Experimental Validation of a Hybrid Photovoltaic Backup System for Critical Load Energy Resilience: Design, Performance Assessment, and Mathematical Model Verification

Power outages pose a significant challenge to the operational continuity of businesses and infrastructure that rely on critical loads. In this context, hybrid photovoltaic systems with energy storage represent a sustainable alternative for improving energy resilience and reducing dependence on conventional backup sources. The objective of this research was to design, implement, and experimentally validate a hybrid photovoltaic system with battery storage for critical-load backup in a commercial facility located in Quito, Ecuador. The methodology included energy-demand assessment, photovoltaic and battery storage sizing, integration of an automatic transfer system, and experimental evaluation under real operating conditions. In addition, a mathematical model was developed to describe the system’s energy behavior, including a backup-autonomy model validated against experimental data. The results showed that the system maintained the power supply to critical loads during controlled grid-interruption events, achieving an average backup autonomy of 3.2 h under an approximate demand of 2.2 kW. The hybrid backup system delivered approximately 7.04 kWh during representative backup events through the combined contribution of photovoltaic generation and battery storage. Furthermore, the backup-autonomy model showed a relative error of 1.9% with respect to the experimental measurements, demonstrating good agreement between the theoretical model and the observed performance. The findings confirm the technical feasibility of hybrid photovoltaic systems for improving energy resilience in critical-load applications. The main contribution of this study is the experimental validation of a commercially implemented hybrid photovoltaic backup system under real operating conditions, providing empirical evidence and a replicable methodology for future implementations in similar commercial and industrial facilities.