A novel multi-generation system integrating thermophotovoltaic and SOFC system for power and green hydrogen with CO2 liquefaction: A techno-economic and multi-objective optimization study

• Power (2,542 kW), H 2 (0.01285 kg/s), and CO 2 (0.744 kg/s) co-produced efficiently. • SOFC heat loss recovery via TPV boosts power output by 4.5%. • Optimal exergy efficiency of the system reaches 35.44%. • Total product cost minimized to 48.97 $/GJ through optimization. This study proposes a novel biomass-fueled multi-generation system that addresses key limitations in existing SOFC-based configurations, such as unutilized radiative heat and the lack of integrated CO 2 capture. The system integrates a digestion unit, solid oxide fuel cell (SOFC), thermophotovoltaic (TPV) unit, closed Brayton cycle, vanadium chloride hydrogen production cycle, and a CO 2 liquefaction module. A major innovation lies in recovering the SOFC’s radiative waste heat via the TPV unit, significantly boosting total power output and improving overall sustainability. The system utilizes biogas and air in separate pathways for electrochemical and combustion processes, while waste heat is recovered to drive the Brayton cycle, support hydrogen production, and enable CO 2 liquefaction through LNG-based cooling. This integrated approach reduces fossil fuel dependency and greenhouse gas emissions. A comprehensive energy, exergy, techno-economic, and environmental analysis is performed, along with multi-objective optimization using the Grey Wolf Optimizer under two scenarios. Parametric studies identify the combustion chamber temperature as a key performance driver. The integration of TPV and cryogenic CO 2 capture improves energy utilization and environmental impact. The optimized system achieves a net power output of 2,798 kW, an exergy efficiency of 35.44 %, and a CO 2 emission index of 0.6353 kg/kWh. The system achieves a hydrogen production rate of 0.01285 kg/s, with payback periods ranging from under four to under seven years depending on electricity price and operational lifespan. These results confirm the proposed system’s potential as a high-efficiency, low-emission solution for decentralized clean energy and fuel production.