Biodiesel is more plausible than every other alternative (vehicle energy) source mentioned, right now as is with existing infrastructure and engines.
I don't know why it isn't talked about a lot more.
And better than the bio-diesel process is the Thermal Depolymerization process. I don't know why this isn't being implemented more than it is:
http://en.wikipedia.org/wiki/Thermal_depolymerization
http://www.thermaldepolymerization.org/
http://www.res-energy.com/index.asp
http://www.usatoday.com/tech/columnist/andrewkantor/2004-01-22-kantor_x.htm
Anselmo testifying before congress today.
http://biz.yahoo.com/prnews/060503/to265.html?.v=27
http://www.texogatech.com/safuel.cfm
A tiny chemical reactor that can convert vegetable oil directly into biodiesel could help farmers turn some of their crops into homegrown fuel to operate agricultural equipment instead of relying on costly imported oil.
"This is all about producing energy in such a way that it liberates people," said Goran Jovanovic, a chemical engineering professor at Oregon State University who developed the microreactor.
The device - about the size of a credit card - pumps vegetable oil and alcohol through tiny parallel channels, each smaller than a human hair, to convert the oil into biodiesel almost instantly....