Abstract: To address large fluctuations in output power and state of charge,as well as short battery life of energy storage capacity in the configuration of grid-connected new energy,an optimized configuration method for energy storage capacity configuration is proposed based on the "dual carbon" background in this paper. First,the typical historical sample is selected as the output sample,and the power fluctuation rate of each continuous time period in the full data sample period is calculated. Second,according to the power fluctuation,the output power reference values of batteries and super capacitors are obtained by smoothing. The traditional energy storage control is improved by using the advance control method. The energy storage capacity is reasonably controlled by maintaining the current state,discharging and charging in advance,and the energy storage cost is optimized on the basis of ensuring the effect of stabilizing fluctuations. The allocation of storage capacity of grid-connected new energy is optimized from both perspectives of power and cost. The experimental results show that the proposed method can stabilize the output power and state of charge and prolong the service life of the battery,indicating that the method can effectively meet the design expectation.