Coordination of Maintenance and Flexibility Retrofit of Coal-fired Units in Generation Scheduling

The volatility and uncertainty of ever-increasing renewable energy pose various challenges to the regulation capability of the low-carbon power systems. Enhancing the flexibility of existing coal-fired units is a cost-effective method to address this issue, especially in coal-dominated regions. This paper considers that the flexibility retrofit of coal-fired units can be coordinated with the maintenance periods. It proposes a co-optimization framework of maintenance and flexibility retrofit of coal-fired units in the medium- and long-term generation scheduling. The problem is modeled in the mixed integer linear programming (MILP) formulation, and it is solved by a generalized Benders Decomposition algorithm. The validity of the model is demonstrated through a case study involving the half-year operation of a modified IEEE 6-bus system.