Fuel for thought: the possibilities of cooking oil

Sean Parks of Davis, Calif., collects his cooking oil from a fish-and-chips restaurant and a corn-dog shop.

The process

He purifies it chemically in a 40-gallon reactor that he built himself for about $200.

The processed oil can be used even when his car's engine is cold, at a cost of about 70 cents a gallon. Parks, 30, a geographer for the U.S. Forest Service, makes enough processed oil to fuel his family's two cars.

Kantor and Parks are willing to go the extra mile to reduce their dependence on petroleum and cut down on pollution.

But these days environmentalists are not the only ones banking on biodiesel, as diesel-engine fuel made from vegetable oil is known. Entrepreneurs and soybean farmers are creating a new biodiesel industry, with some 300 retail biodiesel pumps nationwide so far.

Return to the roots

The greening of the diesel engine is a return to its roots. Rudolf Diesel, the German engineer who in 1892 invented the engine that bears his name, boasted that it ran on peanut and castor oil.

The inventor foresaw a future of virtually unlimited renewable energy from plants, but the idea slipped into obscurity because petroleum was so much cheaper than vegetable oil.

A century later, customers for commercial biodiesel include the U.S. Postal Service, the U.S. Army, the Forest Service, the city of Denver and numerous private truck fleets.

Almost all use blends of 2 to 20 percent biodiesel mixed with standard petroleum diesel. The mixture helps federal and state agencies comply with a 2000 executive order by President Clinton mandating less petroleum consumption. Minnesota recently became the first state to require that all diesel fuel sold there be 2 percent biodiesel.

To spur biodiesel's use, some European nations levy no taxes on it, and in October 2004, President Bush signed into law a 50 cent to $1 credit to fuel manufacturers for every gallon of biodiesel blended into petrodiesel.

Differences

Diesel engines differ from gasoline engines in their use of high pressure rather than a spark plug to ignite the fuel and drive the pistons. Diesel engines can run on fuel that is heavier than gasoline, making it possible to substitute filtered waste grease for petrodiesel.

Both used and virgin vegetable oil contain glycerin, a syrupy liquid used in hand lotions. It burns well in a hot engine, as in Etta Kantor's retrofitted diesel, but clogs a cold one.

Removing the glycerin yields biodiesel, which is suitable for even a cold engine.

More benefits

Another benefit of burning biodiesel is cleaner air. Compared with fossil fuels, it emits less carbon monoxide and hydrocarbons, as well as sulfur compounds related to acid rain.

Pure biodiesel also substantially reduces overall emission of carbon dioxide, a major contributor to climate change, because the plants from which the oil was extracted absorbed atmospheric carbon dioxide while they were growing.

A bus running on pure biodiesel would emit 32 percent less particulate matter.

The inspiration for the do-it-yourself biodiesel movement came from Joshua Tickell, 29, of Baton Rouge, La.

While studying in Germany in 1996, he was astonished to see a farmer using canola oil to run his tractor.

Back in the States, Tickell used his last student loan check to help buy a 1986 diesel Winnebago.

He painted sunflowers on his "Veggie Van" and, for two years beginning in 1997, toured the country, towing a simple reactor that turned restaurant oil into biodiesel. In 2000, he coauthored what would become the biodiesel bible, "From the Fryer to the Fuel Tank."

"My goal is very simply to make OPEC obsolete," he tells Smithsonian magazine.