Abstract
Battery energy storage (BES) is an indispensable resource in stand-alone microgrids. A reliable and cost effective microgrid operation can be achieved when the BES is optimally designed and deployed. The BES lifetime, however, is greatly impacted by its operation where two important operation factors must be considered to prolong its lifetime, namely the depth of discharge and the number of cycles. This paper proposes a stand-alone brownfield microgrid expansion model that determines the optimal size of installed BES while taking into consideration the impact of the operation factors on the BES lifetime. Based on the relationship between the BES depth of discharge and lifecycle, the proposed model can determine the depth of discharge impact on the installed BES lifetime. Mixed-integer linear programming (MIP) is used to formulate the problem and a test microgrid is used to validate the effectiveness of the proposed model.