Solid oxide fuel cells for aviation: A comparative evaluation against alternative propulsion technologies

Conventional aircraft emit high greenhouse gases, hindering aviation decarbonization. Among sustainable so- lutions, battery-electric planes face range limitations, while renewable fuels can cut emissions without sacrificing endurance. Fuel cells enable full electrification, powering propulsion and auxiliary systems. Although they have lower power density than combustion engines, their promising efficiency can potentially reduce overall weight. This study compares fuel cell and conventional propulsion systems, focusing on Solid Oxide Fuel Cells (SOFCs) and Proton-Exchange Membrane Fuel Cells (PEMFCs). The initial literature review emphasizes the potential of SOFCs for aviation and discusses ongoing projects, forming the basis for the subsequent technical analysis. A break-even analysis examines flight durations in which fuel cell systems match the weight of conventional al- ternatives. Additionally, various fuels and storage methods, including jet fuel and hydrogen, are assessed. Results show that jet fuel SOFCs are currently the lightest fuel cell option, while PEMFCs with liquid hydrogen require higher power density and lighter storage to compete. Looking ahead, liquid hydrogen storage appears most viable, with PEMFCs better for short-range and SOFCs for long-range flights. An environmental analysis evaluates CO2 emissions across European countries, identifying break-even grid carbon intensities for jet fuel and hydrogen SOFCs. These findings highlight fuel cells’ potential to reduce aviation’s environmental footprint.