Evaluation of photovoltaic panel and battery energy storage types for optimal stand-alone sizing

This study presents comparative results aimed at minimizing the Total Annual Cost (TAC) of hybrid power-generation systems that integrate renewable energy sources, specifically photovoltaic (PV) systems, battery energy storage, and a diesel generator as a backup to fully satisfy the energy needs of the University of Torbat Heydarieh in Iran. Although hybrid renewable systems effectively meet load demands, determining the optimal component size remains a major challenge due to techno-economic constraints and site-specific load characteristics. In this work, the Mountain Gazelle Optimizer (MGO) was employed to identify the optimal system component sizes, and a rule-based energy management strategy was implemented to regulate power distribution and reduce TAC. Two scenarios were analyzed. In the first scenario, different types of PV modules mono-crystalline, poly-crystalline, and thin film were evaluated to minimize system cost. Considering economic, technological, and environmental factors, the PV/diesel generator/battery (absorbed glass mat) configuration was identified as the most suitable option. In this case, the number of poly-crystalline panels increased by 41.18%, while the total cost decreased by 1.25%. The second scenario focused on minimizing TAC using three types of energy storage technologies: lithium-ion, absorbed glass mat, and lead-acid batteries. Here, the mono-crystalline PV/diesel generator/battery system was found to be the most efficient configuration. An 88.8% increase in the number of PV panels led to a 21.6% reduction in system cost. A fuel-cost sensitivity analysis for both scenarios indicated a significant increase in solar energy utilization as fuel prices rose.