Optimal sizing of supercapacitors for cost-effective hybridization of battery-alone energy storage systems

Battery-supercapacitor (SC) hybrid energy storage systems (HESS) are today known as an effective means to extend the service life of batteries that are prone to early failures, mainly caused by current-related stress. While this holds true in most cases, the overall economic costs and benefits of this architecture are either overlooked or incomplete in previous research works. This paper introduces a life cycle cost optimization model for cost-effective upgrade of battery-alone energy storage systems (BESS) into battery-SC HESS. The case study in this paper shows that the presence of SC can result in up to 1.95% reduction in LCC over the remaining five years of the plant's lifespan. As side benefits, 5.2% decrease in energy consumption and CO2 equivalent emissions associated to the manufacturing and operation of the HESS components. The proposed model can therefore inform about the relevance of a BESS retrofit in both brownfield and greenfield projects.