited.

Green energy is useless imo.