Long-term performance and reliability of crystalline silicon photovoltaic modules

This study evaluates the long-term effects of outdoor exposure and high voltage operation on the performance and reliability of flat-plate crystalline silicon photovoltaic modules. The modules included Mobil Ra-180 EFG ribbon silicon modules, Photowatt MU-7061 and ARCO 16-2000 single-crystal silicon modules with round cells. In all three types of photovoltaic modules (Mobil, Photowatt and ARCO), no significant power loss occurred over more than ten years of outdoor operation in the warm, humid and ocean-salt environments of coastal Florida, USA. However, the wet insulation resistance values of a majority of the modules in all three types were lower than the values recommended in IEEE Standard 1262. The encapsulant discoloration, observed in all three types of modules, generally did not appear to have any effect on the modules' power generation.