On average, well-built solar panels last between 20 and 30 years before their power output begins to decline significantly. Several factors affect the longevity of solar panels, including the type of materials used, the quality of manufacturing and installation of the solar panel, and the climate where they operate.
Older models of solar panels tend to degrade more quickly than newer models and are generally less reliable than those installed after the year 2000. Residential solar panels will often come with a 25-year warranty, after which they are not guaranteed to produce the same amount of electricity as they did when first installed.
Solar Panel Degradation
As solar panels age, they begin to degrade; although they may no longer be considered functional, they still produce electricity to some degree. Degradation is a measure of the decrease in output of a solar panel over time. This is not the same as failure, which happens when the solar panel suddenly stops producing electricity. Solar panels may degrade to the point where they fail, or they may just continue degrading, gradually decreasing their electrical output until it is no longer economically feasible to operate them.
Research by the National Renewable Energy Laboratory has shown that the median yearly degradation rate of solar panels is around 0.5%. If a solar panel has been operational for 10 years, its electricity output will have dropped to around 95% of its original production level. The process of degradation in the hydrogenated amorphous silicon used in many solar panels is known as the Staebler Wronski effect. As the material is exposed to light, its ability to conduct electricity decreases.
Degradation can also occur because of higher temperatures. Solar panels mounted directly on rooftops typically reach higher temperatures than those installed on the ground. Systems in hotter climates also tend to have lower efficiencies than those in more moderate climates. Another cause of degradation includes discoloration of the EVA, or plastic encapsulate, which can interfere with the amount of sunlight the solar cells receive. Delamination can occur when the EVA breaks apart from the glass covering of the solar panel. This can cause degradation because it allows air, dust, moisture, and other harmful contaminants to enter the panel. Other physical failures and damages to the solar panel can also cause the electrical output to decrease.
How Long Do Solar Batteries Last?
Solar batteries can last anywhere from 5 to 15 years on average. Lithium-ion, lead-acid, and nickel batteries are some of the most commonly used types of batteries in solar energy systems.
Just like solar panels, solar batteries degrade over time. Their ability to store energy decreases because of factors like how much load the battery is connected to, how efficiently the batteries charge and discharge, and temperature. By operating solar batteries at optimal temperatures and using a battery management system to make sure it doesn’t overcharge or fully discharge, the lifespan of solar batteries can be extended.
What Happens to Solar Panels After Their Useful Life?
Damaged solar photovoltaic panel.
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Once a solar panel has come to the end of its useful life, it must be decommissioned. In panels made from silicon, glass, aluminum, and copper may be recycled.
While it is possible to reuse or recycle parts of a solar panel, only the European Union has regulations requiring the recycling of these materials. Japan tests solar panels for hazardous waste before disposal and may suggest specific ways to recycle or dispose of the materials.
In the United States, solar panels are handled as hazardous waste and fall under the regulations of the Resource Conservation and Recovery Act. States like California are in the process of developing regulations for recycling parts of solar panels that are at the end of their useful life.
However, not all parts of solar panels can be recycled, and these components are disposed of in a landfill. Reusing or recycling solar panel materials presents a huge opportunity for countries to recover money and resources.
Frequently Asked Questions
Why do solar panels fail?
Besides normal degradation, solar panels can fail because of repeated exposure to high temperatures, damp heat, cracking and breaking (often as a result of weather), internal corrosion, delamination, or structural defects.
How long does it take for solar panels to pay for themselves?
It takes the average home about six to 10 years to recoup the cost of solar installation through energy savings.
Can solar panels be recycled?
The Environmental Protection Agency says everything from the aluminum frame to the copper wire in solar panels can be recycled, but the polymer layers that seal the panel make it difficult to disassemble. It's not an easy or waste-free process by any means, but the recycling industry is discovering new ways to recover solar panel materials all the time.
How can you extend the life of your solar panels?
There are a few things you can do to extend the life of your solar panels, including cleaning them regularly, sheltering them during extreme weather events to prevent scratching, and possibly even installing them on the ground, which is generally cooler rather than on the roof.