Out of the frying pan, into the tractor

Helena, Ark., soybean, rice and wheat producer Buron Griffin Jr. and your typical environmentalist both see green when Griffin’s John Deere 8410 tractor runs across a field.

For the environmentalist the tractor, which runs on waste vegetable oil, is not polluting the air, causing global warming or using up a non-renewable resource. But for Griffin, the tractor is not burning up as much of the hard-earned green cash in his bank account.

Bill Kennerly, owner of Vegetable Fuel Systems, in Malvern, Ark., who installed a vegetable oil fuel system on Griffin’s tractor, says waste vegetable oil could catch on in the agricultural community, once everyone figures out how cheap it is compared to regular diesel or biodiesel, or how environmentally friendly it is.

“In the past, restaurants have had to pay someone to come get the oil and haul it off. Nobody ever realized that it burned. There are hardly any pollutants coming out of the exhaust, very little black smoke.”

Kennerly says running vegetable oil could be a good alternative for farmers looking to cut costs. “With veggie oil, you have to convert your truck or tractor. With biodiesel, you or the community has to spend money for a biodiesel plant and train someone to operate it. But as far as an environmental benefit is concerned, vegetable oil is the best, followed by biodiesel.”

The waste vegetable oil that runs in Griffin’s tractor is collected from restaurants, filtered and stored until delivery. Kennerly says to condition the oil, it is heated to 130 degrees, stored overnight, then pumped through a bag filter and then to another diesel filter. Then it’s ready to burn.

The estimated cost of a veggie system for a tractor is around $3,500, according to Griffin. “At $2.45 for farm diesel, we need to run 6,000 to 7,000 gallons of fuel to pay for the conversion, which is not much considering how much these tractors consume.”

The 100-gallon vegetable oil tank is a separate tank mounted on the front of Griffin’s tractor. The tractor engine is started with regular diesel or biodiesel, whatever is in the tank of the tractor.

The heat from the engine is used to heat the vegetable oil until it reaches the proper viscosity. If the engine is started with vegetable oil when the oil is still thick, or if the vegetable oil is not flushed out of the engine when the engine is to be shut down for an hour or more, the vegetable oil will gum up the system in cold weather.

Inside the tractor cab are a couple of gauges and a switch for monitoring vegetable oil temperature and for switching back and forth between the diesel tank and the vegetable oil tank.

“We haven’t seen any loss of horsepower whatsoever,” says Griffin, who hopes to eventually run every engine on the farm, including center pivot engines, on vegetable oil. “The price of vegetable oil is fluctuating with the market, but it’s a lot cheaper than diesel. We’re also looking at using cottonseed oil.”

Kennerly hopes to have a conversion kit for center pivot engines by spring. He’s also making progress on filtering and preparing cottonseed oil for high volume users.

Kennerly has installed the system on tractors, pickups and big diesel trucks, most of which are out of warranty. Kennerly and Griffin note that engine manufacturers are hesitant about honoring all components of an engine’s warranty if vegetable oil is burned in it. There could be problems if the oil is not filtered adequately, if the tractor is not equipped with the proper heating system, or if the engine is not purged with diesel before shutting down in cold weather.

Griffin’s early 2000s-era 8410 John Deere tractor had about 4,000 hours on it when the conversion was installed. Griffin has two other large horsepower tractors on his 3,000-acre farm.

Kennerly’s Dodge pickup truck is converted to vegetable oil, and he’s converted several other pickup trucks. A Dodge conversion usually runs about $2,500, a Ford about $3,500.

As long as the price of diesel remains high, vegetable oil has an economic advantage for Griffin. “The key is the price of diesel. If the price comes down to $2 or $1.95, this business is going away. As long as we have $3 diesel or more, it’s going to stay.”

Currently, the Biodiesel Tax Credit administered by the IRS allows producers of biodiesel to claim a per gallon tax credit. The credit is valued at $1 per gallon of agri-biodiesel (biodiesel produced from new agricultural products such as soybean oil or animal fats).

Griffin would like to see the $1 tax credit extended to recycled fryer grease as well. Currently, the tax credit is 50 cents per gallon of biodiesel produced from other sources such as recycled fryer grease.

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