roadclosed look at biodeisel...most company fleets in my area, as well as farms and public buses run on the stuff...you can power any car that has a desile engin with the stuff. Clean competitive priced, and the biproduct in making it can be resold (glycerin) (you can get the needed materials from a local fast food joint.) and i have seen indipendent gas stations carrying the stuff, depending on your area its allread mixed into conventional desiel to keep the prices down. Hell some guys have figured out how to get the stuff up to aviation grade.
http://www.biodiesel.org/resources/faqs/

This combined wit hthe continuing drop in price of refineing organic material into petrolium is going break the OPEC strangle hold on the US.