Under the large-scale integration of renewable energy, the power system becomes more volatile and uncertain, imposing higher demands on the flexibility of coal fired power plant (CFPP). In this study, a CFPP coupled with thermal energy storage (CFPP-TES) system is investigated. The main operating modes of the CFPP-TES system are defined, and its operating boundaries under different load levels are clarified. A bi-level optimization model of a virtual integrated energy system incorporating the thermodynamic features of the coupled system is developed for operation optimization. Results show that in the rapid-response mode, the coupled system achieves a peak regulation range of up to 82%Pe but with relatively low efficiency. By combining the rapid-response and steady-efficiency modes, a hybrid operation mode is formed, balancing flexibility and efficiency. In no-curtailment scenarios, the hybrid mode performs best, reducing the payback period to 2.35 years and showing strong adaptability.
Wang et al. (Thu,) studied this question.