Performance study of an advanced adiabatic compressed air energy storage system

Renewable energy sources such as wind and solar, have vast potential to offer cost competitive power supply and reduce dependence on fossil fuels and environmental issues in the electric sector. However, renewable energy systems often have variable and uncertain energy supply which makes electrical energy storage systems highly valuable for renewable energy applications. Compressed air energy storage is one of the most promising technologies that have received wide attention in scientific community. In this paper, a comprehensive thermodynamic model is developed to investigate the thermal performance of an Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) system. The effect of key parameters including storage pressure, pre-set pressure along with compressor and turbine efficiencies on the system performance is studied. The results show that the storage pressure has a significant effect on the amount of energy stored in the AA-CAES and power generated by the expander. As the storage pressure increases from 2 MPa to 10 MPa, the amount of energy stored increases from 7.8 MJ/m³ to 105.6 MJ/m³ while the output power increases from 4.2 to 63.2 MJ/m³. The results also show that the overall energy conversion efficiency is dominated by the efficiency of the compressor and turbine. As the efficiencies of both compressor and expander increases from 0.65 to 0.95, the efficiency of the AA-CAES system is improved from 35% to 74%. This study provides a deep understanding of operation characteristics of the AA-CAES system and useful information for system design and optimization.