HEAT is the problem, and until we invent the (impossible) heatless motor, we're only delaying the inevitable. Oil is only "harder to get" for political reasons. (IMG:
http://www.frrax.com/rrforum/style_emoticons/default/banghead.gif)
Besides, in the future the sun will go red giant and devour the earth. Why leave a planet with combustibles in it? Better explosion? (IMG:
http://www.frrax.com/rrforum/style_emoticons/default/nutkick.gif)