The OVERLEAF project aims to decarbonise the skies by pioneering a groundbreaking liquid hydrogen storage tank to fuel hydrogen-powered aircraft.
The project, which Horizon Europe supports, was launched in May 2022, and will run for three years. OVERLEAF comprises a 10-strong consortium from six European countries, is led by Aciturri Engineering, and includes various leading companies and academics in the aeronautics sector. The project will see the development of a liquid hydrogen storage tank that will make hydrogen-powered air travel significantly more viable.
Decarbonising the aviation sector
The EU is aggressively endeavouring to target climate neutrality and sustainability, with hydrogen power providing a promising alternative to facilitate this goal. The European Green Deal aims to reduce transport emissions by 90% by 2050 compared to 1990 levels, with air travel accounting for 3.8% of total CO2 emissions in 2017.
Moreover, the aviation sector generates 13.9% of the emissions from transport, which makes it the second largest source of transport GHG emissions, only exceeded by road transport. This makes aviation a critical area to target to achieve net zero ambitions.
A powerful method to achieve these goals is through hydrogen-powered propulsion. In contrast to kerosene, hydrogen eliminates all CO2 emissions and the most harmful non-CO2 emissions, including carbon monoxide, methane, soot particles, and oxidised sulphur species. It emits only water vapour and near-zero nitrogen oxides.
Although hydrogen-powered aircraft exist, the costs of storing and using hydrogen as a fuel for long flights make it impracticable. The main obstacle is the lack of hydrogen storage systems in aircraft due to strict limitations in weight, volume, and cost-efficiency.
OVERLEAF pioneers liquid hydrogen energy storage
The OVERLEAF project is developing a cutting-edge liquid hydrogen storage tank to enhance the transition to hydrogen-powered aircraft. The liquid hydrogen storage concept is based on the amalgamation of innovative functional and high-performance materials, thermal insulating materials and hydrogen leak detection sensors.
OVERLEAF will reduce the mass of the liquid hydrogen tank by 50%. This will mean the weight and volume of the aircraft can be lowered, reducing the energy demand, and improving the economics of building and operating it.
The project will also develop and liquid hydrogen propulsion system. This novel fuel cell technology will achieve up to two or three times more system power density than traditional fuel cell systems are projected to achieve, with efficiencies of up to 55 to 60%(LHV).
Emma Celeste Lope, the Project Coordinator, concluded: “Hydrogen is an energy vector for aviation and different EU industries, such as the railway industry, reducing the climate impact and contributing to decarbonisation objectives. The development of new technologies to store hydrogen more efficiently and economically is needed. The OVERLEAF project contributes to achieving this technological maturity.”