Commercial and Utility-Scale PV Systems are Degrading at -0.75%/yr After Accounting for Availability Issues

The long-term gradual performance loss of PV technologies is of great financial importance. Many studies have focused on this topic, yet, confusion often surrounds the subject because of module versus system and recoverable versus nonrecoverable losses. In the PV Fleet initiative, high frequency data from a large number of commercial and utility-scale systems is collected. To date, more than 1,700 sites, with ca. 19,000 individual inverter data streams provide a high-level perspective of the long-term performance of PV systems. The total monitored capacity has surpassed 7.2 gigawatts (GW) or roughly 6% of the entire commercial market in the US.