Field Degradation and Failures of Aged Crystalline Silicon PV Modules in Mexico

This paper presents the visual defects and performance degradation rates of crystalline silicon photovoltaic (PV) modules exposed in two different climatic conditions (Hot-Humid and Temperate) of Mexico between 10 and 25 years. An extensive evaluation of these modules was performed using different visual, optical and electrical tools including 86-point visual inspection, electroluminescence imaging, infrared imaging, module-level visible-near IR reflectance and current-voltage measurements. The dominant visual defects were determined to be encapsulant discoloration, encapsulant delamination and cell metallization corrosion. The average annual power degradation rate was determined to be between 1.4% and 1.5% for all the modules surveyed.