Specific yield allows meaningful comparison of PV system performance across different sites, sizes, and years. A higher specific yield indicates a more productive location or better-performing system. In the UK, typical specific yields for south-facing roof-mount systems at optimal tilt range from approximately 800 to 1,050 kWh/kWp/year depending on location and irradiance.
Specific yield estimates are produced during solar PV system design as part of energy yield modelling. Pre-construction predictions are compared against post-commissioning performance to identify underperformance attributable to shading, soiling, inverter faults, or structural issues. Thermal imaging drone surveys can identify specific panels contributing to below-expected yield.