Abstract: It has engineering application value to study the optimal allocation of energy storage system in power grid. In order to quantify the benefit of saving coal after the configuration of energy storage system, this paper discusses the benefit of saving coal of power grid with energy storage by load shift and improving the operating characteristics of generator set, and proposes the concept of daily coal saving for the unit of energy storage. Meanwhile, this paper comprehensively analyzes the economic value of energy storage in delaying the promotion of distribution network, reducing the network loss, arbitrage of energy storage, etc. With considering the costs of investment, operation, maintenance and disposal, this paper constructs the optimal allocation model of battery energy storage system with taking the maximum annual net income as the objective function. Finally, this paper solve the model with using optimization algorithm to determine the capacity of the energy storage system. The example analysis shows that, the energy storage system in power grid can create better returns by shifting peak and filling valley, and reduce the coal consumption in a certain extent, achieve energy saving and emission reduction.

Key words: energy storage system, load shift, benefit of saving coal, daily coal saving, optimal allocation