When the panels start to degrade under normal use?

[paulcheung]

Hi guys,

How long does these solar panels last? some dealer tell me 20 years and some tell me 25, when will these panels start degrade and lose their efficiency due to normal wear and tear?

Will the panels used on trackers system last less time because of intensive use?

Thanks

[Ian S]

Hi guys,

How long does these solar panels last? some dealer tell me 20 years and some tell me 25, when will these panels start degrade and lose their efficiency due to normal wear and tear?

Will the panels used on trackers system last less time because of intensive use?

Thanks

Typically it's a very gradual loss over time. Most manufacturers provide some kind of warranty for 25 years. Probably the majority of panels made in the last 5-10 years will still be productive 30 years after installation. Apparently there's a German installation from 1976 that was still going strong in 2011.

[paulcheung]

Do you have any idea when it will start to degrade and by how much percent? I know we have some members in this form gone off grid over ten years, do they see any problem with their panel production?

Thanks.

[J.P.M.]

Do you have any idea when it will start to degrade and by how much percent? I know we have some members in this form gone off grid over ten years, do they see any problem with their panel production?

Thanks.

In real life, every sit. is different. Some rate of degradation of output is listed with most panels, often .5% to 1.0%/yr. of original output. That # is probably a good 1st approx. and may be a bit conservative. Additionally, when new, some/most panels will have a faster deterioration for the 1st yr. or, so. That type of decrease often must be deciphered from the warranty or product lit. and may be as much as 3% to 5% the 1st yr. The longer term deterioration may start at manufacture, but more likely by install/startup and may be linear, asymptotic, or something else. Prod. hype will sometimes claim less, and that may in fact be the case, but I'd stick to the written warranty for planning and life cycle costing purposes. If the hype claims were/are true and reflective of reality, the warranty would be a closer match to that hype than they usually are.

[pleppik]

Do you have any idea when it will start to degrade and by how much percent? I know we have some members in this form gone off grid over ten years, do they see any problem with their panel production?

Thanks.

Most panels have warranties against power degradation for 20+ years; generally it's something like not more than 10% drop in power output. Beyond 20 years, the conventional wisdom is that they'll keep working for a very long time as long as there's no physical damage. A PV module is completely solid state and very simple; there's no much to go wrong.

For planning purposes in my upcoming solar installation, I used a degradation of 0.3% per year. Your mileage may vary.

In the real world, I suspect you are much more likely to see failure because of either a) manufacturing defect, which will show up very quickly, b) degraded seals allowing moisture to penetrate the module, or c) physical damage from a storm.

[inetdog]

Hi guys,

How long does these solar panels last? some dealer tell me 20 years and some tell me 25, when will these panels start degrade and lose their efficiency due to normal wear and tear?

Will the panels used on trackers system last less time because of intensive use?

Thanks

Different technologies (crystalline versus thin film for example) will have very different degradation rates.
For the same basic technology, the details of the design and fabrication can have a smaller effect.
For the same technology and design, the life of the panel can be affected by both the effect of sunlight on the cells and the degree to which moisture, for example, can penetrate the seal of the panel.
I would not think that the extra exposure to sunlight in a tracker system will be a very large factor.

[paulcheung]

Ok thanks.

How about the inverter and the charge controllers, are they last more than 10 years? any one still using the same system over 10 years? I guess the batteries is the one more likely to go first.

Thanks again.

[inetdog]

Ok thanks.

How about the inverter and the charge controllers, are they last more than 10 years? any one still using the same system over 10 years? I guess the batteries is the one more likely to go first.

Thanks again.

If you have batteries, they are 99% likely to go first, unless there is an unusual occurrence with some other part of the system.

Inverters and CCs, if not abused, can last for 20 years also, but 10 years is closer to a realistic expectation. Electrolytic capacitors in the electronics are often the first thing to go, and elevated temperatures (roof, attic, outside on wall) are going to decrease the life of electronics.

[peakbagger]

I think the bigger issue with solar panels is defective manufacture. By the time you know about it, the company has probably gone bust and you have no hope of getting new ones even if they were still in business.

[paulcheung]

If you have batteries, they are 99% likely to go first, unless there is an unusual occurrence with some other part of the system.

Inverters and CCs, if not abused, can last for 20 years also, but 10 years is closer to a realistic expectation. Electrolytic capacitors in the electronics are often the first thing to go, and elevated temperatures (roof, attic, outside on wall) are going to decrease the life of electronics.

When you said abused, mean over load and so? well I make sure they are not and also the place I have them is try and cool with plenty ventilation. I just want to have a general idea so know what to expect. I am almost off grid totally, only use the POWco about 100 to 160 kwhs per month to heat the instant water heater in the mornings and occasionally full charge the battery banks.

Thank you.

[SummersWood]

Accelerated panel degradation test results

I was fortunate to attend Solar Summit Conference hosted by the Fraunhofer ISE in Freiburg Germany in 2012.
Previously, I had assumed that UV light slowly disrupted the silicon crystal structure and that PV panels slowly faded away.

One talk at the conference was how one can model the long term degradation of PV panels.
The study used accelerated aging of a few 1000 hours exposure to high temp/high humidity (85°C/85%rh).
A panel can be tested to obvious failure within 4-6 months. The test results were enlightening.

It seems the real achilles heel of a PV panel is the polymeric encapsulation (EVA) of the cells.
The enemies are water vapour slowly being absorbed by this material and UV photo-degradation of the EVA as well.
Moisture causes hydrolysis (Acetic acid from EVA) and thence corrosion of the photoactive silicon.

Mechanical stress on cells and interconnects is caused by daily temperature cycling, which is extreme for PV panels:
from cool night temperatures to greater than 25°C above the ambient when in full sun.

Long term life is quite dependent on the the ambient climate: Alpine (cold) climate has best lifetime,
then desert (hot arid) climate and then tropic (hot humid) climate as worst lifetime.

[J.P.M.]

I was fortunate to attend Solar Summit Conference hosted by the Fraunhofer ISE in Freiburg Germany in 2012.
Previously, I had assumed that UV light slowly disrupted the silicon crystal structure and that PV panels slowly faded away.

One talk at the conference was how one can model the long term degradation of PV panels.
The study used accelerated aging of a few 1000 hours exposure to high temp/high humidity (85°C/85%rh).
A panel can be tested to obvious failure within 4-6 months. The test results were enlightening.

It seems the real achilles heel of a PV panel is the polymeric encapsulation (EVA) of the cells.
The enemies are water vapour slowly being absorbed by this material and UV photo-degradation of the EVA as well.
Moisture causes hydrolysis (Acetic acid from EVA) and thence corrosion of the photoactive silicon.

Mechanical stress on cells and interconnects is caused by daily temperature cycling, which is extreme for PV panels:
from cool night temperatures to greater than 25°C above the ambient when in full sun.

Long term life is quite dependent on the the ambient climate: Alpine (cold) climate has best lifetime,
then desert (hot arid) climate and then tropic (hot humid) climate as worst lifetime.

Any path to a copy of the paper ?

Thanx.

[SummersWood]

PV lifetime research

Any path to a copy of the paper ?

Thanx.

The particular presentation to which I referred, was not made publicly available.
Fortunately there exist publicly google-able presentations with similar/updated information:

http://www.nist.gov/el/building_materials/upload/SLP-koehl-130305.pdf

Is an updated presentation from Monterey 2013 conference but this omits
the explanation of the effects of moisture on PV lifetime as I had stated:

Moisture causes hydrolysis and corrosion (Acetic acid from EVA)

And these presentations indicate the direction of research into moisture effects:

http://www.nrel.gov/docs/fy13osti/58372.pdf

http://www.semiconwest.org/sites/semiconwest.org/files/docs/4_International%20Standards%20on%20PV%20Module%20Quality_%20Reliability_Michael%20Koehl.pdf

The effect of local climate conditions are well explained: cold/arid good, hot/humid bad.
What is striking is the rapid drop of of performance under accelerated ageing.

[J.P.M.]

The particular presentation to which I referred, was not made publicly available.
Fortunately there exist publicly google-able presentations with similar/updated information:

http://www.nist.gov/el/building_materials/upload/SLP-koehl-130305.pdf

Is an updated presentation from Monterey 2013 conference but this omits
the explanation of the effects of moisture on PV lifetime as I had stated:

And these presentations indicate the direction of research into moisture effects:

http://www.nrel.gov/docs/fy13osti/58372.pdf

http://www.semiconwest.org/sites/semiconwest.org/files/docs/4_International%20Standards%20on%20PV%20Module%20Quality_%20Reliability_Michael%20Koehl.pdf

The effect of local climate conditions are well explained: cold/arid good, hot/humid bad.
What is striking is the rapid drop of of performance under accelerated ageing.

Thank you. Looks like interesting reading.

Regards,

J.P.M.