Biomass-to-Methanol, Waste-to-Methanol, or PtX?─Quantifying the Sustainability of Alternative Methanol Production Pathways Using Life Cycle Assessment, Techno-Economic Analysis, and Multi-Criteria Decision Analysis.

The sustainable production of methanol is gaining increasing global interest due to its potential to enable both defossilization and carbon circularity not only for the sustainability transformation of the chemical industry, but also for other carbon-intensive industries such as transportation and energy. This study comparatively evaluates the production of methanol via (1) Biomass-to-Methanol, (2) Waste-to-Methanol, and (3) Power-to-X (PtX) using life cycle assessment (LCA), techno-economic analysis (TEA), and multicriteria decision analysis (MCDA). Focusing on Germany, findings enable insights into technical (i.e., energy demands, product yields), environmental (i.e., impacts on climate change, terrestrial acidification, fossil depletion), and economic (i.e., investments, net present value, investment payback periods) parameters. These are presented as detailed physical results, complemented by economic metrics, and are further aggregated through expert assessment using analytic hierarchy processing. The use of alternative carbon feedstocks in the form of wood and packaging waste is observed to improve both environmental and economic performance. In contrast, PtX leads today not only to significantly more emissions but also to more costs. Study insights thus provide timely quantitative input to inform decision-making processes relating to the sustainability of alternative methanol pathways for the transformation of carbon-intensive sectors.