Techno-Economic Analysis of Biogas-to-Methanol via Integrated Oxy-Combustion and Electrolytic Routes

This study presents a techno-economic analysis of two biogas-to-methanol process designs via integrated oxy-fuel combined heat and power and either Solid Oxide Electrolysis Cells (SOEC) or Alkaline Water Electrolysis (AWE). Both routes are modeled for an inlet biogas flow of 2000 Nm3/h (60%mol CH4, 40%mol CO2 composition). Results reveal that the AWE route achieves a superior carbon conversion efficiency (88.8%), resulting in a higher annual production of chemical-grade methanol (19.7 kt/year) compared to the SOEC counterpart, this exhibiting a carbon efficiency of 76.6% and an annual methanol production of 17.5 kt/year. Oppositely, the SOEC route exhibits lower specific electric consumptions per unit of methanol produced (6.49 MWhel/t of methanol, against 7.45 MWhel/t of methanol for the AWE route). Under assumptions compatible with the Italian context, the SOEC route has better economic performance, achieving a net present value of −105.2 M€, compared to −133.4 M€ for the AWE case. Breakeven methanol prices are found equal to 1919 €/t for SOEC and 2020 €/t for AWE, significantly above the reference fossil-based methanol (884 €/t). A spatial analysis across 27 European countries identifies the electricity price and the grid carbon intensity as the dominant cost drivers, as the economic competitiveness of such technologies is shown to require a combination of low-cost renewable electricity and premium methanol pricing to achieve net positive returns.