From biofuels to e-fuels: an assessment of techno-economic and environmental performance

Abstract

The energy transition, alongside sufficiency measures, demands massive electrification supported by low-carbon electricity. However, carbon-based molecules will remain vital, especially in sectors like long-distance transport (aviation and shipping) and chemicals. Biogenic, atmospheric, or recycled carbon sources offer key alternatives to fossil fuels in the shift toward a circular carbon economy, aligning with sustainability goals like the Renewable Energy Directive (RED III). Based on 183 case studies, this work analyzes thermochemical conversion processes for fuel production, using lignocellulosic biomass, CO₂, and low-carbon hydrogen from electrolysis. Nine biofuel, e-fuel, and e-biofuel processes are evaluated, producing liquid hydrocarbons, synthetic natural gas, or methanol. Material and energy balances, determined using ProSimPlus®, compare carbon conversion and energy efficiency. Economic analysis estimates investment and production costs for industrial-scale units, while greenhouse gas (GHG) assessment considers different electricity mixes and biomass supply chains. The results show that substituting biomass with hydrogen improves carbon conversion: from 35–40% for biofuels to 65–70% for e-biofuels, and up to 80–85% for e-fuels with carbon capture. Hybrid energy sources boost energy efficiency for e-biofuels (61.3%) compared to biofuels (50.3%). However, using electricity (100 € per MWh) raises production costs, which are heavily dependent on electricity price assumptions. Aligning e-fuel and e-biofuel production with RED III requires a largely decarbonized electricity mix, while more comprehensive emission assessments are necessary for biofuels and e-biofuels, considering potential land-use impacts of massive biomass production.