By Jan TenBruggencate
Advertiser Columnist

One of the buses on the flight line at Hickam Air Force Base has a specialized power plant — a big electric motor powered by a bank of batteries, which in turn are charged by a hydrogen fuel cell.

It is a technology that works well for the duties of the bus, which include a lot of short-distance, stop-and-go driving during a long working day.

Whether or not it's a prototype for the future of passenger transportation, the electric motor and fuel-cell combination is more efficient in this application than the diesel engine that originally served as the power plant for the 30-passenger El Dorado National bus, said Ed Moore, vice president for operations of the firm Enova.

The Hickam bus is the result of a joint effort of the Air Force, Hawai'i's High Technology Development Corp., Hydrogenics and Enova, a California-based firm that develops electric, hybrid electric and fuel-cell applications for vehicles and stationary applications. The firm has been in Hawai'i since 1993 and has done several projects with the state's Hawai'i Electric Vehicle Development Program.

One of the recent projects was building 15 all-electric sport utility vehicles in conjunction with South Korea's Hyundai. The 15 Hyundai Santa Fe vehicles ran in Honolulu starting in 2001. Three are still here, while the others have gone back to South Korea.

On the Hickam flight line, alongside the fuel-cell vehicle runs an outwardly identical bus that was converted from its original diesel power plant to a pure electric vehicle. For refueling, it is plugged into an electrical outlet. For the new fuel-cell vehicle, refueling can be done in two ways. Either it can be plugged in to recharge the batteries, or its fuel cell can be refueled with hydrogen, and the fuel cell can charge the batteries.

For the hydrogen refill, tanks of hydrogen are brought to the bus. Plans are under way to install a hydrogen refueling station at Hickam, Moore said.

The process of conversion to fuel-cell power, Moore said, involves removing the diesel engine and the transmission and replacing them with an electric motor that hooks directly to the drive shaft, along with batteries and the fuel cell.

Tom Quinn, director of the Hawai'i Electric Vehicle Development Program, said the partnership that led to the hybrid bus has been a valuable one.

"Over the past 10 years, the joint efforts of Enova, the HEVDP and the U.S. Departments of Defense and Transportation have developed and commercialized many advanced alternative transportation systems for automotive, transit and commercial use," Quinn said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.