Techno-economic evaluation of a combined biomass gasification-solid oxide fuel cell system for ethanol production via syngas fermentation

•Biomass-to-ethanol via syngas fermentation with solid-oxide fuel cell system is designed.•Optimized gasification and fermentation condition obtained for ethanol production.•Optimal configuration of system scale is determined by multi-objective optimization.•Production cost reach 430.1 €/t ethanol with annual 69,595 tons from 200,000 tons woodchips.•Biomass-to-ethanol with solid oxide fuel cell system achieve efficiency of 55%