Solar panels are meant to last more than 25 years.
That’s in terms of the standard performance guarantee from Tier 1 (high-quality) manufacturers. This does not mean that the solar cells will stop generating electricity after 25 years.
Only, the amount of electricity a solar panel can produce will decline every year at the average degradation rate of 0.5 to 0.6 percent for silicon panels and 1% for thin-film products.
Surprisingly, even at a 0.5% degradation rate solar panels should still be able to generate 92% electricity of their minimal rated power output after 20 years.
Now, can performance guarantee alone determine how long do solar panels last?
This is where the truth gets tricky.
Is Performance Guarantee the same as Product Warranty?
No. Most manufacturer claim of a 25-year performance guarantee was based on one study done by the National Renewable Energy Laboratory (NREL).
In 2013, the NREL performed a meta-analysis of studies that evaluated the degradation rates of different photovoltaic solar panels based on the type of technology used on the solar cells.
|Solar cell type||Output loss in percent per year for solar panels manufactured after the year 2000|
|Monocrystalline silicon (mono-Si)||0.36|
|Polycrystalline silicon (poly-Si)||0.64|
|Cadmium telluride (CdTe)||0.4|
|Amorphous silicon (a-Si)||0.87|
|Copper indium gallium selenide (CIGS)||0.96|
Basically, solar panels built after the year 2000 could work well for many decades as long as these panels don’t often suffer physical damage caused by extreme weather conditions and other external factors such as improper installation.
The good news is that with the improved technology in manufacturing solar cells, the degradation rate is decreasing.
In fact, Sunpower boasts of the lowest solar panel degradation rate today at only 0.2 percent per year for their recently launched 400-watt residential panels.
But for any other panel manufacturer, performance guarantee is not the same as product warranty.
How long should solar panels last depends more on the product warranty.
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What is Product Warranty?
A solar panel’s product warranty covers your panel against faulty performance or premature wear and tear due to manufacturing defects.
Today, the limited product warranty for most solar panels is about 10 years.
Product warranty guarantees panel-level assurance and this is where you should read the fine print.
Make sure that your product warranty covers panel hardware construction and functionality that extends to other components such as the inverter and the mounting hardware (if both are from the same manufacturer).
Case in point: one faulty panel could be due to a manufacturer defect and you should not pay for the replacement so it’s critical to review the product warranty before signing anything.
How often do you have to Replace Solar Panels?
In the event that something goes wrong, replacement of parts and other forms of repair should be covered by the product warranty.
Otherwise, solar panels require little to no maintenance over their typical lifespan of 25 years.
Cleaning requires wiping the surface with a soft cloth or directly hosing it down to get rid of dirt, dust, leaves or any form of debris that collects on top. Even a pint of droppings can reduce energy production by 15 to 25%.
For instance, Google found that the number one way to maximize the energy their solar panels produced was to keep the solar panels clean, and no. Leaving the rain to clean the panels don’t count.
Read More: How Much Energy Does a Solar Panel Produce?
How long did Solar panels last in the past?
Amazing fact: Britain’s first ever solar panel manufactured in 1950 was uncovered after 60 years and it still works.
Similarly, Kyocera reports that many of their solar power installations continue to generate electricity even after 30 years.
Perhaps, many more case studies will emerge in the next 20 to 30 years since two-thirds of the world’s solar power systems have been in the field for less than five years.
However, we can bet that solar panels installed today or in the coming years will remain in power for the next 30 years.
That’s what we can expect with the limitless power of the sun.
Or the advancement of technology.
It transforms tomorrow.
Keep Reading: How Efficient are Solar Panels Today?