Kenworth LNG Trucks Coming to California

Kenworth Truck Co. plans to begin large-scale production of heavy-duty trucks powered by liquefied natural gas at its Renton plant next year.

The move to LNG trucks is the latest by Kenworth and its parent company, Bellevue-based Paccar Inc., to look for alternatives to conventional diesel-fuel engines as a way to reduce operating costs and meet increasingly stringent air-emission rules.

Kenworth already has announced plans to market medium-duty hybrid trucks this year, and Paccar is developing a similar hybrid system for heavy-duty trucks, what most people refer to as semis.

How many LNG-powered units Kenworth's Renton plant will produce will depend on market demand, and initially it's not expected to have a big impact on employment, said Bob Christensen, Kenworth general manager.

But with California and other states writing tougher regulations on truck-engine emissions, "We think it's an emerging market," Christensen said.

In LNG systems, natural gas is held as a liquid at minus 260 degrees Fahrenheit. The truck itself doesn't require any special refrigeration equipment; instead, it relies on a vacuum-bottle cryogenic tank system to hold the fuel at that temperature.

Kenworth plans to use its T800, a model frequently used in such applications as regional freight hauling and dump trucks, in combination with a Cummins engine and an LNG fuel system developed by Westport Innovations Inc. in Vancouver, B.C.

Paccar has been researching natural gas as a truck fuel for more than a decade, comparing the merits and drawbacks of compressed natural gas and LNG.

Early on it was thought that natural gas couldn't deliver the horsepower of a diesel engine. Christensen said the gap has been narrowed, and Kenworth will offer 400- and 450-horsepower configurations. "The torque and drivability of the LNG truck has been very good," he said.

One major market for LNG trucks is hauling containers at ports. Kenworth noted that the ports of Los Angeles and Long Beach, Calif., have set up a fund to replace diesel-engine trucks with LNG vehicles and will remove all pre-2007 trucks by 2012.

Improving emissions from trucks through cleaner engines and fuels is also a goal of the Northwest Ports Clean Air Strategy approved recently by the ports of Seattle, Tacoma and Vancouver, B.C.

Kenworth and Westport already have put together fuel systems that can be retrofitted to existing trucks.

Although LNG trucks require specialized tank, fuel injector, pump and electronic systems, which boost the cost of the truck, federal and state programs may offset the cost, Christensen said. Meanwhile, the gap between the cost of diesel fuel and natural gas is widening, he said, giving natural gas an operating-cost advantage.