NEW YORK – With the exception of Chrysler Group, which recently announced it will be the first auto maker to fill one of its diesel-engine models with biodiesel fuel before it leaves the factory, this environmentally friendly alternative to petroleum-based diesel is not making much headway with auto makers.

But there is increasing use of biodiesel in fleets and even among a limited number of individual motorists.

Diesel-powered Liberty will come from factory with biodiesel fuel.

Still, taking biodiesel out of the laboratory and onto the highway in a more significant way is going to be a slow process until government subsidies make it more attractive, sources say.

And it definitely will take more than Chrysler’s decision to fill every diesel Jeep Liberty that rolls off the Toledo, OH, assembly line later this year with biodiesel to give this alternative fuel a big push. (See related story: Liberty To Use Biodiesel Fuel)

General Motors Corp. is closely monitoring trials of its biodiesel-fueled pickups now taking place in Las Vegas, NV. More than 200 diesel-engine vehicles – from each of the domestic auto makers – belonging to water departments and school districts in Las Vegas are running on B20 (20% bio-component diesel and 80% petroleum diesel). In this field test, the bio component of the B20 is “yellow grease” – discarded oil the casinos use for making french fries.

Jack Blanchard, GM’s assistant chief engineer for diesel engineering, says the company also is dynamometer testing four vehicles that burn B20. He forecasts B20 will become the federally approved standard for biodiesel formulation.

Burning 100% biodiesel would be tough in the northern tier of the country.

“It would be like running on lard because biodiesel does not flow in the cold,” Blanchard says.

GM is not directly involved in the Las Vegas trials, but Blanchard says the agencies have agreed to let GM monitor and gather data on their vehicles. Blanchard says a total of 238 GM vehicles have logged more than 5 million miles (8 million km) with B20. However, only 18 of these vehicles are equipped with GM’s latest Duramax 6.6L turbodiesel V-8.

So far, the tests indicate biodiesel exhaust contains fewer hydrocarbons and less carbon monoxide, but oxides of nitrogen emissions are higher and fuel economy is lower. Biodiesel typically has 5%-7% lower energy content than 100% petroleum-based diesel fuel. But overall, Blanchard says, there have been few problems in the vehicles burning biodiesel.

DaimlerChrysler AG is running trials on SunDiesel, a biodiesel fuel made from wood chips and other plant-based sources. However, that program has a long way to go before producing a biodiesel formulation ready for retail consumption, says Dieter Zetsche, president and CEO of Chrysler Group.

Volkswagen AG also has extensive ongoing research into biodiesel production.

The U.S. Dept. of Energy says biodiesel is the fastest-growing alternative fuel in the U.S. About 25 million gallons (95 million L) were sold in 2003. That’s a big jump from 15 million gallons (57 million L) in 2002 and only 500,000 gallons (1.9 million L) in 1999. But the total remains minuscule in comparison with the 34.3 billion gallons (128.7 billion L) of petroleum diesel used by U.S. highway vehicles annually.

Jenna Higgins of the National Biodiesel Board says future growth in biodiesel use is dependent on government tax incentives. “If (an advocated) tax incentive passes, we expect demand for biodiesel to sharply rise,” she says. The NBB is promoting a tax incentive of 1% for every percent of bio component used in diesel-fuel blends.

There are 22 biodiesel plants in the U.S. supplying 1,000 distributors, mostly in the Midwest. More than 400 fleets use biodiesel today and there are more than 300 retail fueling sites. Higgins claims biodiesel is widely available.

Biodiesel is offered in various blends. B20 is the most commonly used and is preferred by fleets, such as school buses, utility-company vehicles, military bases and state motor-pools. But some fleet users, such as the city of Berkeley, CA, use B100. The 100% biodiesel also is available at some public pumps.

Government fleets are the largest biodiesel customers, Higgins says. Some are required to reduce petroleum use and biodiesel is an eligible alternative to conventional petroleum-based gasoline and diesel fuels. Higgins says that about 50 school districts use biodiesel-fueled buses to meet tougher emissions targets. About 31% of soybean farmers use biodiesel blends in their farm machinery.

“They are becoming a significant market force,” she says.

Biodiesel burns significantly cleaner than conventional diesel. An Environmental Protection Agency report shows that B100 emits 67% fewer unburned HC, 47% less CO and 48% fewer particulates. B20 has higher lubricity and cetane (propensity to ignite) than petroleum diesel. Biodiesel blends as low as 1% reportedly can provide up to a 65% increase in lubricity compared with petroleum-based diesel. The cetane rating of petroleum diesel typically is 44, while B20 is marginally higher at 45-46.

Biodiesel can be used in almost any diesel engine, but engines made before 1994 may need new hoses and gaskets because the bio component is not compatible with natural rubber. Replacing hoses and gaskets is especially recommended when using B100, but also is advisable with B20.

Higgins says biodiesel use generally will not void the warranties of major U.S. engine manufacturers. However, Blanchard says GM does not recommend and will not honor warranties for its diesels fueled by B20. GM, he adds, is more tolerant of B5.

Using it as the factory fill for the upcoming diesel-powered Liberty, Chrysler obviously warrants diesels fueled with biodiesel. But warranty implications from most engine manufacturers or auto makers are vaguely detailed.