Hydrogen aircraft company Zeroavia aims to certify its fuel-cell powertrain for planes by 2025, with the first commercial hydrogen-powered flights due to take off in the mid-2020s, the company’s vice-president for strategy, James McMicking, tells Hydrogen Economist.

Earlier in December, the firm signed an agreement with AGS Group—owner and operator of Glasgow, Aberdeen and Southampton airports—to cooperate on hydrogen refuelling infrastructure and the use of Zeroavia’s aircraft on domestic routes once certified.

“The second half of this decade is where we will start having our aircraft flying—2025 is our entry-into-service date for a 9–19-seat aircraft running on gaseous hydrogen. Later in the decade—from 2027–28—is when we want to introduce larger aircraft, regional turboprops running on liquid hydrogen,” McMicking says.

60kg – Hydrogen needed to fuel a 9–19-seat plane between London and Glasgow

Although the exact consumption can vary based on type of aircraft and number of people onboard, McMicking estimates a 9–19-seat single- or twin-propellor plane will require 60kg of hydrogen to fuel a flight the distance between London and Glasgow. A larger, 50–70-seat plane would require around 300kg for the same distance.

“These are relatively small numbers in the grand scheme of the quantity of hydrogen the country wants to produce. This decade, this is a very small offtake,” he says, noting that Zeroavia anticipates airports could supply this demand through onsite green hydrogen production.

While the economics of production versus storage and transportation via derivatives or carriers will vary from location to location, “we think the dominant model will be onsite production of hydrogen overall” owing to the natural resources and available space at airports for renewable energy assets to be installed, McMicking adds.

Competition with SAF

The introduction of hydrogen aircraft will require new refuelling infrastructure. In the near-term, both gaseous and liquid hydrogen can be transported via mobile refuelling vehicles, while, in the longer term, pipelines could be constructed as a delivery route, according to McMicking.

Sustainable aviation fuel (SAF) and synthetic fuels, such as e-kerosene made with green hydrogen and captured CO₂, have been proposed by several companies as an immediate, ‘drop-in’ solution that does not require the complete overhaul of existing aircraft and refuelling infrastructure. Synthetic fuels could also present a potential competitor for limited hydrogen supply.

But McMicking is confident the economics will tip in favour of hydrogen, as the processing of hydrogen and CO₂ into e-kerosene is highly energy-intensive and requires much higher capex throughout the value chain than using hydrogen directly.

Hydrogen-electric engines are also “at least twice as efficient” as existing turbines, reducing the overall volume of fuel required per flight and further cutting costs in comparison to e-kerosene, McMicking adds.

And while e-kerosene theoretically presents a closed-loop for carbon emissions, combustion results in the emission of nitrous oxide and large amounts of water vapour—both greenhouse gases. “Our argument is that hydrogen-electric is the only complete solution to the climate challenge,” he says.

However, he anticipates a transition period. The aviation sector is initially expected to use hydrogen-electric technology for short- and mid-range flights, and increasingly blend SAF into larger aircraft that fly journeys of more than 4,000 nautical miles, which are the most challenging and costly flights to displace, McMicking says.

“These two solutions can—at least in the medium term—sit quite comfortably side-by-side,” McMicking adds.

Taking off

Larger aviation companies are also investigating hydrogen as a possible route for decarbonisation. At the end of November, engine manufacturer Rolls Royce and airline Easyjet successfully tested a converted gas turbine running on hydrogen, while aerospace firm Airbus announced its plans to develop a fuel-cell engine as one of the potential solutions to equip its zero-emissions aircraft.

Airbus will start ground and flight testing its fuel-cell engine architecture onboard its ZEROe demonstrator aircraft towards the middle of the decade, aiming to assess feasibility for entry-into-service by 2035.

The UK has also provided just under £1mn ($1.2mn) to regulator the Civil Aviation Authority to collaborate with industry and academia on investigating hydrogen-related risks to aviation safety and identifying gaps in existing policy.

---

Author: Polly Martin