Design criteria for the optimal sizing of a hybrid energy storage system in PV household-prosumers to maximize self-consumption and selfsufficiency

Abstract

Batteries of photovoltaic (PV) household-prosumers undergo many fast, partial charge/discharge cycles because of the short-term fluctuations of household load and PV profiles. This negatively affects battery lifetime and can increase project cost involving energy storage systems (ESSs). To address this problem, this research developed an innovative analytical technique that assesses the techno-economic impact of battery-aging mechanisms and their influence on the optimal sizing of a hybrid energy storage system (HESS) for prosumers so as to minimize the total energy supply cost. This technique, implemented in a dynamic model of the integrated system, designs battery degradation, supercapacitor (SC) behaviour, converter hardware implementation, and power management strategy (PMS). The results, as reflected in technical short and long-term assessments, showed a potential improvement in self-consumption and self-sufficiency ratios due to PV, battery, SC, and the extension of battery lifetime in various PV-ESS sizing scenarios. The optimal PV-battery configuration was then determined by a techno-economic assessment, as well as the most suitable HESS sizing, while preserving the previous ratios of optimal PV-battery configuration, though with a lower life-cycle cost. The optimal PV-battery configuration was found to depend on the long-term power fluctuations of input profiles, whereas short-term fluctuations determined the optimal HESS sizing.