The Grease Lady Comes Clean on Biodiesel


No way would you call Sarah Miller a greaser. In her mid-thirties, she’s working on a Master’s in Sustainable Studies at Goddard College in Vermont. However, she does drive a greasecar, an oil-burner that sometimes smells like French Fries, and she is a good sport about it.

We got together to discuss what it means to own and operate one of these babies—and why it may make sense in this world of crazy gas prices and unsustainable habits.

Tell me what got you started on this path.

Well, it probably evolved naturally from my values about creating a sustainable way of living and my attachment to mobility and my car. I’m a car lover, but more than that a mobility lover. I do lots of commuting and trips to visit family.

My cousin Megan introduced me to the idea of alternative fuel. She started making her own biodiesel, which is either some kind of veggie-based oil or a blend of that and petroleum-based diesel. So I started searching for a diesel in 2005, and they were hard to find. I was ready to get on a plane and fly to the Midwest, the only place I was finding them online. But this one showed up in Rhode Island, so I trekked down there and bought it, a 2003 VW Golf.dscn19121

Nine months later I went to Western Massachusetts to and had my grease kit installed. What’s involved is a second fuel tank—in the trunk where the spare was—with a capacity of 12-13 gallons. You need separate fuel lines, and there’s a heat exchanger in the tank to heat the grease, especially in our climate. Everything else is the same except for a separate fuel pump.

The whole thing—to buy the kit and have it installed—was approximately $2000. You can save money by doing your own installation.

Did you find the performance any different? The power?

No different as far as miles per gallon, and sometimes it has run more smoothly on my grease setting than on my regular diesel setting. Power is the same. You can switch over whenever you want, but you always start up on regular diesel, then when you reach about 140 degrees, you can switch.

What about the fuel? Where do you get it? How do you process it?

dscn1925I get it from a local restaurant and bar called The Depot in Gardiner, and they have plenty of it. I approached Steve the owner and was very professional, had this little contract written out and everything, and he looked at me like . . . “I don’t need a contract, I’m happy to leave the oil out for you.” They have a Fry-O-Lator, and after a week they clean it out, and instead of paying a renderer, they leave it for me for free.

Every week I get about 10-15 gallons of used oil, which is ample. I’ve got a stockpile now and haven’t picked up any in probably two months. Stays warm in the cellar.

Storage Corner (batteries not included)

Storage Corner (batteries not included)

Filtration Corner (toilet not included)

Filtration Corner (toilet not included)

I have a 50-gal. plastic barrel, pour the grease into that, and let it settle (debris from the French Fries and other goodies). Then I siphon from that to a transfer container and go over to my Filtration Corner, a series of polyfiber gravity filters hanging over 5-gal. buckets. There are two steps: filter once at 5 microns and filter again to 1 micron. Then it’s ready to go to the car.

As to the time it all takes: that depends on the quality of your oil and the temperature and the kind of oil. I’ve been using soy oil which can be thicker than corn oil or canola.

What kind of mileage are you getting?

Just under 40 mpg for highway miles. I wanted to know how long I could make a tank of diesel last by supplementing with the veggie oil. I’ve gone 2000 miles without having to refill diesel. Biodiesel is a little scarce – a few stations sell it in Maine, usually just a B-20 or a B-5 blend, which means percentage of the bio component. Some people make their own. I recently found a company in Maine called Bean’s Commercial Grease, in Vassalboro. They pick up grease from restaurants, institutions, take it back to their processing plant and make biodiesel from 100% Maine sources.

What about the cost of regular biodiesel? It must be more expensive.

It can be, depending on your oil source. If it comes from Iowa cornfields, yes, plus the cost of transportation. But Bean’s gets its oils locally and cheaply, so this summer when gas prices were really high, it was much cheaper to get my fuel there. Currently, there’s maybe a 10-cent difference in the price.

In the gas crisis, it’s been wonderful to have basically free fuel, and that wasn’t my intention with the car. I was very lucky.

Have you had any maintenance issues, problems?

Not really, besides a filter change. I have taken it to a couple of local garages, and I tell the mechanics not to worry if they see some different things under the hood. Sometimes I get a raised eyebrow. They haven’t seen too many of these around.

I’m sure you get plenty of comments and cute remarks.

Oh, yeah. You know, “You can smell Sarah coming,” and “Here comes the Fish Fry lady.” I don’t smell it in the car, and if people stand behind the car when it’s running, it’s their problem. They send me stories like “Thefts of vegetable oil from restaurants on the rise,” things like that, and the Internet is full of stories. Like the one about someone with a veg oil sticker on the back of their car being pulled over by police because they aren’t paying their road tax on fuel. I kind of hope that will happen to me.

So what do you think is the future of using veg oil or biodiesel?
It’s not the silver bullet, but just another strategy to answer the question of how are we going to power our machinery when the petroleum runs out. And of course, not everyone has a diesel vehicle. The issue is complicated by politics and power and money and marketing, consumer choice, consumer habits and the market, and then the shifts in petroleum supply. I support veggie oil and biofuels as one of several avenues for addressing this problem.

But it’s an involved process, messy and takes a lot of time, right?

Well there are lots of ways to do it. You can have a collective in order not to do it yourself, but it’s worth it. I’m not afraid of a little elbow grease—or elbow fat.

Clearly, biodiesel and grease cars are not for everyone. Would you try one? Any other biodiesel owners out there?



  1. @Davod
    Hi Davod– What seems to be agreed upon is that burning veggie oil releases no SO2 (sulphur dioxide) and is arguably close to carbon neutral (although this depends on your source). For a more complete answer, here are a couple places to start that seem credible. Also, you can check out Joshua Tickell’s book, From the Fryer to the Fuel Tank.

    On Grease:
    On biodiesel:

  2. @Randy
    You’re right, Randy– using recycled fry oil will never be a viable way to fuel all of our diesel vehicles, but it certainly is one way to fuel some of those vehicles. The point here is not about finding the one panacea but about identifying a multitude of solutions (diversification of the portfolio, if you will)and making intelligent use of resources that we have. I like where you’re going with the federal requirements and tax credits.

  3. I’m always amused by the tree huggers pushing this technology. Take all the greasy spoons in your town, multiply them by twenty or thirty gallons of waste oil a week, and then divvy it up between the thirty thousand vehicles using fifteen or twenty gallons of fuel a week in the immediate vicinity. You’ll quickly realize that this will NEVER be a viable way to fuel our vehicles because the potential supply is miniscule. (It’s kind of like what happened when California realized that, if half the cars in the state were all-electric, the whole power grid would collapse if most if them tried to charge their batteries overnight.)

    Sarah’s real contribution is driving a 40MPG diesel. That’s where the USA really lags behind Europe, and creating a viable clean diesel-based vehicle fleet in the country, especially with the addition of plug-in hybrid technology, has the potential to push our CAFE fleet mileage close to the 100MPG mark. Add federal requirements and tax credits to remove older gasoline vehicle from the roads and you might just have something there.

  4. When I graduate from college and settle down, I plan on doing this, but is this cleaner for the enviroment then driving a gasoline car? I know it is, but i heard arguments about how it can release unburned oil or grease into the air and that can land on plant leaves, killing plants…blablabla! and also how diesel in not as much cleaner then gas, and we’re still using petro fuels…blabla?

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