The global aviation industry is set to require 120 million tonnes (Mt) of clean hydrogen a year by 2050, with 100Mt to produce sustainable aviation fuel (SAF) and 20Mt for H2-powered aircraft, according to trade body International Air Transport Association (IATA).

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Producing that much green hydrogen using current electrolyser technology would require more renewable energy than is installed in the world today.

The 20Mt figure would only apply if hydrogen-powered aircraft were to enter service by 2035, said Hemant Mistry, IATA’s director of energy transition, told the organisation’s Global Media Days event this week in Geneva, Switzerland.

“The scale-up of hydrogen to address aviation requirements will be necessary, but when we consider the use of hydrogen for aircraft propulsion only, it is only 3% of the forecast global supply by 2050.”

Airbus is planning to introduce hydrogen-fuelled aircraft by 2035, while Brazilian aircraft maker Embraer this week announced it is developing regional fuel-cell planes with up to 30 seats, having put its H2-powered jet-engine concept on the backburner.

Boeing, the world’s second-largest airplane manufacturer, is not pursuing H2-powered designs due to the fact that liquid hydrogen (LH2) would require four times larger fuel tanks than today’s planes to provide the same amount of energy, as well as “big cooling systems” to keep the LH2 below minus 253°C.

Rolls-Royce recently completed a successful ground trial of a hydrogen-powered turboprop engine.

Mistry said that refuelling planes with LH2 would be challenging, but added that hydrogen-powered aircraft could be more aerodynamic due to lighter and thinner wings, because the fuel would be unlikely to be stored in the wings, as in planes today.

He added that the fastest route to market for hydrogen-powered aircraft would be to retrofit small existing planes — as three airlines announced they would do last year.

IATA says that 15 airlines have expressed interest in hydrogen-powered planes, while 15 airports are looking into deploying H2 as a fuel.

Hydrogen is required to produce the most technically mature and popular form of SAF, known as HEFA-SPK (hydroprocessed esters and fatty acids synthetic paraffinic kerosene), which is derived from vegetable oils, waste oils or fats.

It is also needed to produce SAF from cellulosic biomass, such as wood waste, which US airline Delta is planning to use at scale.

Hydrogen can also be combined with captured CO2 to produce carbon-neutral synthetic aviation fuel — known as e-fuel or e-SAF when derived from green H2 made using renewable electricity.