Water Electrolysis Facing the Gigawatt Challenge—Comprehensive De‐Risking of Proton Exchange Membrane and Anion Exchange Membrane Electrolyser Technology

ABSTRACT Green Hydrogen (H 2 ) is generally considered to play a key role in enabling sustainable energy storage, as well as a renewable feedstock to various industrial sectors. Accordingly, the production of H 2 by water electrolysis at an industrial scale is a key prerequisite for a transformation of our energy system. With respect to water electrolysis, proton exchange membrane (PEM) electrolysers are generally considered a technology option for the production of green H 2 on a large scale. Prior to market ramp‐up PEM electrolysers have to undergo substantial de‐risking for a technology ramp‐up. For a comprehensive de‐risking, a fundamental and holistic understanding of the degradation phenomena of electrolysers on an industrially relevant scale is a prerequisite. Field data with different application‐specific load profiles needs to be acquired in order to develop countermeasures against possible degradation patterns induced by the operational mode. This is not only crucial for the more mature PEM technology but also in the future relevant for other more novel membrane electrolysis technologies such as anion exchange membrane (AEM) looking to make the step from laboratory operation to large‐scale production and deployment. This editorial aims to outline the current status and general workflow of the de‐risking process and serve as an introduction to the topics of this special issue ranging from fundamental studies on degradation processes on the catalyst level up to novel factory concepts for ramping up of electrolyser production.