Potential and technical challenges of on-board hydrogen storage technologies coupled with fuel cell systems for aircraft electrification

Electric aircrafts are being developed to reduce greenhouse gas emissions in the aviation sector. The use of hydrogen in combination with fuel cells is likely to be a suitable solution to power electric motors with almost zero emissions, but its technical feasibility still needs to be investigated. Hydrogen is characterised by a very low density at room temperature, requiring very large storage volumes and heavy tanks. This could be a limitation in the aviation sector, where compactness and low overall weight are needed due to limited space and the need not to increase the required propulsion power. Moreover, hydrogen-based mobility concepts directly depend on the availability of storage options that meet the requirements of safety, quick hydrogen release, technical maturity, economic viability, efficiency and environmental sustainability. In this work, the main hydrogen storage technologies are investigated and compared on the basis of key performance parameters identified as crucial for the aviation sector. The aim is to identify the most promising solutions for on-board hydrogen storage. Then, the sizing of a propulsion system is carried out based on a real mission profile, and the weight increment is compared to that of a conventional aircraft powered by kerosene. A regional passenger aircraft, ATR72-600, is selected for this work. The potential reduction in the overall weight of the aircraft is also explored, considering both future improvements in storage technologies and fuel cell systems.