How long will panels really last?

[Brian53713]

I would love to hear all the trusted experts opinions on how long modern solar panels might really produce their rated power and prorated power?
And if brand or origin, or size determines any of that .

[J.P.M.]

I would love to hear all the trusted experts opinions on how long modern solar panels might really produce their rated power and prorated power?
And if brand or origin, or size determines any of that .

I don't claim trustworthiness but as an opinion based on observation, I'd say PV panels have been around a long time, but in large numbers for maybe ~ 10 - 12 years. With not too many failures (so far), it may well be that a lifespan of 25 - 30 or more years is possible, but I'd suggest that no one has a lock on certainty for the future. With that said, if I was a betting person, I'd say that most arrays less than 10 yrs. old today will still have meaningful production 20 years from now.

Seems like panels may be fine. Inverters may well be the weak link and need service sooner, or be the area where things improve the most based on the squeaky wheel principle.

I'd also bet that it's more likely technology and/or the need to have the latest toys will make today's products obsolete before failure or production drop off becomes a common problem.

[solarix]

I would wager that the typical PV panel will still be operating and productive (within the generally used 0.8%/year degradation rate) at least 50 years from now. The world may have gone to hell, or the coasts may be underwater, and your inverter will be replaced, but the PV panels will still be going strong.

[cebury]

That % of degradation isn't based off original rating is it? Ie at year 10 is it approx, 8% or is it like compounded interest in the negative, so whatever recursively .8% is each year, by year 10? I realize it's just an estimate and this is mostly academic, but curious.

[J.P.M.]

That % of degradation isn't based off original rating is it? Ie at year 10 is it approx, 8% or is it like compounded interest in the negative, so whatever recursively .8% is each year, by year 10? I realize it's just an estimate and this is mostly academic, but curious.

The way I read the warranties, it's a constant rate/yr., not compounded. That is, a 300 Watt panel that is warrantied to lose no more than, say, 0.7 % of it's output/yr. would lose no more that (0.007 * 300) = 2.1 Watts of it's prior year's output per year.

So, at, say, 10 years, that 300 Watt panel ought to test at no less than 300 - (300*.007*10) = 300 - 21 = 281 Watts under test conditions identical to the original test conditions.

The 0.7% degradation is off the original STC rating, not what that panel would have tested the prior year (except at year one of course). At least, and to repeat, that's how I read the written warranties.

Verifying actual output however, is next to impossible for homeowners in any realistic, practical sense, making the question effectively moot.

[bcroe]

Come back in 50 years when there is better data. Bruce Roe

[SunEagle]

Let me set my cryogenic alarm clock for that one.

[inetdog]

Note also that unlike the situation for compound interest where you are adding to the original sum, the result of a compounded yearly calculation would be a lower degradation at the end of N years than a loss of n% of the original capacity each year.

Looking at it another way: A straight 10% per year would leave no capacity at all at the end of 10 years, while a 10% loss of the remaining capacity would never actually reach zero output.

[sdold]

We have several radio sites that have panels that have been there for over 30 years. The only replacements I can remember have been due to lightning, vandalism or theft.

[Brian53713]

What technology or style were some of those panels?

[sdold]

They look like they are constructed like the panels that are made today, I don't know what the differences are. I think they were mostly made by Siemens and ARCO. I don't know if my modern grid tie panels are less rugged, but I'm not worried about it. My panels aren't mounted on a mountain top with snow, ice, lightning, vandals or any of that.

[Brian53713]

So is it safe to say, when the president-elect more than once said panels only last 10 years and take 25 years to pay for themselves he was mixed up? I was encouraged, but not supportive when he mention them early on and then later. But that's when I heard him sound mixed up.

[SunEagle]

So is it safe to say, when the president-elect more than once said panels only last 10 years and take 25 years to pay for themselves he was mixed up? I was encouraged, but not supportive when he mention them early on and then later. But that's when I heard him sound mixed up.

Well panels may last 30 years but in some place still take 25 years to pay for themselves. It all comes down to multiple factors like; installation costs, electric power rates, electric power usage, location of the pv system, efficiency of the pv cells, cloud cover, damage from hale or other objects, etc.

There are just too many variables to make a blanket statement of when a solar pv system will show an ROI. For some it can be just a few years. For others it can be decades.

[J.P.M.]

So is it safe to say, when the president-elect more than once said panels only last 10 years and take 25 years to pay for themselves he was mixed up? I was encouraged, but not supportive when he mention them early on and then later. But that's when I heard him sound mixed up.

Whatever else can be said about the president-elect, I don't think it would be accurate to suggest he's what one would call a solar expert.

If you believe much of anything any politician says, I still have a bridge for sale.

[Logan5]

I have an 30+ year old Siemens 75 watt panel, compared to today's high watt panels, it is much stronger aluminium and thicker glass. I have used and abused, from Pond to pond, battery to battery. I have drilled holes in the frame and mounted it a hundred different ways. If I had to guess, I would say it can last another 20 to 30 years. the new high watt panels i have are made efficiently with less metal, thinner glass, not as durable for experimentation.

[SunEagle]

I have an 30+ year old Siemens 75 watt panel, compared to today's high watt panels, it is much stronger aluminium and thicker glass. I have used and abused, from Pond to pond, battery to battery. I have drilled holes in the frame and mounted it a hundred different ways. If I had to guess, I would say it can last another 20 to 30 years. the new high watt panels i have are made efficiently with less metal, thinner glass, not as durable for experimentation.

Like everything now. To get the price down for most commodity items the quality in materials and manufacturing has also been reduced.

I remember when a 5 hp motor was really a 10 hp frame but only rated a 5. Built like a tank. Now a 5 hp motor (while maybe more efficient) is much smaller and looks like a paperweight and lasts 1/3 the life it use to.

[J.P.M.]

Like everything now. To get the price down for most commodity items the quality in materials and manufacturing has also been reduced.

I remember when a 5 hp motor was really a 10 hp frame but only rated a 5. Built like a tank. Now a 5 hp motor (while maybe more efficient) is much smaller and looks like a paperweight and lasts 1/3 the life it use to.

And probably costs less, but admittedly and probably not 1/3 as much as it would if it would if it were built like the 10 HP motor you remember.

Like using gold bars for paper weights when lead - or a rock - will do, excess quality comes at a price. While perhaps comforting, as long as a product and its quality are fit for purpose, overbuilt and overkill beyond some thoughtful common sense is usually not cost effective.

If I need a 5 HP motor, I don't like the idea of paying for more than I need because of someone else's quite possibly ill informed idea of quality if I can help it. That would be sort of like wanting PV power for my house and only having Sunpower panels to choose from.

[Brian53713]

Am I hearing that a 36 cell panel maybe more sturdy than the larger ones. Making it important for if one was making a ground mounted movable human powered tracking device? Another question how long have inverters& charge controllers been lasting? And how long have mppt been around?