Overview of safety challenges associated with integration of hydrogen-based propulsion systems for climate neutral aviation

Abstract

Electrification through hydrogen-based fuel cells as well as hydrogen combustion in gas turbines is a key strategy in aviation for achieving substantial reduction of emissions. However, this transition presents multifaceted challenges. Besides the development and improvement of technologies required for such hydrogen-fuelled aero engines, the safety of hydrogen storage and distribution systems on aircraft is paramount. Challenges associated with hydrogen in terms of its material properties, the design and selection of components for the conditioning and distribution, as well as the system design are being presented and discussed in this work. This includes the consideration of high diffusivity, flammability and reactivity of hydrogen and the consequences of these traits: hydrogen embrittlement, hydrogen-induced cracking and leakage, for instance. The challenges elaborated in this work are pertinent to both hydrogen fuel cell-based propulsion systems and hydrogen combusting gas turbines. Design considerations were derived and are being outlined in this work. These are transferable to applications in other industries such as automotive and stationary power plants. The need for novel rigorous safety protocols to enable a sustainable future in aviation is being highlighted.