Hoping to drastically cut polluting fumes, several of the largest districts in California are investing in environmentally friendly technology for school buses.
The state, the federal government, and British Petroleum-Amoco PLC are subsidizing most of the cost of the technology, which consists of an engine and a muffler-type device specially developed for low-sulfur diesel fuel. Major trucking companies are working on the new technology with the view that within six years it will essentially replace traditional diesel-run systems.
In the new systems, a particulate-filter trap replaces the muffler and acts as a muffler and catalytic converter to cut down on soot, hydrocarbon, and nitrogen oxides. Low-sulfur diesel fuel has only 15 parts per million of sulfur, vs. an allowable 500 parts per million in regular diesel.
The 24,000 school buses in the state rely on diesel for more than 97 percent of their fuel, officials with the California Air Resources Board said. The 722,000-student Los Angeles Unified and 142,300-student San Diego Unified districts took part in the 18- month pilot program, which ended in June and included a number of public and private fleets. Patrick J. Fitzgibbon, a marketing manager for BP-Amoco, said the London-based company spent around $5 million on the test. Now the Los Angeles and San Diego systems are taking steps to use the technology more widely.
In June, Los Angeles began using low-sulfur fuel in all of its buses and plans to install new engines and filters in 19 buses by next summer, said Antonio M. Rodriguez, the director of transportation for the district.
San Diego has installed the traps in 10 buses, and two others have been equipped with both the traps and engines needed to fully cut emissions. Both orders are being subsidized heavily by the California Environmental Protection Agency, which will allot $50 million this year in grants to reduce harmful emissions from the state’s oldest, highest-polluting school buses. The plans call for scrapping 375 buses built before 1977 and paying for filters to cut emissions from 1,875 existing diesel buses.
Most of the grants are expected to pay for low-sulfur fuels. State officials pointed out that natural gas, another alternative fuel used for buses, sometimes isn’t a good fit for rural districts.
“Ninety percent of California is rural, and sometimes compressed natural gas has more limited range than diesel, because of colder climates,” said Jerry A. Martin, a spokesman for the Air Resources Board.
Officials with the U.S. Environmental Protection Agency estimate that nationwide, 8,300 premature deaths, 5,500 cases of chronic bronchitis, and 17,600 cases of acute bronchitis in children would be prevented annually by use of the low-sulfur fuel technology. In addition, the agency is studying whether diesel fuel causes cancer. The EPA has required that nearly all heavy-duty trucks and buses switch to ultra-low-sulfur fuel starting in June 2006. The rule, issued in the last month of the Clinton administration, was embraced by the Bush administration.
In February 2000, California required that all transit buses use alternative fuels or cleaner diesel technology by 2007 to cut down on pollution.
New and Expensive?
But in states where the use of low- sulfur diesel technology isn’t subsidized, districts have yet to buy it.
Officials from Arizona, New York, and Texas have expressed interest in buying the technology, but have not done so, said Mike Martin, the executive director of the National Association for Pupil Transportation, an Albany, N.Y.- based organization that represents bus makers and contractors. “It’s still relatively new and emerging as a new technology,” he said.
One reason may be cost. In California, a bus powered by low-sulfur technology costs $6,000 to $8,000 more than a regular diesel-powered bus, which costs around $100,000. Moreover, low-sulfur fuel costs from 3 to 10 cents more per gallon.
A low- sulfur diesel bus would cost $40,000 less than a bus powered by natural gas, however, officials in the state said.
Roger A. Hansen, the fleet manager for the San Diego schools, said a dozen of the district’s buses used the low-sulfur technology for two years. Their tailpipes were spotless, he said, a far cry from the black, pungent fumes they used to emit.
San Diego school officials would like to equip all of the district’s 530 buses with the technology.
Mr. Hansen doubts whether many other districts will order the new technology. If a district lies hundreds of miles from a distribution center and wants only a few thousand gallons of fuel, delivery costs are high, he notes.
“For some of these rural districts, to have a huge truck delivering it, whew. The delivery service charges on that,” he said.
Few districts are likely to switch to low- sulfur diesel systems anytime soon, added Mr. Martin of the National Association for Pupil Transportation.
“I think it will be like electricity and compressed natural gas, where some districts like and use it and other districts don’t,” he said of other types of bus fuel. “I would not expect it to be widely used, quite candidly, for another three to five, maybe 10 years.”
