DuPont Photovoltaic Solutions has established an extensive fielded module evaluation programme to develop the knowledge base which will enable a better understanding of how modules and materials age and degrade in the real world environment. As part of this work, solar field visits have been conducted on a global scale with over 60 fields inspected in the United States, Canada, India, China, Japan, Europe, Turkey, and the Middle East. These fields have ranged from newly commissioned to 30 years old.
During field inspections, a Fourier transform infrared spectrometer (FTIR) was used to identify the chemical composition of the outer layer on the back of the module. This aids in determination of the type of backsheet used by module manufacturers. The inspections focus on checking for any visual changes in the module such as yellowing, issues with the backsheet protection, snail trails, etc.