How long is the service life of solar panels?

Photovoltaic systems mainly consist of solar modules. But how long do they last? In this article, we look at the lifespan of solar panels and explain why they have a limited lifespan. We also looked at the various manufacturers' warranties.

Crystalline solar modules can last at least 30 years. However, the service life can exceed 40 years with regular solar panel maintenance and cleaning. Thin-film solar panels (amorphous solar panels), on the other hand, only last 20 to 25 years. The lifetime of a solar cell depends on various factors, such as cell type and module construction, as well as the manufacturer.

On average, monocrystalline solar panels last slightly longer than polycrystalline solar panels. The reason for this lies in the generation of cells. Monocrystalline solar panels consist of a single silicon crystal cut from a single block, resulting in higher surface purity and uniformity. On the other hand, polycrystalline solar panels are made up of many smaller silicon crystals, so they are slightly less efficient and have an uneven surface.

Therefore, monocrystalline solar panels are less susceptible to material fatigue and degradation. But there is not much difference in the service life of monocrystalline and polycrystalline solar panels, which is mainly affected by other factors such as material quality and component glass.

Thin-film solar modules are much more sensitive than conventional crystalline solar modules. As the name suggests, they are very thin and, therefore, very flexible. However, for this reason, their average lifespan is only 20 to 25 years.

The structure of the solar module also plays an important role. Glass-glass solar modules are much more stable than glass-foil modules. As a result, their service life can be extended to 40 years or more. Since these are premium models, monocrystalline solar panels are usually used. Glass foil modules are more sensitive and have a shorter lifespan of around 30 years.

Degradation of solar modules

Solar module degradation is how solar cell performance decreases over time. This performance loss is attributed to various factors such as the materials used, high temperature, humidity, UV radiation, and mechanical stress. There is age-related degeneration and light-induced degeneration.

Both forms of degradation are normal processes during the life of a solar module and occur in all types of PV modules. However, the degree of performance degradation depends on the type and quality of the solar cell. On average, crystalline solar panels degrade at a rate of 0.1% to 0.5% per year related to aging. Solar modules lose between 0.1% and 0.5% of their yearly output.

For thin-film modules, the annual degradation is hardly measurable. On the other hand, they have higher photo-induced degradation, also known as initial degradation. It describes the performance degradation of bifacial solar panels when exposed to sunlight for the first few days after installation. The initial degradation is usually already taken into account when specifying the efficiency. Thin-film solar panels lose nearly 25 percent of their capacity within the first 1,000 hours of operation. On the other hand, for crystalline components, it's only 1% to 2% in the first year.

A monocrystalline 300W solar module will lose 1.5% of its performance during the first year of operation due to initial degradation. The annual power loss is 0.5%. After ten years, the module's output is thus 94% or 282 watts. After 25 years, it is 86.5% or 259.5 watts. However, the power loss is only around 0.15% annually.

There is also potential induced degradation (PID). This happens when different components in a solar panel operate at different voltages. As a result, the amount of current the module can send to the inverter is reduced. PID can cause the solar panels, often located near the frame, to malfunction. This happens due to the large amount of electrons flowing through these solar panels and the voltage difference in the solar panel. While PID is uncommon, it can reduce the performance of a solar panel by 30% or more.

Manufacturer's Performance Warranty

Therefore, degradation largely determines the service life of photovoltaic cells. As a result, many solar module manufacturers offer performance guarantees over 25 years, some even longer. Crystalline solar panels typically guarantee 90% output after ten years and 80% output after 25 years. In reality, the degradation isn't that high. Consequently, solar modules usually perform very well after 30 or 40 years, so they can still be used without problems even after 25 years.

Solar modules come with both performance and product warranties. A performance guarantee refers only to guaranteed performance after a certain period. On the other hand, a product warranty refers to material defects and the product's general freedom from defects. Lengths vary between manufacturers. Asian manufacturers typically offer a 12 to 15-year warranty. German and European manufacturers offer 20 to 40-year warranties for their PV modules. The type of solar module and module construction also play a role here.

This will prolong the life of the solar panel

Various measures can be taken to reduce the degradation of solar modules and extend the life of the modules. One way to do this is to look for quality materials when purchasing and ensure the solar panels are installed and installed correctly. The same applies to PV owners: if you buy cheap, you buy twice.

Regular cleaning of solar panels will help remove dirt and other damage that can affect solar cell performance. To do this, regularly monitor the PV system. Check the yield curve for any "dips" or sudden yield drops. In this case, carry out a visual inspection of the PV system.

Check the following:

Is the module dusty, dirty, or even covered in leaves?

Is the module becoming a hotspot, or is it corrupted?

Are moisture, UV radiation, or rodents damaged or pinched the wires?

Are all connections plugged in correctly?

These errors should be eliminated as soon as possible, as they can lead to a drop in current yield and critical defects. You can usually clean it yourself. In the event of damage, it's best to schedule a repair appointment with a professional company and have them inspect the system before you take action. They can often repair damage directly on-site or advise you on what to do.

In conclusion

The service life of home solar kits depends on various factors, such as cell type and module construction, as well as the quality of the materials. Solar cell degradation is a normal process that occurs over time. However, in the case of high-quality modules, the degradation is significantly lower than in the case of cheap variants. However, even with high-quality PV modules, it is important to maintain and clean PV modules regularly to ensure maximum life and performance.

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