Solar- and biomass-assisted hybrid solid oxide fuel cell, thermophotovoltaic, and photovoltaic system for sustainable ammonia and synthetic natural gas production: multi-objective LCA-TEA optimization

This study proposes a novel solar- and biomass-assisted hybrid energy system integrating a solid oxide fuel cell (SOFC), thermophotovoltaic (TPV) unit, PV-powered alkaline electrolyzer, and downstream methanation and ammonia synthesis units. The system is designed for multi-product generation, producing electricity, synthetic natural gas (SNG), ammonia, and liquefied CO₂, while efficiently managing carbon using LNG cold energy. Key innovations include TPV-based recovery of high-temperature SOFC radiation for electricity, integration of PV-powered hydrogen production, and combined methanation and ammonia synthesis to enhance product diversity and efficiency. System performance is comprehensively evaluated using energy and exergy analysis, techno-economic assessment, life cycle assessment (LCA), and multi-objective optimization with the Gray Wolf Optimization (GWO) algorithm. At baseline conditions, the system achieves 32.74 % exergy efficiency, 2776 kW net power output, and production rates of 0.67 kg/s CO₂, 0.0264 kg/s methane, and 0.0692 kg/s ammonia, while the unit energy cost is 37.04 $/GJ. LCA confirms the environmental sustainability of the system, and optimization further improves efficiency (up to 33.23 %) and reduces costs (down to 36.06 $/GJ) and emission index (down to 0.0902 kg/kWh). The proposed system demonstrates strong potential for sustainable green fuel production, efficient carbon capture, and enhanced economic performance compared to existing hybrid energy approaches.