Driven by carbon peak and neutrality goals, the rapid development of renewables will significantly change the structure and distribution of energy resources of the power system in China. This also brings great opportunities and challenges for the development of energy storage in the power system. First, the locations of the load centers and the changes of the structure and distribution of energy resources are studied, based on which the new pattern of future power system is predicted, i.e., from-outside-to-inside power transmission. Then, the critical role of energy storage in supporting the secure, efficient, and low-carbon operation of the future power system is analyzed. The development superiority of pumped hydro storage in the new pattern is highlighted considering the topographical characteristics of China. Accordingly, a pumped hydro storage-predominating energy storage grid is proposed, whose necessity is further analyzed from the perspective of system-wide active power balance. Finally, key technologies for the energy storage grid are investigated, including planning, operating, and market, and some thoughts on the development of the energy storage grid are also provided. This work is supported by the Innovation Research Group Project of the National Natural Science Foundation of China (No. 51821005).