How Long Do Solar Panels Last?

Solar panel lifespan and degradation

Updated:
Reviewed by
George Duval

Solar panels are a long-term investment. Knowing how long they last is imperative to making an informed decision. Luckily, most solar panels last quite a while, with an average lifespan of well over 20 years. Of course, there are quite a few factors that affect the life of your solar panel. The local climate, the way the panels are installed, and whether or not you maintain them, all factor into the lifespan of your solar array. The brand and type of solar panel have an effect as well. If properly maintained, your solar panels could remain functional for up to 40 years.

This solar cell is over 15 years old.
Source: Wikimedia/Department of Energy

Do Solar Panels Go Bad?

Over time, you can expect to see some decrease in functionality. This gradual decrease is called the degradation rate. The average degradation rate is about 0.5% per year. After 10 to 15 years, this might increase slightly per year. Around the 15 to 20-year mark, you might see a yearly degradation rate of around 1%.

Solar panels do fall apart if not maintained properly, especially under certain climatic conditions. If they are maintained, then they won’t “go bad” per se, but they will no longer perform up to your needs. You can choose to either add more solar panels to make up for lost performance or replace your solar array altogether.

Replacing Solar Panels

Solar energy researchers are constantly at work. Solar panel efficiency is improving with every year that goes by. It’s not a bad idea to take advantage of the newer technology and replace your panels, even if your old ones still work fine. You’ll be getting panels that will last even longer and are more efficient than your old ones. Some solar installers may offer you a discount on a new set of panels if you’re already a customer. Many solar panels can be refurbished, so your old solar panels might get a new life somewhere else.

Warranties

Solar companies offer warranties with their solar panels. The standard is a 25-year warranty, though this can differ depending on the brand. The warranty covers defects, malfunctions, and regular servicing. The warranty will also guarantee a certain output within said timeframe, usually guaranteeing at least 80% of the rated efficiency at the end of the 25 year period. This means that a 300-watt solar panel should still be producing at least 240 watts after 25 years. When averaged out on a yearly basis, this is still above the average degradation rate of 0.5% per year. Just because the warranty ends doesn’t mean that it’s the the end for your solar panels. High-quality solar panels that are well maintained will last a decade or two after the warranty expires.

Many solar panels that were installed decades ago are still functional.
Source: Wikimedia

What Causes Solar Panels to Go Bad?

Don’t get the wrong idea, solar panels are resilient. They spend all day getting beaten down by the sun, and still function well enough to power your home after two decades. Still, it’s good to know what makes your solar panels degrade.

Climate and Weather

Your local climate has a major effect on the life of your solar panels. Large temperature fluctuations can cause the metal framework, glass, or solar cells to crack as they expand and contract. This allows moisture and dirt to get inside the panel, causing corrosion. Hot desert climates will see a higher degradation rate due to higher UV exposure. The high temperatures can also cause delamination, where the solar cells detach from the laminate. Cold temperatures are less of a worry, but you should still be wary of extremely frigid temperatures. Ice and snow can bend and crack solar panels, and if water gets into the crevices and freezes, then the panel may get damaged.

Again, solar panels are quite resilient, and solar manufacturers have thought much of this through. Solar panels are built to be resistant to high wind and heavy rains, but strong storms can still blow heavy objects into your panels. Some panels are rated to withstand hailstorms, but they can still damage your system. Lighting is a major threat to your solar array. A direct hit on your home will melt the panels and blow your inverter, though most inverters can at least stand an indirect hit with built-in surge protectors. Extreme events like strong tornadoes and hurricanes will destroy your system, but in that case, the solar panels are the least of your worries.

Snow and ice accumulating on your solar panels can damage your system.
Source: Wikimedia/1010 Climate Action

Potential Induced Degradation (PID)

Potential induced degradation, or PID, is the degrading of silicon PV panels by stray currents. PID is exacerbated by high temperatures, high humidity, and high voltages. Environmental factors like being near the ocean can also accelerate PID. Though it’s is undetectable by just looking at the module, solar technicians have an array of instruments that can be used for diagnosis. PID can cause power losses upwards of 30%. The solar panels that are grounded are the most exposed to PID.

Lack of Maintenance

Solar panels are relatively low maintenance. They have no moving parts, and they generally take care of themselves. But that doesn’t mean that they should be neglected! Over time, they will accumulate dirt and dust. Birds and wasps might find the crevices under your panels an appealing place to build a nest. If you don’t perform regular maintenance, you can expect the efficiency to drop, as well as see faster corrosion around the frame.

The wires and inverters need to be serviced as well. Corroded groundings and connectors will affect the ability of the panels to transmit electricity. Corrosion can also spread to the frame of the panel. Bad wiring might also cause short-circuiting, which can damage your electrical system.

Damage to the Panel

Panels are tough, but you should still be careful while handling them. Dropping the panels can break the glass and solar cells, causing a drop in efficiency and decreasing the lifespan. The fractures can then expand due to extreme temperatures. The same goes for standing or walking on panels. The stress can damage the interior and shorten the lifespan of your solar panels. Environmental hazards, such as an especially strong hailstorm or a heavy object blowing in the wind, can also damage your solar panels.

How Do I Make My Solar Panels Last Longer?

There’s no way around it; your solar panels are going to lose their functionality over time. However, there are some things you can do to make sure that your panels last longer. There are also ways to predict how much your panels will degrade over time, allowing you to plan accordingly. Your solar array is a long-term investment, and like any investment, it’s wise to make sure that it pays off.

Maintenance

Maintaining your solar panels is key to ensuring a long lifespan. Panels accumulate dirt, dust, and bird droppings over the years. In addition to blocking sunlight and lowering efficiency, dirt can also make its way inside the panel, scratching and corroding the sensitive electronics. Periodically cleaning the solar panels helps ensure functionality.

Most warranties come with a servicing plan. Make sure to get your panels inspected and serviced every three to five years. The service technicians don’t only work on your panels, they also check your wiring, inverters, major connection points, and battery bank if you have one. Proper maintenance is key to making sure your panels provide energy for decades to come.

Cleaning the solar panels at the Googleplex in California.
Source: Wikimedia/Avinash Kaushik

Panel Type & Installation

Different panels have different lifespans. Monocrystalline panels, being of the highest quality, have the longest lifespan. Monocrystalline solar panels will last well over 25 years if well maintained. Polycrystalline panels aren’t too far behind, lasting over 20 years, though cheaper brands may not last as long. Thin-film solar panels have the shortest lifespan, usually average around 15 years. Being that they’re so thin, Thin-film panels are also more susceptible to damage. This can decrease the life of the panel. If you want a solar panel array with a longer lifespan, go for a monocrystalline array.

The quality of installation has a big effect on your lifespan. Solar technicians that aren’t well trained might drop or damage the panels during transportation or installation. They might even walk or stand on top of the modules. This creates microfractures that grow over time, affecting performance and lowering the lifespan. Some hallmarks of shoddy installation jobs include exposed wiring, panels hanging off the side of the roof, and an unapproved inverter, all of which will increase the stress on your panels and cause them to degrade faster. Make sure you find an installer who is trusted and well known in the solar industry. Shy away from those who are ridden with bad reviews, or are the “new kid on the block.” Digging around for good solar technicians might take some time, but it can save you tens of thousands of dollars.

Inverters

The solar panels aren’t the only part of your solar array. The inverter converts the DC power from the solar panels into usable AC power for your home. Inverters also communicate with your solar panels and power grid to regulate any power that enters or leaves the grid. Higher grade inverters give you real-time information on the productivity of your panels via an app on your phone. In the case of a power outage or short-circuit, the inverter will also act as a breaker, shutting off the flow of electricity to protect the solar panels, your appliances, and anybody who may be working on your electrical system.

Inverters have an important job. You want to keep them in good condition. High-quality inverters can last long as your solar array, while others might only have a lifespan of a few years. Make sure to keep up with regular maintenance of your inverter. You don’t want to risk a malfunction that damages your solar panels. Using the wrong inverter for the capacity and voltage of your solar array can increase PID and cause panels to degrade quickly.

Solar Panel Recycling

Though solar energy is clean, solar panels are not, especially when it’s time to dispose of them. Solar panels contain toxic chemicals, like cadmium and lead, which will end up in the environment if they aren’t properly disposed of. Solar panels also contain precious metals, some of which are quite rare and need to be preserved, like gallium and indium. As solar panels are still a new technology, we are just now learning about how to properly dispose of them.

As it turns out, around 95% of the material in a solar panel is recyclable. From the aluminium frame to the glass cover, much of it can be reused. Silicon solar panels can be recycled like most other objects. The glass, plastic, and metal can all be separated at a recycling plant. Non-silicate panels, on the other hand, require specialized processes like chemical baths to recover the semiconductor materials. Any hazardous substances that can’t be recycled must be properly disposed of.

FAQs

What’s the average lifespan of a solar panel?

Most solar panels come with warranties that ensure 15 to 25 years of functionality. They usually guarantee at least 80% efficiency at the end of the warranty. But the life of the solar panel isn’t over when the warranty ends. A well-maintained and high-quality solar panel system can last for about 40 years.

What causes solar panels to degrade?

Solar panels naturally become less efficient over time, though at a very slow rate. You’re likely to see a less than 1% drop in functionality on a yearly basis, though things like extreme weather, lack of maintenance, and physical damage to the solar panel can lower the lifespan of your system.

How can you improve the lifespan of a solar panel?

It’s best to start with good installation. High-quality panels last longer, and trusted solar technicians will make sure that your equipment is secure, ensuring a long lifespan for your panels. You should also keep your panels clean and free of debris, and service the solar panels and the associated electrical equipment every 3 to 5 years.

What kind of solar panels last the longest?

Monocrystalline solar panels have the longest lifespans. A well-maintained system can last 40 years, long after the warranty expires. A good set of polycrystalline panels can also last quite some time if they are well maintained. Thin-film panels tend to have lower lifespans, partially because they are structurally less equipped to handle extreme conditions.

George Duval

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Author Bio

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George Duval

George Duval is a writer and expert in sustainability and environmental studies. After graduating with a B.A. in Sustainability from Florida International University, George began dedicating his life to researching new ways to make the world a greener place. His expertise ranges from organic gardening, to renewable energy, to eating plant-based diets. He is currently writing and editing for a number of publications, most of which focus on the environment.

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