This section provides an estimation of the environmental performance of the five electrolysers of the case studies from a Life Cycle Assessment (LCA) perspective through two impact categories: Climate Change and Water use.
The functional unit selected to estimate the potential environmental impacts associated with electrolysers was 1 kg of hydrogen. The system boundaries were focused on the materials of electrolysers, and the electricity and water requirements in the electrolysers operation. The water demand included the water for the electrolysis process and the cooling system.
Inventory data for materials were extracted from literature [1, 2], and the stakeholders of the case studies provided the operational data.
The inventory data was modelled using the LCA for Experts software and supplemented with the Ecoinvent 3.12 database [3]. The method to calculate the environmental impacts was the Environmental Footprint (EF) 3.1, and the impact categories selected were Climate change, expressed in kg of CO2 equivalent, and Water use, expressed in m3 of water world equivalent.
The environmental LCA results are shown in percentage contribution (%) and overall values (kg CO2 eq./kg H2 and m3 world/kg H2) disaggregated by process (materials, electricity and water) and impact category (the first bar is Climate change, and the second one is Water use).
References:
[1] Eiken E. et al. Critical and strategic raw materials for electrolysers, fuel cells, metal hydrides and hydrogen separation technologies; International Journal of Hydrogen Energy 71, 2024, 433-464. https://doi.org/10.1016/j.ijhydene.2024.05.096
[2] Gerloff N. Comparative Life-Cycle-Assessment analysis of three major water electrolysis technologies while applying various energy scenarios for a greener hydrogen production; Journal of Energy Storage 43, 2021, 102759. https://doi.org/10.1016/j.est.2021.102759
[3] Stoikou N., et al. 2025. Documentation of changes implemented in Ecoinvent database v3.12. Ecoinvent Association, Zürich, Switzerland.