Optimizing the energy storage capacity of a high proportion of new energy system is of great significance for improving new energy consumption and reducing the construction cost of energy storage stations. The capacity and electricity benefit of energy storage stations are studied, such as pumped storage power station, compressed air, and electrochemical energy storage. A cost-benefit analysis model for energy storage stations participating in peak regulation is proposed, and a new method of determining capacity and type of energy storage in a high proportion new energy system is proposed. Taking the actual high proportion of new energy system in northwest China as the research object, the energy storage capacity requirements, the costs and benefits of various energy storages are analyzed, and the research results can be used for China’s high proportion new energy systems to study energy storage capacity requirement, energy storage planning and operation.