Shared Energy Storage Planning Considering User Complementarity and Complementary Surplus Energy Utilization

Shared energy storage (SES) improves storage utilization by aggregating the storage demands of multiple users. When users exhibit complementary charging and discharging behaviors, part of the energy conversion process can be avoided, resulting in energy retained in the physical storage system. However, such retained energy has not been explicitly modeled in existing studies. Meanwhile, existing studies mainly optimize prices under given billing metrics, while the influence of billing metric selection on users’ charging and discharging behaviors has been overlooked. To address these limitations, this paper proposes a bi-level SES planning method considering complementary surplus energy (CSE) utilization and virtual energy storage (VES) billing mechanisms. A CSE model is established to quantify the energy retained in the physical storage system resulting from complementary operation, and a real-time release mechanism is developed to reduce unnecessary capacity occupation. Moreover, different VES billing metrics are compared according to their effects on user storage behaviors, and a billing mechanism based on charging power is proposed to improve user complementarity. The proposed mechanisms are integrated into the bi-level planning framework. Case studies demonstrate that the proposed method reduces storage capacity requirements, improves SES utilization, and enhances economic performance.