Performance data extraction from dynamic long-term operation of proton exchange membrane and alkaline water electrolysis cells

The direct coupling of wind turbines to water electrolyzers promises scalable, green hydrogen production, but little is known about the impact of the fluctuating power provided by renewable energy sources on electrolyzer longevity. Therefore, we developed a realistic, semi-synthetic wind power profile to operate polymer electrolyte membrane (PEM) and alkaline water electrolysis (AWE) cells. We also established two analysis methods for the dynamically obtained I-V data. The methods enable the extraction of I-V curves, voltage degradation, and resistances. A major advantage of these methods is the highly accurate extraction of performance metrics without interrupting dynamic operation. Cell voltage degradation in both electrolysis technologies depends on both the current density and operation mode. While extracting an accurate ohmic cell resistance for AWE cells proved challenging, we found good agreement for PEMWE cells with the high-frequency resistance measured by impedance spectroscopy. With the proposed methods, the stability of all types of electrolysis systems can be studied during dynamic operation.