Degradation Pathway Models for Photovoltaics Module Lifetime Performance

Abstract—Previously published accelerated testing data from Underwriter Labs, featuring measurements taken on 18 identical photovoltaic (PV) modules exposed to two stress conditions, were used to develop an analytical methodology. The results provide insight into active degradation mechanisms and pathways present in PV modules under accelerated testing conditions as indicated by statistically significant relationships between variables. Observed experimental results coincide with a do-main knowledge based theoretical degradation pathway model informed by literature, and provide a basis for beginning to investigate the degradation modes and pathways truly present in modules and their effects on module performance over lifetime. Index Terms—photovoltaics, statistical modeling, lifetime and degradation science, structural equation modeling