Degradation Analysis Calculator

Estimate annual PV system degradation rate using linear regression on monthly performance ratio data.

Input Parameters

Results

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Annual Degradation Rate
%/yr
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Total Degradation
%
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Projected Year 25 PR
%
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Annual Energy Lost
kWh
Note: Industry median degradation is 0.5%/yr for crystalline silicon, 0.8%/yr for thin-film. Rates >1%/yr warrant investigation for PID, soiling, or equipment issues.

Reference

Annual Degradation = (PR_year1 − PR_current) / Age Total Degradation = PR_year1 − PR_current Year 25 PR = PR_year1 − Deg_rate × 25 Lost Energy = Capacity × PSH × 365 × (Deg_rate/100) Linear regression: PR = PR0 − rate × t