Analysis of Carbon Emissions and Carbon Reduction Benefits of Green Hydrogen and Its Derivatives Based on the Full Life Cycle

Under the constraints of the “dual carbon” goals, accurately depicting the full life cycle carbon footprint of green hydrogen and its derivatives and quantifying the potential for emission reduction is a prerequisite for hydrogen energy policy and investment decisions. This paper constructs a unified life cycle model, covering the entire process from “wind and solar power generation–electrolysis of water to producing hydrogen-synthesis of methanol/ammonia-terminal transportation”, and includes the manufacturing stage of key front-end equipment and the negative carbon effect of CO2 capture within a single system boundary, and also presents an empirical analysis. The results show that the full life cycle carbon emissions of wind power hydrogen production and photovoltaic hydrogen production are 1.43 kgCO2/kgH2 and 3.17 kgCO2/kgH2, respectively, both lower than the 4.9 kg threshold for renewable hydrogen in China. Green hydrogen synthesis of methanol achieves a net negative emission of −0.83 kgCO2/kgCH3OH, and the emission of green hydrogen synthesis of ammonia is 0.57 kgCO2/kgNH3. At the same time, it is predicted that green hydrogen, green ammonia, and green methanol can contribute approximately 1766, 66.62, and 30 million tons of CO2 emission reduction, respectively, by 2060, providing a quantitative basis for the large-scale layout and policy formulation of the hydrogen energy industry.