Synergistic optimization of renewable Energy-Driven methanol Synthesis: Coupling alkaline water electrolysis and CO2 hydrogenation with Full-Chain performance analysis

CO 2 hydrogenation to green methanol using renewable hydrogen represents a promising pathway for deep decarbonization. This study develops an integrated, full-process Aspen Plus model coupling alkaline water electrolysis (AWE) with a methanol synthesis loop to quantify system-level synergistic effects and assess overall techno-economic performance. Process optimization results indicate a 9.7% increase in annual hydrogen production and an enhanced methanol output of 11.416 t/h. The integrated system achieves an overall energy efficiency of 44.88% and a net CO 2 emission intensity of −1.15 t/t MeOH . Full-chain techno-economic analysis estimates a green methanol production cost of 3315 CNY/t under an optimistic future scenario with a green electricity price of 0.25 CNY/kWh. Sensitivity analysis identifies electricity price and electrolyzer investment as the primary levers governing economic feasibility. Crucially, the results demonstrate that a regulation strategy incorporating hydrogen storage to buffer renewable intermittency achieves a total system energy utilization efficiency of 85.41%, significantly outperforming a grid-interactive strategy. These findings provide quantitative guidance for the design of efficient and economically viable renewable power-to-methanol systems.