Solar Panel Lifespan: How Long Do Solar Panels Last and What Affects Their Durability?

Throughout the years, solar panel manufacturers have become innovative at improving solar panel efficiency and solar panel longevity. For instance, recent advancements in solar technology, such as the development of perovskite-silicon tandem solar cells, have pushed efficiency rates beyond 30 percent, significantly improving energy output. Additionally, the adoption of bifacial solar panels, which can capture sunlight from both sides, has further enhanced performance, particularly in diverse environmental conditions.

Modern solar panels need to be able to resist extreme weather such as harsh wind and heavy rainfall. In most cases, they are rigorously tested and even certified to withstand hailstones up to two inches in diameter (or larger) falling at 50 miles per hour. This example only confirms such a great solar panel durability.

The National Renewable Energy Laboratory (NREL) campus in Golden, Colorado was put to an unexpected test when a severe hailstorm hit the area in May 2017. The storm left a trail of destruction in its path, leaving tennis ball-sized dents in the roofs and damaging hundreds of cars [1].

After the storm, the campus employees set out to assess the damage of the laboratory’s solar array. Of the more than 3,000 panels on the roof of this net-zero energy building, only one panel sustained some damage. This is a great example of the ability of solar panels to withstand strong physical impacts [2].

Such exceptional resilience, bolstered by innovations like anti-reflective coatings and UV-resistant materials, makes emerging solar technology promising as a reliable power supply for our homes. Solar panels will offset your energy use for a very long time without requiring much maintenance. However, being exposed to the elements day in and day out will decrease their efficiency in the long run.

Here’s a breakdown of important things you need to know about solar panel lifespan and what causes their degradation.

Understanding solar panel lifespan: How long do solar panels last in real life?

Compared with other appliances, solar panels have a remarkably long life expectancy. Traditionally, most panels have come with warranties guaranteeing 80 percent system performance or higher for up to 25 years. However, recent developments in solar technology and materials have led to even more robust warranty terms, reflecting the industry’s confidence in the longevity of modern solar panels.

For example, some of the latest solar panels now come with warranties that extend up to 30 years. They guarantee performance of at least 85 percent during three decades! This shift underscores the growing efficiency of solar panels driven by continuous advancements in materials and manufacturing processes.

This doesn’t mean your solar panels need to be replaced after this period; even after the warranty period, the majority of panels continue to produce electricity but with less efficiency. The lifespan of solar panels can indeed extend well beyond the manufacturer’s warranty. As time passes (and solar panels age), we get real-life proof of a much longer average lifespan due to solar panels’ outstanding durability.

Examples of longevity in solar panels

One of the oldest solar panel installations can be found in Germany on the building of the University of Oldenburg. To the surprise of researchers, their “experimental” solar array installed on the roof in 1976 is still producing energy with a minimum variation of the original output. And this is the older version of photovoltaic panels, modern ones are even better now.

Similar evidence of reliable performance is documented on the Kyocera array from 1984 in Stockholm [4]. In more recent years, other examples of enduring solar installations have emerged. For instance, a solar array installed in the Mojave Desert in California in the 1980s continues to operate at over 80 percent of its original capacity. This example is particularly noteworthy given the harsh desert environment, which subjects the panels to extreme temperatures and UV exposure.

These case studies are further bolstered by data from residential solar installations in more temperate climates, where panels have been shown to maintain high performance for over 35 years. Such examples have appeared more and more frequently in recent years. And many solar energy proponents claim that solar panels can perform for over 40 years [3]! 

Wait for it. Recent advancements such as the use of bifacial solar panels and next-generation materials like perovskite layers are expected to extend the lifespan of solar panels even further, potentially pushing the average life expectancy closer to 40 or even 50 years. As these newer technologies become more widespread, we can expect to see even more examples of solar panel longevity that surpass current expectations.

But before you pop that champagne in celebration of a good investment, it is good to know that the longevity of your solar panel is affected by many factors, including weather patterns or the quality of the material.

Understanding solar panel degradation: How efficiency changes over time

What most interests every solar owner is the gradual power decline over time, commonly referred to as “degradation rate of solar panels.” Over years of continuous exposure to changing weather, solar cells begin to wear down and produce slightly less and less power each year.

According to a recent study conducted by the National Renewable Energy Laboratory (NREL) in 2020, the average degradation rate of modern solar panels has improved compared to earlier reports mentioning that solar cells lose about 0.5 percent of efficiency per year. 

The 2020 study found that the average annual degradation rate is approximately 0.3 percent per year, which means that after 20 years, a solar panel will typically operate at about 94 percent of its original efficiency. 

For example: A twenty-year-old 5 kW system will equate in terms of the energy output to a 4.7 kW system.

Some high-quality panels, particularly those using newer technologies like monocrystalline PERC (Passivated Emitter and Rear Cell) or bifacial designs, have degradation rates as low as 0.2 percent per year. This means that after 25 years, these panels can still operate at over 95 percent efficiency, which significantly extends their useful life.

Although solar panels are very resistant and last a long time, we cannot expect three-decades-old arrays to perform as well as they did when they were brand new. Factors such as exposure to UV rays, weather conditions, and material quality contribute to the degradation rate of solar panels.

Key factors that impact solar panel degradation rates

There are three main factors affecting the performance of all photovoltaic modules:

1. Varying levels of water vapor in the air
2. Exposure to UV rays
3. Mechanical damage

This means that solar panels placed in cold climates with heavy precipitation (in the form of rain or snow) or in countries closer to the equator with high UV index, are vulnerable to faster degradation rates than those in moderate climates. This happens because the material must withstand tough conditions for longer periods of time.

Climate and weather: How environmental factors influence longevity

While traditional factors like UV exposure and temperature fluctuations continue to play a significant role in solar panel degradation, newer research has identified additional factors that can impact the longevity of solar panels.

One emerging factor is the impact of extreme weather events, which are becoming more frequent due to climate change. For instance, in regions prone to severe hailstorms, high winds, or intense heat waves, solar panels may experience accelerated degradation unless they are specifically designed to withstand these conditions. 

Manufacturers are responding by developing panels with enhanced durability features, such as thicker glass, improved sealing materials, and advanced anti-reflective coatings that reduce wear and tear.

Another factor influencing degradation is the quality of the materials used in the encapsulation process. Panels that utilize next-generation encapsulants with better moisture resistance and UV-blocking capabilities have shown slower degradation rates, particularly in humid or high-UV environments. 

Innovations like back-contact cells and heterojunction technology (HJT) are also reducing the rate of degradation by minimizing stress on the cells and improving overall efficiency.

Moreover, recent studies have shown that pollution and soiling—the accumulation of dirt, dust, and other particulates on the surface of solar panels—can contribute to increased degradation if not properly managed. In response, manufacturers are developing self-cleaning coatings and hydrophobic surfaces that help maintain panel cleanliness and reduce performance losses.

Material quality: The role of construction in solar panel durability

Even though some panels wear down more quickly than others, time will eventually take its toll on all of them. The most common signs of degradation that affect how long will solar panels last are:

• Corrosion
• Loosen frame
• Deterioration of anti-reflective coating
• Short-circuited solar cells at corroded or damaged spots
• Cracked cells [5]

Whether you will encounter one or more of these problems depends greatly on the resistance of your solar panels’ construction materials. Unfortunately, some modern models are still prone to manufacturing failures, which speed up the degradation within the cells and shorten lifespan of solar panels.

Common manufacturing issues that can shorten solar panel lifespan

Yes, we have mentioned it a lot throughout this article – solar panels are a durable product, in general. However, some are still prone to manufacturing defects that can accelerate degradation rate and reduce their productive lifespan. 

Some common problems arising from the low-quality production include:

• The absence of UV-blockers in encapsulation foil, leading to quicker discoloration and backsheet degradation;

• Solar cells having micro-cracks, which are not visible to the naked eye but affect the output of the panel instantly by blocking incoming sunlight [6];

• Latent cracks of solar cells, which only appear after some time of usage but were caused during processing [7];

• Thinner frames to reduce the amount of aluminum in production, which bends when snow puts pressure on some parts and can damage solar cells [8].

Here are some examples more in detail:

In recent years, there have been several reports and recalls related to construction flaws in solar panels. In 2022, a major solar panel manufacturer issued a recall for a batch of panels due to micro-cracks in the solar cells, which were caused by improper handling during production. These micro-cracks are though often invisible to the naked eye but can disrupt the flow of electricity through the cell quite significantly.

Additionally, in 2023, there were reports of delamination issues in some models, where the protective layers of the panel began to separate prematurely. This has led to moisture issues inside the solar cells. 

Another concern has been the use of thin aluminum frames in an attempt to reduce costs. However, these frames are more prone to bending under heavy snow loads or high winds. Not so good during some unexpected weather events. Some manufacturers have responded to these issues by reinforcing their panel designs with thicker, more durable frames. You want to make sure your solar panels are produced with these.

Because based on the severity of the defect, you might have to replace your array prematurely (even within the warranty period). In any case, make sure you choose a verified solar company with great customer service. It will save you a lot of trouble when dealing with any problems.

Material advancements in modern solar panels

In response to these challenges, the solar industry has made significant strides in improving the materials and technologies used in modern solar panels. 

One notable advancement is the adoption of heterojunction technology (HJT), which combines the best properties of crystalline silicon and thin-film solar cells. HJT panels are more resistant to degradation and have higher efficiency rates, even in challenging environments. The use of advanced anti-reflective coatings and UV-resistant materials has further improved the longevity of these panels by protecting them from the harmful effects of prolonged sun exposure.

Manufacturers are also incorporating next-generation encapsulants that offer better protection against moisture and thermal cycling. These encapsulants are designed to resist yellowing and cracking over time, which helps maintain the structural integrity and efficiency of the solar panels for longer periods.

Another promising material advancement is the development of bifacial solar panels, which are designed to capture sunlight from both the front and back sides. This not only increases overall energy output but also reduces the stress on individual cells, leading to lower degradation rates.

Moreover, the use of self-healing materials in the construction of solar panels is an emerging technology that shows great potential. These materials can repair minor cracks and defects on their own, extending the lifespan of the panels and maintaining their efficiency over time.

What happens after 25 years of solar panels?

After 25 years of service, your solar panels will likely experience some decline in efficiency, but they won’t simply stop working. In fact, most panels will continue to produce electricity, albeit at a reduced rate.

By this point, the average solar panel will operate at around 80 to 90 percent of its original efficiency. This reduction in performance is a result of the gradual degradation that occurs over time, as solar cells are continuously exposed to the elements. Despite this decrease, your panels will still be capable of generating a significant amount of power.

The 25-year mark is also when the manufacturer’s performance warranty typically ends. This means that while the panels will likely continue to function, they are no longer guaranteed to produce a specific amount of energy. However, it’s not uncommon for panels to remain productive well beyond this period, often for another decade or more.

As your panels age, you might notice that they require a bit more attention. Regular maintenance, such as cleaning and inspections, becomes increasingly important to ensure they continue to operate efficiently. Additionally, other components of your solar system, like the inverter, may need replacement as they generally have a shorter lifespan than the panels themselves.

At this stage, you may face a decision: should you keep using your existing panels or consider replacing them with newer, more efficient models? Advances in solar technology mean that today’s panels can produce significantly more power in the same amount of space, making replacement an attractive option for maximizing energy production.

If you decide to upgrade your system, it’s important to consider the environmental impact. Fortunately, most parts of your old panels—such as the glass, aluminum frames, and some semiconductor materials—can be recycled. Alternatively, older panels can be repurposed for less demanding applications, like powering smaller systems or off-grid projects.

Challenges and opportunities of solar panel recycling

Most countries have not developed a recycling strategy for discarded solar panels yet. Considering the lifespan of solar panels, the technology is still fairly new, and the number of old panels reaching waste facilities remains too low to warrant special treatment.

This “quiet” state will not last much longer, as the amount of discarded solar panels worldwide is expected to rise to 78 million tons by 2050. For a more accurate approximation, it is estimated that the number of solar panels going to waste will roughly equal the number of new installations [5].

Such numbers can no longer be neglected. Old solar panels will soon represent a significant portion of the world’s electronic waste, which contains many precious materials well-suited for reuse. For example, most crystalline silicon modules are made of easily recyclable materials such as glass and aluminum.

A nonprofit organization, PV CYCLE, based in Europe, offers the first solar panel recycling program of all types of photovoltaic technologies [9]. According to an announcement last year, they have achieved a 96 percent recycling rate of silicon-based solar panels. This is important achievement because efficient recycling strategy is the key to minimizing the environmental footprint of the solar industry.

Europe is also the birthplace of strict solar waste regulation—the Directive on Waste Electrical & Electronic Equipment (WEEE). The Directive dictates the “Extended Producer Responsibility,” where producers must take panels back from customers and recycle them free of charge. This strategy aims primarily to reduce the demand for more natural resources [10].

Other countries (including the United States) classify solar panels as general or industrial waste, which has to be tested for hazardous contents and disposed according to country’s regulations. Given the high recycling rate of solar panels, these practices are wasteful.

If other countries adopted the same recycling scheme as Europe, the amount of globally recovered material would be immense. According to the report from the International Renewable Energy Agency, the value of materials recovered from all old photovoltaic systems would reach an unbelievable USD 450 million in the next 13 years [5]. So the argument that the cost of recycling is too high is losing its validity as time passes and more solar panels enter our waste stream.

Maximizing solar panel lifespan: What you can do to extend the life of your solar system

Solar panels are designed to last for decades, but there are steps you can take to ensure they continue to perform at their best throughout their lifespan. Proper care and maintenance play a crucial role in maximizing the longevity and efficiency of your solar system.

One of the simplest yet most effective ways to extend the life of your solar panels is to keep them clean. Dust, dirt, and debris can accumulate on the surface of the panels, blocking sunlight and reducing their efficiency. Regular cleaning, especially after seasonal changes or storms, can help maintain optimal performance. Most panels are easy to clean with just water and a soft brush, but it’s important to follow the manufacturer’s guidelines to avoid damaging the panels.

Monitoring your system’s performance is another key to ensuring long-term efficiency. By keeping an eye on the energy output, you can quickly spot any drops in performance that might indicate a problem. Many modern solar systems come with monitoring apps or systems that make it easy to track performance in real time. If you notice a significant decline in energy production, it could be a sign that your panels need maintenance or that there’s an issue with other components like the inverter.

Protecting your panels from potential physical damage is also important. This includes making sure the panels are securely mounted and checking for any loose or damaged components after severe weather. If you live in an area prone to heavy snowfall or hail, you might consider investing in protective coverings or shields to minimize the risk of damage.

Another way to extend the life of your solar system is by choosing high-quality components from reputable manufacturers. Panels with better construction materials and advanced technologies tend to have lower degradation rates and longer lifespans. Investing in a durable, well-designed solar system upfront can save you from headaches and extra costs down the road.

Finally, regular professional inspections can help catch potential issues before they become serious problems. A qualified technician can check the integrity of your panels, wiring, and inverters, ensuring everything is in good working order. Routine inspections, ideally once a year, can prevent minor issues from escalating and keep your system running smoothly for years to come.