Wind and Temperature Effects on Long-Term Degradation Within a Utility-Scale PV Plant in a Semi-Arid Region

An inverter-level analysis of a large photovoltaic (PV) plant is evaluated over four years with regard to the long-term degradation caused by wind and temperature effects. The large utility-scale PV plant is located in a semi-arid region in South Africa. The degradation rate is determined using the performance ratio as a comparison metric between the different inverters. The degradation from the first year of operation up to the fourth year shows that different parts of the PV plant have varying degradation rates. The spatial degradation analysis indicates that inverter blocks operating at higher ambient temperatures and lower wind frequency measurements show higher rates of degradation compared to inverter groups operating at lower temperatures and higher wind frequency. The lowest degradation rates within the plant were positively correlated with the direction and frequency of the wind from the North and North-East, which subsequently has a cooling effect on the PV modules. The gap between the best- and worst-performing inverters grows yearly, supporting the claim that certain inverters’ PV modules are degrading at different rates within the large PV plant. The layout of PV plants can be designed to take advantage of the wind as a cooling tool, further improving the longevity and sustainability of large PV plants.