Cost analysis of battery-supercapacitor hybrid energy storage system for standalone PV systems

Abstract

Standalone photovoltaic (PV) system is usually supported by intermediate energy storage devices to balance the intermittency in PV generation and variation in residential loads. Lead Acid (LA) batteries have been the mainstream energy storage solution in residential energy systems. To mitigate the impact of fluctuating power exchange on battery lifetime, battery-supercapacitor hybrid energy storage systems (HESSs) of different topologies have been proposed to address the short life expectancy issue of LA battery. This paper presents a comprehensive cost analysis and performance evaluation of different HESS configurations in standalone PV based residential energy systems. A standalone PV-based microgrid model with HESS is developed in MATLAB Simulink to evaluate the effectiveness of different HESS configurations in mitigating battery's stress. A battery health cost function is formulated to analyze the impact of dynamic power exchange on battery's health. The results show that the actively controlled HESS significantly mitigates the battery's stress and reduces the health cost, thus improves the life expectancy of LA battery.