Assessing the arbitrage of integrating a molten salt thermal energy storage (TES) into a coal-fired combined heat and power (CHP) plant

The integration of molten salt thermal energy storage (TES) into coal-fired power plants has been increasingly recognized as an effective approach for operational flexibility enhancement. However, limited research has focused on the arbitrage of the molten salt TES-integrated combined heat and power (CHP) plant in electricity markets. This study fills the research gap by developing an operational optimization model for a molten salt TES-integrated CHP plant, which maximizes its profit by considering real-time electricity prices and heating loads. Results show that integrating an 800 MWh molten salt TES into a 330 MW CHP plant can improve the plant's annual profit from 67.5 to 83.7 million RMB, primarily through capitalizing on peak-valley electricity price differences and expanding industrial heating capacity. Moreover, the TES integration can gain greater economic benefits in heating seasons compared to summer months. The net present value (NPV) of this TES integration is 62.7 million RMB, and the payback period is 10.0 years. Furthermore, the sensitivity analysis indicates that, compared to the baseline capacity of 800 MWh, a 40% decrease in the total energy storage capacity would improve the NPV up to 83.0 million RMB and shorten the payback period to 7.1 years. In addition, when the electricity prices rise by +60% from the baseline, the NPV of the TES integration would increase to 177.3 million RMB, representing an increase of 182%. This study provides insights to the planning and operation of molten salt TES and its integration in CHP plants.