With support from the California Air Resources Board, Japanese auto giant Toyota and truck maker are collaborating to develop and build a limited run of hydrogen fuel trucks. The vehicles, which are Kenworth T680 trucks modified with Toyota’s hydrogen fuel cell powertrains, are expected to drive on routes around Los Angeles and further inland to San Bernardino. The actual specs of the vehicles have not been announced by either company, but the range of the hydrogen fuel cell T680 trucks are said to be 300 miles in “normal drayage operating conditions.”

Toyota and Paccar, the parent company behind Kenworth, took the wraps off the first hydrogen fuel cell long-hauler at this month’s Consumer Electronics Show in Las Vegas. The vehicle, which is classified as a Class 8 truck, stands to be a possible competitor for upcoming all-electric trucks like the Tesla Semi in the future. In a statement to CNBC, Brian Lindgren, Kenworth’s director of research and development, noted that utilizing hydrogen as a source of propulsion makes more sense for Class 8 vehicles than batteries, which power vehicles like Tesla’s all-electric long-hauler.

“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,” he said.

Lindgren’s point about faster refilling times for hydrogen fuel cell vehicles is quite justified, considering that a passenger car such as a Toyota Mirai could refill its tank with around 300 miles of range in roughly five minutes. That’s significantly faster than Tesla’s Superchargers, which are capable of charging roughly 200 miles of range in 30 minutes. Larger vehicles such as the hydrogen-electric Kenworth T680 trucks would likely take longer to refill than a passenger car such as the Mirai, but there’s a good chance that the long-hauler could still refill its tank faster than the Tesla Semi could charge its batteries, even if it is plugged into the upcoming Megacharger Network.

Toyota-Paccar’s Kenworth T680 hybrid fuel cell trucks caught the attention of some CES attendees due to the vehicle’s silent operation, which is nearly comparable to an all-electric truck. Lindgren, for his part, noted that drivers who have operated the truck actually appreciated the silence of the vehicle. “Drivers like these trucks because they are peppy and quiet,” he said.

Andy Lund, the Toyota chief engineer on the project, further stated that the hydrogen-electric trucks would have the same payload capacity as a diesel rig. Unlike its fossil fuel-powered counterparts, the hydrogen fuel cell Kenworth T680 long-haulers would only require a four-speed transmission, which is far simpler than the 18-gear transmissions usually fitted on Class 8 diesel trucks.

If there is one thing that would probably go against Toyota and Paccar’s hydrogen trucks, though, it would be their fuel efficiency. Kenworth’s director of research and development noted that the prototype trucks currently consume hydrogen at roughly the same rate as present diesel trucks, at around 5-7 mpg. The only advantage of the vehicles, of course, is that the trucks would only produce water vapor from their exhausts. This is a substantial advantage, considering that the trucking industry accounts for about 23% of carbon emissions from transportation in 2016, according to the Environmental Protection Agency.

That said, this would be something that Tesla could capitalize on. During the electric long-hauler’s unveiling, Musk noted that the Semi would cost operators $1.26 per mile to run, less than the standard $1.51 per mile that diesel-powered vehicles cost. Musk’s estimate has been met by skepticism by veterans of the trucking industry, but if the Tesla Semi’s operating costs stay true to the CEO’s estimate, then the vehicle would most certainly give itself a notable advantage over diesel and hydrogen-powered rivals when it starts operating on America’s roads.

Hydrogen fuel cells remain a polarizing solution for sustainable transportation. Elon Musk, for one, has openly discussed his dislike for hydrogen-electric transportation. In a statement to Autocar in 2014, for one, Musk went so far as to describe hydrogen fuel cell systems as “mind-bogglingly stupid.”

“They’re mind-bogglingly stupid.  You can’t even have a sensible debate. Consider the whole fuel cell system against a Model S. It’s far worse in volume and mass terms, and far, far, worse in cost. And I haven’t even talked about hydrogen being so hard to handle. Success is simply not possible. Manufacturers do it [FCEVs] because they’re under pressure to show they’re doing something ‘constructive’ about sustainability. They feel it’s better to be working on a solution a generation away rather than something just around the corner. Hydrogen is always labeled the fuel of the future – and always will be,” Musk said.

Elon Musk initially announced that the Tesla Semi would start production sometime in 2019. That said, later statements from Tesla’s head of investor relations Martin Viecha suggested that the electric car maker would “earnestly” start producing the Semi by 2020.