Why do you drive a grease-powered car, and should I do it too?

Why do you drive a grease-powered car, and should I do it too? The Editors Santa Fe, New Mexico


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Before you read the next sentence, please follow this one simple instruction: go jump off a bridge. Okay, it appears that most of you aren’t taking my words as direct commands. That’s unfortunate. (To those of you who actually did just jump off a bridge, I hope it was a low one, and I offer you my sincere thanks as I try to live up to my role as your eco-messiah.)

I originally thought that converting an old diesel to run on vegetable oil was some hippy-dippy thing that only young trustafarians did when they weren’t too busy making their clothes out of hemp. My wife Ann Marie—who just graduated from medical school and I shall respectfully call Dr. Wife, MD, from this point forward—told me otherwise. She said the process was fairly simple and it would save us money. She made the point that many restaurants pay for someone to dispose of the dregs from their deep-fat fryers, so they’re happy to unload the stuff on grease-powered drivers for free.

Suddenly a lightbulb (a compact fluourescent, no doubt) illuminated over my head: Ha! The chance to get free gas and flip the bird at the oil companies. Sign me up! Dr. Wife, MD, was actually more gung-ho about the potential environmental benefits, which are immense. Consider that biodiesel made from virgin vegetable oil reduces NREL life-cycle carbon emissions—all the emissions it takes to produce a product—by 78 percent compared to dino-diesel, according to the National Renewable Energy Laboratory. And then take into account that french fry grease is a waste product.

So the two of us bought an old, half-dead Mercedes, fixed it up, ordered a kit from, and paid someone to install it. I thought of trying to install the kit myself, but Dr. Wife, MD, said no. She pointed out—correctly—that I’d mess everything up and would ultimately have to pay someone to install it anyway, so I might as well skip that first time-consuming step. The kit and installation cost a little more than $2,000, and I’ve easily made that money back in gas savings over the past couple of years.

Now to answer the second half of the question: Should you do it too? Before deciding to convert an old diesel, find a good grease supplier. Someone who’s willing to set the stuff aside each week in sealed jugs, so it’s not exposed to the elements and so you don’t have to suck it from a dumpster in the restaurant’s back parking lot. Given the growing demand for grease across the country, securing a reliable supply is harder than you might think. Here in Asheville, North Carolina, I get my stash from the Early Girl Eatery, one of the best restaurants in town. They use high-quality oil, and since they don’t fry many meats in it, it’s high-test stuff without a lot of impurities to filter out.

I’d also recommend that you have a garage where you can store the grease and filter the particles out of it. (For me the filtering process involves heating the grease under the sun in a black gas can, and pouring it through a felt sock filter.) No matter how meticulous you are, grease is messy, and you need to have a designated area where you can contain it.

If you can meet these criteria, and if you’re willing to set aside the 45 minutes a week—give or take—for gathering the oil and filtering it, by all means go for it. Though I’m skeptical that you’ll heed my advice, seeing how you didn’t jump off that bridge.

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