Influence of plant dimensioning and location on the ecology of PEM electrolysis

PV and wind systems with PEM electrolysis offer great potential for producing hydrogen with low emissions. Our research has identified the ecologically optimal size of PEM in relation to fixed PV/wind capacities. We calculate efficiencies and production volumes for PEM with 240 capacity and site variations. We analyse the global warming potential of all systems and draw conclusions about the optimal system design. The lowest GWP is achieved at the site with the highest full load hours with 1.32 kg CO 2 -eq/kg H 2 (Wind, 28 MW electrolysis) and 4.24 kg CO 2 -eq/kg H 2 (PV, 23 MW electrolysis). We have identified a clear trend: increasing PV/wind full load hours leads to higher ideal PEM capacities. However, there is a significant discrepancy between the ideal economic and ecological capacity. Furthermore, higher electrolysis capacities can achieve lower emissions as they increasingly operate at a more efficient partial load. • Development and analysis of 240 LCA models for wind/PV based PEM electrolysis. • Lowest GWP from wind power at 28 MW electrolysis capacity with 1.32 kg CO 2 -eq/kg H 2 . • Lowest GWP from PV at 23 MW electrolysis capacity and 4.24 kg CO 2 -eq/kg H 2 . • Large electrolysis capacities are beneficial due to higher partial load efficiencies. • Increasing PV/Wind FLH leads to higher ideal PEM capacities (economic and ecological).