Performance analysis of integrated solar and natural gas combined cycle power plants in high solar potential regions

This study offers a comprehensive techno-economic and environmental evaluation of a hybrid solar-natural gas combined cycle power plant designed for the Kirkuk region, taking advantage of its high solar irradiance. The proposed system incorporates advanced technologies to maximize efficiency and sustainability, including absorption refrigeration systems, steam Rankine cycles, and organic Rankine cycles. Two configurations were analyzed: Model 1 integrates a conventional gas turbine with a steam Rankine cycle driven by exhaust gases and solar energy collectors and an organic Rankine cycle; Model 2 combines all the components of Model 1 with the absorption refrigeration system (ARS) to enhance turbine efficiency through compressor inlet air cooling. The results indicate that Model 2 delivers a net power output between 235 MW and 245 MW, exceeding Model 1 by up to 12.7 MW. It offers significant 5-10% reductions, with electricity costs ranging from $70/MWh to $76.5/MWh, while also cutting CO₂ emissions by 0.7 to 2 kg CO₂/MWh, particularly during hotter periods. In June, Model 2 achieved the lowest power cost of $70/MWh and a peak output of 245 MW, compared to $72/MWh and 235 MW for Model (1) During December, however, Model 1 shows slightly better performance due to cooler conditions, with costs of $78/MWh versus $76.5/MWh for Model (2) Exergy analysis highlights the combustion chamber as the main contributor to system losses, accounting for 46.07% of total exergy destruction. Nevertheless, Model 2 integrates solar energy and ARS effectively, achieving energy and exergy efficiencies of 59.25% and 57.21%, respectively, demonstrating its superior overall performance. These findings demonstrate that integrating gas turbines with renewable energy and advanced cooling technologies provides a scalable, economically viable solution to Iraq's energy challenges. Additionally, this research establishes a replicable framework for regions with high solar potential, emphasizing the transformative potential of hybrid energy systems in achieving sustainable energy security while mitigating environmental impacts.