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.
I wonder if new panels last even better, since there’s been more R&D done and manufacturers should have more experience now
Or worse because how to make.money selliing more panels, aka the enshitifcation of solar.panels.
That said I had some installed on my off grid solar cabin 20 yrs ago, 220w per panel, had some new panels installed on my small rural cottage late last uear, 370W per panel, same size panel, so that was sweet. I retired decades ago and run my home through the day on solar (hot wayer system only switches on to use solar thru the day, induction cooktop etc). and sell the excess solar to the grid, including charging my ecar off solar only.
I am not sure how this is new though, i’ve always worked on a 1%-2% degredation per year for panels, not a cliff like degradation.
Proofreading never killed anyone.
I highly suspect so. Chemicals are just so much better than they were in the past.
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.
In most industries for expensive items, manufacturers devise warranties to run out before the product is broken. Making it longer has a relatively small benefit (consumers might put a little bit more confidence in the longevity of a product with a 25 year warranty than one with a 20 year warranty), and making it too long has a pretty high cost (a bunch of warranty claims).
Especially if the useful lifetime is not well known, the incentive is for manufacturers to underpromise in their warranties. All of this applied to solar panels sold 25 years ago, and 25 years was long enough to sell people in solar panels and a line of credit as something that would pay for itself. In that context, I think it would be surprising if the panels didn’t last far longer than the warranty promised.
It’s just the time the manufacturer is willing (or forced) to be held liable for certain defects to be caused by manufacturing errors instead of expected wear and material degradation.
Unless something is mission- or safety-critical, replacing it before it breaks is wasteful.
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.
The development in recent years has been insane. I’m positively astounded.
accounting depreciation is different from real world performance
Depreciation says a computer evaporates after 3 or 5 years in most companies.
These days computers are replaced after the 3-year service warranty in many companies, we would just toss them to the recyclers (or the back of my car sometimes if I had a project happening at home…) Occasionally they would find second use somewhere reliability didn’t matter, but a lot of IT managers won’t risk it, production downtime for a $700 PC is not worth it. My last job in a factory I had to get written permission from an IT manager to redeploy an out-of-warranty system, or could be fired when it failed.
I see. that’s good for us, since lightly pre-owned corpo laptops are cheap
With planned obselecence they might as well
Most roofing in the US barely lasts 25 years.
25 years? Good luck getting even that far, unless you put solar panels on top of them…
(Replaced roof after 15 years, and lots of repairs starting at 10 years)
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.
Modern LED bulbs last far longer than incandescent ones
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.
apparently insurance companies will replace the whole array if one panel gets hail damage. this means there’s plenty of perfectly good panels for free out there. perfect for powering or heating a tool shed or something
What roof only lasts 30 years? I’ve seen even unglazed concrete tiles, the really cheap ones that were from the 60s and still fine.
Asphalt shingles in rainy locations. Unless you want to shell out for slate, concrete, or metal roofing, expect to replace the roof every 15-20 years.
Slate is the way to go if your structure can support the weight. You’ll get 100+ years out of it, but it’s up to 10x more expensive than asphalt shingles and many owners want the cheapest option due to finances or not intending to live in the home long term.
Oh, okay. Around here, those are only used for garden sheds, maybe.
This is like my wet dream right now. Please let perovskites cover the world!
I’m sure they will build them to fail
Same goes for EV batteries. It’s just fear mongering.
Those do degrade. New chemistries will hopefully lead to longer lasting though. Also different tech, solar doesn’t have the same chemical reaction that can degrade. Not sure how solar degrades, it might be more from the manufacturing process.
I have been a licenced tech for 30 years. Have worked on EV since 2013, and have never seen a degraded battery to the point it requires replacement.
QED for everything everywhere forever.
the older nissan leafs didn’t have any mechanisms to cool their batteries so they degraded really fast and they’re about the only cars old enough to have that long range real world data on, they’ve fixed that issue now
Do you guys seriously think the batteries don’t degrade? They do, and they will need replacing. Plenty of hybrid batteries have been replaced. Or is everyone still stuck in “cars only last 200,000 miles” mentality, because electric motors last a hell of a lot longer.
they do, just not as fast as many assume
So even you conclude they will need replacement, and apparently your big point is “later than many assume”. Emphsis on many and assume. Not experts that calculate. JFC. I’m out.
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.
That’s an entirely different technology. A solar water heater is essentially a specialized greenhouse with tubes and no moving parts. You just need go clean them every one to 4 years.
Oh no. Water heaters are the most efficient form of solar. Newer solar water heaters might be a bit more efficient than old systems, but we are talking like 80->90%. PVC solar peaks in the 20% range.
20% of a looot of energy is still a lot though
What’s funny is it’s enough energy that a heat pump water heater + solar ends up being more efficient than a solar water heater. Especially in a warm environment.
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.
exactly! they can last at least 2.5 decades.
At least add “more” afterwards…
They could last up to 2.5 decades or more!
How’s that?
but that would be grammatically incorrect, wouldn’t it?
Right, maybe it’s “longer” instead? Not sure!
