Energy storage systems have excellent power regulation and frequency control ability, so they play an important role in absorbing new energy. The AGC control strategy of the whole station and energy storage unit of Zhejiang power grid-side energy storage power stations is introduced. The AGC control strategy is optimized based on battery energy efficiency, and a load distribution strategy considering the battery energy consumption factor is proposed. At the AGC site of an electrochemical energy storage power station, the conventional equal proportion distribution strategy is used to test the AGC of the energy storage unit and the whole station, respectively. The test results show that the regulation rate, response time, and steady-state error of AGC control of the energy storage unit are significantly improved. Then, AGC tests are carried out by using equal proportion distribution, equal margin distribution, and optimal distribution strategies. The test results show that after using the load distribution strategy considering the battery energy consumption factor, the load distribution results of PCS in the energy storage unit are different, which is conducive to the rapid load response of the energy storage system.