ZeroAvia Eyes Hydrogen-Electric “Air Transport Category” Flights

Could a 76-seat regional aircraft powered by a hydrogen-electric propulsion system be in flight testing by the end of next year and in airline operations by 2027? That is the vision of ZeroAvia, the U.S./U.K. firm that in May was presented with a retired Alaska Airlines De Havilland Canada Dash 8 turboprop to be retrofitted with its ZA2000 hydrogen-electric engine. ZeroAvia counts Alaska, United Airlines, and British Airways’ parent International Airlines Group as investors.

During the same Seattle event at which the airline handed over the Dash 8, ZeroAvia also unveiled a multi-megawatt modular electric motor system called the HyperCore that the company said will enable it to develop “commercially-relevant hydrogen fuel cell engines for larger aircraft.”

ZeroAvia Head of Business Development Rama Myers, who was on hand in Seattle for the Dash 8 handover, told Avionics International the company is targeting first flight with the retrofitted aircraft for “some point in 2024.”

He added: “We have already conducted substantial ground testing of our HyperCore electric motor units with the stock gearbox and propeller aboard our 15-ton HyperTruck test rig. Once this is complete, we will retrofit the ZA2000 prototype hydrogen-electric powertrain to the aircraft. Ground testing with the system aboard the aircraft is planned for the back end of this year.”

Myers said the HyperCore motor system design “is very close to what will be integrated into the testbed” aircraft. The HyperCore “can achieve very high RPM, matching the turbine engine speed, and is a modular, stackable system to enable scaling up from 900kW up to 5.4MW, and it offers unprecedented motor power density,” he explained, describing it as “a high-power, high-speed 900kW permanent magnet radial flux machine.”

The engine will use fuel cells to generate electricity from liquid hydrogen that will power the electric motors. The only emissions are water vapor and oxygen-depleted air.

Myers said two HyperCores stacked in series have been ground tested in a 1.8MW capable configuration. “For the flight demonstration, we are targeting three units in series,” he noted.

The ZA2000 engine will feature high temperature polymer electrolyte membrane (PEM) fuel cells and liquid hydrogen fuel storage. The Dash 8 project is aimed at producing the “world’s largest zero emissions aircraft,” according to ZeroAvia, but the company is developing engines for various aircraft sizes and types, including smaller fixed-wing aircraft and rotorcraft.

In January, ZeroAvia flew a retrofitted 19-seat aircraft with its prototype ZA600 hydrogen-electric engine. In March, the company reached an agreement with Skellefteå Airport in northeast Sweden and Braathens Regional Airlines to explore potential commercial operations. Energy company Skellefteå Kraft is also involved.

ZeroAvia and Braathens said they could potentially “operate a range of regional aircraft on commercial passenger routes.” Braathens currently operates 14 ATR-72 aircraft on domestic routes in Sweden, plus service to Denmark and Finland. According to Myers, the partners will consider both 9- and 19-seat regional aircraft flights, plus using larger aircraft powered by the engine to be retrofitted and tested on the former Alaska aircraft.

Sweden has mandated that all domestic flights be net-zero carbon emissions and fossil-fuel free by 2030.

“The timeline for the project in Skellefteå is not disclosed, but we envisage the project supporting both ZA600-relevant aircraft operations with a target entry in service of 2025 and ZA2000-relevant aircraft operations with a target EIS of 2027,” Myers said.

He added that ZeroAvia does not place a ceiling on the size or type of aircraft that could be powered by a hydrogen-electric engine. “Our vision is fundamentally a hydrogen-electric engine in every aircraft,” Myers explained. “The technology is maturing to the point where applications, including retrofit of existing airframes up to 80 seats, can be certified within five years.”

While eventually possible, a hydrogen-electric-powered Boeing 737 or Airbus A320 or larger aircraft will likely take some time to come to fruition, Myers said. “Ultimately, some development is needed to improve the specific power of the systems to support larger aircraft and to optimize hydrogen storage given the volumetric requirements of hydrogen fuel,” he explained. “A clean sheet design might be required beyond regional aircraft operations. Hence, this initial focus on retrofitting regional aircraft, which allows a speedier path to market.”

Alaska Airlines CEO Ben Minicucci, speaking at the handover event, said the Seattle-based carrier has a goal of net-zero carbon emissions by 2040. “For an airline, that's a big goal because right now we burn a lot of gas to get you where you want to go,” he explained. “In fact, this year we will burn 800 million gallons of gas with today's technology … A hydrogen-powered electric motor is really, really exciting.”

He added: “We believe because we have a large regional fleet that the future regional fleet is going to be around green airplanes like the technology that [ZeroAvia is] developing. So, that's why we're making this bet to say our next fleet of regional airplanes are going to be powered by clean energy.”

ZeroAvia CEO Val Miftakhov said at the event that the company wanted to find an “air transport category aircraft” for its engine and decided “to focus on an aircraft that is in production and that is flying today.”

He said commercial aviation “requires a real scalable solution” to decarbonize. “If you do the math, if you look at the fundamentals of flights, you will see that you need to get away from combustion over the long term, which means that you need to electrify aircraft, but the only way to get enough electricity onboard the aircraft is through hydrogen,” he explained. “You cannot do it with batteries. Large aircraft are too heavy [to be powered by batteries]. So, the only way to do it is through hydrogen-electric.”