Pursuing Opportunity: A Multi-Dimensional Analysis of Green Hydrogen Production Technologies

Abstract The European Union’s (EU) decarbonisation strategy identifies green hydrogen as a critical energy vector for achieving climate neutrality by 2050. Electrolysis powered by renewable electricity is the most mature zero-carbon pathway for hydrogen production, yet four main electrolyzer technologies: Alkaline Electrolysis (AE), Proton Exchange Membrane Electrolysis (PEM), Solid Oxide Electrolysis (SOE), and Anion Exchange Membrane Electrolysis (AEM), differ significantly in their technical, economic, and environmental characteristics. This study presents a comprehensive comparative assessment of these technologies, integrating peer-reviewed literature, manufacturer data, and case study evidence from industrial and pilot-scale deployments. Technical parameters analysed include efficiency, operating pressure, temperature, hydrogen purity, current density, lifetime, and operational flexibility. Economic indicators cover capital expenditure (CAPEX), operating expenditure (OPEX), cost-reduction trajectories, and material availability constraints. Environmental performance is assessed using life cycle considerations, including raw material sourcing, operational emissions, and recyclability. The findings indicate that AE offers cost-effective large-scale production but is less suited to variable renewable integration, PEM provides high efficiency and load flexibility at higher cost, SOE delivers maximum electrical efficiency when coupled with high-temperature heat sources, and AEM shows promise for cost reduction but requires durability improvements. Results support the hypothesis that no single technology meets all requirements, and a diversified electrolyzer portfolio will optimise the EU hydrogen deployment. Policy, investment, and infrastructure planning should therefore prioritize technology complementarity, supply chain resilience, and integration strategies tailored to regional renewable energy profiles.