Comparative analysis and trends in performance of identical PV panels under different climatic conditions

In this paper, a comparative analysis and trends in performance of identical photovoltaic (PV) panels under different climatic conditions are presented. Three PV demo sites situated in Oslo, Norway; Tozeur, Tunisia; and Sevilla, Spain are included into performed comparative analysis. Each site includes sets of identical mono-Si based PV panels supplied by the same manufacturers. The PV panel configurations include: (i) mono-facial, (ii) bi-facial, and (iii) innovative bi-facial PV panels with front glass covered by hydrophobic (HFB) or hydrophilic (HFL) coatings. At all three locations, each panel is equipped with Tigo optimizers, enabling module-level monitoring and DC energy-based performance assessment. Performance metrics are evaluated using IEC 61,724 based indicators, with irradiance derived from global horizontal irradiance data. Statistical analyses are applied to validate observed performance differences between panel types across locations. The results provide a technology-controlled comparison of PV panel behavior across cold-wet, warm-wet, and warm-dry climates, highlighting the influence of temperature, surface reflectivity, and coating type on relative performance trends.