'Is it safe?' | Boeing executives cast doubt on viability of hydrogen as an aviation fuel

Aircraft maker says H2 is best used in the production of sustainable aviation fuels

 

Executives at US-based aircraft maker Boeing are doubtful about hydrogen as an aviation fuel on account of its safety and sustainability challenges.

 

Speaking at the prestigious Farnborough International Airshow in the UK this week, Boeing’s chief technology officer Todd Citron warned that the high flammability of hydrogen poses safety concerns that will take time to overcome, according to specialist aviation title Flight Global.

 

Citron flagged that hydrogen is significantly more flammable that Jet-A fuel typically used in aircraft.

 

“Is it safe and certifiable? That’s a really big question,” he told the event.

 

Citron was one of a trio of Boeing executives speaking at the show, with another, chief sustainability officer Brian Moran, issuing a second warning, this time on hydrogen’s environmental credentials, pointing out that “98% of hydrogen is not green”.

 

Most hydrogen produced today is made with unabated fossil gas, and with final investment decisions still delayed on green H2 projects and large production subsidy programmes in the US still awaiting firm regulatory guidelines, production of renewable hydrogen is not expected to ramp up at significant scale until early next decade.

 

Boeing has carried out six hydrogen propulsion-related demonstration projects since 2008, with the latest, in 2021 to develop a composite cryogenic fuel tank to store liquid H2.

 

But in a briefing note dated March 2024, the company highlighted that “the larger fuel volume and very cold temperatures required for storage of liquid hydrogen present significant innovation opportunities in aircraft design and systems integration.”

 

The company has also conducted a total of three programmes to demonstrate hydrogen fuel-cell propulsion in unmanned aircraft.

 

“Boeing’s position is that the first, best and primary use of hydrogen in aviation should be used to develop and scale SAF [sustainable aviation fuels],” a spokesperson for Boeing told Hydrogen Insight today. “SAF is enormously important to reaching the commercial aviation industry’s net zero by 2050 goals and Boeing is working to advance green hydrogen to support the industry’s need to scale SAF through collaborations with entities including Equatic, Masdar, Mitsubishi Heavy Industries and Zero Petroleum.”

 

Green hydrogen can be used to make synthetic kerosene, by mixing it with carbon. It can also be used in the Fischer-Tropsch process to make biomass-based aviation fuels.

 

Boeing’s rival Airbus, by contrast, has pledged to bring hydrogen-powered aircraft to the skies by 2035 as part of its Zero-E programme — and has promised to make a decision on whether these planes will be powered by fuel cells or H2 combustion this decade.