Green Hydrogen Production Plants: A Techno-economic Review

Green hydrogen stands as a promising clean energy carrier with potential net-zero greenhouse gas emissions. However, different system-level configurations for green hydrogen production yield different levels of efficiency, cost, and maturity, necessitating a comprehensive assessment. This review evaluates the components of hydrogen production plants from technical and economic perspectives. The study examines six renewable energy sources—solar photovoltaics, solar thermal, wind, biomass, hydro, and geothermal—alongside three types of electrolyzers (alkaline, proton exchange membrane, and solid oxide electrolyzer cells) and five hydrogen storage methods (compressed hydrogen, liquid hydrogen, metal hydrides, ammonia, and liquid organic hydrogen carriers). A comprehensive assessment of 90 potential system configurations is conducted across five key performance indicators: the overall system cost, efficiency, emissions, production scale and technological maturity. The most cost-effective configurations involve solar photovoltaics or wind turbines combined with alkaline electrolyzers and compressed hydrogen storage. For enhanced system efficiency, geothermal sources or biomass paired with solid oxide electrolyzer cells utilizing waste heat show significant promise. The top technologically mature systems feature combinations of solar photovoltaics, wind turbines, geothermal, or hydroelectric power with alkaline electrolyzers using compressed hydrogen or ammonia storage. The highest hydrogen production scales are observed in systems with solar PV, wind, or hydro power, paired with alkaline or PEM electrolyzers and ammonia storage. Configurations using hydro, geothermal, wind, or solar thermal energy sources paired with alkaline electrolyzers, and compressed hydrogen or liquid organic hydrogen carriers yield the lowest life cycle GHG emissions. These insights provide valuable decision-making tools for researchers, business developers, and policymakers, guiding the optimization of system efficiency and the reduction of system costs.