How long do solar panels last?

We’ve seen a lot of solar panels reach their ‘end of life’, and we have just as many reasons as to why. 

There is a lot of confusion in the public regarding how long solar panels ‘last’ and we are often asked ‘can’t they be reused?’.

In this FAQ article we are going to address some questions we are asked and provide some common scenarios in which solar panels reach their end of life.  The content here is most applicable to homeowners and residential systems and the purpose is to be informative. If in doubt it is best to talk to to your locally recommended and accredited installer.

FAQ Article Contents

Summary

There are several factors that contribute to damaging or reducing a solar panel’s output such as weather events, faults, or failure.  However, when it comes to deciding to remove a solar panel, or panel or installation, it generally boils down to one of the following:

  • The installation or solar panels are not compliant or do not meet current Australian Standards
  • The power output of a solar panel or panels has reduced or there is no output.
  • Solar panels or installations are visibly damaged or broken.
  • It makes more economic or environmental sense to upgrade to a new, more powerful, and efficient system.

Warranties - “I thought solar panels last 25 years?”

Whilst this may be true in some cases, it is not in others.  To understand this let’s look at solar panel warranties.  There are several types of solar panel warranties.  Let us break them down.

  1. Solar panel performance warranty usually 25 years.
  2. Solar panel product warranty usually 10 years.
  3. Inverter warranty which is usually 5 years.
  4. Installation warranty. This is provided by the installer and is usually 1-2 years but can be higher than this.

We are going to focus on the last two, because they are specific to solar panels and generally are the cause of lots of confusion and people being misled.

 

Solar Panel Performance Warranty

A solar panel performance warranty (or linear performance warranty) guarantees that a solar panel will produce a certain percentage of its output over time.  For example, the manufacturer might guarantee that the power output of the solar panel will not decrease more than 10% over the first ten years and will not decrease another 10% over the next 15 years. 

So applying this example to a 300W panel, if its peak power output drops below 270W in the first ten years, it should be covered under warranty.

Solar Panel Product Warranty

The solar panel product (or workmanship) warranty covers materials, faults, defects, and poor workmanship in the solar panel.  The warranty period is usually ten years.  For example, a new panel has a fault and is not producing any power, or a new solar panel has a frame that is loose – these should both be covered under warranty.

Now you can probably see how these two warranties may intersect and it becomes grey very quickly.  It is hard to guarantee performance in year 15 when the manufacturer can blame materials and workmanship after the initial ten-year product warranty period.

So if you hear a solar installer tell you “the solar panels last for 25 years” they are referring to the solar panel performance warranty, which is more clever marketing than a guarantee outside of the initial ten year period.

After this initial ten-year period, it is more likely that a panel will suffer from issues such as weather damage, delamination or water ingress.

Here's a warranty scenario:

A homeowner notices that their 13-year-old solar system isn’t performing as it should be.  They have it inspected, and the performance has dropped enough to be covered under the performance warranty.  However, the installer has also noticed that the solar panel has delaminated, and water is getting inside the panel.  Although the solar panel is covered under the performance warranty, the manufacturer can blame delamination for the drop in performance which is not covered because the solar panels are now older than ten years.

Now that we have covered warranties, let us look at some common reasons why an owner may remove their solar system.

Australian Standards, Accreditation and Safety

Australian standards exist for the safe design, installation and use of solar systems.  Clean Energy Council (CEC) accredited installers must adhere to them.  The CEC manages lists of approved retailers, products and accredited installers.

The Australian and New Zealand Standards (AS/NZS) that relate to solar installations, and there are many, outline best practice design and installation methods.

Are they important?  You bet!  On a practical level they prevent your new solar panels from blowing off your house and reduce the risk of the installation setting fire to your home!  They reduce the risk of fires and other potential issues caused by weather such as high winds and lightning. 

Solar installations may no longer comply with these standards because they become weathered, damaged, or due to an upgrade of the standards themselves.  CEC accredited installers have a responsibility to advise the owner of a system if it does not comply with the current standards.

Whether or not a solar installation meets current standards really depends on several factors including when the system was installed, its condition, the quality of the installation and the products used.

For this reason, the owner may decide to decommission the system and replace it with a new one that meets current product, installation, and design standards.

For an in-depth analysis on Australian Standards you can read our other post,
How do Australian Standards affect End of Life?

Building Maintenance

Building maintenance and renovations often lead to solar system replacements.  Before any work is done, the solar system will need to be removed from the roof or building.  Once removed, works can be undertaken, and the solar system will need to be put back on when finished. 

However, at this point, depending on when the system was installed, it may make more economic and environmental sense to decommission the old system and install a new one.  This is because once removal has already taken place, that is half the work done.  Installing a new, more efficient, solar system may enable the owner to save more on their energy bills and reduce greenhouse gas emissions.  Furthermore, many older installations will not meet today’s safety and design standards so this also needs to be taken into consideration.

Here are some common scenarios:

  • Roof replacement and roof repairs. The roof may be leaking or damaged and needs to be tended to.  Unfortunately, in some cases the original installation may not have been done correctly causing leaks that only become noticeable later.
  • The owner is undertaking renovations. A homeowner may decide to renovate their home, add a second story or redesign and build their dream home meaning the solar system must come off.  

Weather Damage

Weather is another contributing factor to solar panels reaching their EOL earlier than expected.  Hail damage is arguably the most common, however high wind events, bushfires, lightning, and storms are also an issue.

There are Australian Standards and mandatory testing requirements in place to help ensure that solar panels can withstand these events.  For example, hail testing requirements mean that panels must be able to withstand 25mm ice balls being fired at 23m/s on 11 different points across the module. 

After a hail event, the solar panel glass may look like it has survived intact.  However, it is important that there are no micro-cracks.  Micro-cracks within the silicon are not visible to the naked eye and they can cause a reduction in output.  This may not occur immediately but could happen down the track.  As the panels expand and contract with the changing of seasons, heat of day and cool of night, these micro-cracks get bigger and bigger whilst remaining invisible to the naked eye.  Hail may also cause cracks in the back sheet which can let water in (or electricity out) and will be detrimental to a solar panel’s performance.

For a detailed explanation on hail damage and micro-cracks, click the following link to read an article by Dr Michelle McCann from PV Lab.
Great balls of hail … the invisible PV peril.

If your solar panels have been through a severe weather event it may be worth having them inspected and tested to make sure they are functioning okay and safe.

It is also important not to neglect other system components such as isolators and inverters.  These components may also be damaged due to weather so they must also be inspected.

Some scenarios may include:

  • Hail damage causing the glass to break or micro-cracks in the silicon.
  • An extremely high wind event causing solar panels to blow off a roof, or the cells and backsheet to blow out.
  • A severe storm passing through which blows debris, such as tree branches, onto a roof and damages the solar installation.

Water Ingress and Delamination

Delamination occurs when the bond between the backsheet (on the bottom) and the glass (on the top) separate.  This allows air and moisture to get into the panels causing corrosion and parts to fail or the solar panel to reduce in output.  Water ingress means that water can get inside the solar panel and into places it should not be, whilst electricity can also get out and thus the panel isn’t performing efficiently. 

Water ingress and delamination can be caused by several factors.  Many of the solar panels we collect today suffer from these issues and it is detrimental to a solar panel’s performance.  As previously mentioned, this can be caused by hail or weather damage.  It can also be caused by defects in workmanship such as loose frames or low-quality solar panels.

Advancements in Solar Panel Technology

Solar panel technology has gone a long way in a short period of time.  Nearly all the solar panels we collect are between 170W and 200W, however most of the panels being installed today are above 300W.  This is a huge gap in output and efficiency. 

I have previously mentioned the phrase “it may make more economic and environmental sense to upgrade to a new, more powerful and efficient system.”  What I mean by this is that by installing a new system, the owner may be able to offset more of their electricity bill using solar power and in doing so save more on Greenhouse Gas emissions.

Here is an example – a client of ours had a 15kW system that was installed nearly ten years ago.  They did some calculations and worked out they could replace it with a new 51kW system using the same amount of roof space.  This would allow them to reduce their grid electricity consumption by 27%, save 61.2 tonnes of greenhouse gas emissions per year and reduce their energy bills.

But the panels still work – can’t they be reused?

This is a question we get asked often.  Yes, your panels may still ‘work’ but who will buy them?  Some panels have been used for caravans, camping and yachting.  However, there are so many used panels on buy/sell/swap markets that it is simply flooded with supply.  Moreover, many of these panels do not meet today’s standards, as previously mentioned, they are not eligible for government incentives nor are they covered by any warranties and there are issues with consumer law.  Depending on their age they are also likely to already have issues causing a reduction in output.  Lastly, if they still ‘work’ then why are they being removed? 

We can use mobile phones as an analogy.  Yes, that old Nokia handset with the buttons in your electronics draw might still turn on but how many people are going to want to purchase it when new touch screen models are accessible and affordable.

Solar installations are relatively cheap to begin with, especially with the help of government incentives, and they pay themselves back after a few years, so it seldom makes sense to purchase a second-hand solar system.  There are exceptions to this rule, like one or two damaged panels which could potentially be replaced to extend the life of a system rather than replacing it as a whole, because damaged panels need to be replaced with one of similar specifications.  However, this causes issues around consumer guarantees and safety, but rest assured, it is something PV Industries is working on.

A Final Story

Whilst putting this FAQ article together I was reminded of a house we visited which really exemplifies a bunch of the issues mentioned here.

We picked up 8 solar panels from a home in Sydney.  The homeowner was removing the solar system because they were about to undertake renovations on their house.  However, once the panels were off the roof it was obvious these panels had delamination issues as condensation was visible on the inside of the panel.  This home was situated in a valley that often sees fog and cooler temperatures, which may have helped contribute to the issue.  It was even foggy at the time of collection, and this was also demonstrated by the build up of moss and lichen on the solar panels – another important reason to keep them clean and well maintained!

Conclusion

There are so many factors contributing to solar panels and installations reaching their end of life.  Each system is different and will need to be assessed on a case by case basis.  Consumers need to have a system that is safe and fit for purpose. If you are unsure about the performance of your system, or have safety concerns it is best to contact your local and reputable installer. They will be able to inspect and provide advice regarding your own system and circumstances.  For whatever reason, when solar panels or a system reaches end of life, it is important that they are disposed of sustainably and recycled.  If you are not sure why solar panels should be recycled, you can read about the economic and environmental benefits by clicking the link below to another FAQ article.

Why should solar panels be recycled?

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