Cleaner biodiesel powering city's vehicles | www.tucsoncitizen.com ®

Cleaner biodiesel powering city's vehicles | www.tucsoncitizen.com ®: "The city has begun a program to reduce the choking fumes of diesel vehicles, all the while saving money.
A new federal regulation dramatically limiting the amount of sulfur allowed in diesel fuel goes into effect Sunday. It is intended to further help rid the air of harmful tailpipe emissions.
After months of testing, Tucson's City Fleet Services Division started last week to convert to a blend of 80 percent petroleum diesel fuel and 20 percent vegetable oil, usually soy oil, said Colleen Crowninshield, manager of the Clean Cities program for the Pima Association of Governments.
That's good for the environment because it is cleaner burning, and the blend, called B-20, is a cheaper alternative to 100 percent petroleum, she added. B-20 costs about a nickel a gallon less than pure petroleum.
Changing to B-20 will not affect warranties on the vehicles, Crowninshield said. The vegetable oil contains no sulfur.
There is another important saving in using B-20. It reduces the nation's dependence on foreign oil, she said. Initial estimates indicated the change will allow Tucson to use 200,000 fewer gallons of foreign oil per year.
Sunday is the federally mandated deadline for switching to diesel fuels with ultra-low sulfur content, Crowninshield said. The new fuel contains only 3 percent of the sulfur levels of diesel fuels sold in the past.
The old allowable level of sulfur in fuel was 500 parts per million. The new mandate is 15 ppm.
In addition to using ultra-low-sulphur fuels, new large trucks in the model year 2007 and beyond must have tailpipe filters before they can be licensed.
According to the U.S. Environmental Protection Agency, the cleaner fuel and filter systems should reduce air pollution from large trucks by 90 percent, Crownin"