Likely Bedfellows?

Propane council seeks partners in school bus industry to bring dedicated engine to market

By Shanna Thompson | Associate Editor

ALVIN, Texas - Twenty-five years ago when Alvin Independent School District converted its bus fleet to propane, the decision to go with alternative fuel had nothing to do with the environmental benefits that such a switch touts today.

The year was 1980, and the district, located 25 miles south of Houston , was feeling the economic crunch of the gasoline and diesel shortage of the late 1970s and early 80s. The availability and reasonable cost of propane made financial sense to Alvin ISD, and the district converted 30 buses.

"Alvin ISD chose propane as a fuel primarily because it was readily available, inexpensive and the conversions were reasonable priced," said Reuben "Butch" Passmore, fleet maintenance manager for the school district. "The decision committed us to alternative fuel long before there was an environmental issue."

Still, the school district enjoyed the other advantages of propane. The cleaner burning fuel reduced emissions, and the engine's smaller crankcase and coolant capacity produced much less hazardous waste than comparable diesel engines, he said.

Alvin also found that the lighter weight of the converted gas engine corresponds to longer tire and suspension life and that the propane-throttled engine assists in braking resulting in a longer brake life.

Plus, it is safe, Passmore said, citing two accidents where Alvin buses took direct hits to the propane tank. In one a pickup truck traveling at an estimated speed of more than 45 mph collided with an Alvin bus. While the truck was engulfed in gasoline fire, the school bus had only a slight leak to the supply line valve, which was tightened to stop the seep. A second accident involved a crash that resulted in only a small dent to the bus' fuel tank but left the other vehicle totaled.

"Propane requires an ignition temperature of 950 degrees compared to gasoline's 650 degrees meaning it is more difficult to start a propane fire," Passmore said. "These incidents display the strength and integrity of the propane fuel tank and its related components."

For its dedication to propane power, this year the Propane Education & Research Council recognized Alvin Independent School District with the 2005 Propane Exceptional Energy Fleet Award.

The fleet size and the decades-long use of propane made Alvin stand out as a strong supporter of the alternative fuel, said Brian Feehan, managing director of the engine fuels programs at the Propane Council.

The honor came despite the fact that 2003 was the last year Alvin ISD was able to purchase the GM gasoline engines for large school buses and special needs buses that are compatible with conversion to propane.

"We do not have an option of buying propane power because there is no gasoline engine or OEM LPG engine available at this time for the type C school bus chassis," Passmore said.

The school district currently operates 99 buses on propane and expects to use 420,000 gallons of the alternative fuel this year, said director of transportation John Ralph. Alvin operates an additional 19 diesel buses.

With a 13-year bus replacement cycle in place, Ralph expects that Alvin 's entire fleet will shift back to diesel in five to seven years.

"The recognition (by the Propane Council) was appreciated, but it would seem that the propane industry and the federal government should spend more of their efforts in developing and reintroducing LPG capable large school buses to assist in having cleaner air," Ralph said.

In fact, the discrepancy between the propane push and the unavailability of infrastructure is receiving attention from the Propane Council, which, Feehan said, is involved in a two-phase process with Hino, a division of Toyota , to develop a dedicated engine. The Hino engine is scheduled to be available in 2008, and fleets will have the option to buy just the engine or the engine and truck in a chassis.

"The integration between the engine and the supplier of the bus itself is the challenging we are facing," he said.

Although no formal agreement has yet been formed with any school bus manufacturers, $1.2 million in funding has been committed to the project. The investment by the Propane Council coupled with environmental and economic advantages of using propane, said Feehan, offers an optimistic outlook for the future of the alternative fuel.

"I see significant opportunity for propane over the next several years," he said.