Earth-Friendly Diesels to Compete Against Hybrids

Updated on February 11, 2008.

ENVIRONMENTALLY-CONSCIOUS CAR buyers are turning to hybrids more than ever, but soon, a new (and rather surprising) contender will join the green line-up at dealerships: diesel.

An earth-friendly diesel may sound like an oxymoron to those who remember Detroit's first attempts with these engines back in the 1980s. General Motors' diesel Oldsmobiles were "smelly, noisy and horribly unreliable," says John O'Dell, senior editor of Edmunds.com's Green Car Guide.

It's no surprise then that Americans have stayed away from diesel ever since. First impressions, after all, last. Despite its fuel efficiency — on average 20% to 40% better than gasoline, according to industry trade group, Diesel Technology Forum — less than 1% of all registered vehicles on the road today are powered by diesel.

That should soon change. In October 2006, clean, ultra-low sulfur diesel was introduced that has enabled auto makers to work on improving pollution-cutting technologies and creating diesel engines that are 95% cleaner than their predecessors, according to Rich Kassel, director of the Clean Fuels and Vehicles Project at the Natural Resources Defense Council.

The result: clean, green, fuel-efficient diesel cars that are set to hit dealerships in every state as soon as this year. Here's what you need to know about the "new" diesel and whether it merits a spot in your garage.

Those issues are now history. The diesel fuel that's currently in use has 97% less sulfur than the stinky, sooty, carcinogenic diesel that was offered at the pump up until last year. That, in turn, has enabled auto makers to add special filters, fuel catalysts that reduce emissions and other pollution-cutting technologies that didn't work well with the old diesel. As a result, diesel cars that meet the stringent emission requirements of all 50 states will soon hit the dealerships.

Meeting those standards is no small feat. Eight states, including California and New York, enforce such stringent emissions requirements that they've practically banned auto makers from selling new diesel cars, explains Edmunds.com's O'Dell. California alone accounts for 12% of all new car sales and the eight states together add up to one-third of all cars sold nationwide.

Barely a dozen diesel-powered models are available today, most of them in the SUV, heavy truck and pickup categories. But over the next couple of years, a wave of new models will become available to consumers, says Allen Schaeffer, executive director of the Diesel Technology Forum. Among the auto makers that have announced plans to introduce diesels by 2010 are General Motors, Hyundai (the Veracruz Crossover), Nissan (Titan by 2009, Maxima by 2010) and Honda, according to data compiled by the industry group. Volkswagen's 2008 Jetta diesel will hit the streets as early as this spring. BMW has made a commitment to unveil a 50-state certifiable diesel by 2009, says Schaeffer, while Mercedes-Benz will make its current lineup of E320, E350, GL, ML and R-series diesels 50-state certifiable by 2009 or 2010.

While the diesel cars on the road today still emit roughly 30% more smog-producing nitrogen oxide than gasoline cars, Schaeffer says, the new 50-state certifiable diesels will be as clean as their gasoline counterparts.