Performance Ratio (PR)

Performance ratio measures how much of a plant’s theoretically possible generation is actually delivered, after temperature, soiling, wiring, and inverter losses. Well-run Indian rooftops achieve 75–80%.

PR is the industry’s plant-health metric: it strips out weather, so a falling PR means something is wrong (soiling, string fault, inverter derating) rather than a cloudy month. Commercial O&M contracts often guarantee a minimum PR.

Part of the HUM Solar Glossary — 75+ plain-language definitions for India’s solar ecosystem, maintained as a neutral reference. Browse all terms →