Author: Jiangfeng Wang (Xi'an Jiaotong University) - With the increasing global focus on renewable energy utilization, the energy storage field has gained significant attention. The integration of intermittent and fluctuating renewable sources is crucial for sustainable development. As a typical large-scale energy storage technology, compressed air energy storage systems offer promising solutions to enhance renewable energy integration and improve grid stability. This paper analyzed the performance of an adiabatic compressed air energy storage system including multi-stage compressors, multi-stage turbines, and inter-stage heat exchangers. Specifically, the compressor with intercooling and the turbine with reheating are the core components of the energy storage and release processes, respectively. By establishing off-design mathematical models of the system, the variations in the 4E (Energy, Exergy, Economic, Environmental) performances of the system with key parameters, such as the design storage pressure and the turbine inlet temperature changes are investigated. To improve the efficiency and economy of the system, the multi-objective optimization of the system is carried out based on genetic algorithm. The results show that within a certain range, as the storage design pressure increases, the deviation between the system and the design condition also increases, leading to a decrease in system performance. The system performance is improved with a higher turbine inlet temperature, as it enhances the turbine power generation capability. The greater the design efficiency of turbines and compressors, the smaller the losses, and the greater the system efficiency. The exergy destructions of turbines and compressors are relatively large. The exergy destruction of turbine III is the largest, reaching over 15%. The optimization results show that under the design condition, the system achieves a round trip efficiency of 58.2%, levelized cost of storage of 0.106 $/MWh, and cost of CO2 emission of 1.80 $M/year.
