Can vegetable-oil cars save the world?

Used restaurant cooking oil is free, clean burning and can power your vehicle. So why aren’t more people using it?

NEW YORK (CNNMoney.com) — Gas is expensive. Old vegetable cooking oil from restaurants is free. A car can actually run on either. So why aren’t more people ditching petroleum and running on peanut power?

“[Making the switch] couldn’t be simpler,” said Patrick Kuhn, who converted one of four trucks at his company, Charlotte Moving Truck Rentals, to run on vegetable oil earlier this year.

He said his customers love it and constantly choose the veggie-powered vehicle over his others. “I never see that truck anymore,” he said.

But while Kuhn’s truck may be a hit, for many people life with a veggie car might not be so easy. And although this alternative fuel may be cheap and clean, there simply isn’t enough of it to make a big dent in our gas consumption.

CNN/Money