Toward efficient green methanol from biomass and renewable power.

Green methanol could help decarbonize transport and industry, but its production roadmap remains uncertain because biomass conversion, renewable hydrogen supply, the emissions and cost of electricity are tightly coupled. Here we show, using pilot-scale gasification data and industrial process parameters, how four biomass- and renewable-power-based methanol routes differ in technical performance, life-cycle greenhouse gas emissions and production cost, and identify deployment-relevant boundary conditions. Gasification integrated with renewable hydrogen balances carbon utilization and energy efficiency, reaching 92% and 54%, respectively. Direct combustion followed by carbon dioxide hydrogenation raises carbon utilization to 96% but requires substantially more electrolysis-derived hydrogen. Under hybrid wind and solar power, all routes remain below the European low-carbon fuel threshold, although the maximum electricity emission factors compatible with this threshold vary from 0.057 to 0.373 kilograms of carbon dioxide equivalent per kilowatt-hour. Gasification without added hydrogen is currently the least-cost route. Hydrogen-integrated gasification approaches its cost when renewable electricity falls below US$21 per megawatt-hour, and approaches coal-based methanol costs at carbon prices of US$40-90 per tonne of carbon dioxide. These results define practical boundaries for route deployment.