Powering Propeller Planes With Hydrogen to Green the Skies

(Bloomberg Businessweek) -- Airlines have a huge carbon footprint and few good options for shrinking it. The big batteries that Tesla Inc. uses to power climate-friendly cars, after all, weigh too much for a passenger plane.

A team of aerospace veterans has another idea: hydrogen. Universal Hydrogen Co., founded by Airbus alumni, and Plug Power Inc. will work together to retrofit a regional airplane with hydrogen fuel cells to power its two propellers. Together the companies aim to have a plane ready and government-certified to fly by 2024.

The retrofit will try to prove to the airline industry that hydrogen can work for regional aircraft traveling several hundred miles, even if fuel cells remain a stretch for long-haul flights. The technology’s backers say it’s safer than jet fuel on several fronts. In an accident, for example, hydrogen vents upward, because it’s lighter than air, while jet fuel pools on the ground and burns there.

If the hydrogen is produced from water using hydrolysis that’s powered by renewable energy, it offers a realistic way to “decarbonize the skies,” says Keith Schmid, Plug Power’s chief operating officer. Fuel cells generate electricity through an electrochemical reaction rather than combustion. When powered with hydrogen, their only exhaust is water. “Hydrogen fuel cells essentially make zero-emission flight possible at ranges that are commercially viable,” Schmid says.

Universal was co-founded by Paul Eremenko, a former chief technology officer for Airbus SE and United Technologies Corp. Rather than build planes, his startup wants to supply the hardware for moving and using the fuel.

Universal has developed Kevlar-coated, pill-shaped pods, about 7 feet in length by 3 feet in diameter, that can serve as both a storage container for transporting the hydrogen and a gas tank when loaded into a plane. They can be stacked in racks so 54 of them would fit inside a standard freight shipping container, eliminating the need for airports to have pipelines or storage tanks. The lack of fueling infrastructure that’s held back fuel-cell cars wouldn’t be a problem for planes. “We want to basically turn hydrogen into dry freight,” Eremenko says.

Plug Power has spent more than 20 years losing money in an effort to find profitable applications for hydrogen fuel cells. It’s best known for offering fuel cells that run forklifts and other freight-handling gear. But it’s also expanded into stationary fuel cells to run data centers and mobile ones for delivery vans.

“The aerospace market is a little bit further out than some of the other sectors, but we do see the value proposition for hydrogen fuel cells in aerospace to be particularly strong,” Schmid says.

Plug Power will provide a fuel cell generating 1.5 to 2 megawatts for each propeller on the plane, while another company, MagniX, will supply the electric motors.

Air travel accounts for about 2.5% of global greenhouse gas emissions. While some engineers are developing small electrified aircraft, current batteries are too heavy to power commercial planes on their own.

Hydrogen storage could one day be used in other industries, Eremenko says. Cargo ship builders, for example, are exploring fuel cells as a power source. But he prefers to start with planes. “Ultimately we think aviation is the killer app, because aviation doesn’t have an alternative.”
 
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