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

Abstract

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 CO2 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 CO2 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 CO2 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 CO2 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 CO2 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.