Energetic And Exergoeconomic Evaluation Of A Combined Cycle Power Generation System with blends Of Hydrogen and Natural Gas

Abstract Colombia's electricity sector faces increasing electricity demand and growing pressure to reduce carbon emissions. In this context, natural gas–hydrogen blends offer a promising pathway for decarbonizing gas turbine-based power generation. However, limited studies have evaluated their performance under tropical climate conditions, where high ambient temperature and humidity can significantly affect combined cycle operation. This study presents an integrated energy, exergy, and exergoeconomic analysis of a combined cycle power plant fueled by natural gas–hydrogen blends. Hydrogen content was varied from 0% to 100% in 10% increments, while compressor inlet air-cooling temperature was evaluated from 8.8 °C to 15 °C. Results show that cooling the compressor inlet air to 8.8 °C maximizes gas turbine power output and helps limit nitrogen oxide emissions. Increasing the hydrogen fraction improves power output, with a stronger effect above 60% H2, where each additional 10 percentage-point increase produces gains between 0.06% and 0.54%. Hydrogen enrichment also reduces CO2 emissions and decreases exergy destruction by up to 1.52%. However, electricity generation costs increase significantly when hydrogen fractions exceed 60%, mainly due to the higher unit cost of hydrogen compared with natural gas. Overall, moderate hydrogen blending appears to be a technically attractive and economically reasonable option for improving combined cycle performance and reducing carbon emissions under tropical conditions, whereas high hydrogen operation requires careful economic assessment before implementation.