Airbus Is Working on a Superconducting Electric Aircraft
One of the greatest climate-related engineering challenges right now is the design and construction of a large, zero-emission, passenger airliner. And in this massive undertaking, no airplane maker is as invested as Airbus.
At the Airbus Summit, a symposium for journalists on 24 and 25 March, top executives sketched out a bold, tech-forward vision for the company's next couple of generations of aircraft. The highlight, from a tech perspective, is a superconducting, fuel-cell powered airliner.
Airbus's strategy is based on parallel development efforts. While undertaking the enormous R&D projects needed to create the large, fuel-cell aircraft, the company said it will also work aggressively on an airliner designed to wring the most possible efficiency out of combustion-based propulsion. For this plane, the company is targeting a 20-to-30 percent reduction in fuel consumption, according to Bruno Fichefeux, head of future programmes at Airbus. The plane would be a single-aisle airliner, designed to succeed Airbus's A320 family of aircraft, the highest-selling passenger jet aircraft on the market, with nearly 12,000 delivered. The company expects the new plane to enter service some time in the latter half of the 2030s.
Airbus hopes to achieve such a large efficiency gain by exploiting emerging advances in jet engines, wings, lightweight, high-strength composite materials, and sustainable aviation fuel. For example, Airbus disclosed that it is now working on a pair of advanced jet engines, the more radical of which would have an open fan whose blades would spin without a surrounding nacelle. Airbus is evaluating such an engine in a project with partner CFM International, a joint venture between GE Aerospace and Safran Aircraft Engines.
Without a nacelle to enclose them, an engine's fan blades can be very large, permitting higher levels of bypass air," which is the air sucked in to the back of the engine-separate from the air used to combust fuel-and expelled to provide thrust. The ratio of bypass air to combustion air is an important measure of engine performance, with higher ratios indicating higher efficiencies, according to Mohamed Ali, chief technology and operating officer for GE Aerospace. Typical bypass ratios today are around 11 or 12, but the open-fan design could enable ratios as high as 60, according to Ali.
The partners have already tested open-fan engines in two different series of wind-tunnel tests in Europe, Ali added. The results have been extremely encouraging, not only because they are really good in terms of performance and noise validation, but also [because] they're validating the computational analysis that we have done," Ali said at the Airbus event.
A scale model of an open-fan aircraft engine was tested last year in a wind tunnel in Modane, France. The tests were conducted by France's national aerospace research agency and Safran Aircraft Engines, which is working on open-fan engines with GE Aerospace.Safran Aircraft Engines
In parallel with this advanced combustion-powered airliner, Airbus has been developing a fuel-cell aircraft for five years under a program called ZEROe. At the Summit, Airbus CEO Guillaume Faury backed off of a goal to fly such a plane by 2035, citing the lack of a regulatory framework for certifying such an aircraft as well as the slow pace of the build-out of infrastructure needed to produce green" hydrogen at commercial scale and at competitive prices. We would have the risk of a sort of Concord of hydrogen' where we would have a solution, but that would not be a commercially viable solution at scale," Faury explained.
That said, he took pains to reaffirm the company's commitment to the project. We continue to believe in hydrogen," he declared. We're absolutely convinced that this is an energy for the future for aviation, but there's just more work to be done. More work for Airbus, and more work for the others around us to bring that energy to something that is at scale, that is competitive, and that will lead to a success, making a significant contribution to decarbonization." Many of the world's major industries, including aviation, have pledged to achieve zero net greenhouse gas emissions by the year 2050, a fact that Faury and other Airbus officials repeatedly invoked as a key driver of the ZEROe project.
Later in the event, Glenn Llewellyn, Airbus's vice president in charge of the ZEROe program, described the project in detail, indicating an effort of breathtaking technological ambition. The envisioned aircraft would seat at least 100 people and have a range of 1000 nautical miles (1850 kilometers). It would be powered by four fuel-cell engines" (two on each wing), each with a power output of 2 megawatts.
According to Hauke Luedders, head of fuel cell propulsion systems development at Airbus, the company has already done extensive tests in Munich on a 1.2 MW system built with partners including Liebherr Group, ElringKlinger, Magna Steyr, and Diehl. Luedders said the company is focusing on low-temperature proton-exchange-membrane fuel cells, although it has not yet settled on the technology.
But the real stunner was Llewellyn's description of a comprehensive program at Airbus to design and test a complete superconducting electrical powertrain for the fuel-cell aircraft. As the hydrogen stored on the aircraft is stored at a very cold temperature, minus 253 degrees Celsius, we can use this temperature and the cryogenic technology to also efficiently cool down the electrics in the full system," Llewellyn explained. It significantly improves the energy efficiency and the performance. And even if this is an early technology, with the right efforts and the right partnerships, this could be a game changer for our fuel-cell aircraft, for our fully electric aircraft, enabling us to design larger, more powerful, and more efficient aircraft."
In response to a question from IEEE Spectrum, Llewellyn elaborated that all of the major components of the electric propulsion system would be cryo-cooled: electric distribution system, electronic controls, power converters, and the motors"-specifically, the coils in the motors. We're working with partners on every single component," he added. The cryo-cooling system would chill a refrigerant that would circulate to keep the components cold, he explained.
A fuel cell aircraft engine," as envisioned by Airbus, would include a 2-megawatt electric motor and associated motor control unit (MCU), a fuel-cell system to power the motor, and associated systems for supplying air, hydrogen fuel, liquid refrigerant, and other necessities. The ram air system would capture cold air flowing over the aircraft for use in the cooling systems.Airbus SAS
Llewellyn did not specify which superconductors and refrigerants the team was working with. But high temperature superconductors are a good bet, because of the drastically reduced requirements on the cooling system that would be needed to sustain superconductivity.
Copper-oxide based ceramic superconductors were invented at IBM in 1986, and various forms of them can superconduct at temperatures between -238 C (35 K) and -140 C (133 K) at ambient pressure. These temperatures are higher than traditional superconductors, which need temperatures below about 25 K. Nevertheless, commercial applications for the high-temperature superconductors have been elusive.
But a superconductivity expert, applied physicist Yu He at Yale University, was heartened by the news from Airbus. My first reaction was, really?' And my second reaction was, wow, this whole line of research, or application, is indeed growing and I'm very delighted" about Airbus's ambitious plans.
Copper-oxide superconductors have been used in a few applications, almost all of them experimental. These included wind-turbine generators, magnetic-levitation train demonstrations, short electrical transmission cables, magnetic-resonance imaging machines and, notably, in the electromagnet coils for experimental tokamak fusion reactors.
The tokamak application, at a fusion startup called Commonwealth Fusion Systems, is particularly relevant because to make coils, engineers had to invent a process for turning the normally brittle copper-oxide superconducting material into a tape that could be used to form donut-shaped coils capable of sustaining very high current flow and therefore very intense magnetic fields.
Having a superconductor to provide such a large current is desirable because it doesn't generate heat," says He. That means, first, you have much less energy lost directly from the coils themselves. And, second, you don't require as much cooling power to remove the heat."
Still, the technical hurdles are substantial. One can argue that inside the motor, intense heat will still need to be removed due to aerodynamic friction," He says. Then it becomes, how do you manage the overall heat within the motor?"
An engineer at Air Liquide Advanced Technologies works on a test of a hydrogen storage and distribution system at the Liquid Hydrogen Breadboard in November, 2024. The Breadboard" was established last year in Grenoble, France, by Air Liquide and Airbus.Celine Sadonnet/Master Films
For this challenge, engineers will at least have a favorable environment with cold, fast-flowing air. Engineers will be able to tap into the massive air flow" over the motors and other components to assist the cooling, He suggests. Smart design could take advantage of this kinetic energy of flowing air."
To test the evolving fuel-cell propulsion system, Airbus has built a unique test center in Grenoble called the Liquid Hydrogen Breadboard," Llewellyn disclosed at the Summit. We partnered with Air Liquide Advanced Technologies" to build the facility, he said. This Breadboard is a versatile test platform designed to simulate key elements of future aircraft architecture: tanks, valves, pipes, and pumps, allowing us to validate different configurations at full scale. And this test facility is helping us gain critical insight into safety, hydrogen operations, tank design, refueling, venting, and gauging."
Throughout 2025, we're going to continue testing the complete liquid-hydrogen and distribution system," Llewellyn added. And by 2027, our objective is to take an even further major step forward, testing the complete end-to-end system, including the fuel-cell engine and the liquid hydrogen storage and distribution system together, which will allow us to assess the full system in action."
Glenn Zorpette traveled to Toulouse as a guest of Airbus.