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The benefits of biodiesel


People ask me all the time if I’ve heard of the guy who runs his car on the waste oil from McDonald’s fryolators. Forget fuel cells, they say, we can run our cars on clean vegetable byproducts!

Well, yes and no. While cars can and do run on vegetable oil (animal fat, too), and converting them is a favorite cottage project for people who read Mother Earth News, it’s hard to imagine it as the holy grail replacement for fossil fuels.

First, the good stuff. The Department of Energy’s renewable energy office points out that biodiesel is nontoxic and biodegradable, that it can help reduce dependence on foreign oil and cut down on greenhouse gas emissions. It’s an oxygenated fuel, so it burns more completely than other fossil-based products. Filling your car with biodiesel cuts down on emissions of unburned hydrocarbons, carbon monoxide, sulfur and the nastiest of all diesel byproducts — particulate matter.

Drawbacks? There are some. Biodiesel exhaust actually contains more emissions of nitrogen oxide (NOx) than regular diesel. In Europe, where rape seed is used as the basis for biodiesel, a study indicates that carcinogenic (and air-polluting) organic compounds are produced when the fuel is burned.

Car performance is decreased by 8 to 15 percent because of biodiesel’s lower energy content. There may be cold starting problems. And then there’s the fact that biodiesel fuel is often a blend of 20-percent vegetable oil and 80-percent standard diesel. That’s because older engines will suffer seal and gasket problems if they burn 100-percent biodiesel.

Cars built since 1994 that are already equipped with diesel engines can run even 100-percent biodiesel with little or no modification. Some work will be needed to run on pure vegetable oil, but you may be able to do it yourself. (You’ll need an extra fuel tank connected to the car’s coolant system, so the oil can be heated and thinned before it’s burned.) A $795 kit to convert your diesel vehicle to biodiesel operation is available from Greasecar, P.O. Box 60508, Florence, Mass. 01062. Get information at 413-586 2432 or by visiting www.greasecar.com.

Environmentalists are touting the benefits of biodiesel and converted vehicles are showing up at festivals and fairs. People are driving them cross-country, attracting crowds wherever they go. Joshua Tickell’s "Veggie Van" is world-famous, and he’s also converted a Datsun 240Z. He says his work will be done when "there is a biodiesel pump at every service station and when biodiesel is part of the core curriculum of every school."

Old Mercedes diesels are popular conversion cars, and I saw a group huddled under the engine of one at the recent Grassroots Festival in upstate New York. The "Bio-Beetle" is a biodiesel-powered Volkswagen running on 100-percent vegetable oil that can be rented for $199 a week by tourists visiting the Hawaiian island of Maui. Get the details at mauigreenenergy.org/Bio-Beetle.htm.

There are some biodiesel tax benefits in the Senate’s recently passed energy bill, which also contains vast subsidies to the Midwestern senators’ favorite charity, corn-based ethanol. And here’s the biggest biofuel boondoggle: The auto industry builds millions of "bifuel" vehicles that can run either on gasoline or an ethanol blend. But since there is very little service-station infrastructure for ethanol, most of these vehicles run only on plain old gas.

Ethanol is a windfall for the Bush administration, since it helps major corporate contributors like Archer Daniels Midland and throws a bone to farm-state senators and voters. Does it help the environment? Not much.

So by all means, let’s support grassroots biodiesel. But let’s be very careful.

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