In order to optimize the comprehensive configuration of energy storage in the new type of power system that China develops, this paper designs operation modes of energy storage and constructs a power balance model considering the regulation priority of energy storage incorporated into the grid, the designed charging and discharging power and capacity of energy storage, and restrictions from external power systems. An electricity leveling per kWh cost model is established on three different types of energy storage. Data in Qinghai Province are used as a model application example to calculate and analyze the energy storage configuration and cost under a certain power curtailment target. The results show that among the multiple configuration plans that meet the curtailment rate target, molten salt storage characterized by high charging power, long discharging duration and low capacity cost, is the most advantageous.