Performance analysis and optimization of the integrated energy system based on gas turbine and compressed gas energy storage

To improve the work capacity of compressed gas energy storage technology and efficiently utilize the waste heat from gas turbine flue gas, this paper proposes an integrated energy system combining compressed gas energy storage and a gas turbine. The system is evaluated using energy efficiency, exergy efficiency, and levelized cost of energy (LCOE), and its thermodynamic and techno-economic performance is optimized accordingly. The impact of using compressed air energy storage and compressed carbon dioxide energy storage technologies on the comprehensive performance indicators of the system are compared and analyzed. The results indicate that reducing the excess air coefficient of the gas turbine and increasing the pressure ratio of the gas turbine can significantly improve the thermodynamic performance of the integrated energy system, however it will also reduce the cost performance of the system. The multi-objective optimization indicate that, the optimal performance of the integrated energy system coupled with compressed air energy storage technology was determined under design conditions, achieving an exergy efficiency of 35.06% and an LCOE of 40.05 USD/MWh. In comparison, the energy system coupled with compressed carbon dioxide energy storage technology under the same conditions achieved an exergy efficiency of 35.28% and an LCOE of 39.51 USD/MWh. Compared with the design condition, the optimized integrated energy system coupled with compressed air energy storage technology exhibited a 3.67% improvement in exergy efficiency and a 0.52% reduction in the LCOE. Similarly, the integrated energy system coupled with compressed carbon dioxide energy storage technology showed a 3.89% increase in exergy efficiency and a 0.63% decrease in the LCOE. This study is of great significance for the development of distributed integrated energy systems that accommodate high penetrations of renewable energy.