Photovoltaic (PV) modules deployed outdoors can degrade due to exposure to the various elements. This includes exposure to UV light, a range of fluctuating temperatures and humidity and exposure to a range of operating currents and voltages. Different weather conditions have an important influence on degradation rate. Evidence indicates that both degradation and failure mechanisms are location dependent. This paper presents a research investigating the prevalence of various forms of physical degradation experienced by photovoltaic panels which have been in operation in Kenya under various climatic conditions. To study degradation of PV systems, identification and analysis of modules that had been deployed in various locations in Kenya, and which had been in operation for at least the last 2 years was carried out. Imaging instruments were used to study visible signs of weathering and other physical defects. The results indicated that despite the fact that panels are designed to operate in outdoor environment, numerous cases do exist whereby the panels degrade physically, in various ways, and consequently exhibit total failure, diminished performance or just physical manifestation of wear. Apart from manufacturer defects, user ignorance on installation and usage was also proved to contribute to the diminished life span of some panels.
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