A study by the International Council of Clean Transportation (ICCT) has confirmed the viability of hydrogen-powered aircraft for short-haul aviation.
The study by Jayant Mukhopadhaya and Dan Rutherford assessed two Liquid Hydrogen (LH2) combustion designs: a smaller turboprop aircraft targeting the regional market benchmarked against the ATR 72; and a narrow-body turbofan aircraft suitable for short and medium haul benchmarked against the Airbus A320neo.
It found that both hydrogen-powered designs would require an elongated fuselage to accommodate LH2 storage behind the passenger cabin. Seating pitch values of 29 and 30 inches, mimicking the seating density of low-cost and regular airliners, were used for the study, which also looked at variants of the baseline design with different range and passenger capacities.
Compared to fossil-fuel aircraft, LH2-powered aircraft will be heavier, with an increased maximum takeoff mass (MTOM), and will be less efficient, with a higher energy requirement per revenue-passenger-kilometre (MJ/RPK). They will also have a shorter range than fossil-fuel aircraft.
Despite these disadvantages, the study estimated that an LH2-powered narrow-body aircraft could transport 165 passengers up to 3,400 km and LH2-powered turboprop aircraft could transport 70 passengers up to 1,400 km.
Together, they could service about one-third (31 to 38 per cent) of all passenger aviation traffic, as measured by RPK.
The challenge of decarbonising aviation is considerable because of what the study calls ‘The stringent mass and volume requirements for aviation fuel.” The study explored the “potential performance characteristics, fuel-related costs and emissions, and replaceable fossil fuel market of LH2-powered aircraft entering service in 2035. In keeping with aviation’s conservative approach to new aircraft design, only evolutionary advances in design parameters that are feasible by 2035 are considered.”
“LH2 emits no CO2 during combustion and can be produced with near-zero carbon emissions if made using renewable electricity (“green hydrogen”). However, its low energy density and heavy cryogenic tank requirements incur performance penalties when compared to Jet A-powered aircraft.”
The report recommends that “to the extent that manufacturers need to prioritise aircraft development, we recommend a focus on narrow-body LH2 designs since they would provide the highest potential emissions coverage.”
It also makes clear that “Supportive government policies will be needed if LH2-powered aircraft are to succeed. These include carbon pricing, low-carbon fuel standards, or alternative fuel mandates to bridge the cost gap with fossil jet fuel, and life cycle accounting to ensure that aviation has access to the cleanest sources of hydrogen.”
Johan Lundgren, CEO of easyJet, said:
“We welcome the findings of this important report by the ICCT, which shows that carbon-free flight is possible over shorter ranges, something we have long argued. Hydrogen is an opportunity for British and European aviation, so we continue to urge governments to quickly put incentives in place to support it, develop regional hydrogen infrastructure, and level the playing field with sustainable aviation fuels.”
The full report can be downloaded from the website of ICCT