Comparison of AEL and AEM Electrolyser Technologies

David Martinet1, Christoph Ellert1
1HES-SO Valais-Wallis, Sion, Valais, Switzerland
Published in 2023

Alkaline Electrolysis (AEL) technology is known and used in industries for half a century. It is a key technology for large-scale hydrogen production powered by renewable energy for example chemical industries. Flows of 99.999% pure hydrogen up to 20’000 Nm³/h with an electrical power of 100 MW are nowadays common. However, research is done to go from AEL to alkaline anion exchange membrane (AEM) electrolysers, in which the anions OH- are transmitted through the membrane and not the entire electrolyte. Several advantages are claimed by R&D groups around the world. The Water Electrolyzer interfaces, the CFD Module and the Heat Transfer Module were used to model these two different types of electrolysers, to highlight the differences in the geometrical properties and material properties and their impact on the polarisation curves. Effects of temperature, pressure, electrolyte conductivity, porosity of the electrodes and gas diffusion layers are parameters which can be modified to maximise the current density towards the separator (diaphragm for AEL and membrane for AEM).