Impact of Generation Flexibility on the Operating Cost Under a High Penetration of Renewable Power Integration

The penetration of renewable energy is gradually increased. Therefore, power system flexibility, which is required to maintain system security and to cope with renewable generation uncertainty, becomes more important. Various technologies, such as flexible generators, demand management, energy storages, network reconfiguration, and even efficient system operations, are capable to improve power system flexibility. Nevertheless, among them, flexible generation resources can provide a direct way to enhance the power system flexibility. This work first applies fuzzy analytic hierarchy process (FAHP) to calculate the flexibility index of generation resources. Then, the process of unit scheduling is implemented under various operation scenarios to investigate the relationship between the generation flexibility and the cost of unit scheduling. Finally, the required flexibility and the corresponding capacity of flexible generators under a specified penetration of renewable power generation are investigated under different operation scenarios.