Study of operation strategies for integrating ice-storage district cooling systems into power dispatch for large-scale hydropower utilization

Hydropower curtailment for the run-of-over stations has become serious in Southwest China. The ice-storage district cooling system is believed as an effective approach to provide flexibility for hydropower utilization. However, the existing ice-storage operation strategies in demand-side management cause that the ice storage cannot be adjusted in real-time to match the surplus hydropower, which brings difficulties for large-scale hydropower utilization. Therefore, this paper proposed the integration of ice-storage district cooling systems into power dispatch based on smart grid. Two operation strategies were developed for the integration to achieve power supply-side management of ice-storage district cooling system. One is the new ice-storage power-linked operation strategy, which was proposed to determine the ice storing/melting capacity in the power dispatch. The other one is the cooling pipelines dynamic-characteristics-considered operation strategy, which was applied in the power dispatch. The dynamic characteristics were calculated based on a linear model to be compatible with the linear constraints in power dispatch models. Finally, effects of two strategies were studied by taking scenes in Chongqing as the example. Results showed that the application of the first strategy only reduces the hydropower curtailment frequency, while application of the second strategy reduces both the curtailment frequency and amount. Furthermore, the simultaneous applications of the above two strategies enhance hydropower consumption by 7.5% (200 million kW.h) and reduce carbon emission by 7.4% (34,000 tons) every year. In addition, there exists an optimal total ice-storage capacity per day, i.e. 8600 MW.h, under which the system's performance reaches the highest value.