Do you know what bio-diesel is?
Manufacturers take used coking oil and refine it into a usable fuel for diesel engines.
That process and lack of demand typically makes bio-diesel 50 to 60 cents more expensive per gallon.
But at Rising Phoenix Bio-Fuels in Phoenix, Oregon prices for bio-diesel are actually less expensive than conventional diesel.
But bio-diesel isn't specific for special cars with special engines. Depending on the mix of the refined oil, you can pour it straight into your gas tank.
It's sustainable (doesn't pollute nearly as much), and its local (made right in the United States), now it's cheaper.