Degradation Analysis of Utility-Scale PV Plants in Different Climate Zones

Accurate performance modeling of utility-scale PV plants is crucial for reducing the risk of investment, as well as improving operations and maintenance. In spite of much research, the precise rate at which PV plants degrade is still not well known. This article uses a well-known methodology for calculating degradation rates to assess the impact of climate on long-term performance. The RdTools analytic approach is used to perform a comparative case study of two utility-scale PV plants with the same setup and almost identical technology yet located in distinct climates. A significant difference is observed between the degradation rates of each park. The median of the nominal system degradation rate measured at the dc-side of the inverters in the hotter and more humid climate is -1.4%/yr, with 95% of the inverters between -1.5%/yr and -1.3%/yr, whereas in the temperate climate the median rate is -0.94%/yr, with 95% of the inverters between -1.0%/yr and -0.9%/yr. These results suggest that climate zones must be included when evaluating the long-term performance of PV plants.