I have been doing research into biodiesel. The part that's the kicker to me is that, currently...the only sedans available in the US are either the small VW models or a few Mercedes that are coming in. All the american stuff are trucks. I contemplated something the size of the new Chevy HHR with a diesel engine...using biodiesel...and running a green, efficient, and profitable taxi service. Having a real hurdle trying to find a vehicle that would do.
Evidently, at the moment, the most common here in the states is B20. A step in the right direction and easily produced. Also it requires NO engine modifications at all.
Ern