Airbus has announced plans to test a hydrogen-powered jet engine by the middle of the decade, as the world’s largest plane manufacturer pushes to meet its 2035 deadline of building a zero emission aircraft.
The aircraft manufacturer will fit out a superjumbo A380 with a hydrogen propulsion engine – a fuel that is entirely carbon neutral if produced with green electricity.
The hydrogen engine will be fitted to the main body of the aircraft, with four traditional jet turbines remaining under the wings.
The cutting edge technology will be developed in partnership with turbine manufacturer CFM International, a company jointly owned by General Electric and France’s Safran Aircraft Engines. The test is expected to take place in 2026.
“This is the most significant step undertaken at Airbus to usher in a new era of hydrogen-powered flight since the unveiling of our ZEROe concepts back in September 2020,” said Sabine Klauke, Airbus chief technical officer.
Achieving emission-free flying is seen as the Holy Grail for the aviation industry, which is facing increasing pressure from regulators to stem flight pollution. Within the EU, aviation is responsible for some 3.8% of CO2 emissions.
But while significantly less harmful to the climate than kerosene, hydrogen poses a number of challenges compared to fossil fuels.
To remain in a liquid form, hydrogen must be kept at an extremely low temperature – around -252 degrees Celsius – which requires cryogenic storage.
Hydrogen is also more voluminous than kerosene, meaning more space on the aircraft must be dedicated to fuel storage. The A380, the world’s largest passenger aircraft, will be fitted with four cryogenic tanks to store liquid hydrogen for the test flight, located at the rear of the fuselage.
Prior to combustion, the hydrogen will be converted from liquid form into gas. As hydrogen gas burns at a higher temperature than kerosene, the plane must be adapted to withstand the extreme heat.
While the Toulouse-based manufacturer aims to have a commercially available zero-emission aircraft by 2035, hydrogen-powered jets are unlikely to be widely used until at least 2050, according to the company.
Airbus has also cast doubt on the suitability of the technology for long-haul journeys, stating that storage issues make hydrogen more suited to regional and shorter-range aircraft.
The future of zero emission aviation?
With hydrogen and electric aircraft still decades away from widespread usage, both industry and EU lawmakers are looking to sustainable aviation fuels (SAF) to cut emissions in the short term.
Under proposals tabled by the EU Commission in July, all aircraft refueling in the EU would be required to uplift kerosene mixed with a set percentage of green jet fuel. This percentage will scale up over time, reaching 63% of the fuel mix by 2050.
SAFs are popular with airlines as they can be dropped into current aircraft models without changes to the engine. Adaptations are required only at very high percentages when the share of SAF goes over 50%, the industry says.
But what constitutes a “sustainable” aviation fuel has proven controversial.
Demand for SAFs in the short term is likely to be met by refining waste oils such as used cooking oil. Environmental campaigners have warned that importing high quantities of used cooking oil from Asia, the EU’s chief supplier, may lead to fraud, with restricted feedstocks such as virgin palm oil used to bulk up quantities.
Environmentalists tout green electro-fuels as their preferred option because those are theoretically endlessly scalable if produced with renewable electricity. However, at present e-fuels are available only in minute quantities and command an extremely high price, making them unattractive to airlines.
[Edited by Frédéric Simon]