PhD defence by Rodrigo del Prado Santamaría

Abstract

Solar power plants are built to operate for more than 25 years, but in reality, solar modules are exposed to conditions that gradually reduce how much energy they can produce. Degraded modules in PV plants can generate less electricity which results in a loss of profit but also poses safety risks for the installation.

This PhD thesis investigates how imaging technologies can be used to diagnose problems in solar panels while they operate in the field. Electroluminescence images can reveal hidden cracks and other faulty electrical components in the modules. However, using it at large solar farms is challenging because it is slow and costly.

This thesis reviews recent progress in performing electroluminescence imaging in daylight using drones and identifies its main challenges. Furthermore, we introduced two innovative diagnostic techniques that expand what daylight electroluminescence can detect. The first improves the identification of Potential Induced Degradation (PID), a common fault that lowers the performance of solar panels.

The second technique reveals cracks in the glass surface of solar panels, which are often hard to detect but pose a severe safety risk. The research shows that these cracks can be consistently identified using drone-based daylight
electroluminescence.

The final part evaluates whether daylight EL images can be used to estimate how much power a damaged panel loses.

Overall, this thesis contributes new tools and knowledge that make solar plant inspections faster, more reliable, and easier to perform at large scale. These innovations can help solar plants operate longer and more efficiently.

Supervisor

• Sergiu Viorel Spataru

Evaluation Board

• Chairman: Ole Bjarlin
• Marc Köntges, Institut für Solarenergieforshung, Germany
• Bengt Jäckel, Fraunhofer Center for Silicon Photovoiltaics, Germany

Master of Ceremony

• Sune Thorsteinsson