Dunn Lumber is using Kenworth Truck Company’s first medium duty hybrid-electric truck to hit the U.S. market. “It’s still very early, but fuel economy is up an estimated 35% in the first few weeks of operation compared to one of our similarly spec’d Kenworth T300s,” said Mark Geyer, fleet manager for Dunn Lumber Co. in Seattle. “The truck also looks great and is extremely quiet, which is a big plus.”

Kenworth’s goal for its new medium duty hybrid is to enhance fuel economy by up to 30 percent in start-and-stop applications, such as pickup and delivery and utility trucks. Kenworth is offering limited production of medium duty hybrid trucks for municipal fleets and utility companies this year with full-scale production expected to follow in 2008.

Above 30 mph, the Kenworth hybrid operates like a standard diesel vehicle with all power coming from the engine during steady driving conditions. Below 30 mph, it uses a combination of diesel and electricity with the system automatically switching between the two modes of operation. Electricity generated through regenerative braking is stored and used for acceleration, assisting the diesel engine.