Techno-economic analysis and life-cycle assessment of methanol synthesis plants using renewable hydrogen and carbon dioxide feedstocks

Abstract

This paper presents a cradle-to-gate techno-economic analysis (TEA) and life-cycle assessment (LCA) of synthetic methanol production leveraging low-carbon electrolytic hydrogen and renewable CO2 captured from biomass- or biogas-powered bioenergy with capture (BEC) or direct air capture (DAC) facilities. Using a detailed chemical process model and a comprehensive cash flow analysis, we evaluate the mass and energy requirements for renewable methanol production plants using an integrated approach that couples scale effects, feedstock and energy prices, process emissions, and several other variables. In the baseline scenario, amortization of the total green methanol production costs reveals levelized costs of fuel (LCOF) equal to $0.76, $1.19, and $1.06 per kg of methanol when CO2 is sourced from biomass BEC, biogas BEC, and DAC, respectively. From this baseline, sensitivity analysis is used to consider the dependence of these results upon plant/production scale and feedstock/energy costs and generalize findings to a broad range of local markets. These findings quantify strong economies of scale where methanol from biogas BEC is optimal at small production volumes, but where biomass BEC eventually becomes favored as production volumes approach 1000 tonnes of methanol per day. The findings also reveal significant opportunities if future H2 prices below ∼$1.50/kg can be attained. While the baseline TEA indicates that the considered renewable methanol synthesis process currently carries a green premium of 70% or more, the LCA reveals dramatic GHG reductions equal to 2.6-3.3 kg of CO2-e per kg of methanol relative to conventional methods. Overall, this research quantifies both a notable economic challenge and a considerable environmental incentive associated with low-carbon methanol production, which could inform future decarbonization efforts in the chemicals industry.