“What is solar panel performance?” Solar panel performance is how much electricity your system produces in the real world compared to what it should produce under the sun and weather you actually had.​ “How do I measure solar panel performance correctly?” Use your monitoring data plus PR, because PR compares actual energy output to the theoretical energy possible under those conditions.​ “What is a good Performance Ratio for a PV plant?” PR varies by system, but sources commonly cite ~80% as a h