Optimal planning of lithium ion battery energy storage for microgrid applications: Considering capacity degradation

By adding battery energy storage (BES) to a microgrid and proper battery charge and discharge management, the microgrid operating costs can be significantly reduced. But energy storage costs are added to the microgrid costs, and energy storage size must be determined in a way that minimizes the total operating costs and energy storage costs. This paper presents a new method for determining the optimal size of the battery energy storage by considering the process of battery capacity degradation. In this method, initially, the battery degradation functions are modeled; then, these functions are incorporated in the problem of determining the optimal battery size. The impact of different cycles with various depths of discharge is also considered that is the prominence of the present work. The proposed method is formulated as mixed-integer linear programming (MILP). Notably, the degradation model was implemented through two different formulations, by considering cycles with various depths of discharge in the second formulation, and the results of each formulation is compared that demonstrates the effectiveness of the second formulation.