As Airbus Bets on Hydrogen, Boeing Opts for Pragmatism

Since electric planes—such as the 19-seat aircraft that United Airlines and Mesa are investing in—will only fly very short ranges, the onus is on Boeing and

Airbus

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to make their replacements for the 737 and A320 families more sustainable. Whereas Airbus has unveiled plans for hydrogen-powered aircraft to perhaps enter service by 2035, Boeing has suggested this is unlikely before 2050.

Of course, both are researching all options. But the Chicago-based company is quite publicly placing most of its green chips on sustainable fuels. Back in January, it established a goal to build planes that run 100% on them by 2030, rather than the maximum 50% blend currently allowed.

“Drop-in” fuels require very few changes in aircraft design and infrastructure. Their big disadvantage is paltry production capacity: Less than 1% of aviation fuels are sustainable, and they will only make up 20% of demand by 2040, the International Energy Agency thinks.

The cheapest biofuels, such as those that come from processing vegetable oils and waste fats, cost twice as much as conventional jet fuel. Worse, studies suggest that their costs won’t fall by much even with the economies of scale of ramping up production, and that the extra land use could have devastating ecological consequences—as automobile biofuels have shown. Alternatives like “power to liquid” processes have more potential for improvement, but need far more investment to slash their costs.

Yet, as Boeing Chief Sustainability Officer

Chris Raymond

said, “for some pathways you can make a reasonable estimate of costs, for others you have to learn by doing.”

SkyNRG’s U.S. operations will focus on fuel production, but also on how to source feedstocks from municipal solid waste and establish supply chains to major airports. “The key is to create an investible business case that allows project finance to become available,” said Maarten van Dijk, the company’s managing director. “You need access to the feedstock at prices that are predictable, and have the technology at the maturity level required to know how much it will cost you to build a facility.”

Indeed, the only way to overcome the chicken-and-egg problem in sustainable aviation fuel is to start producing more of it. The economics could suddenly become more favorable thanks to the Sustainable Skies Act that the U.S. aviation industry is lobbying for, and the blend mandates being considered by the European Union.

Ultimately, it will be very hard to get radical new propulsion technologies ready for the next generation of narrow-body jets—and 42% of emissions come from wide-bodies anyway. For all their problems, sustainable fuels have one big edge: The technology works. Throwing money at them has a chance of leading somewhere.

Write to Jon Sindreu at jon.sindreu@wsj.com