Next-generation alkaline water electrolysis is re-emerging as a key technology for decentralised, renewable-driven hydrogen production, where dynamic operation, cost efficiency and system integration define performance beyond simple scale enlargement. This review examines recent advances in electrocatalyst design, bubble dynamics, cell configuration and operational strategies that target these new requirements. Testing catalysts under industrially relevant temperatures, electrolyte concentrations and current densities reveals realistic active states and degradation pathways, while improved electrode microstructures demonstrate that intrinsic activity and gas–liquid transport must be co-optimised. Bubble behaviour remains a central performance factor, with electrode architectures showing how gas evolution, mass transfer and transport losses are deeply interconnected. At the cell- and system-level, uniform electrolyte distribution, pressure management and hydrogen crossover emerge as critical constraints, particularly under fluctuating loads. Overall, progress increasingly relies on integrating materials innovation with system-level and dynamic validation, highlighting the need for standards and testing protocols tailored to renewable-coupled operation. • Engineering challenges for next-generation alkaline water electrolysis. • Shift from laboratory catalyst screening to industrially relevant testing. • Coupled role of electrode structure and bubble dynamics under operation. • Identification of key cell- and system-level efficiency bottlenecks.
Hoffmann et al. (Tue,) studied this question.