Diesel turns green.

Clean diesel has arrived! It is increasingly being used in new heavy-duty diesel vehicles, as well as being applied to old diesel vehicles and equipment. Clean diesel technology incorporates clean fuels, clean engines and emissions controls. The use of these new technologies can reduce emissions from 20 percent to 90 percent. For example, it would take 60 new clean diesel trucks built in 2007 to equal the soot emission of one truck sold in 1988.

The most common clean technologies include exhaust system catalysts and filters, cleaner fuels, idling control equipment and the early replacement of inefficient engines.

In 2000, the Environmental Protection Agency created a Voluntary Diesel Retrofit Program that encourages states to create legislation that puts emissions control devices on heavy-duty diesel vehicles. The EPA and the California Air Resources Board have approved several retrofit technologies for a variety of applications. These technologies vary widely in price depending upon the age and type of vehicle being retrofitted. The three most common technologies include crankcase vent filters, diesel oxidation catalysts and diesel particulate filters.

Thanks to the nationwide introduction of ultra low sulfur diesel fuel in October 2006 and the new technologies it has enabled, regions around the country can use clean diesel to help meet the National Ambient Air Quality Standards for particulate matter and ozone, and to help states to meet their clean air quality goals set out in most State Implementation Plans.

Since diesel vehicles are 20 percent to 40 percent more fuel efficient than gasoline engines and emit 10 percent to 20 percent fewer greenhouse gas emissions, they are also of increasing interest to policymakers, manufacturers and consumers. Today, clean diesel has the potential to play a vital role in preserving the environment, decreasing U.S. dependence of foreign oil imports and reducing greenhouse gas emissions that contribute to climate change.