Arbitrage strategy and technoecnomic analysis for transcrtical compressed carbon dioxide energy storage

Compressed gas energy storage is characterized by its large capacity, extended operating life, cleanliness and low carbon emissions, making it an important and promising development trend in energy storage technology. Compared with compressed air energy storage (CAES) mainly composed of nitrogen, compressed carbon dioxide energy storage (CCES) has higher energy storage capacity due to its superior fluid properties. Existing literature mainly focuses on the thermodynamic performance of CCES and the optimization of parameters and structures. There are few studies on carbon energy storage power plants participating in power system scheduling. This paper proposes an arbitrage strategy and techno-economic analysis for transcritical compressed CO
2
storage (TC-CCES) system. Taking into account the physical properties of CO
2
at high temperature and pressure, a refined model is proposed to overcome errors resulting from the ideal gas assumption commonly used in conventional CO
2
modeling. Incremental piecewise linear method is used to solve nonlinear problems in the model. Based on actual calculation examples from four provinces in China, the effectiveness of the arbitrage strategy model with TC-CCES proposed in this paper is verified in the electricity market. The revenue of the TC-CCES with active power reserve increased by 7.46%. The breakeven point of the peak-valley ratio is 1.71, below which TC-CCES will not participate in the energy market. Under the same design conditions, the energy storage density of TC-CCES is 7.9 times that of CAES, resulting in higher annual income.