ANN ARBOR, Mich. — Consumers can save big bucks if they drive a diesel-powered vehicle instead of its gasoline counterpart; that’s the conclusion of a recent study out of the University of Michigan’s Transportation Research Institute (UMTRI).

Total Cost of Ownership: A Gas Versus Diesel Compari-son was conducted by U-M for the Robert Bosch Corp., and the results were released June 27 at the Alternative Clean Transportation Expo in Washington, D.C.

“Overall, the results of our analyses show that diesel vehicles provide owners with a TCO (total cost of ownership) that is less than that of the gas versions of the same vehicles,” the study concludes. “The estimates of savings for three and five years of ownership vary from a low of $67 in three years to a high of $15,619 in five years, but most of the savings are in the $2,000 to $6,000 range, which also include the extra cost that is usually added to the diesel version of a vehicle.”

When asked how biodiesel might fit into the overall picture of such engines, Diesel Technology Forum Executive Director Allan Schaeffer described it as a tricky question.

“The study didn’t factor in the use of biodiesel, since biodiesel use isn’t widespread enough at this time. That’s why the studies haven’t looked at it yet. A study that we’ve commissioned is going to touch on biodiesel,” he added.

The Diesel Technology Forum is an educational nonprofit association that doesn’t lobby. Schaeffer said biodiesel is manufactured as pure biodiesel, but “in the real world” it is used as B5, or 5 percent biodiesel to 95 percent regular diesel. “Part of the problem with biodiesel is actual availability,” he said. “Most states are at a B2, B5 and B10 requirement. Minnesota has a higher requirement. Most manufacturers are comfortable using B5.”

One exception to this is Chevrolet, which will cover at least some of its vehicles under warranties, to use B20. Heavy-duty pickup trucks tend to use B20 as well. Schaeffer said his organization is comfortable with the auto manufacturers’ guidelines, because he wants people to have positive experiences with diesel-powered vehicles. “We’ve worked quite hard to get the image of diesel improved,” he stated. “At the end of the day we want people to pay attention to what the manufacturer requires.”

Schaeffer asserted diesel-powered vehicles hold their value better than gas-powered vehicles, which is an important consideration when looking at TCO. Diesel engines are built to withstand higher pressures and, because the engines tend to be more powerful than gas-powered engines, the other parts have to be a bit stronger as well, he said. “It’s not unusual to see diesel-powered vehicles lasting 500,000 miles,” he said.

According to the study, a person operating a Volkswagen Jetta with a diesel powertrain for five years and traveling 75,000 miles will save $5,475 over its gas-powered counterpart. TCO includes the initial cost of the vehicle, the cost of fuel, insurance, repairs and other factors, as well as resale value. The lack of availability of diesel-powered vehicles is seen as a problem for the industry, but more diesel-powered cars and trucks are scheduled to come on the market in upcoming years.

A potential problem with the TCO advantage of diesel versus gas is the spread between the cost of diesel fuel and gasoline, according to the study. At some point during the study this cost spread became greater and had some effect on the results. The study’s authors said this issue needs to be looked at more, going forward.

But Schaeffer doesn’t think this is going to be a problem. “(The U.S.) Department of Energy is anticipating that diesel and gasoline will track much more closely going forward,” he said.

For a copy of the report, go to www.dieselforum.org