A Method for Sizing and Siting of an Energy Storage System in Microgrid Concerning Generation Adequacy

Abstract

This paper presents a method for sizing and siting of an Energy Storage System (ESS) in microgrid concerning the cost of lost load due to generation inadequacy. This cost is considered together with the typical total cost of microgrid, usually including the investment cost of ESS and all operation costs of microgrid. From the study results, the suitable size of an ESS resulted from the proposed method is larger than that given by the conventional approach for any selected bus of microgrid because it helps to decrease the cost of lost load. On the other hand, existing methods commonly overlook the generation adequacy issue, and result in a smaller size than it should be. In addition, it has been found that the location of an ESS significantly affects distribution power losses in microgrid. During a charging period, the ESS located far from the energy sources tends to increase the energy losses of microgrid. This can be more severe when its size is larger because an increased amount of generated power will be fed to the ESS over long distribution lines. In contrast, when the ESS is placed close to major load areas distant from their energy sources, less amount of electrical power from the main grid will be transferred through the distribution lines during a discharging period. It results in a decrease in energy losses, and also reduces the amount of lost load due to generation inadequacy. Finally, the effectiveness of the presented method is assessed by a comparison of the total costs resulted from the proposed method against the conventional method. The results demonstrate that the total cost of microgrid resulted from this method is lower than that given by the traditional approach.