Environmental impacts study of high temperature electrolyzers

Abstract A life cycle assessment of Solid Oxide Electrolysis Cells (SOEC) and Proton Conducting Ceramic Electrolyzers (PCCEL) is performed to identify and compare the environmental hotspots associated with their production and use. System boundaries include raw material extraction, manufacturing, and operation of SOEC and PCCEL units. Information available in the scientific literature is used to develop the life cycle inventories for the electrolyzers examined. These units are implemented in the SimaPro software using the Ecoinvent database. The Environmental Footprint (EF) 3.1 method is adopted for the impact assessment. The results highlight that the operating phase for all electrolyzers analyzed in this study has a greater impact than the manufacturing phase, primarily due to the high electricity consumption required to power these electrolyzers. Regarding the manufacturing phase, the environmental impacts depend on how the electrolyzers are produced, as they can differ. In this study, two SOECs and one PCCEL are analyzed: cobalt oxide, used for manufacturing the interconnects of the first SOEC, has the highest environmental impact across all assessed impact categories, whereas in the second SOEC and PCCEL, stainless steel, also used for the interconnects, impact more than the other layers. Energy consumption associated with the production of cathodes in these three electrolyzers also significantly contributes to the overall environmental impact.