Two-Stage Day-Ahead Capacity Allocation Method for Shared Energy Storage in Multi-microgrid System

Shared energy storage (SES), with its cost-sharing and centralized management characteristics, provides an effective energy solution for modern power systems. To rationally allocate the day-ahead capacity of SES, this paper proposes a two-stage day-ahead capacity allocation method for SES in a multi-microgrid system (MMS). In the first stage, a day-ahead optimization scheduling plan for microgrids considering SES is developed. The objective is to minimize the daily operating cost of the MMS while considering constraints such as power balance, SES, and photovoltaics. In the second stage, SES capacity trading is conducted based on the scheduling results from the first stage. The actual charge and discharge power of SES capacity of each microgrid in MMS is calculated, and then SES capacity transaction is carried out between microgrids. The objective of the second stage is to minimize the overall transaction cost of the MMS while considering microgrid storage capacity and capacity trading constraints as conditions. Extensive evaluations were conducted on an MMS consisting of three microgrids. The results show that compared to distributed energy storage, this method reduces the total operating cost by $\mathbf{2 . 7 \%}$, confirming the effectiveness of the proposed two-stage day-ahead capacity allocation method for SES in an MMS.