Laying the foundations for climate-neutral aviation in Europe
As Europe accelerates its journey towards low-emission aviation, the EU-funded TRIATHLON(opens in new window) project has reached a pivotal milestone. Two years into its four-year journey, the consortium – coordinated by Stichting Materials Innovation Institute in the Netherlands – has successfully advanced the main building blocks of integrated hydrogen-electric propulsion systems needed for low-emission regional and short-haul aviation. TRIATHLON is addressing the critical challenges of combustion, storage, thermal management and full powertrain integration required for megawatt-class aircraft emerging as the next step in sustainable aviation. By bringing together universities, research centres and industry partners, the project is developing more robust, low-maintenance, low-emission and highly responsive hydrogen-electric powertrains for these aircraft.
Milestones towards hydrogen-powered aviation
At its progress meeting held in Florence in November 2025, the project presented its key achievements over the past 24 months. In hydrogen combustion, led by Dutch project partner Delft University of Technology, researchers validated simulations for a 100 % hydrogen-fuelled combustor. The team confirmed that stable operation with controlled nitrogen oxide emissions is achievable at different operating conditions, a crucial step for safe and environmentally friendly engines. The optimisation of multi-state hydrogen storage was undertaken by German partners Dresden University of Technology and Cryomotive. By combining gaseous, liquid and cryo-compressed hydrogen, the team aims to maximise energy density while reducing system weight. Thermal management innovations are equally promising. Project partners Lithoz (Austria), Ergon Research (Italy) and Sabancı University (Turkey) are developing ceramic heat exchangers using aluminium nitride. These components withstand higher operating temperatures than conventional metals, enabling more compact and efficient thermal systems by leveraging waste heat from fuel cells. Lastly, Ergon Research is integrating hydrogen storage, fuel cells, thermal management, power electronics and turboprop propulsion into a complete hydrogen-electric propulsion system. This system-level approach evaluates performance across the full flight envelope, ensuring that individual innovations function reliably together to support future industrial deployment. “We are at the halfway point of the TRIATHLON project and all the separate building blocks are really starting to come together,” remarks Julien van Campen, an assistant professor at Delft University of Technology’s Faculty of Aerospace Engineering, in a TRIATHLON press release(opens in new window). “I am confident that the technologies developed in TRIATHLON will contribute to the realization of a disruptive hybrid hydrogen-electric powertrain for megawatt class aircraft.” The project’s advances will promote safer combustion, more efficient energy use and more reliable hydrogen storage.
A workshop exploring sustainable fuel solutions
Beyond technical development, TRIATHLON is also fostering collaboration within the European hydrogen ecosystem. A prime example is its participation in the upcoming Clean Fuel Horizons Workshop(opens in new window) scheduled for 26 May in Prague. The event gathers experts from academia, research organisations and industry to discuss the latest developments powering the transition to clean and low-carbon energy solutions. Two TRIATHLON (THERMODYNAMICS-DRIVEN CONTROL MANAGEMENT OF HYDROGEN POWERED AND ELECTRIFIED PROPULSION FOR AVIATION) representatives will contribute to ‘Session 1: Engineering the Hydrogen Future’ of the workshop. Delft’s van Campen will discuss multi-state hydrogen fuel systems, highlighting their role in flexible energy management for next-generation aircraft. Christoph Ebert from Dresden University of Technology will address the key material challenges in cryo-compressed storage, contributing to the development of advanced Type V tanks. The event offers the opportunity to learn how cutting-edge research is shaping Europe’s energy and mobility systems of the future. For more information, please see: TRIATHLON project website(opens in new window)
