Integrated hydrogen system analysis across the resource–environment–economy nexus: A case study of China

The hydrogen industry requires an integrated decarbonization strategy that aligns supply-side optimization with demand-side growth to support effective policy design and long-term sustainability. This study develops an energy–economy–carbon accounting framework that combines flow analysis with a hybrid input–output approach to trace emissions across the hydrogen supply chain from production to final demand. Applied to China, the model projects hydrogen demand to increase fourfold, from 33.0 Mt in 2020 to 140.9 Mt in 2060, driven by expanding use in industrial sectors, transport, and utilities. With electrolysis becoming the dominant production route, direct carbon emissions peak at 625.3 MtCO\textsubscript{2} in 2030 and fall to 175.1 MtCO\textsubscript{2} by 2060, representing a 72.1% reduction achieved through technology substitution and renewable power integration. Decomposition analysis shows that hydrogen-based technologies can contribute 46.7% of total mitigation in hard-to-abate sectors. The results highlight hydrogen’s central role as a low-carbon energy carrier, conditional on early policy intervention, renewable integration, and coordinated infrastructure investment.