Comparative life cycle assessment of electrolyzers

Abstract

This thesis presents a life cycle assessment (LCA) comparing the environmental impacts of three electrolyzer technologies: Smart Alkaline Electrolyzer (SAE), Proton Exchange Membrane (PEM), and conventional Alkaline Electrolyzer (AEC). SAE, a novel technology distinguished by its modularity and scalability, offers seamless integration with renewable energy sources (RES). The study's scope, encompassing a cradle-to-gate analysis for 1 MW electrolyzers in Spain powered by solar PV, highlights the critical influence of electricity sources on environmental impacts. SAE outperformed PEM in seven of the eight assessed impact categories—climate change, terrestrial acidification, freshwater eutrophication, marine eutrophication, terrestrial ecotoxicity, ozone depletion, and photochemical oxidant formation potential (PCOF)—with a notable reduction in Global Warming Potential (GWP) at 7.39 kg CO₂ eq per kg H₂. Compared to AEC, SAE performed better in three impact categories and similar results in others. Key drivers of environmental impact were identified, with copper usage in power electronics being a significant contributor. The sensitivity analysis showed that 30% reduction in copper usage improved SAE's performance across 5 impact categories compared to AEC (climate change, acidification: terrestrial, eutrophication: marine, ozone depletion, PCOF: terrestrial ecosystems). The study identifies the key drivers of impacts within each electrolyzer and clearly delineates the subsystems of the BoP to make the comparison and analysis clear and to assess the overall impacts. The study also provides a structured and consistent inventory for the electrolyzers, enabling easy inclusion of other electrolyzer technologies, which several studies recommend.