Wednesday, September 06, 2006

Clean diesel a promising fuel

Denver Post
September 4, 2006

Diesel engines may seem an unlikely target for praise by environmentalists. But new "clean diesel" rules that go into effect Oct. 15 have transformed diesels into key tools for reducing U.S. dependency on foreign oil and cutting carbon dioxide emissions in the bargain.

Diesels are much more efficient than gasoline engines. Passenger cars, pickup trucks and SUVs powered by diesels get 20 to 40 percent better fuel economy than their gasoline-powered equivalents. The 2005 Volkswagen Golf diesel, for example, is rated by the Environmental Protection Agency at 38 miles per gallon in the city and 46 mpg on the highway - numbers that rival or exceed many gasoline-electric hybrids. And even greater fuel savings may result from diesel-electric hybrids now under development by General Motors and other manufacturers.

In Europe, where taxes have long driven fuel costs well over $5 a gallon, diesels have been popular for many years. In the U.S., however, diesels routinely power trucks, farm tractors and heavy equipment but have played only a modest role in the automobile fleet. At least part of the reason was that diesel fuel contained a relatively high sulphur content and so ran afoul of environmental sensitivities. While diesels naturally emit very low levels of carbon monoxide, the sulphur-laden older fuels were prone to emit small particles that could pose problems for victims of respiratory ailments. And who wasn't put off by a generation of diesels that emitted unsightly exhaust?

That's why the advent of the new ultra-low sulfur diesel fuel is so important. It will power new clean diesel engines that will start being available in January and are equipped with advanced exhaust after-treatment technologies comparable to the catalytic converters in gasoline-driven cars.

The new diesel engines are expected to emit 90 percent less pollution than their older counterparts - and eliminate those black puffs of smoke you're used to seeing from 18-wheelers lumbering under a heavy load in the mountains.

The new clean diesel fuel is expected to cost between 5 and 10 cents more per gallon than the older, sulphur-laden variety. But the higher milage offered by diesels will still mean major savings for motorists who buy the new diesel-powered cars.

Saving money while reducing dependence on foreign oil and cutting greenhouse emissions is a combination worth celebrating.

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