Energy, environmental, and economic assessment of sustainable fuels from wet biomass via hydrothermal, sorbent-enhanced gasification, and Fischer-Tropsch route

Decarbonizing aviation requires low- and net-negative-carbon sustainable aviation fuels that can significantly reduce greenhouse gas emissions while remaining compatible with existing fuel distribution systems and aircraft engines. This study evaluates a novel Fischer-Tropsch sustainable fuel pathway using highly wet and difficult-to-handle biomass. The process integrates hydrothermal carbonization with sorbent-enhanced conversion. Three configurations are assessed: biomass-to-liquid with carbon capture and storage; power-assisted biomass-to-liquid with carbon capture and storage and integrated water electrolysis; and a benchmark case incorporating water electrolysis without carbon sequestration. The biomass-to-liquid configuration achieves the highest energy efficiency (51.16%) and the strongest carbon-negative performance (−115.89 g CO₂/MJ). These achievements are driven by limited electricity demand, low dependence on grid power, and high carbon capture and sequestration rates. The power-assisted biomass-to-liquid configuration shows lower energy efficiency (39.44%) but remains carbon-negative (−41.96 g CO₂/MJ). Its performance is constrained by high electricity consumption and inefficient use of electrolytic hydrogen, a substantial share of which is combusted to supply process heat and power. Sensitivity analysis indicates that the sequestration-oriented scenarios are robust to variations in grid carbon intensity, whereas the benchmark is highly sensitive to electricity-related emissions. Production costs range from 0.155 to 0.271 €/MJ, approximately 10 to 17 times higher than current fossil-based jet fuel prices. A synergetic combination of carbon market revenues with national-level sustainable aviation fuel policy support, while preventing double counting, has the potential to achieve cost parity at moderate carbon taxes. Recognizing and rewarding carbon-negative performance in policy frameworks would markedly strengthen the competitiveness of advanced Fischer-Tropsch kerosene integrated with carbon capture and sequestration.