Three decades ago, Switzerland took its first steps into the realm of solar energy, installing photovoltaic systems in various environments, from urban rooftops to alpine research stations. These early installations have exceeded expectations, continuing to generate electricity reliably even now.
A recent collaborative study by researchers in Switzerland, Austria, and Germany explored the longevity of six photovoltaic systems installed between 1987 and 1993. These systems, spread across diverse Swiss climates, have shown resilience and continued performance after over 30 years.
The Surprising Longevity of Solar
The study revealed that the Swiss solar panels experienced an average annual performance loss of just 0.24%, a degradation rate much slower than typical estimates. Remarkably, the panels continue to operate at over 80% of their initial capacity, surpassing the longevity anticipated by most manufacturer warranties.
Lead researcher Ebrar Özkalay of the University of Applied Sciences and Arts of Southern Switzerland highlighted the significance of these findings, stating: “This [data] really shows that photovoltaics can last [longer than expected], and it’s an important message to the photovoltaic industry,” as reported by Chemistry World.
Comparable results were noted in France, where a renewable energy nonprofit, Hespul, analyzed the country’s oldest rooftop solar system from 1992. After 31 years, these panels were functioning at nearly 80% of their original capacity, consistent with the Swiss data. Hespul emphasized that these outcomes underscore photovoltaics’ potential as a major energy source globally.
Climate, Materials, and the Solar Recipe
Examining why some solar panels endure better than others, the Swiss study found location plays a crucial role. Panels in lower-altitude locations, exposed to temperatures soaring to 80°C in summer, degraded more rapidly due to thermal stress and material corrosion.
Conversely, panels situated in alpine regions, despite facing high UV exposure and temperature fluctuations, maintained performance more effectively than their lowland counterparts.
Beyond climate, the “bill of materials” was paramount. Panels constructed with durable encapsulants, adhesives, and backsheets demonstrated greater longevity. Early 1990s models employed resilient EVA encapsulants, Tedlar backsheets, and robust glass/foil structures, contributing to their sustained performance.
While not all panels aged equally, with older models showing more wear, the enduring functionality of many panels highlights their durability.
Lessons for the Terawatt Age
As solar energy now accounts for over 8% of global electricity and dominates new renewable capacity additions, the durability of solar panels is increasingly pertinent. The Swiss study suggests that prioritizing robust materials over cost-cutting measures is essential for long-term sustainability.
Dirk Jordan, a photovoltaics expert at the U.S. National Renewable Energy Laboratory, noted, “The bill of materials — everything that goes into a panel — has a great influence on performance, even when made by the same company.”
The trend of using thinner, less expensive materials in modern modules could jeopardize panel longevity. Instances in Gujarat, India, illustrate this, where solar systems from 2009-2013 required early replacement due to poor quality and defects.
These observations serve as a reminder that durability must be balanced with efficiency and cost in solar technology to ensure its sustainability and economic viability in the long run.
The research findings are detailed in the journal EES Solar.
This article originally appeared in August 2025.
Original Story at www.zmescience.com