Techno-economic and environmental assessment of SOFC–GT–SG integration in a Chilean combined cycle power plant under natural gas and green hydrogen scenarios

This study develops a comprehensive 0-D mathematical model to evaluate the integration of Solid Oxide Fuel Cells (SOFCs) into a large-scale combined-cycle power plant in Chile operating with natural gas and hydrogen. The proposed methodology combines thermodynamic, economic, and environmental analyses using local fuel-price projections, carbon pricing mechanisms, and Chile’s National Green Hydrogen Strategy. The integrated SOFC–GT–SG configuration increases the overall efficiency of the reference plant from 46,9% to 69,5% when fueled with hydrogen and to 76,2% when fueled with natural gas. At the design operating point, the hybrid system increases net electrical output from 180 MW to approximately 232 MW while maintaining the original gas turbine operating conditions. Economic results indicate that natural gas remains the most competitive option in the near term, achieving an LCOE of 146 USD/MWh in 2025 compared with 244 USD/MWh for hydrogen. However, declining hydrogen costs improve its long-term competitiveness, reducing the LCOE to approximately 97 USD/MWh by 2050. From an environmental perspective, hydrogen operation reduces CO2 emissions by 71%, while natural gas achieves a 42% reduction relative to the reference combined-cycle plant. The results suggest that natural gas may serve as a transitional pathway for early SOFC deployment, whereas hydrogen represents a long-term option for deep decarbonization of the Chilean power sector.