This question is part of the Super Big Solar Panel FAQ from Solar Mango, where expert answers to over 100 important questions on solar panels are provided.


This is an interesting question, for two reasons:

  1. A solar panel’s output, assuming you have purchased a good quality solar panel, will still be hovering around 80% of its first year generation even after 25 long years.
  2. Now, you might ask what happens after 25 years? Does the solar panel suddenly break down and has to be thrown out? Hardly. The solar panel will continue to generate electricity even after 25 years. Its efficiency and output will continue to decrease gradually but will continue to be in the high seventies until 30 years. We do not have too many recorded examples of solar panel output beyond 30 years, but it stands to reason that even at 40 years, one can expect a a solar panel to be generating a reasonable amount of electricity at generation of over 60%. Now, that’s really something, isn’t it?


Super Big Solar Panel FAQGet to know answers to over 100 important questions on solar panels from here.


Solar panel manufacturers typically give performance guarantees many of which explicitly promise a 80% panel performance after 25 years. This is usually under the Standard Warranty. Then there are Linear Warranties under which the output of the solar panel decreases by 1% for the first year and beyond that it decreases by about 0.7%. Now, if you take up this Linear Guarantee, your solar panel’s output would have decreased by only about 18% after 25 years. Put differently, the solar panel will be generating about 82% of its original generation even at the end of 25 years.

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