With the growing penetration of RES, more flexibility is required in power system. District heating system with large capacity is able to offer flexibility to power system. Based on the model of a district heating system built by heat current method, this work proposes a quantification method to evaluate the flexibility of district heating system, which is a hybrid algorithm utilizing simulations and dichotomy method. Quantitative indicators including average power shifting capability and available storage capacity are defined to describe the flexibility. The results of case study present the flexibility of system under a general working condition. Then, influence factors are discussed that with the increase of dispatch time and decrease of the time of heat migration delay, the storage capacity of heating network increases.
Keywords Thermal storage, energy flexibility, heat current model, system simulations