It is a very good question to ask as the photovoltaics technology itself is relatively new and there are no exact evidence determining how long new panels are going to last. What is known though, there are cases when Europe based companies make panels which reliably operate much longer than expected. Thus to answer this question properly, there are few more important factors, such as quality and maintenance, which requires our attention too.

What panels must go through to have certified quality? When we start talking about solar product lifespan, the very first thing to do is to think which supplier it has been bought from and where it was made. There are quite a lot of companies located in various parts of the world offering their production. However, can all of them guarantee quality? EU based companies works in-line with European quality standards. So does “Metsolar” with its in-house photovoltaics testing laboratory capacity to carefully inspect every product they manufacture, even uniquely developed modules.

Examination based on IEC 60068-2-78, IEC 61215, IEC 61730 standards covers various types of spheres. For example, UV Exposure test determines if exposure of particular materials to radiation over an extended period of time causes any degradation in their properties. Climatic tests simulate an impact of time ageing over shorter time and allow the manufacturer to predict the real time performance of the production or material used. Tests cover temperatures from -72 to +180 degrees Celsius and relative humidity testing from 5% to 97% above 25 degrees Celsius temperature. Also, standard and custom on-demand modules are gone through Damp Heat test (+85 degrees Celsius and 85% relative humidity) for 1000 to 3000 hours.

One more necessary inspection is done with Wet leakage current test which is designed to detect currents on electrical systems, equipment or insulating materials exposed to moisture, humidity and for determination of product insulation quality – damaged insulation, stray wire strands, conductive or corrosive contaminants and cable fractures. Electroluminescence test highlights the defects within the solar cells in the module that cannot be detected with visual inspection alone. It is done before and after the lamination process to ensure the highest quality standard for the final product.

To assure its highest quality, “Metsolar” also does AAA class flasher test which determines the electrical parameters of the solar panel (rated power, current, voltage), Steady state solar simulator that is used for light soaking and pre-conditioning of the solar panels, Cell testing where ribbon adhesion strength to solar cell after soldering test determines the quality of the soldering. Spectral response testing of the solar cell allows to evaluate IQE, EQE and other solar cell parameters which determine their quality and performance.

When needed, additional chemical lab tests and visual inspection is done. The first one – Gel Content tests of the encapsulates – is used for lamination process. GC determines the polymerization degree of the encapsulate (EVA, POE) which is crucial factor for long term performance of the solar panel. The second is done during crucial steps of the assembly of the solar panels to avoid unwanted impurities, defects before and after lamination. All these tests are done in “Metsolar’s” in-house laboratory, which allows company to go along with highest European IEC 60068-2-78, IEC 61215, IEC 61730 standards and make quality production. So if you want to be sure your product is high quality, ask your supplier whether your panels has gone through these important quality assurance steps.

Is there a difference between European and Chinese quality? Perth Solar Warehouse has made an interesting comparison of German made and average Chinese solar panels production to illustrate huge quality differences in the market. For example, under -40 to +85 degrees Celsius conditions german-made product has passed 9125 cycles test which equals 25 years while Chinese’s one – has made 200 cycles examination which equals only 0.5 year. In other words, it was tested only to see if it’s working. Salt spray (maritime climates) test also showed European dominance over Chinese production – 100% in comparison to 2%. The average Chinese solar panel could work indoors, under mild conditions only, while those made in Germany operates fully even in extreme outdoor environment. Thus, if production is bought from trusted, high-end manufacturer, one may assume that solar panel would last for even longer than from cheaper, yet questionable company. On the other hand, why would somebody, which is genuinely interested in renewable energy and solar in particular, buy a product from a company which is not in-line with sustainable rather consumerism way of life?

Germany companies give 20-30 years warranty, where Chinese only 10-12 years

How long it is covered by warranty? Warranty period offered by manufacturers vary quite a lot. According to The Eco Experts, as new solar panels – either monocrystalline or polycrystalline – likely will last for 40-50 years, warranty is for at least half that time in the United Kingdom. Performance of the product is also included in warranty, it could not drop below 80% during the period. Similar warranty is offered by many of Germany based companies – they give from 20 to 30 years of warranty to a product and its performance. In comparison, Chinese companies for premium solar panels give only 12 years of product warranty and for average solar panels – only 10. However, in both cases Chinese solar modules provides 25 years of performance warranty.

Maintenance Usually maintenance is done by companies you ordered your production from or firms specializing in this area. However, if we are talking about household environment, there are some steps to take. Firstly, one should be aware that solar panels are expected to be placed in harsh environment thus are built to endure those conditions. This make panels almost maintenance-free, as keeping them clean – removing dirt, dust or snow – is by far the main thing to do. Keeping an eye on systems also should be something one should do regularly, check the output of panels, an inverter or a monitoring system. Needless to say, that if any of those aren’t working properly then solar panels would not be able to perform at its best too.

So, how long solar panels work? The answer depends on various aspects – if set-up PV installation works fine, if it was well taken care of and by far the most important – which company it was made by. Even though there are a lot of manufacturers in the world selling solar panels with warranty, not all of them can assure highest quality, even lesser have in-house laboratory which allows company to do tests by itself.