Tests Show Solar Panels Still Strong After 30 Years

New research finds 1990s-era panels still producing 80% of their power — challenging critics and reshaping how we measure solar’s value.

Solar panels used to be the new kid on the block — untested, a little awkward, and easy to dismiss. Utilities and skeptics alike warned the panels wouldn’t last, that warranties capped out at 20 years for a reason, and that the first wave of rooftop systems would be headed for the junkyard before they ever paid for themselves.

But now that kid is middle-aged — and still going strong. In Switzerland and France, both early testing grounds for solar, recent tests reveal panels installed in the early 1990s have logged more than three decades of service — most still producing over 80% of their original power. It’s an outcome that defies not only critics, but even the cautiously optimistic allies who once hedged their bets on a fledgling technology.

Which raises the real question: if durability of solar panels was supposed to be solar’s Achilles’ heel, what does it mean now that time has proven otherwise? How should we recalibrate its true value compared to the sources it competes with? The answer depends not just on how long equipment lasts, but on what it costs — in dollars, in pollution, and in reliability.

The Skepticism vs. The Science

For years, skeptics doubted solar panels could last long enough to justify the investment. Warranties were short, and critics warned panels would crack under weather or pile up as waste before delivering their value.

But recent field tests tell a different story. In Switzerland and France, panels installed in the late 1980s and early 1990s are still producing strong power after three decades. Researchers tested systems mounted on remote Alpine huts and valley homes alike. Despite decades of wind, rain, and snow, most panels are still generating more than 80% of their original output, degrading by only about a quarter of a percent per year. “This data really shows that photovoltaics can last longer than expected, and it’s an important message for the photovoltaic industry,” says Ebrar Özkalay, lead researcher at the University of Applied Sciences and Arts of Southern Switzerland.

There are caveats. Panels built with thicker glass, rugged encapsulants, and sturdy frames performed better than budget models. Harsh lowland heat sped up degradation, while cooler alpine conditions helped panels endure. And let’s be clear: inverters still need replacement every 10–15 years, so solar systems aren’t maintenance-free. But the central truth remains:

Solar has outlasted its skeptics — and its warranties.

How Other Sources Compare — and What They Cost

If longevity is the yardstick, other technologies clearly shine. Nuclear reactors are licensed for 40 years and often extended to 60 or even 80. Hydropower dams can run for a century with periodic refurbishments. Coal plants often operate for half a century, and gas plants for 25–30 years, as long as fuel keeps flowing. By comparison, solar’s three decades might look modest.

But years alone don’t tell the whole story. When economists and grid planners compare resources, they look at the Levelized Cost of Energy (LCOE) — essentially, how much electricity a plant produces over its life divided by what it cost to build and operate. On that measure, solar is hard to beat. New utility-scale solar in the U.S. comes in at $38–$78 per megawatt-hour. Gas runs $48–$109. Coal: $71–$173. Nuclear: $149–$251. Even if nuclear plants outlast solar, they do so at a far higher price tag.

There’s another wrinkle: Solar doesn’t run around the clock. Once the sun sets, production falls to zero, and cloudy stretches can cut output. Other technologies — nuclear, gas, coal — can run 24/7 as long as they have fuel. That’s why most homes with rooftop solar still stay connected to the grid, drawing power at night and exporting excess during the day. At the utility scale, batteries are increasingly stepping in to store solar power for evening use, while wind and hydro help fill in the gaps.

So yes, solar leans on other resources. But that doesn’t diminish its role. Every extra year a panel keeps producing is another year less coal is burned, another year less gas is piped, another year of clean electricity flowing at low cost.

Solar’s staying power isn’t just about its own longevity — it’s about how much it reduces reliance on the dirtiest, most expensive fuels.

Why It Matters Now

The timing couldn’t be more important. Electricity demand in the U.S. is spiking, driven by electric vehicles, energy-hungry data centers, and a surge in domestic manufacturing. Utilities are pouring record amounts of money into new power plants and transmission lines. Every assumption about how long equipment lasts — and what it costs — shapes those investments.

Knowing solar can perform for 30–40 years reshapes the risk calculus. It makes banks more comfortable financing projects. It stretches out the timeline for recycling and waste challenges. And it builds confidence for households wondering whether rooftop panels are worth it. In an era when the grid is under historic strain, durability isn’t just a nice-to-have — it’s part of how we keep the lights on.

The Bottom Line

Thirty years ago, skeptics doubted solar energy would survive the decade. Today, it’s proving itself as one of the longest-lived, lowest-cost, lowest-harm sources of electricity we have.

Still, solar is far from a perfect energy source. Nuclear and hydro last longer, and solar can’t run at night without help. But the real measure of success isn’t just how many years a plant runs — it’s what those years deliver. Coal’s longevity comes with poisoned air and climate damage. Gas carries price swings and methane leaks. Solar, by contrast, delivers affordable power with minimal harm — and now, proof it lasts.

Here’s what it means for you: solar is real, legitimate, durable infrastructure with staying power: decades on your rooftop mean decades of savings, cleaner skies, and a grid that bends a little further away from fossil fuels.