Solar Panel Degradation: How Long Do Solar Panels Last?

by | Jul 21, 2021 | Blog

The setting sun behind a row of solar panels

Summary

  • A solar panel’s optimum performance tends to be guaranteed for an average of 25 – 30 years. However, it is possible for panels to go on producing electricity for much longer than this initial “useful life” period.
  • All solar panels gradually degrade over time, meaning they will generate a smaller amount of electricity from the same amount of sunlight. There is no way to avoid degradation as it is a normal, unavoidable part of a solar panel’s lifecycle.
  • Most of the factors contributing to solar panel degradation are hard to control, especially given that the main factor is the weather. Extreme hot and cold temperatures, humidity, snow, and ice can all contribute to solar panel degradation.
  • Solar panels actually lose a few degradation percentages immediately after installation due to sunlight damage. Following installation, the degradation rate significantly slows down for the remainder of their lifetime. The average solar panel degrades at a rate of approximately 1% per year.
  • The solar cell manufacturers are required by law to ensure solar panels do not become yet another environmental burden. Solar recycling research has resulted in numerous advancements and is now able to achieve a 96% recycling efficiency.

Introduction

Unlike a good bottle of wine or fine cheese, solar panels do not improve with age. Like any piece of equipment you invest in, solar panels do not last forever and eventually need replacing. Whether it’s a car, computer, or cell phone, most machines have a finite “useful life”.

Solar panels can be a promising long-term investment for many businesses, homes, and renewable energy projects, but their natural degradation processes should be understood. This article will examine how long a solar system is expected to last, the effects of time on solar panels, and what you can do to get the most out of your solar system investment.

The Average Solar Panel Lifespan

Confusingly, the term “useful life” does not mean the timeframe in which the solar panel is of any use. Instead, it is the period that it performs at its best.

Subject to the manufacturer, solar panel performance is usually guaranteed for at least 25 years, but it is possible for panels to go on producing electricity for longer than that. The initial 25 to 30 years after your solar equipment has been installed is considered the system’s useful life, but panels can continue to produce electricity in the decades to come. The world’s first modern solar panel is, in fact, still generating electricity, and it’s 60 years old.

Confusingly, the term “useful life” does not mean the timeframe in which the solar panel is of any use. Instead, it is the period that it performs at its best. As with most other pieces of equipment, solar panels do not perform at 100% for their entire life. However, this does not mean they stop working when they get to 30 years post-installation. On the contrary, solar panels will start to very slowly produce less electricity over a long time period. This is the process known as “degradation”.

Due to solar panel degradation, the majority of production warranties change as they age. Solar manufacturers usually guarantee 90% of energy production for the first ten years. However, once the ten years are up, the percentage tends to drop to 80% for the remaining 15 – 20 years.

Following the solar panel’s useful life, the system can continue to produce electricity but perhaps not with the same efficiency. Depending on the financial goals of the solar project, it may be decided to replace the old panels with new ones to ensure solar power is producing electricity at the highest rate.

What is Solar Panel Degradation?

As there are so many different ways for a solar panel to degrade, it can be challenging to identify the cause and solve the problem.

As discussed above, all solar panels gradually degrade over time, which means they generate a smaller amount of electricity from the same amount of sunlight. This happens due to a variety of external factors (such as weather) that wear down the panels and eventually have a negative impact on their ability to generate electricity.

One of the more common causes of solar panel degradation is the formation of micro-cracks (also known as micro-fractures) that develop in the silicon of the solar cells. These small cracks cause the electrical connections to deteriorate, resulting in fewer paths for the electrons from the sun to take. Therefore, there is less energy going to the inverter and back into the home or business. Other significant issues include junction box adhesion failures and discolouration.

As there are so many different ways for a solar panel to degrade, it can be challenging to identify the cause and solve the problem. Solar panel degradation development is an area that manufacturers are focusing on so they can evolve and come up with new ways to reduce degradation to lengthen the panel’s power output. As solar technology continues to advance, panels are guaranteed by manufacturers to degrade at or below a specific rate.

The Causes of Solar Panel Degradation

You may also be surprised to find out that the very thing which makes solar panels work can also cause degradation – sunlight.

Most of the factors contributing to solar panel degradation are hard to control – one of which is the weather. For example, micro-cracks most commonly form through thermal cycling (the disparity of temperature between night and day). When it is cold outside, materials contract, and when it is warm, they expand. Unfortunately, solar panels are not yet immune to this, and constant temperature variations put them under strain and can create micro-cracks.

Another weather problem is strong winds that cause the panels to flex and create what is known as a dynamic mechanical load. This is an area that can be overlooked by traditional solar markets (such as Europe) due to their lack of typhoons and other wind-related natural disasters. However, dynamic mechanical loads can be a concern for counties located in high wind hot spots, such as Japan and other South-East Asian countries.

Extreme hot and cold temperatures, humidity, snow, and ice can all gradually cause solar panel degradation, along with solar system components with different voltage potentials. You may also be surprised to find out that the very thing which makes solar panels work can also cause degradation – sunlight. Thankfully, most panel manufacturers include UV blockers in their designs, which protect the panels from the majority of the damage. However, the sun itself contributes to degradation.

Panels can degrade at one of the highest rates just a couple of hours following installation when they are fully exposed to sunlight and intense UV rays. This degradation process is known as light-induced degradation (LID). UV rays may take a toll on new solar panels in this small window of time, but after that, the degradation decelerates.

How Fast is the Degradation Process?

The average solar panel degrades at a rate of around 1% per annum.

Although solar panels do lose a few percentages immediately after installation due to LID, the degradation rate significantly slows down for the remainder of their lifetime. The average solar panel degrades at a rate of around 1% per annum. A study performed by the National Renewable Energy Laboratory (NREL) reveals a more detailed portrait of solar panel degradation. The NREL study analysed the degradation rates of nearly 2,000 solar systems across the globe in a variety of climates. They discovered that monocrystalline panels that were manufactured after the year 2000 degraded at a rate of just 0.4%, which is less than half of the 1% rate used for the majority of warranties.

There are a few measures that can be taken to help keep solar panels performing at their best. Just as you look after a car by changing the oil and getting it serviced once in a while, there ways to extend the useful life of solar panels.

As solar panels do not have any moving components, there is not a whole lot that needs to be done. However, many of the factors that could help reduce the rate of degradation should be completed during the planning phase before the solar panels are installed – for example, choosing the most appropriate location for installation. This involves selecting an area where the solar panel is least likely to get obstructed or impaired (i.e. away from things that could cause physical damage). It is essential to consider things like trees and bushes that could get blown against the panels, which can speed up degradation.

Solar panels overall are a relatively low-maintenance investment. However, periodic checks and spot cleaning can potentially help to extend the solar panel lifespan. When these types of practices are completed on the panels, it is vital that they are carried out by solar experts who know the proper methods for cleaning and maintenance. Poor techniques can cause more harm than good.

With a solar system, whether it is a large commercial solar array or small domestic rooftop panels, only certified industry experts should be entrusted with the installation process. This will help ensure that energy production is at its highest and will continue to generate power beyond the system’s life expectancy.

What Happens to Solar Panels After They Expire?

Green recycling symbol made of icons representing sustainability.

The solar cell manufacturers are required by law to comply with specific legal requirements and recycling standards to ensure solar panels do not become yet another environmental burden.

From a regulatory standpoint, solar panel waste worldwide falls under a general or industrial waste classification. The European Union (EU) is an exception where they have defined it as e-waste within the Waste Electrical and Electronic Equipment (WEEE) Directive. Solar panel waste within EU member states is regulated by the WEEE directive, in addition to national frameworks and laws.

The solar cell manufacturers are required by law to comply with specific legal requirements and recycling standards to ensure solar panels do not become yet another environmental burden. There is now huge investment backing technological advancements to improve solar panel recycling. In addition, photovoltaic producers are collaborating with governmental institutions to come up with new approaches to tackle solar waste.

There are two leading types of solar panels; silicon-based and thin-film based. Fortunately, both solar panel types can be recycled, but they require a unique industrial recycling approach. Silicon-based panels are currently more common, but this does not mean that there are no benefits associated with the materials found in thin-film based solar cells.

Solar recycling research has resulted in numerous technologies. Some of them have even managed to achieve a 96% recycling efficiency, although the solar industry is aiming to improve on this in the future.

Closing Thoughts

There is no way to avoid degradation as it is a normal, unavoidable part of solar panel technology. However, when a solar system has reached its expected end of life, it does not mean it will not continue producing energy.

Manufacturers consider the solar panel’s “useful life” to be over once energy production dips below 80%, but this does not mean the solar system is now worthless. Solar panels will go on to generate energy for many years (albeit with reduced efficiency).

Once the solar panel has reached its end, it must be disposed of in a responsible manner. Recycling methods continue to improve and aim to be as environmentally friendly as possible – particularly where solar technology is concerned.

Frequently Asked Questions (FAQs)

How often do solar panels need to be replaced?

There are many factors at play when considering the rate at which solar panels need to be replaced. When looking at a high-quality solar system, it will likely produce power for between 20 to 25 years at high efficiency. As with other devices, individual solar panels may need to be replaced in some cases, but this should be considered a last resort. For example, if a solar panel is damaged beyond repair, it will most likely need to be replaced.

 

What does solar degradation mean?

Solar panel degradation is a process that causes a solar panel to lose its power output over time. This period is often measured against the panel’s lifetime. A high-quality solar panel will have low degradation rates that will not have much of an impact on the performance of the solar system.

 

Do solar panels need yearly maintenance?

As a general rule, it is advised that solar panels are cleaned between two and four times per year. This is not an arduous job and can be done quickly and with little difficulty. Most of the time, the maintenance check-ups will be more of a preventative measure, especially after harsh weather conditions. The panels will be checked to make sure they are not covered in materials such as sand or snow and ensure they are still stable within their mounting brackets.

 

Can solar panels be recycled?

Yes, it is possible to recycle solar panels. Each panel has around 80% of crystalline silicon, which can be salvaged through a refined recycling process. There are also other recyclable components, including electric junction boxes, glass and plastics, and aluminium frames and brackets.

 

Are solar panels worth it in Canada?

The Canadian National Energy Board recently conducted a study into the financial viability of typical solar power projects. They completed this in over 20,000 Canadian communities across every province and territory. Their findings indicated that installing solar panels made financial sense in areas where electricity rates are high.