Thermoeconomic and environmental evaluation of a SOFC-driven multigeneration framework integrated with desalination and Electrolysis: Performance assessment and multi-objective optimization

Fuel cells represent a promising avenue for sustainable power generation, offering reduced emissions and high-power density. This study investigates an integrated energy system composed of a solid oxide fuel cell fueled by methane steam reforming, a steam Rankine cycle, a multi-effect desalination unit, and a proton exchange membrane electrolyzer for the simultaneous production of electricity, freshwater, and hydrogen. A comprehensive thermodynamic, economic, and environmental analysis is conducted, supported by sensitivity analysis and multi-objective optimization. The system achieves a total power output of 1039 kW under base conditions, with freshwater and hydrogen production rates of 0.88 kg/s and 0.00175 kg/s, respectively. Thermal and exergetic efficiencies are found to be 33.28 % and 26.87 %. The solid oxide fuel cell contributes the highest exergy destruction (498 kW), while the afterburner exhibits the largest cost rate of exergy destruction at 239,591.65 $/year. The overall payback period is estimated at 5.73 years, and the system reaches an exergoenvironmental impact rate of 14.48 Pt/h. Parametric studies reveal that fuel utilization factor strongly affects power output, and the afterburner's stack flow temperature is a key driver of exergy efficiency. At the optimal design point, net power output improves to 1201.58 kW, freshwater production increases to 0.95 kg/s, and hydrogen generation is 0.0016 kg/s. Additionally, the second-law efficiency improves to 29.86 %, the payback period shortens to 3.63 years, and the exergoenvironmental impact rate is reduced to 13.92 Pt/h. These results confirm the system's viability for integrated energy and resource production with improved performance, economic return, and environmental compatibility.