{"id":97113,"date":"2026-01-08T04:30:14","date_gmt":"2026-01-07T19:00:14","guid":{"rendered":"https:\/\/www.solarquotes.com.au\/blog\/?p=97113"},"modified":"2026-01-08T04:30:44","modified_gmt":"2026-01-07T19:00:44","slug":"panel-performance-degradation-mb3353","status":"publish","type":"post","link":"https:\/\/www.solarquotes.com.au\/blog\/panel-performance-degradation-mb3353\/","title":{"rendered":"Solar Panel Degradation Testing: A Sting In The Long Tail"},"content":{"rendered":"

\"Solar<\/p>\n

Current testing standards have been called into question after new research indicating 20% of solar panels tested in a study had 1.5 times worse than average degradation rate.<\/p>\n

Why Do Solar Panels Degrade?<\/h2>\n

All solar panels<\/a> degrade over time. This is largely due to natural wear from environmental factors such as ultraviolet rays, heat, humidity, salt, temperature changes (causing expansion\/contraction, microcracks), wind and inherent chemical changes.<\/p>\n

This leads to gradual (and should be small) annual efficiency losses over a panel’s lifespan. A permitted maximum annual loss is noted in the panel’s performance warranty (more on warranties below), which are usually 25 – 30 years.<\/p>\n

Then there’s those modules that degrade more and faster than they should through manufacturing flaws and poor quality control.\u00a0Or fail totally, prematurely.<\/p>\n

What Did The Research Discover About Solar Panel Performance?<\/h2>\n

Researchers from UNSW’s School of Photovoltaic and Renewable Energy Engineering analysed information collated previously; obtained from nearly 11,000 different photovoltaic samples globally. They observed a so-called \u2018long tail\u2019 in the probability distribution of performance data; indicating that up to 20% of all samples perform 1.5 times worse than the average.<\/p>\n

\u201cFor the entire dataset, we observed that system performance typically declines by around 0.9%1<\/a><\/sup> per year.” said Yang Tang<\/a>, one of the authors of the paper on the subject. “However, our findings show extreme degradation rates in some of the systems. At least one in five systems degrade at least 1.5 times faster than this typical rate, and roughly one in 12 degrade twice as fast.”<\/p><\/blockquote>\n

\"Solar<\/p>\n

This has big implications for the useful service life of such panels; which could be closer to 11 years \u2014 long before the 25 – 30 years of a warranty ends.<\/p>\n

\u201cOr, in other words, they could lose about 45% of their output by the 25-year mark,” Tang said.<\/p><\/blockquote>\n

3 Major Reasons For Panel Failure<\/h2>\n

There were three major reasons for failures in the long tail group:<\/p>\n