Abstract: With the large-scale integration of new energy, its intermittent and volatility problems have become increasingly prominent. To alleviate the intermittency and volatility of new energy and improve the utilization rate of new energy, this paper proposes a capacity optimization configuration method of battery, thermal, and hydrogen hybrid energy storage system based on the regulation characteristics of energy storage battery, molten salt thermal energy storage system, and electrolytic water hydrogen production system. In the scenario construction stage, the minimum total net load is considered to optimize the installed capacity of new energy, and the typical daily data are selected as the basic parameters for the optimal configuration of hybrid energy storage system capacity based on K-means clustering and cumulative fluctuation index. Frequent charging and discharging will affect the battery life. To avoid optimistic planning results, a capacity optimization configuration model of a battery, thermal, and hydrogen hybrid energy storage system is proposed, which considers battery life and aims to maximize daily comprehensive net income. Considering the demand side response, adjusting the time-shiftable load reduces the mismatch between the power generation and the demand side. The simulation test is carried out based on wind, light, and load data in a certain area of northwest China. The results show that the battery, thermal, and hydrogen hybrid energy storage system can consider the system reliability and economy and improve the utilization rate of new energy. Considering the battery life, the planning results can be avoided to be optimistic, and the economic optimization of the system can be ensured. Considering the demand side response, the economic benefit of the system can be improved, and the model's effectiveness is verified.