Sizing of II-life batteries for grid support applications and economic evaluations

Power systems are facing increasing stress due to modernization changes in both supply, through the growing penetration level of renewable sources, and demand due to the spread diffusion of electric vehicles (EVs). In this scenario, the use of energy storage systems (ESSs) is becoming technologically attractive but problems of economic and ecological sustainability are still evident. For these reasons, II-Life battery modules are a possible solution for supporting power systems: they are a promising prospect for the modernization process. We propose a method to size an ESS of exhausted plug-in EV battery packs for grid support applications. The method estimates the residual value of cycles for II-Life battery modules, the decrease in the supplied power due to the battery ageing and the number of EV battery packs to meet service requirements. Then, an economic assessment is presented to compare them with an equivalent I-Life storage system.