Solar That Lasts: Why Commercial Solar Is a 30+ Year Asset, Not a 25-Year Gamble

If you’ve ever looked into commercial solar, you’ve probably heard the same question asked again and again:

“But how long do solar panels really last?”

A major new long-term study provides one of the clearest answers yet and it’s excellent news for businesses considering solar today.

The short answer?

Well-built solar systems can operate reliably for more than 30 years, with far less performance loss than most financial models assume.

What the Study Looked At

Researchers analysed six commercial-scale solar PV systems in Switzerland, installed between the late 1980s and early 1990s.

These systems:

• Have been operating for 20–35 years

• Were exposed to very different climates (hot lowland rooftops, cold alpine sites, snow, wind, high UV)

• Were monitored using high-quality performance data, not estimates or lab simulations

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This is rare. Most solar studies rely on short-term data or accelerated ageing tests. This one looked at real solar systems, working in the real world, for three decades.

Key Finding #1: Solar Degrades Much More Slowly Than Assumed

The study found an average performance loss of just ~0.24% per year.

To put that into context:

• Many commercial financial models assume 0.75–1% per year

• At 1% per year, a system loses ~28% of output over 25 years

• At 0.24% per year, it takes over 30 years to lose just 8%

Even more impressive:

Most of the systems still delivered over 80% of their original output after 30–35 years of operation.

This fundamentally changes how commercial solar should be viewed, not as a 25-year asset, but as a 30–40 year infrastructure investment.

Key Finding #2: Quality Matters More Than Climate

One of the most important conclusions was this:

The bill of materials (panel quality) mattered more than climate conditions.

The longest-lasting systems shared:

• High-quality encapsulants

• Durable backsheets (Tedlar-based)

• Robust glass and framing

• Conservative, well-engineered designs

Where lower-quality materials were used, degradation increased, even when installed in the same location.

What this means for commercial projects

• Cutting costs on panels can quietly destroy long-term returns

• Panel choice matters far more than most buyers realise

• A cheaper system is not cheaper if it degrades faster

Key Finding #3: Heat Is a Bigger Enemy Than Cold

Interestingly, the study found that:

• Hot, low-altitude rooftop systems degraded faster

• Cold, high-altitude (alpine) systems often performed better over time

Why?

• Heat accelerates chemical ageing inside panels

• Higher temperatures increase corrosion risk and electrical resistance

• Cold environments slow many degradation mechanisms

For commercial buildings:

• Poor ventilation and heat buildup on rooftops matters

• Good system design and airflow improve long-term performance

• Thermal management is part of asset protection

What This Means for Commercial Solar ROI

This research strengthens the commercial case for solar in several ways:

✔ Longer effective system life

Solar assets can continue generating value well beyond warranty periods.

✔ Lower real-world cost of energy

Slower degradation means more kilowatt-hours over the system lifetime,

reducing true LCOE.

✔ Reduced risk for investors and owners

Long-term performance is more predictable than previously assumed.

✔ Stronger sustainability credentials

Longer lifetimes mean:

• Less panel replacement

• Lower embodied carbon per unit of energy generated

• Better environmental outcomes

Quality is non-negotiable at Lucent Energy.

Solar done properly is a multi-decade asset and we believe it should be treated as such. That’s why we never pursue cheap installs, low-grade equipment, or compromised workmanship. The research is clear: longevity, performance, and value come from quality materials and careful engineering, not from cutting corners. We design systems to endure, not just to win on price, because real value in solar is measured over decades, not at installation day.

The Takeaway for Businesses Considering Solar

Commercial solar isn’t a short-term technology experiment anymore.

When:

• High-quality components are used

• Systems are properly designed and installed

• Thermal and environmental stresses are managed

Solar becomes a multi-decade infrastructure asset, comparable to roofs, plant equipment, or electrical infrastructure.

Thinking About Commercial Solar?

If you’re considering solar for:

• Breweries or food production

• Warehouses or logistics centres

• Farms or estates

• Manufacturing or industrial sites

The real question is no longer “Will it last?”It’s “How well is it designed to last?”

If you’d like help assessing:

• Long-term ROI

• Panel and system quality

• Design choices that protect performance over decades

Feel free to get in touch.

Ózkalay, E., Quest, H., Gassner, A., Virtuani, A., Eder, G. C., Vorstoffel, S., Buerhop-Lutz, C., Friesen, G., Ballif, C., Burri, M. & Bucher, C. Three decades, three climates: environmental and material impacts on the long-term reliability of photovoltaic modules. EES Solar 1, 580–599 (2025). DOI: https://doi.org/10.1039/D4EL00040D