Running Non-Stop for Over 40 Years: Switzerland’s Forgotten Solar Panel That Redefines PV Longevity

Solar panel warranties typically promise 25 years of performance, subtly implying that photovoltaic systems are designed to last roughly that long. Yet on the rooftop of a university building in Switzerland, a solar installation has been operating continuously since 1982, quietly challenging one of the most persistent assumptions in the solar industry.

More than four decades later, this historic photovoltaic system is still feeding electricity into the European grid. Its performance, degradation rates, and material resilience are not just impressive—they are transformational for how the solar industry should think about quality, lifetime value, and investment strategy.

Switzerland’s Forgotten Solar Pioneer Still Feeding the Grid

The solar array, known as TISO-10, is located at the University of Applied Sciences and Arts of Southern Switzerland (SUPSI) in Lugano. Commissioned in 1982, it is the oldest continuously grid-connected solar PV system in Europe.

Key system facts:

• Commissioned: 1982

• Installed capacity: 10 kW

• Location: Lugano, Switzerland (Alpine climate)

• Technology: Monocrystalline silicon

• Status: Still operational after 40+ years

Despite enduring decades of snow, temperature fluctuations, UV exposure, and mechanical stress, the system has never been fully decommissioned. Instead, it has become one of the most valuable real-world performance experiments in solar PV history.

Early-Generation Solar Panels with Surprisingly Advanced Design

The system consists of 288 Arco Solar photovoltaic panels, each rated at 37 watts—a reminder of how far solar technology has evolved in terms of power density.

Each module contains:

• 35 monocrystalline silicon cells

• Cell diameter: 102 mm

• Module efficiency: ~10% (exceptional for the early 1980s)

At the time of installation, the total system cost was approximately CHF 284,000, or about CHF 21 per watt—a figure that appears high today but must be understood in historical context.

What matters more is not the upfront cost, but the four decades of continuous energy generation that followed.

A 35-Year Scientific Evaluation of Real-World Performance

Researchers Alessandro Virtuani (École Polytechnique Fédérale de Lausanne) and Mauro Caccivio (SUPSI PVLab) conducted a two-year forensic analysis of the system’s performance after 35 years of operation.

Their work transformed TISO-10 from a historical curiosity into one of the most important long-term solar reliability studies ever conducted.

Material Quality: The Hidden Factor That Determines Solar Lifespan

One of the most critical findings was that not all panels aged the same, even though they were installed at the same time and used the same base technology.

The decisive variable was material choice, specifically the encapsulant formulation.

Although all modules used polyvinyl butyral (PVB) encapsulants, different additives from different suppliers resulted in drastically different aging behavior.

The researchers identified three distinct performance groups:

• Some modules exhibited yellowing and brown spotting

• Others retained near-original optical clarity

• A third group showed discoloration but surprisingly low electrical degradation

This proves a key lesson for modern solar PV suppliers, installers, and EPCs:

Changing a single material supplier can affect PV performance for generations.

running-non-stop-for-over-40-years-switzerlands-forgotten-solar-panel-that-redefines-pv-longevity

Degradation Rates That Defy Industry Expectations

The most astonishing result lies in the degradation data.

After 35 years of continuous operation:

• The best-performing modules lost only 13% efficiency

• Other modules showed losses of around 21%

• Many panels still meet or exceed the performance guarantees of modern 35-year warranties

Performance groups after 35 years:

• Group 1:

  • 21.5% of modules

  • ~-0.2% annual degradation

• Group 2:

  • 72.9% of modules

  • ~-0.2% to -0.7% annual degradation

• Group 3:

  • Severe visual yellowing

  • Surprisingly modest electrical degradation

In practical terms, around 70% of the panels would still qualify under today’s extended performance warranties.

Mechanical Robustness: Built Like Tanks

The study also highlighted the mechanical durability of early solar panels.

Compared to modern lightweight modules, these panels were:

• Thicker

• Heavier

• Structurally more rigid

Despite minor delamination and the need for:

• Junction box upgrades

• Replacement of five inverters over 40 years

…the original solar panels themselves remained operational.

This challenges today’s industry trend toward ever-thinner modules and raises important questions about mechanical longevity versus manufacturing optimization.

Economic Implications: Rethinking Solar ROI and Asset Life

The findings have profound implications for solar investment strategies, particularly for:

• Solar wholesalers

• EPC companies

• Asset owners

• Institutional investors

As Virtuani noted:

“Just by changing one single element, the whole PV array will behave differently. In this case, changing the supplier affects the system for generations.”

This reframes solar economics:

• Solar panels are 40–50-year assets, not 25-year assets

• LCOE improves dramatically over extended lifetimes

• Material quality has more impact than marginal efficiency gains

For professional buyers, this reinforces the importance of bankable manufacturers, proven encapsulants, and long-term reliability data.

What This Means for Modern Solar Installations

Modern solar panels are far more efficient, but the TISO-10 system proves that durability is just as important as wattage.

For today’s solar PV systems, the lessons are clear:

• Encapsulant quality matters as much as cell technology

• Supplier selection is a multi-decade decision

• Cheap materials can silently erode lifetime value

• Solar panels should be evaluated as infrastructure, not consumables

For solar distributors and wholesalers, this also strengthens the case for quality-first procurement, even in price-competitive markets.

Solar&Solar Perspective: Longevity Is the Ultimate Efficiency

From a Solar&Solar perspective, this historic Swiss installation delivers a powerful message:

The most efficient solar panel is the one that still works after 40 years.

As the industry moves toward:

• 30–35-year warranties

• Utility-scale solar assets

• Long-term PPAs and storage integration

…the true differentiator will be material science, manufacturing discipline, and lifecycle thinking.

Solar panels are no longer short-term hardware—they are generational energy assets.

#SolarPanels #PhotovoltaicPanels #SolarEnergy #SolarPV #SolarPowerPlants #SolarInverter #SolarWholesaler #SolarDistributor #RenewableEnergy #PVTechnology #SolarLifespan #EnergyInfrastructure