Prospective techno-economic assessment of carbon capture & utilization and biobased processes for methanol and ethanol production

Abstract

A sustainable future will require a phase-out of fossil-based resources if we want to reduce greenhouse gas emissions. However, trade-offs occur between costs, energy use, and CO₂ emissions or land use. Choosing between different fossil-based, biobased and CO₂-based routes requires knowledge of these parameters. We evaluated chemical methanol and microbiological ethanol production routes from different feedstocks (sugar, side-streams, CO₂ and biogas) under a prospective 2050 scenario to determine future scenarios that would allow for the use of alternative routes. Conventional routes for methanol and ethanol production showed the lowest production costs. The highest costs in the alternative methanol and ethanol routes based on CO₂ are associated with the conversion of CO₂ to the more reactive, hydrogen-enriched syngas. The CO₂-based routes require large amounts of renewable energy. The biogas alternatives require less energy, but show higher CAPEX and raw material costs. To enable complete comparison to fossil-based production, ethanol results were extrapolated to ethylene production. The subsequent scenario analysis indicated that non-fossil methanol and ethylene production should be feasible from an economic point of view when carbon taxes are applied, starting from around 100 € per ton CO₂ for methanol and 270 € per ton CO₂ for ethylene production routes. For both bioethanol and bioethylene production, the 1st and 2nd generation processes are limited by the amount of available land to grow the crops. In the end, there are multiple variables that influence the feasibility of the alternative routes. A combination of technology development, market price development and governmental measures can allow for cost parity.