Looking at six solar arrays in Switzerland that have been running since the late 1980s and early 1990s, the team found most panels still produced more than 80% of their original power after three decades.

Temperature turned out to be a major character in the story. The study reports that lower-altitude systems faced higher thermal stress, with module temperatures reaching about 20 degrees Celsius warmer than high-altitude sites, and those hotter panels tended to degrade faster.

Some of the wear mechanisms were very specific but easy to picture. The encapsulant, the clear plastic layer that helps protect and hold the solar cells, showed more breakdown in hotter conditions, and the researchers linked that to chemical byproducts that can contribute to corrosion over time.

Decades?

25 years is “decades” too

Three decades, three climates: environmental and material impacts on the long-term reliability of photovoltaic modules† https://pubs.rsc.org/en/content/articlelanding/2025/el/d4el00040d

the paper

"warranty" is a label that manufacturers put on the product for legal reasons. there's no reason to assume that the product will break after that point. literally some products last 5x what's written on the warranty.

We have some 25yo panels around, small 25-40W ones. They usually die because the diode goes (which is fixable) or one of the traces in the back gets water in it and it shorts. We're probably down to about 2 out of 10, and those were high quality panels at the time.

And for what we paid for one 40W panel then, you could buy 2000W worth today.

accounting depreciation is different from real world performance

Most roofing in the US barely lasts 25 years.

Most roofs last 25-30 years or so. I suspect the amount of time that solar panels need to be replaced is around the same time since replacing the panels after you replace the roof only a few years beforehand might be most costly.

This is like my wet dream right now. Please let perovskites cover the world!

I’m sure they will build them to fail

examined six grid-connected solar systems installed between 1987 and 1993 across different Swiss regions

tldr, ambient heat makes a huge difference. Switzerland doesn't get that hot anywhere, and even less so in mountains.

But these are extremely old panels. Panels in 2020 started shipping with 40 and 50 year warrantees. But even panels that drop to 50% of original capacity, 60-100 years later, the best strategy for adding more power is more panels rather than ripping out and replacement. For a house, that can mean balcony solar, east/west, solar sheds, driveway awnings or solar RVs.

My grandmother had an incandescent light bulb in her house that had been there since the early 1900s and still worked. But, compared to modern bulbs it was pretty dim, used very thick glass, and was pretty overbuilt. Modern incandescent bulbs are not built to last. They're brighter, and they're cheaper, but not as durable.

Looking at the picture, I wonder if modern panels will last the same way.

Solar panels in the 1980s were big, inefficient, chonky things. If they weren't hand assembled, they sure looked hand-assembled.

Modern solar cells are much more efficient and clearly machine assembled. They use much finer wires, which might be more fragile:

It wouldn't surprise me if part of the trade off to get cells that have double the efficiency at half the price you also have to give up on some durability.

I have a few solar panels installed in 2008.

They are mounted in an extremely bad location: on a south facing wall, without proper airflow on the back side.

They continue to work, even if output is degraded. Newer planels installed in the same location overheated and their elements cracked, indicating inferior manufacturing quality, but the oldest batch is not showing this symptom.

25 years is still a very long time.

The real question is, will it be worth replacing them with whatever is out after 25 years of efficiency improvements.

Many Japanese homes are still using solar water heaters that were installed in the 1980s. They’re very inefficient now, but they still work if you take care of them.

exactly! they can last at least 2.5 decades.

Same goes for EV batteries. It’s just fear mongering.

Two and a half decades, to be precise.

Let me know when solar efficiency is significantly higher.

25 years

Decades

Solar panels don't "die" at all, they just slowly lose production over time.

This would be a big problem for capitalism, but thankfully it's 30 years in the future making it impossible for capitalism to foresee.

I bought my current house with a specific clause that the solar panels were 11 years old at the time, the transformers were at the end of their lifespan and the panels strongly degraded.

now, 12 years later, the panels are performing at abooout 95% of new, when adjusting for what the sticker claims and how the new panels perform on the same roof. 1 of the 6 transformers has also died. Granted, that was shitty to replace, it was one of those "plug one panel into an outlet" things that were common back then.

It's definitely not altitude that's saving them, I live about as low as anyone on earth, below sealevel