Investigating defects and annual degradation in UK solar PV installations through thermographic and electroluminescent surveys

As the adoption of renewable energy sources, particularly photovoltaic (PV) solar, has increased, the need for effective inspection and data analytics techniques to detect early-stage defects, faults, and malfunctions has become critical for maintaining the reliability and efficiency of PV systems. In this study, we analysed thermal defects in 3.3 million PV modules located in the UK. Our findings show that 36.5% of all PV modules had thermal defects, with 900,000 displaying single or multiple hotspots and ~250,000 exhibiting heated substrings. We also observed an average temperature increase of 21.7 °C in defective PV modules. Additionally, two PV assets with 19.25 and 8.59% thermal defects were examined for PV degradation, and results revealed a higher degradation rate when more defects are present. These results demonstrate the importance of implementing cost-effective inspection procedures and data analytics platforms to extend the lifetime and improve the performance of PV systems.