When Josh Tickell drives his 1971 Datsun 240Z, powered by a straight six-diesel engine, he gets 44 miles to the gallon. He also gets disbelieving stares from everyone else on the road. The bright-red hot rod, with flames shooting out of a dandelion-rimmed globe on the hood, proclaims in fiery yellow letters: "Powered by vegetable oil."
Electric and hybrid cars may be getting more attention from the car-buying public, but in the past year the number of biodiesel fueling stations jumped nearly 50 percent. Even Click and Clack, NPR's wise-cracking car guys, dedicate a page on their website to the fuel's benefits.
At a time when the ups and downs of gas prices are front-page news, autos that can run on soybean oil - even after it's been used to cook French fries - are getting a fresh look. The concept isn't new, and the price isn't quite right (still a bit higher than gasoline). But America's new awareness of its fossil-fuel vulnerability is at least raising the question of whether people like Mr. Tickell are visionaries - not just garage-bound tinkerers.
"I think we're on the verge of an American energy revolution," Tickell says. "Previous generations have been steeped in black oil. That was the answer. That was prosperity. It made America powerful. Our generation is steeped in the idea that oil equals war. Clean energy to us is sexy."
Tickell - author of "From the Fryer to the Fuel Tank" - may be unusually passionate about the source of his fuel, but his clarion call to buy homegrown oil is drawing a chorus of biodiesel enthusiasts.
"Every one of us in America will at some point get in a car," he continues. "Who out of all those people can say they have used a fuel that's grown in this country, that's putting money back into their pockets and advancing civilization?"
But how many wrongs can vegetable oil right? Fans of biodiesel hype its cleanliness and point out that every car smelling of popcorn is one less using foreign oil. Even President Bush said in April: "Biodiesel makes a lot of sense."
Making the idea a reality, however, is something else. While supporters note the industry's growth since the late '90s, they say the fuel can never be truly popular while it costs more than petroleum, the standard fuel for diesel engines.
"It's obvious that the product works," says Ron Heck, president of the American Soybean Association and a supporter of biodiesel - which could be a boon for farmers. "You don't get that kind of market acceptance [of a costlier product] unless everything is going great."
Biodiesel debuted a century ago. When Rudolph Diesel unveiled the diesel engine at the Paris Exhibition in the early 1900s, it ran on peanut oil. "The diesel engine can be fed with vegetable oils and will help considerably in the development of the agriculture of the countries which use it," he declared.
Biodiesel is typically made out of vegetable oils and animal fats, and cars could actually run on McDonald's wasted grease if it's processed correctly. All diesel engines can run on any percentage of biodiesel without harming the car - Tickell claims the natural lubricant is better for the engine - with mixtures as low as 20 percent biodiesel (called B20) reducing toxic emissions. Burning pure biodiesel (B100), as the Veggie Car does, contributes no fossil carbon to the atmosphere at all.
But critics worry that biodiesel fuel may be worse for the environment than unleaded. Diesel engines have long been considered dirty because they run on petroleum, which emits high levels of carbon monoxide. But because biodiesel contains oxygen along with carbon and hydrogen, it produces up to 90 percent less carbon monoxide and soot. Still, biodiesel actually releases more smog-forming pollutants - and critics say a revival of diesel engines may prompt drivers to resort to petroleum, which is cheaper, but dirtier.
Still, David Allen, an automotive designer in Manchester, Mich., recently bought a Volkswagen Beetle for its diesel engine. "It's a wonderful way to give the farmers [a new market]," he says. "I got a car I like that will last a long time." (Diesel engines have longer life expectancies.) He says biodiesel fuel costs him about $15 extra each month. It's roughly 15 cents a gallon more than regular diesel - but high gas prices mean it's about 15 cents less than unleaded.
Some argue that choices like Allen's are a true mark of patriotism.
"We have many friends and relatives serving in the Middle East, and we would be naive to think we're not there in part because the strategic oil reserves of the world are there," says Bob Metz, chairman of the National Biodiesel Board. "Any time we can lessen our dependence on that oil, it will certainly make a lot of sense."
How much energy it takes to produce fuel should also be considered, says the South Dakota farmer. When he looks at a soybean field, he sees 75 gallons of it - and 2,500 pounds of protein feed for livestock.
"The ... critical difference is that it's solar energy," Tickell explains. "It's free."
Diesel engines, which fell out of favor in the US in the late '70s as gas prices fell, remain popular in Europe. They're commonly seen as more efficient and durable, which is why they're used in large vehicles like trucks and trains, says Matt Schrimpf at Piasa Motor Fuels in Columbia, Mo.
Biodiesel fans are sometimes thought to be granola-munching hippies - though the movement is young. Tickell calls it a generational divide. "Who are the early adopters? They're movie stars. Financial brokers. These are young thinkers. And it comes down to the fact that we are in the middle of an energy crisis that will only worsen, and our generation is sick of it."