PV Temperature Derating Calculator
Calculate power loss due to elevated panel operating temperature.
Temperature Derating Formula
Tcell = Tambient + (NOCT - 20) x (G / 800)
Power Loss = Pmax x Coeff x (Tcell - 25)
Derated Power = Pmax + Power Loss
STC reference temperature is 25C. Temperature coefficients are negative, so power decreases as temperature increases.
Temperature Coefficients by Technology
| Panel Type | Pmax Coeff | Typical NOCT |
|---|---|---|
| N-Type/HJT | -0.26 to -0.30% | 42-44C |
| Mono PERC | -0.32 to -0.38% | 43-45C |
| Polycrystalline | -0.38 to -0.45% | 45-47C |
| Thin Film CdTe | -0.18 to -0.25% | 45-48C |