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Courtesy of people who have a financial stake in the success of biodiesel, today has been declared the Official Biodiesel Day in the United States, in honor of Rudolph Diesel's birthday. (Not to be confused with International Biodiesel Day, which is August 10.)
Biodiesel is getting big! Between 2004 and 2006, use increased 10 times, from 25 million gallons to 250 million gallons. Biofuel "fueling point" and advocacy company Propel Biofuels claims
Typically, commercially available biodiesel is combined with regular petroleum diesel. Common mixes include B2 (2% biodiesel, 98% regular), B20 and B60, but B100 is available some places -- though usually at noncompetitive prices.
However, one of the tantalizing prospects of biodiesel is the ability for ordinary citizens to create their own fuel. Not counting the hours spent, you can typically make your own for as little as 50 cents a gallon. Here's the process as described by Rob Elam (not coincidentally the co-founder of Propel) in his article "Making Biodiesel" in The Best of MAKE.
Filter and de-water (and presumably, de-onion-ring) the oil
Determine the acidity of the oil
Process the oil with lye and methanol (HEET gasoline additive)
Allow to settle and skim off the biodiesel from the waste (glycerine)
Unbiased information might be tricky to find, but if you're interested in learning more, check out this biodiesel basics article on the Union of Concerned Scientists website.
Photo: Rob Elam. (cc)