Stochastic optimal scheduling considering reserve characteristics of retrofitted combined heat and power plants

• Published in: International journal of electrical power & energy systems 2022-09, Vol.140, p.108051, Article 108051
• Main Authors: Guo, Xusheng, Lou, Suhua, Chen, Zhe, Wu, Yaowu, Wang, Yongcan
• Format: Article
• Language: English
• Subjects: External thermal storage; Internal thermal storage; Operation flexibility; Reserve capacity; Retrofitted CHP units; Wind power
• ISSN: 0142-0615
• DOI: 10.1016/j.ijepes.2022.108051

•Develop the flexibility potential of CHP units by utilizing double thermal storages.•Propose the operation model of retrofitted CHP units considering thermal power coupling and technical characteristics.•Present day-ahead scheduling model considering CCGP-based reserve risk.•Illustrate the expansion of thermo-electric feasible region about a single retrofitted CHP unit.•Analyze the impact of different wind power installed capacity and different internal thermal storage capacity on operation benefits of PHIES. Increasing the proportion of non-fossil energy and developing renewable energy are greatly conducive to building a clean and low-carbon energy system. However, in the current power system, the strong thermo-electric coupling limits the feasible operating regions of combined heat and power (CHP) units, which causes serious problems about wind curtailment and reserve capacity insufficiency. To cope with this issue, it is technically feasible to retrofit inside and outside CHP units, so as to improve the operation and reserve flexibility of the system. This paper focuses on illustrating the flexible operation and hourly-level reserve characteristics of retrofitted CHP units in a power and heat integrated energy system (PHIES) with high proportion of wind power. The designed flexibility retrofit scheme based on internal thermal storage (ITS) and external thermal storage (ETS) is firstly analyzed. Secondly, the corresponding refined operation model for retrofitted CHP units is proposed to describe their technical features and energy flow process. Then, a coordinated optimization model for operation scheduling and reserve risk is presented from the perspective of the overall system. Finally, numerical simulations are performed to demonstrate the favorable influence of double thermal storage on wind accommodation improvement and reserve risk reduction in the PHIES. The impact of different wind power installed capacity and different thermal energy storage capacity is also studied in the sensitivity analysis.