Abstract
Microgrids expansion problems with battery energy storage (BES) have gained great attention in recent years. To ensure reliable, resilient, and cost-effective operation of microgrids, the installed BES must be optimally sized. However, critical factors that have a great impact on the accuracy and practicality of the BES sizing results are normally overlooked. These factors include the wide range of characteristics for different technologies, the distributed deployment, the impact of depth of discharge and the number of charging/discharging cycles on the BES degradation, and the coordination of microgrid operation modes. Thus, this paper proposes a comprehensive BES sizing model for microgrid applications, which takes these critical factors into account when solving the microgrid expansion problem and accordingly returns the optimal BES size, technology, number, and maximum depth of discharge. The microgrid expansion problem is formulated using mixed integer linear programming. The nonlinear relationship between the BES depth of discharge and lifecycle is linearized using piecewise linearization technique and implemented to model the BES degradation. The proposed model is validated using a test microgrid. The conducted numerical simulation shows that the proposed model is able to determine the optimal BES size, technology, number, and maximum depth of discharge and further enhances the accuracy and practicality of the BES sizing solutions.