A comprehensive performance comparison between compressed air energy storage and compressed carbon dioxide energy storage

Currently, working fluids for adiabatic compressed energy storage primarily rely on carbon dioxide and air. However, it remains an unresolved issue to which of these two systems performs better. Therefore, this paper compares the advantages and disadvantages of both systems in terms of thermodynamic and economic performances under the given boundary conditions. To accurately obtain the performance of energy storage systems, quasi-dynamic models are established for key components. On this foundation, corresponding thermodynamic- economic models are developed. The results indicate that at thermal storage temperatures of 120 degrees C, 140 degrees C, and 160 degrees C, 100 MWx5h x5h compressed carbon dioxide energy storage systems have higher round-trip efficiencies than compressed air energy storage systems. However, the compressed carbon dioxide energy storage also faces the difficulties of higher cost and longer payback period. Specifically, at the thermal storage temperature of 140 degrees C, round-trip efficiencies of compressed air energy storage and compressed carbon dioxide energy storage are 59.48 % and 65.16 % respectively, with costs of $11.54 x 107and 7 and $13.45 x 107, 7 , and payback periods of 11.86 years and 12.57 years respectively. Compared to compressed air energy storage system, compressed carbon dioxide energy storage system has 9.55 % higher round-trip efficiency, 16.55 % higher cost, and 6 % longer payback period. At other thermal storage temperatures, similar phenomenons can be observed for these two systems. After comprehensively considering the obtained thermodynamic and economic performances, the overall performance of compressed air energy storage is superior to that of compressed carbon dioxide energy storage. In addition, in practical engineering, key components of compressed air energy storage are more mature than those of compressed carbon dioxide energy storage, and air has higher safety than carbon dioxide. In the future work, the comparison for performances between different types of compressed carbon dioxide energy storage and compressed air energy storage should be taken into account, and dynamic models of the systems should be developed. Additionally, the industry chain of compressed carbon dioxide energy storage should be accelerated to reduce equipment costs, enabling it to compete with compressed air energy storage.