Berk Tuttle, owner of Taggart's Grill in Morgan County, gets phone calls on a weekly basis from people looking for waste vegetable oil. "We get people begging us," he says. "In contrast, we used to have to pay people to get it less than a year ago."

Tuttle purchases 115 pounds of vegetable oil a week, and for the past five months, an Ogden resident has turned the waste oil into biodiesel. However, that arrangement may not last for long. Tuttle is considering purchasing a diesel pickup and filling up with biodiesel. "It would be free fuel for me," he says.

But it's against state tax law to burn biodiesel without paying fuel taxes, says Utah State Tax Commission spokesman Charlie Roberts, and if drivers make the fuel in a garage, they must pay, too. For each gallon of gasoline purchased, the federal gasoline tax is 18.4 cents and 24.4 cents for diesel, according to the Energy Information Administration. In Utah, gas and diesel are taxed an additional 24.5 cents a gallon.