- The Washington Times - Wednesday, April 24, 2002

A new study says the $94.5 million that Metro has spent on "environmentally friendly" natural-gas buses would have been better spent on diesel buses that operate just as cleanly and cost about half as much.
The District is under a mandate from the Environmental Protection Agency to clean up the region's air by 2005 or face transportation funding cuts, said Metro board Chairman Chris Zimmerman. The Washington Metropolitan Transit Authority board, according to a statement released by Mr. Zimmerman, bought the 250 buses that used compressed natural gas as part of its anti-pollution efforts.
"There have been lots of studies, and I don't think there is any question that natural gas outperforms clean diesel over the long haul," said Mr. Zimmerman, Arlington Democrat.
He said natural-gas buses are cleaner and quieter than diesel.
But at least one board member disagreed with Mr. Zimmerman's assessment.
"I think, unfortunately, the symbolism of the natural-gas buses carries more weight than their actual effectiveness in cutting down on smog-producing emissions," said Dana Kauffman, Fairfax Democrat and the only dissenting vote on the Metro board for diesel over natural gas.
The day the Metro board decided to purchase more natural-gas buses, the California Air Resources Board (CARB) released a study showing that clean-diesel buses performed better than natural-gas buses in all but one category the production of nitrogen oxide gases.
"The diesel bus equipped with a particulate filter … produced lower emissions than either the [normal] diesel and the natural gas 'baseline' buses," the study said.
But the filtered-diesel bus produced more nitrogen dioxide emissions the chemical most attributed to increasing smog. Manufacturers of the clean-diesel engines say those emissions can be reduced.
Jerry Martin, a CARB spokesman, said it is fair to say the clean-diesel outperforms the natural-gas bus.
"But keep in mind, the natural-gas bus we tested did not have the particulate filter, nor did it have a catalytic converter," Mr. Martin said.
The Diesel Technology Forum, an organization that represents the two companies that make both clean-diesel and natural-gas buses, says the study indicates diesels perform better.
"We don't argue that the natural-gas buses weren't fitted with the filtering mechanisms, but 90 percent of them already on the road don't have them," said Allen Schaeffer, executive director for the group.
Metro has 164 natural-gas buses in its fleet, but only 38 are on the street. In order to use the natural-gas buses, fueling stations have to be retrofitted with gaseous tanks instead of traditional liquid-fuel tanks.
"Each refueling retrofit costs $22 million," Mr. Kauffman said, "and the natural-gas buses cost $40,000 more than the clean diesels."
"The natural-gas buses just don't pass the common-sense test for me," he said.
Metro spokeswoman Lisa Farbstein told The Washington Times that retrofitting of the Bladensburg Road fueling station in the District would cost $15.4 million.
"Once it is complete, it will be able to accommodate 202 buses," she said.
Metro has 1,443 diesel buses fitted with filters and running on low-sulfur fuel to reduce emissions.
"Your region is probably number one in the nation with that many [clean-diesel] buses," Mr. Martin said.
Metro will be replacing the old "dirty-diesel" buses over the next two years with the natural-gas buses, but Mr. Kauffman and Mr. Schaeffer say they think the clean diesel is more cost effective.
The most important question to answer, Mr. Kauffman said, "is which approach gets us the most buses on the street and gives us better options. Clean diesel seems to be the right choice."

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