Solar Panel Degradation Rate
The degradation rate describes how a solar panel’s performance declines over time. Most high-quality panels lose only about 0.5% of output per year. For the solar panels manufactured today, it is usually with less than 20% power loss than claimed rated power after using 25 years or 30 years, and they are given 25 or 30 years warranty for the power output.
Example chart showing the rate of solar panel degration over a 30 year period – Trina Solar Vertex S+ Series
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Definition: Annual decrease in power output from the panel.
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Standard Rate: 0.3%–0.8% per year for most Tier 1 panels.
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25-Year Expectation: Typically, 80%–90% of original output remains.
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Material Impact: Better materials = slower degradation.
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Warranty Relevance: Often tied to performance warranties.
