Green Hydrogen for Deep Decarbonization: Technology Progress, Cost Evolution, Infrastructure, and Global Deployment Pathways

Abstract

Green hydrogen is increasingly viewed as a strategic option for decarbonizing energy- and carbon-intensive sectors while improving long-term energy system flexibility. Produced by water electrolysis powered by renewable electricity, it offers a low-emission alternative to fossil-derived hydrogen and a potential bridge between variable renewable generation, industrial fuel demand, and emerging clean-fuel markets. This review synthesizes recent progress in electrolyzer technologies, national deployment strategies, cost trajectories, infrastructure development, and market formation. Comparative discussion is provided across major regions including the European Union, North America, Australia, China, and the Gulf, highlighting differences in resource endowment, policy support, and export orientation. The assessment shows that the economics of green hydrogen remain highly location-dependent, but declining electrolyzer costs, larger project scales, and access to low-cost solar and wind resources are expected to narrow the gap with conventional hydrogen. Key barriers persist in water availability, transport logistics, storage, certification, and manufacturing supply chains. Overall, the literature indicates that levelized green hydrogen costs could approach or fall below about $2/kg in favorable settings by 2030, provided that policy support, infrastructure build-out, and technology scale-up advance in parallel. The paper concludes by identifying research and governance priorities needed to accelerate robust and equitable market growth.