A container delivery truck heads for one of the terminals at the Port of Long Beach in Long Beach, California. Frederic J. Brown | AFP | Getty Images

The twin ports in Los Angeles and Long Beach are cited by environmental authorities as some of the worst sources for the region's endemic air pollution, a problem regulators aim to address with a planned phase-out of the 16,000 smoke-spewing diesel trucks that service the shipping centers. What sort of clean technology will replace them is far from certain, but Paccar, one of the world's largest heavy-duty truck manufacturers, is teaming with Toyota to test one promising alternative. At this month's Consumer Electronics Show in Las Vegas, the partners unveiled the first of 10 prototype trucks that will rely on hydrogen fuel cells. That puts the partners in competition with players like Tesla that are focusing on battery-powered semis. "We believe that carrying energy in the form of hydrogen for heavy-duty Class 8 trucks makes more sense than carrying it in batteries" because the trucks can be refilled faster and offer longer range, said Brian Lindgren, director of research and development for Paccar subsidiary Kenworth.

Fossil fuel replacement

While hydrogen could be used as a direct replacement for fossil fuels in internal combustion engines, most efforts focus on using it to power fuel cells. That technology — which was conceived back in the 1850s — forces hydrogen gas through a catalyst-coated membrane where it bonds with oxygen from the air. The process creates water vapor and a stream of electrons that can power the same electric motors that are found in a battery-electric vehicle. That's why some experts refer to fuel cells as "refillable batteries." In passenger cars such as the Toyota Mirai or Honda Clarity FCV it takes about five minutes to refuel a hydrogen tank with a range of around 300 miles, far less than required to recharge a battery. Though refilling a Class 8 truck's hydrogen tank will take longer, it still would be substantially less than the time needed to charge the batteries needed for a similar semi. Fuel-cell technology is nearly as quiet as the drivetrain in battery-electric vehicles, Lindgren noted — so quiet, in fact, that reporters attending a CES news conference were surprised to learn the truck behind the Paccar engineer had been idling the whole time.

Toyota Motor's hydrogen fuel cell powered semi-truck is displayed at AutoMobility LA ahead of the Los Angeles Auto Show Patrick T. Fallon | Bloomberg | Getty Images

'Peppy and quiet'

"Drivers like these trucks because they are peppy and quiet," Lindgren said. The fuel-cell system that will be used in the prototypes will be supplied by Toyota and is an updated version of an original test vehicle that operated at the ports this past year. The new trucks will actually pair two stacks producing about 228 kilowatts, or 306 horsepower. That understates the power the technology delivers because the electric motors that drive the wheels produce tremendous amounts of torque — though Paccar and Toyota officials didn't have the final torque numbers available. Improving performance and easing the job of a fuel-cell truck's driver, the Paccar/Toyota technology will require only a four-speed transmission, rather than the 18-gear transmissions in the typical Class 8 truck. In production, meanwhile, Andy Lund, the Toyota chief engineer on the project, said the trucks would have the same payload capacity as a diesel rig.

5 to 7 miles per gallon

From a fuel economy perspective, Lindgren said the prototype trucks will be roughly equivalent to a current diesel, or around 5 to 7 mpg. But Lund stressed that the vehicles will produce nothing but water vapor in terms of exhaust. The new project will provide answers as to whether fuel-cell technology can serve as a viable replacement for the conventional diesel trucks that now ply the ports, hauling goods from ship to shipping depots, Lund added. Paccar and Toyota aren't the only ones looking at fuel cells for the trucking industry. Salt Lake City-based Nikola Motor is developing several of its own hydrogen-powered heavy-duty rigs, including the Class 8 Nikola One it hopes to start building later this year. It claims to have received about 8,000 advance orders worth more than $6 billion.

'Fool cells'