Solar panels installed in Switzerland between 1987 and 1993 continue to operate after three decades, still delivering more than 80% of their original capacity—a testament to their remarkable durability.
A Study in Longevity
Researchers from Switzerland, Austria, and Germany evaluated six photovoltaic systems deployed across diverse environments: from temperate valleys to snow-covered mountain cabins and high-altitude research stations. Despite prolonged exposure to vastly different climatic conditions, these panels have demonstrated exceptional resilience. On average, panel performance declined by just 0.24% per year—nearly three times slower than typical estimates. In practice, these panels have continued producing well beyond the standard 25–30 year warranty period.
Ebrar Özkalay, lead researcher at the University of Applied Sciences and Arts of Southern Switzerland, emphasized: "These data clearly show that photovoltaic systems can last longer than expected, which is an important message for the PV industry."
Similar findings from France support this conclusion. Renewable energy nonprofit Hespul reported that a rooftop system installed in 1992 still retains approximately 80% of its original generation capacity after 31 years.
Key Factors Behind Extended Lifespan
The study identified two primary factors:
Environmental effects: Panels at lower elevations experience greater thermal stress from frequent heating and cooling cycles, making them more susceptible to corrosion and reduced conductivity. In contrast, high-altitude installations—despite exposure to extreme cold and ultraviolet radiation—maintained performance more effectively.
Material quality (bill of materials): Panels manufactured with high-quality materials, such as EVA encapsulants, Tedlar backsheets, and robust glass or foil substrates, aged more slowly. Certain models, like the Siemens SM55-HO panels, benefited from specialized laminate fillers that enhanced efficiency and contributed to greater durability. Conversely, panels produced before UV stabilizers became standard were more prone to discoloration, delamination, and solder joint failures.
Implications for the Solar Industry
This empirical research comes at a time of rapid global solar expansion. In 2023, solar accounted for more than 8% of global electricity generation and represented 70% of new renewable energy installations.
The longevity of these early panels sends an important message to the industry: prioritizing lower upfront costs through thinner or cheaper materials may compromise long-term performance. Notably, some installations in Gujarat, India, have experienced severe degradation within 8–12 years due to poor construction quality, microcracks, solder joint issues, and lack of maintenance.
As the world enters the terawatt-scale era of solar deployment, the industry must strike a balance between cost efficiency and durability. Longer-lasting panels mean fewer replacements, lower overall lifecycle costs, and a smaller environmental footprint.