A bi-level MILP approach for optimizing shared energy storage in multi-microgrid system

With the rapid growth of renewable energy deployment, multi-microgrid systems have become crucial for improving energy flexibility and reliability. However, challenges such as renewable intermittency and energy imbalance necessitate more advanced storage solutions. This paper proposes a shared energy storage (SES) allocation and scheduling strategy tailored for multi-microgrid environments. A bi-level optimization framework based on Mixed-Integer Linear Programming (MILP) is developed, aiming to simultaneously minimise the annual investment cost of SES and the operational costs of the microgrid cluster. The model incorporates renewable energy utilisation constraints and performs cost-benefit analysis under varying utilisation rates. Case studies demonstrate that the proposed approach significantly reduces wind and solar curtailment, enhances renewable energy consumption, and improves overall economic performance. The results validate the model's effectiveness and provide practical insights for the integrated planning and operation of SES in multi-microgrid systems.