Definition
Module degradation rate is the annual percentage decline in PV module power output over its operating lifetime. Typical 0.4–0.7%/year for modern modules; cumulative loss 88–90% at year 25.
Degradation Rates by Technology (2024)
| Technology | Annual Rate | Year 25 |
|---|---|---|
| Standard PERC | 0.55–0.70% | 85% |
| Premium PERC | 0.45–0.55% | 88% |
| TOPCon | 0.40–0.50% | 89% |
| HJT | 0.25–0.35% | 92% |
| Premium HJT | 0.20–0.25% | 95% |
Key Takeaways
- Module degradation = annual power decline.
- 0.4–0.7%/yr modern modules; HJT lowest.
- Year-25 cumulative: 85–95% of original.
- Required input for LCOE and EYA calculations.
- Premium HJT carries lower-degradation warranties.
Frequently Asked Questions
4 commonly searched questions about Degradation Rate.
What is degradation rate?
Annual fractional power decline of PV modules. Typical 0.4–0.7%/year. Result of UV exposure, thermal cycling, microcracks, encapsulant aging, cell degradation.
What's the warranty?
Linear power warranty: year 1 ≥ 98%, year 25 ≥ 80–85%. Premium TOPCon/HJT: year 25 ≥ 87%.
How is degradation modeled?
PVsyst applies cumulative annual rate. Energy_year_N = Energy_year_1 × (1 − rate)^(N-1). 0.5%/yr gives 89% at year 25.
Newer modules degrade slower?
Yes. PERC: 0.55–0.70%/yr. TOPCon: 0.40–0.50%/yr. HJT: 0.25–0.35%/yr.
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