Mitigation of Performance Degradation of PEM Water Electrolyzers by Power Distribution Control of Fluctuating Renewable Energy

Durability of a PEM electrolysis cell against voltage fluctuation prepared from actual wind power data was analyzed. Two fluctuation patterns were prepared; the pattern A prepared by scaling the wind power data and the pattern B prepared by applying the power distribution control (PDC), that is, converting the pattern A into an alternative sequence of a high-operating rate pattern and a low-operating rate pattern. During 240-h durability tests, the current density continuously decreased for the pattern A, while no distinguishable decrease was observed for the pattern B except the initial 30 h. It was found that the performance degradation is mostly reversible and attributed to increase in the diffusion overpotential consistently with the previous studies. Our results suggest that the PDC suppresses reversible degradation by avoiding gas stagnation at the anode surface, which is important for mitigating irreversible degradation during long-term operation.