Seriously use biodiesel. It is renewable, and the waste from making it can be used to make biodegradable plastics.
The <a href="http://en.wikipedia.org/wiki/Biodiesel">benefits</a> of biodiesel make me say "Why aren't we using more of it?" on a regular basis.
Primarily because the vast amount of farm land needed to replace fossil fuels (by which I mean a great deal more than is currently in use) would probably cause just as much ecological damage as fossil fuels are right now.