Abstract: With the increasing installed capacity of wind power and photovoltaic power in west Inner Mongolia power grid, the permeability of wind power and photovoltaic power increase continuously. Due to the stochastic fluctuation and intermittent nature of renewable energy sources, the peak shaving and frequency modulation of power grid are particularly severe. According to the actual problems faced by the west Inner Mongolia power grid, this paper introduces the energy storage technology which can reach the scale of 100 MW or more. On this basis, combined with the current national energy storage policy, large-scale energy storage is applied to solve specific problems such as frequency modulation and peak shaving. Combined with the operation situation of the west Inner Mongolia power grid, the large-scale energy storage are prospected in frequency modulation and peak shaving and black-start.