I know of some people who just strain the used cooking oil and mix it 50-50 with regular diesel and it runs fine. Cuts their fuel cost in half. My SIL uses biodiesel in his work truck made by a local guy who sells it for $1.85/gallon. He has a liscense, so I think the $1.85 includes the tax. My SIL's truck is a 1996 Ford F250 diesel. He has over 200,000 miles on it. For purists, a 40 gallon electric water heater set at 100 Degrees works fine to process the biodiesel, mixing in a little lye. Of course one can build a still and make alcohol by just fermenting and cooking off twice to get 180 proof which is 90 octane. This can't be mixed with gasoline though, because it is about 10% water. Exxon has invested $250-300 million in development of an algae farm. If they are interested, you know it is coming. Algae can produce way more oil per acre than corn, sugar cane, or soybeans. About 10 years ago, they could make coal oil at about $25 a barrel equivelant to oil. Wonder why we aren't using coal oil with an 800 year supply?