How long do solar panels last? A lifespan guide
Investing in renewable energy sources can feel like a big commitment, so it’s only natural that you want to know your investment will last. After all, part of being sustainable is avoiding throwaway culture. And with the rise in energy bills, renewable energy sources provide a way to save money long-term, as well as reduce carbon emissions. Solar panels can produce more energy in a year than you need to fuel your home, allowing you to sell the excess back to the grid. For example, while the average UK household uses 3,100kWh of energy per year, the amount of energy produced by solar power in the north of England can be up to 4,158.45kWh.
Do solar panels degrade with time?
The short answer is yes. Like every device, solar panel systems degrade over time, which means that they generate a smaller amount of electricity over time, even though the amount of sunlight they receive doesn't change. Luckily, the degradation rate has improved as solar panel technology has developed, and is currently less than 1% per year.
The lifespan of solar panels
The lifespan of solar panels depends on how they were made. In general, their lifespan ranges between 25 and 30 years, with monocrystalline models typically lasting over 30 years. Many manufacturers offer warranties that protect the solar panels for at least half of their expected lifespan, with a guarantee that performance won’t drop below a specified level during that time.
There are two main types of solar panel: monocrystalline and polycrystalline. They both work in the same way, but the way they’re made is different. The silicon which makes the cells for monocrystalline solar panels is shaped into bars, then cut into wafers. The silicon which makes the cells for polycrystalline solar panels is melted together into wafers. Monocrystalline solar panels last around five years longer than their polycrystalline counterparts.
It’s worth noting that the reliability and longevity of solar panels has grown considerably over the years, and just because a solar panel no longer has a warranty or is older than its predicted lifespan, doesn’t mean it won’t still produce energy. It may not produce as much as it did at the peak of its life, but will still work if cared for appropriately.
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Which solar panels have the longest lifespan?
When considering solar panel types, monocrystalline solar panels usually have a longer lifespan than their polycrystalline counterparts. Monocrystalline solar panels typically last up to 40 years and have a low degradation rate. In contrast, polycrystalline panels can last up to 35 years, besides their efficiency and power production are generally lower.
Another factor to consider when discussing the lifespan of solar panels is the degradation rate. Generally, solar panels with the longest lifespan have a degradation rate of about 0.30%, whereas less efficient types may have a degradation rate of 0.80% or more.
What is the warranty on solar panels?
A reputable panel manufacturer will typically offer two types of manufacturer warranties on panels. First they will offer a product warranty that protects the panel itself. These are typically 15 years but can be as long as 25 years. Second a manufacturer will warranty the performance output potential of a panel which takes into account the expected degradation of a panel. The best panels offer at least 25 years of performance output with a minimum output of 85% of the panel power, an expected degradation of only 15% over 25 years.
The warranty is different depending on the manufacturer and model, but is normally based on a number of years combined with a percentage of production. The most common example is a guarantee of 90% production for the first 10 years, then 80% production for the next 25 years. Some solar panels can still run at 80% production beyond this timeframe.
Solar panel performance over time
The performance of solar panels fades over time, with the panels producing less energy than they did at the start of their lives. This is known as the degradation rate. Luckily, the degradation rate has improved as solar panel technology has developed, and is currently around 0.2-0.5% per year.
What causes solar panel degradation?
The most common cause of solar panel degradation is general wear and tear from things such as:
Environmental factors:
- High temperatures
- High winds or other types of extreme weather
- Snow
Debris-related factors:
- Bird droppings
- Dirt and dust
- Leaves
- Pollen
This accumulation of debris is known as soiling and it reduces the amount of energy the panels can absorb and it can affect solar panels in terms of the produced energy. In many cases, its impact can be reduced with careful maintenance. In many cases, its impact can be reduced with careful maintenance and help avoiding many common problems with solar panels.
Besides external factors, solar panel degradation can be greatly reduced if we take into account the following aspects:
Product quality:
As a general rule, high-quality solar panels last longer. Therefore, it is crucial to choose products from well-established manufacturers known for the quality of their products and who offer an extended warranty. It is also important to check that a panel manufacturer is part of the Bloomberg Tier One list which vets manufacturers for bankability.
Professional installation:
In addition to selecting quality products, it is equally important to choose your solar panel installer wisely. The key to the perfect PV installation lies in accurate estimation of power requirements, reliable products, and flawless installation. By doing so, your chances of harnessing solar energy for extended periods are greatly enhanced.
Solar panel maintenance
Solar panels are designed to withstand all sorts of weather conditions. That said, taking care of your solar panels can increase their lifespan (and the amount of time they provide you and your household with energy). You can look after them by:
- Cleaning the surface of the panels regularly to remove any debris, using a soft brush to sweep it away. More stubborn marks can be washed using warm water and a cloth. It’s best to do this in the morning or evening, as they can get hot during the day when it’s warmest.
- Checking them regularly for any signs of damage, so it can be fixed as soon as possible.
- Reaching out to professionals if your solar panels need more than a good clean, you notice anything unusual in your utility bills, or the space under the panels needs cleaning (the wiring makes it dangerous to do this yourself).
How can I enhance the lifespan of solar panels?
To ensure you enjoy the benefits of a solar panel installation for as long as possible, it's crucial to consider the following aspects:
High-quality solar panels: Choosing solar panels of good quality from reliable manufacturers not only improves efficiency but also extends the lifespan. It's important to select the appropriate number and output of solar panels tailored to your roof type and energy consumption needs. A well-chosen photovoltaic installation is future-proof. If space is a concern, ensure your panels are residential grade as opposed to commercial grade panels which are much larger (therefore have higher power) but are less efficient on a per square meter basis.
Installation by a certified installer: Having your solar panel installation carried out by a certified installer is essential. This ensures optimal functioning and longevity. MCS certification should be your first check.
Regular solar panel maintenance and cleaning: Although solar panels are low-maintenance, keeping them clean and protected from dust, dirt, and bird droppings can prolong their lifespan. Regularly clean the panel surfaces to remove debris, using a soft brush to sweep away dirt. Stubborn marks can be washed with warm water and a cloth. It's best to clean them in the morning or evening when temperatures are cooler. For more information on cleaning your solar panels, refer to our article on solar panel cleaning and maintenance tips.
In the table below, we provide a summary of factors that enhance the lifespan of your solar panels, as well as those that increase the risk of premature damage:
| Factors in favour | Factors against |
|---|---|
| High-quality solar panels | Low-quality solar panels |
| Solar installation by a certified installer | Installation by an uncertified individual |
| Regular maintenance and cleaning | Excessive dirt, bird droppings, or extreme temperatures |
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What happens at the end of a solar panel’s life?
As solar panels become more common and the earlier models start to reach the end of their lifespans, it’s likely that conversation will turn to how they can be disposed of responsibly. Understandably, given the ethos of renewables, recycling is the preferred option over simply sending solar panels to landfill sites. When solar panels are recycled, their components, including glass and metals, get separated out so they can be made into something new. The solar industry is working with recyclers to make this process as efficient as possible.
When is the ideal time to consider solar panel replacement?
While solar panels can often operate efficiently for longer than 30 years, there are certain cases where replacing them earlier may be necessary. This is directly related to their performance. If you notice, for example through a monitoring app typically provided with a PV installation, that your solar panels are generating less electricity than before, it's time to assess their functionality and consider replacement.
Another possible scenario for replacement is when visible damage is present on one or more solar panels. In this case, it is recommended to replace them as soon as possible to prevent further damage to the entire PV system. Solar panels work together in a string so if one panel in the string malfunctions it can affect the entire production.
Conclusion
The subject of the lifespan of solar panels is full of good news. On the one hand, especially with proper maintenance they stay efficient and work up to 30 years. On the other hand, manufacturers are constantly working on improving the durability of their products which makes an investment in solar energy even more profitable.
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