But do not lose faith. The exhaust from Nelson's diesel-powered Mercedes smells like peanuts, or French fries, or whatever alternative fuel happens to be in his tank.

While Bono tries to change the world by hobnobbing with politicians and Bob Geldof hosts his megabenefit concerts, Willie Nelson has birthed his own brand of alternative fuel. It is called BioWillie. And in BioWillie, Nelson, 72, has blended two of his biggest concerns -- family farmers and the Iraq war.

BioWillie is a type of biodiesel, a fuel that can be made from a number of crops and run in a normal diesel engine. If it sounds like a joke, a number of businesses, as well as city and state and county governments, have been switching to biodiesel blends over the last year in their transportation fleets. The rationale is that it is a domestic fuel that can profit farmers and that it will help the environment, though environmentalists are not universally enthusiastic about it.

"We needed to have something that would keep us from being so dependent on foreign oil," Nelson said in an interview this month.

He added, "It seems like that's good for the whole world if we can start growing our own fuel instead of starting wars over it."

In some ways, it is a return to the origins of the diesel engine; some of Rudolf Diesel's first engines ran on peanut oil more than a century ago.

Last week, a cargo loading company that operates in the Port of Seattle said it would buy 800,000 gallons of biodiesel, mostly a blend with 80 percent conventional diesel known as B20, to fuel its equipment next year. As of late September, Minnesota requires almost all diesel fuel sold in the state to contain 2 percent biodiesel, and Cincinnati started using a 30 percent biodiesel blend, B30, in its city buses because of concern about fuel shortages after Hurricane Katrina.

Biodiesel can cost as much as a $1 a gallon more than regular diesel when pure, though it is typically sold as B20. Prices vary depending on volume and region, and new tax incentives are aimed at closing the cost gap. In fact, BioWillie was selling for $2.37 a gallon this week in Carl's Corner, Nelson's own truck stop in Texas that serves as headquarters of his year-old company, Willie Nelson BioDiesel. That was just 4 cents more than the conventional diesel selling at another station nearby.

Nelson's BioWillie is aimed mostly at truckers and usually sold as B20 -- pure biodiesel can congeal in colder climates. BioWillie is sold at 13 gas stations and truck stops in four states, mostly in Texas and is used for his tours.

If BioWillie demonstrates anything, it is that the combination of Middle East wars, global warming and rising prices at the pump have led many people to offer solutions to the world's energy's crunch. Depending on whom you ask, cars will someday run on hydrogen, electricity, natural gas or ethanol.

Nelson is betting on biodiesel.

"I don't like the war," he said. "In fact, I don't know if you ever remember a couple years ago, it was Christmas day, and my son Lukas was born on Christmas Day, he's like 16 years old, and we were watching TV and there was just all kind of hell breaking loose and people getting killed and I was talking to my wife, Annie, and I said, 'You know, all the mothers crying and the babies dying,' and she said, 'Well, you ought to go write that.' So I wrote a song called 'Whatever Happened to Peace on Earth?' "

The song includes the line, "Just how much oil is human life worth?" He continued, "I've been upset about this war from the beginning, and I've known it's all about oil."

But every alternative has drawbacks. Biodiesel would reduce most emissions of smog-forming pollutants and global warming gases. But some studies show it increases emissions of one pollutant, nitrogen oxide. Biodiesel could not be produced in vast enough quantities to supplant oil-based fuel, unless the nation starts turning suburbs over to farmland. And like producing ethanol, producing great quantities of biodiesel from corn or soybeans could drive up food prices.

Bill Reinert, a top engineer at Toyota, said in an interview earlier this year: "I frankly don't see biodiesel being an early alt-fuel player across a wide swath of geography. It's a boutique fuel. There's not enough payoff and not enough people into it."

Peter J. Bell, CEO of Distribution Drive, a distributor of biodiesel that is working with Nelson, said of the nation's nearly 200,000 gas stations, "650 carry biodiesel, so we have a job in front of us." Nelson sits on the board of Distribution Drive's parent, Earth Biofuels, a public company.

Daniel Becker, the Sierra Club's top global warming expert, said he would prefer to see wider usage of a cleaner alternative fuel, such as natural gas.

Referring to biodiesel, he said, "In order to grow soybeans, you need multiple passes over the field with diesel tractors, you need a lot of fertilizer that's energy intensive to produce and, at the end of the day, you have a product that is no boon for the environment."

He added: "If you're going to go to the trouble of using an alternative fuel, use a good alternative fuel. If you really want to listen to Willie Nelson, go buy one of his records and play it in a hybrid."

Get it all with convenient home delivery of The News & Observer.