H2Giga-DegradEL3 aims at advancing the understanding of the degradation mechanisms of the three types of electrolyzers considered, namely alkaline (AEL), proton exchange membrane (PEMEL) & High-temperature (HTEL). The target is to analyze the evolution of the degradation by scaling-up from cell to short-stack. Several characterization methods will be used as well as modelling. In addition, taking into account these results, life prediction methods will be developed. In turn, these findings will be transferred to the industry in order to increase the performance and the durability of the single unit and module.