Optimal Sizing of Battery Energy Storage System in Commercial Buildings Utilizing Techno-economic Analysis

Abstract

Finding the correct battery size is important to the project's financial success. Many studies utilize complicated simulations to identify the optimal battery size. It is also difficult to reuse the outcomes of such optimization in other projects. In this paper, by introducing the factor β as the energy to power ratio, a simple techno-economic model is proposed to allow a quick evaluation of the feasibility of a building-integrated battery energy storage system (BI-BESS) and can apply to all commercial buildings that use the same tariff structure and is independent on the building load profile. Because the battery's energy and power are coupled, defining β allows both metrics to be addressed, resulting in high accuracy. For validating the results, the load profile from a commercial building based on Malaysia's tariff structure is used, and the optimal size of the battery is obtained from the proposed techno-economic model with the help of a Benefit-cost ratio (BCR) and simple iterative model for peak shaving. The results reveal that after finding the optimal BCR=1.08, the optimal battery size is achieved at 66.84 kWh. However, considering the market interests in the payback period, the economic feasibility of installing BESS is evaluated at BCR= 1.7, which is higher than our results. Hence, the impact of battery cost reduction is assessed.