Prospective life cycle assessment of methanol synthesis from plasma-assisted waste gasification with carbon capture

The decarbonisation of chemical production requires moving away from fossil feedstocks, yet methanol, a versatile one-carbon compound and potential fuel or chemical feedstock, is still predominantly synthesised from natural gas. Waste-valorisation systems such as thermal plasma-assisted gasification of refuse derived fuel could close material loops and integrate carbon capture, but comprehensive environmental evaluations are scarce. This study tests whether such methanol can offer environmental benefits over conventional production, and how this depends on the future decarbonisation of the energy system. A prospective life cycle assessment was performed for three process configurations and two reference pathways (natural gas reforming and biomass gasification) across 16 Environmental Footprint 3.1 impact categories, with background inventories transformed using the Premise tool linked to the REMIND integrated assessment model under various future pathways from 2025 to 2050. Under current average European energy conditions, the waste gasification scenarios reached net climate change impacts of approximately 1.62–1.69 kg CO 2 eq. per kg methanol, below the natural gas reforming baseline (1.82 kg CO 2 eq.) but above the wood chip biomass gasification pathway (0.32 kg CO 2 eq.). Electricity consumption, hydrogen supply, and end-of-life carbon release are the dominant climate change contributors. Carbon capture benefits progressively offset energy-related burdens from around 2030, with net impacts potentially falling as low as 0.58 kg CO 2 eq. per kg methanol under ambitious decarbonisation pathways. Although its performance strongly depends on the pace of energy system decarbonisation, thermal plasma-assisted waste gasification represents an environmentally viable route for lower-carbon methanol production, complementing existing waste-to-energy infrastructure.