A German research project focused on hydrogen-powered flight has concluded its work on a fuel cell stack designed specifically for aviation. The H2Sky initiative, funded by the Federal Ministry for Digital and Transport, sought to create technology optimized for the unique demands of aircraft.
Aerostack, a joint venture between Airbus and ElringKlinger, played a central role in the consortium. The project focused on developing fuel cell stacks with a power output ranging from 100 to 200 kW. These stacks are intended to power an electric motor that drives a propeller or engine.
The engineering team addressed the particularly high requirements for power density, efficiency, reliability, and lifespan found in aviation. Specific data regarding the new fuel cell stack’s performance has not been made available.
Launched in 2022, the project received around €26.5 million in funding. It was part of the National Innovation Programme for Hydrogen and Fuel Cell Technology (NIP). According to the ministry, H2Sky represents one of the largest projects in Germany focused on developing hydrogen-based fuel cell technologies for aviation.
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Creating a functional stack is only the initial hurdle in a much longer engineering race. The aviation industry requires systems that are not only powerful but incredibly lightweight and durable enough to withstand the extreme physical stresses of flight, which makes this specific type of research a foundational prerequisite rather than a final solution.
“Climate-friendly mobility will succeed where innovation and competitiveness go hand in hand. In aviation, hydrogen plays a key role,” said Germany’s Minister for Digital and Transport Patrick Schnieder (CDU) at a closing event.
Andreas Hubert, CEO of Aerostack, provided a technical assessment of the results. He stated that the team successfully advanced fuel cell technology to meet aviation requirements and significantly increased its technological maturity. Hubert added that the results provide a robust foundation for preparing the technology for market readiness.
Integration Challenges Remain
An aviation-ready fuel cell stack is just one component needed for hydrogen-powered flight. A complete powertrain requires cryogenic tanks for storing liquid hydrogen at -253 °C, thermal management systems, and power electronics.
Beyond the hardware, years of testing and certification by authorities will be mandatory. This complexity explains why the Federal Ministry for Digital and Transport avoided the term “aircraft” in its press release. A commercial fuel cell-powered aircraft remains a distant prospect.
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Airbus, involved through its stake in Aerostack, had initially targeted 2035 for hydrogen-powered aircraft under the ZeroE programme. The manufacturer has since deprioritized that effort. The new timeline pushes the potential arrival of such technology closer to 2040.
Future Development Shifts
Despite the delays, partners have launched the new “GENtwoPRO” project. This initiative aims to develop a scalable fuel cell system for regional aircraft with up to 100 seats. It involves Airbus, Aerostack, the PEM Chair of RWTH Aachen University, and the German Aerospace Centre.
The now-concluded H2Sky project was coordinated by the national organisation NOW and implemented by Project Management Jülich (PtJ). The consortium included a wide range of research entities.
Partners featured in the collaboration included EKPO Fuel Cell Technologies, Hahn-Schickard, the Fraunhofer Institute for Solar Energy Systems ISE, the Technical University of Munich, the Centre for Solar Energy and Hydrogen Research Baden-Württemberg, and the University of Freiburg.