Is it illegal to run a car on vegetable oil?

Is Vegetable Oil Worth the Cost?

The amount of cooking oil discarded by restaurants every day is nothing compared to the millions of barrels of fuel Americans consume every day. fluxfoto/Getty Images

We know that some engines can really run on vegetable oil, but is it worth the effort? In terms of financial value, it’s almost certainly not. The cost of the engine conversion will be very difficult to recover in fuel savings. On top of that, the cost of vegetable oil is approximately the same as diesel fuel.

Veggie oil might be cheaper depending on where you live or whether you can buy it in bulk from somewhere like a restaurant supply store, but it generally doesn’t represent a major cost savings over petroleum-based fuels.


What about all that talk of getting used vegetable oil for free from restaurants? If you can get your fuel for free, wouldn’t that represent a huge savings? It would — for now. Veggie oil is used as fuel by a relatively small number of hobbyists who like tinkering with their engines and adjusting their vehicle’s fuel ratios.

But make no mistake: The amount of cooking oil discarded by restaurants every day may seem like a lot, but it’s nothing compared to the millions of barrels of fuel Americans consume every day [source: Energy Information Administration]. There’s no way used vegetable oil could ever become the primary way we fuel our vehicles, and there’s even less chance it would ever remain free.

Unfortunately, there’s really no way to save money by running on vegetable oil, but there might be other reasons to use it. There are no widespread statistics available for veggie oil mileage rates, but in Consumer Reports’ own tests, a car running on biodiesel produced slightly less pollution than the same car running on conventional diesel, but it achieved slightly fewer miles per gallon.

In light of these minor benefits, converting all vehicles to run on vegetable oil sounds less like a great deal.


Originally Published: Sep 3, 2008

Turning Used Cooking Oil into Fuel

Luckily, there are ways to turn used cooking oil into a clean-burning, effective fuel that won’t damage your engine. This method is called transesterification, during which a chemical compound called an ester (used cooking oil) is mixed with alcohol. In addition, a small catalyst – usually sodium chloride – is used to kick-start the process.

When transesterification is complete, two substances remain. One is methyl ester, which is the technical term for Biodiesel fuel. The other is a new alcohol, glycerin, which can be filtered out and used for other purposes. SeQuential uses a complex process and distributes our biodiesel throughout the West Coast.


Veggie-Capable Vehicles

Finding just the right car to burn vegetable oil can be more challenging. First and foremost, it has to have a diesel engine. The best cars to convert tend to be older models, according to Lovecraft. The exception appears to be the Volkswagen Jetta TDI — even more recent editions can be converted easily. Among the better older models for veggie conversions is the Mercedes 300 SD, particularly model years 1981 to 1985. Greasecar, on the other hand, says the majority of its kits go in newer domestic trucks or Volkswagen cars.

Diesel trucks get plenty of power out of vegetable oil. Martin said his 1990 Dodge Ram pickup made the switch without slowing down. Lovecraft and Greasecar both said the Ford F250 diesel models from 1995 to 2000 are well-suited for conversions. These trucks easily accommodate the necessary plumbing changes for burning vegetable oil.

Straight Talk on Biodiesel, Veggie Oil

William Kemp is the author of Biodiesel Basics and Beyond, a how-to on making fuel from all manner of oil-producing plants. While he is an advocate of the technology, he offers a sobering assessment of its limitations in his answers here:

Mechanically, what is the difference between grease cars and biodiesel cars? What it boils down to is biodiesel can be used with the existing fuel infrastructure of any diesel vehicle, while straight vegetable oil can’t be combusted in a modern diesel engine without modifications. Also, in grease cars you need a system to preheat the oil and filter it before the fuel can be combusted.

And what about the costs? Straight vegetable oil has the advantage in that the cost and complexity of the fuel drops dramatically, compared to biodiesel. If you look at the costs of making biodiesel, 70 percent of the cost of the fuel is the feedstock — that’s the canola, soy or peanuts that are used to eventually produce the fuel. The rest of the cost is processing that feedstock. You don’t have those costs with straight-oil fuel, although capital costs must be amortized.

Which is easier to use? Biodiesel. You still need some petrodiesel or biodiesel fuel to run a vegetable oil car. The car has to start on diesel and it has to be shut down on diesel. So owning a vegetable oil car becomes more of a tinker’s game.

Once the oil is hot, what’s the difference between the two fuels? Once the temperature of the vegetable oil gets to 176 degrees, viscosity of the oil comes down to the level of diesel fuel and it becomes much like straight diesel fuel.

Will vegetable oil cars ever be a mainstream mode of transportation? In a word, no. I think using virgin vegetable oil or waste vegetable oil is always going to be a fringe sector of the transportation industry. Automakers will never get behind it.

Which is better for the environment? With biodiesel you have the farming and harvesting for the feedstock that’s eventually processed to make the biodiesel. That has to be taken into consideration in the overall formula for the carbon released when you burn it. Then there’s also the toxicity of the chemicals used to make biodiesel — those can endanger the environment. The beauty of using waste oil is it’s something that’s already been used and you’re giving it a second life, providing low carbon and air pollution emissions.

Do you support one fuel over another? I’m not a big advocate of using food crops for fuel. Even if we exploited all the biofuel potential in North America it would be no better than enforcing higher fuel efficiency standards for all vehicles. And does anyone really need a 300 horsepower car to get to work? Energy efficiency first, energy generation second; that is the sustainable path.

Originally published as “Would You Use Veggie Oil to Fuel Your Vehicle?” December 2007/January 2008 MOTHER EARTH NEWS.


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