How Dust Impacts Photovoltaics (PV) Performance Ratio Sponsored by Kipp & ZonenApr 29 2021 Photovoltaics (PV) is the fastest-growing renewable energy source of the 21st century: the increase in installed PV capacity worldwide is near-exponential, with cumulative installed capacity exceeding 623 GW at the end of 2019. 1 Ongoing research and development efforts continue to realize reductions in the cost of photovoltaic cells, alongside incremental improvements in efficiency. As a result, PV installations offer an increasingly attractive means of generating renewable energy. For PV investors and operators alike, being able to accurately gauge the performance of a PV plant is critical. The performance ratio (PR) of a photovoltaic installation is a globally accepted parameter that enables direct comparison of grid-connected PV systems.