The University of Granada, a Spain-based academic institution, has developed a method to estimate severely degraded PV modules using only string open-circuit voltage (Voc). The method was tested on three agro-industrial rooftop systems located in high-temperature, high-humidity areas where rooftop maintenance is hazardous. According to the University of Granada, the plants showed energy losses of 67.58%, 47.22%, and 32.06% over ten years compared to their average output in the first four years. The researchers applied four regression models to correlate Voc with the number of degraded modules, achieving adjusted R² values between 0.64 and 0.82. The method enables safe diagnostics without rooftop access and supports repowering decisions in degraded PV systems. The findings were published in Solar Energy and offer a practical approach for identifying PID-related degradation in solar pumping installations.