CalMAX Connections—Spring 2003

Vegetable Oil: Not Just for French Fries

by Maggie Coulter, CalMAX Coordinator

Tod Kershaw, an electrical engineer and graduate student at UC Davis, has been thumbing through the CalMAX catalog looking for used restaurant oil—and he’s found it. Kershaw is one of a growing number of people turning this greasy gold into energy by converting it into biodiesel fuel.

Kershaw, who does most of his commuting on a bicycle and public transportation, heard about biodiesel, but thought it was too good to be true. A few months later he was convinced that it was indeed a viable alternative when he saw a demonstration of a vehicle running on biodiesel at an annual earth day event. He then got Joshua Tickell’s book, From the Fryer to the Fuel Tank, and started making the stuff himself. “It was so simple,” says Kershaw, “the book tells you what equipment to get and gives you easy-to-follow exact instructions.”

“The first diesel engine ran on rancid peanut oil,” explains Kershaw. “Rudolph Diesel, who invented the diesel engine at the end of the nineteenth century, had a vision of a biologically based energy infrastructure. Biodiesel is clean-burning and producible with much less impact on humans or the environment than petroleum. Instead of noxious gas coming out the tailpipe, you have the smell of French fries.”

Although engines can be made to run on pure vegetable oil, any standard diesel engine can run without any mechanical alternations on biodiesel including cars, tractors, and electrical generators. Kershaw is currently working with a local farmer to produce biodiesel for the farm’s equipment using used cooking oil from local restaurants. Kershaw gets the oil, filters it, heats it to a specified temperature, and adds methanol and lye in a mixture. The formula is calculated based on the acidity of the oil. The lye and methanol cause the glycerin in the oil to settle out, lowering its viscosity so that it will burn effectively in the regular diesel engine. The methanol also becomes part of the biodiesel (which is technically known as methylesters).

Kershaw used to drive a hybrid. “I was gloating over the mileage I got, but as I was driving away from a gas station one day, I heard a program about the environmental destruction and human rights abuses related to oil production in Africa. Then there was the Arctic. By driving a hybrid, I was still demanding oil and thereby supporting the problems associated with its extraction, production, and use. With biodiesel, the source is right here at home and the impacts are much lower.”

Slowly catching on in the United States, biodiesel is already “mainstream” for other parts of the world. “There are over a thousand biodiesel filling stations in Germany,” notes Kershaw. Although it is a good use for used vegetable oil, most biodiesel comes from virgin vegetable oil. Kershaw notes, “In the U.S. the primary source is soy, in Canada it is hemp seed oil, which lowers the environmental impact even more because of the low water and pesticide needs for hemp production.”

There are many improvements to be made in the production of biodiesel and its efficient use in internal combustion engines. Kershaw is working on enhancing the components of hybrid electric vehicles that utilize biodiesel. “These vehicles are already in test fleets” says Kershaw, “but they need improvements before going into mass production.”

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Last updated: August 01, 2008