Measurement
The performance ratio (PR) is a metric used to evaluate the efficiency and quality of a solar PV system by comparing its actual energy output to the theoretical maximum output under ideal conditions. Expressed as a percentage, PR accounts for system losses such as inverter inefficiency, temperature effects, wiring losses, and shading. For instance, a performance ratio of 80% means the system is delivering 80% of the energy that it could under perfect conditions. A high PR (closer to 100%) indicates a well-performing solar installation, while a lower PR suggests more significant losses or issues. PR is useful for identifying performance issues and benchmarking different solar plants regardless of their size or location.