As part of an ongoing commitment to protect the environment, Tacoma, Wash., has begun using a blend of diesel fuel and biodiesel — a product made from soybean oil — in its 85-truck garbage fleet. The fuel has reduced levels of harmful emissions from city vehicles without hurting the performance of the trucks or the city's budget.

Although Tacoma, which is located between Mount Rainier and the Puget Sound, does not have major problems with air pollution, city leaders want to ensure that it does not develop problems. Steve Hennessey, the city's fleet manager, had followed the use of biodiesel as an alternative fuel with cleaner emissions for several years. “So when we put our fuel contract out for bid, we put in an option for it,” he says. “I was very surprised at how little it cost. Using biodiesel means we can do the environmentally right thing without spending a lot of money.”

In November 2001, the city contracted with Kent, Wash.-based Petro Card to provide B20, a fuel that is 80 percent diesel and 20 percent biodiesel. Because the city committed to using 200,000 gallons a year, the fuel costs only about 20 cents a gallon more than straight diesel. In addition, the city required the contractor to deliver the fuel in a tanker truck each evening. With on-site fueling — instead of each garbage and recycling truck driver visiting the pumps each day — the time, wages and fuel saved more than offset the per-gallon cost, Hennessey says.

The alternative fuel has not affected the performance of the trucks, and maintenance crews have not experienced any mechanical problems because of its use. While the fleet's mechanics originally suspected that they might have to change the trucks' fuel filters more frequently, they have found that step unnecessary.

Since the conversion to biodiesel, Tacoma's garbage and recycling trucks have helped create cleaner air by emitting fewer harmful pollutants such as carbon dioxide, carbon monoxide, sulfur dioxide, hydrocarbons and particulate matter.

While most organizations use biodiesel made from virgin soybean oil, some use biodiesel made from recycled frying oil. Tacoma officials hope to explore using that kind of biodiesel when it becomes more available locally.

In the meantime, Hennessey said the city is happy with the mix it is using. In fact, “Tacoma is looking into increasing the number of city trucks that use biodiesel,” he says.

Although other cities have used biodiesel on a trial basis, Tacoma is the first city in the Pacific Northwest to commit an entire fleet to use of the fuel. That commitment attracted the attention of the U.S. Department of Energy Clean Cities Program, which awarded Tacoma its National Partner Award and inducted the city into the Clean Cities Hall of Fame last summer.