This paper focuses on the battle for a dominant design for renewable hydrogen electrolysis in which the designs, alkaline and proton exchange membrane, compete for dominance. First, a literature review is performed to determine the most relevant factors that influence technology dominance. Following that, a Best Worst Method analysis is conducted by interviewing multiple industry experts. The most important factors appear to be: Price, Safety, Energy consumption, Flexibility, Lifetime, Stack size and Materials used. The opinion of experts on Proton Exchange Membrane and alkaline electrolyser technologies is slightly skewed in favour of alkaline technologies. However, the margin is too small to identify a winner in this technology battle. The following paper contributes to the ongoing research on modelling the process of technology selection in the energy sector.