Diesel-electric buses hit streets next year

Less thick, black exhaust will spew from a new fleet of more than 200 diesel-electric hybrid buses the region's two biggest mass-transit agencies plan to roll out next year.

When the 60-foot articulated buses lurch into motion, they don't chug through fuel. At low speeds, they run on a hybrid electric drive, which King County Metro Transit expects will save 750,000 gallons of fuel and at least a half-million dollars a year.

"The reason you save so much fuel is that the bulk of what a bus does is starting and stopping," said Matthew Kester, a spokesman for General Motors Corp., which manufactures the hybrid electric drive at a transmission plant in Indianapolis.

As the bus speeds up, it uses a mix of electricity and diesel fuel. The diesel engine, made by Caterpillar Inc., takes over once the bus reaches 20 or 25 mph, Kester said yesterday.

"Because you're not dumping all the fuel through this diesel engine to get this bus moving, you're getting a 90 percent improvement on emissions (of soot, hydrocarbon and carbon monoxide)," Kester said. "Plus you've improved fuel economy by about 50 to 60 percent."

New Flyer, a Canadian bus manufacturer based in Winnipeg, Manitoba, makes the buses.

King County signed orders for 213 buses Friday, and Sound Transit, which runs regional express buses in King, Pierce and Snohomish counties, bought 22 -- a combined investment of more than $150 million.

"Obviously, it's a technology we're excited about because of the cleaner air, the fuel savings and the maintenance savings," Sound Transit spokesman Lee Somerstein said.

The first new hybrids are expected to hit the streets by next spring.

Today in Seattle, General Motors Corp. plans to show off the 60-foot model that King County Metro Transit tested out before its recent purchase.

Hybrid buses cost more up front -- about $645,000 apiece, compared with $445,000 for a standard diesel-powered bus, Metro Transit spokeswoman Linda Thielke said.

But because they use less fuel, hybrid buses don't need their oil changed as often and are easier to maintain, General Motors estimates that the county will recoup its costs within about seven years.

Metro Transit bought its test model last year and put more than 40,000 miles on it before deciding to buy the new fleet.

"It performed remarkably well," Thielke said, noting it had plenty of power motoring up hills, ran quietly and required very little maintenance.

Sound Transit bought a 40-foot test model. "Our operations people just love it," Somerstein said. "They've had virtually no problems."

The hybrids will replace an aging fleet of dual-mode buses that run on overhead electric wires while they pass through the downtown bus tunnel, then switch to diesel outside the tunnel.

Because the new buses will have their own electricity supply, they'll no longer rely on those overhead wires while inside the tunnel, making them easier to maneuver.

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