Solar panel degredation

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Originally Posted By: BMWTurboDzl
I've read reports where 20 yr old panels were putting out the same amount of rated power as when new.

Now much depends on the quality of the panel of course. That varies from manufacturer to manufacturer.


Some panels exceed their rated output when new. High quality PV does last longer, unlike my Chinese panels. I only have 8 panels, one of which degraded into uselessness in 14 years, but it was clear that panel was degrading many years ago. Two others are not far behind.

Take a conventional high end, name brand 200W panel. It may actually produce 220W at 1000W/M2 irradiance when new. It's degradation rate remains within the norm, but it's output still meets rated specs after many years.

Not unlike the Tesla P100D battery pack. It can lose some percentage of cells, and experience normal degradation, while still providing 100% of rated capacity for quite some time.

Yes, it's akin to "sandbagging" but it's not uncommon.
 
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what is the degradation of a typical internal combustion engine? Top Gear had done some testing on the used car classics and found out that many of the original horses do leave the engine after a decade or two.

sandbagging? it is more like bad block re-vectoring of disk drive.

talking about degradation, any time I see tv or phone with missing line of pxiels, it just happens to be a Samsung one. I have seen handful of them so far.
 
Poor analogy...
Typical IC engine is grossly oversized for the task required of it, of propelling it at along the highway, could probably lose half it's performance and still meet that mission statement.

Solar cells, which are there to harvest every scrap of energy from the environment are totally and completely different in concept.

But yes, degradation of a thermal power station is typically guaranteed at 0.5% per year...the vast majority with reasonable care come nowhere near that. And also, generally can produce over 105-110% of their nameplate rating meaning that 100% is still available most days.
 
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could probably lose half it's performance and still meet that mission statement
I just don't see solar detractors accepting a vehicle with half the horsepower, especially those specific people!

There is also no technical reason why solar is not massively over provided just like an ICE. They could do one better why software selected cells aka re-vectoring done for disk drives.

Frankly, yours or Overkills's agenda is quite clear regarding solar. We all get that.
 
Originally Posted By: Vikas
There is also no technical reason why solar is not massively over provided just like an ICE. They could do one better why software selected cells aka re-vectoring done for disk drives.


No technical reason...of course it's commercial reasons.

WHY would you pay for infrastructure that was 200% greater capacity than was required just so that it met the end of life at 100% ?

When you get paid, as a non schedulable generator at the maximum market price available in every dispatch interval for every interval that it's operating ?

You wouldn't would you ?

You put in the cheapest capital investment that you can, and take what is harvested at todays price for as long as it is generating...then someone else cleans up the problem later...just like those windmills we drove through in Ca...50 year old generators on spars, sitting there amongst new turbines...no one took down the old. Bit more difficult with Solar.

Originally Posted By: Vikas
Frankly, yours or Overkills's agenda is quite clear regarding solar. We all get that.


What agenda ?...I was responding to your post

Some people believe in a seamless transition to unicorn offgassing...I'm not one of them
 
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"It is difficult to get a man to understand something, when his salary depends upon his not understanding it!"
 
Originally Posted By: Vikas

There is also no technical reason why solar is not massively over provided just like an ICE.


Sure there is, it would take massively more space. Solar has the lowest energy density of all presently available generation mechanisms. Until that improves, using 400 acres because you want the output of 200 acres in 20 years is pure lunacy as you'll be knocking on panel EOL anyways and the whole works will need to be replaced.

I'll use a couple local examples here:

1. Lily Lake Solar Farm - 10MW nameplate, completed in 2011. Annual output is ~14,300MWh. Cost was $45 million. At $0.42/kWh subsidized rate, the facility was expected to be paid for in ~10 years (that was before 1/3rd of the panels were replaced), or just under half the life of the panels. Occupies 200 acres of land.

2. London St. Generating Station - 10MW nameplate as of 2016, Unit 1 was completed in 1884, two more turbines were added as Unit 2 in 2016. Annual output is ~40,000MWh. No idea what the original cost was because it is 133 years old. The 6MW expansion was added at a cost of $30 million and will have a lifespan of 80+ years.

The dam produces 2.8x the power at the same nameplate and will last 4x longer. Heck, half of it is already 5x older than the lifespan of the solar farm! On top of that, the 6MW expansion was $15 million cheaper. The size difference between the two installs is also staggering!

I've created the below from Google Maps to demonstrate the size difference (entire dam assembly is in the upper right corner box):




I'm not against solar. But it needs to increase in density, drop in cost, increase in longevity and stop being subsidized to push its market penetration when it is incapable of doing the job of far less expensive modes that don't only work on a specific schedule and sporadically vary their output requiring other modes to be on standby to prop them up.
 
Originally Posted By: Vikas
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it!"


Ahhh...projection onto others usually means that it's a flaw that you observe in yourself.

Nope, I'm pretty cogniscent of what's out there...can't really comment on the projects that I've kicked off, completed, and had still born over the last 25 years.

But honestly, in your own engineering assessment, would you spend 20-30% more capital cost on cells then not use them today ?

Really ???

The only way projects like that fly is when you are spending handfuls of other people's money.
 
I agree with Overkill on hydroelectric. The ROI on hydro projects that are in use has been spectacular. In the PNW, we are blessed to have an abundance of hydroelectric produced power. Another benefit is the irrigationthe dams produce which has transformed huge regions of arid land into very productive farmland. WA state in particular has been very fortunate.

The Greenies however would love to get rid of the dams and set us back a hundred years or more.
 
Originally Posted By: OVERKILL
Originally Posted By: JHZR2
Originally Posted By: OVERKILL
Originally Posted By: JHZR2


...

Without all these and more verified and fully understood, it's not clear to me how the panels can be assumed to be degrading nad the definite root cause.


...

So obviously there are other factors in play here to create what appears to be the trend demonstrated in the table.


My point exactly. Lots of other phenomena may affect the output, not just the panels....


Certainly, but there's what appears to be a trend with the reduction in output if you look at the table. So while degradation may be a factor in this, as another poster pointed out, it would be above the warranty threshold on the panels, so what else is going on? It isn't desirable, that's why I'm interested. Obviously there is a degrading trend in output, and if it isn't from the actual panels themselves losing efficiency, there's something else creating the trend.


Which again is why without suitable assessment and resolution of many of the items I listed, the question will remain rhetorical.

Im curious what chemical phenomena can be well defined to justify performance loss beyond what the vendors claim and warranty to. Time at temperature affects everything, and so even if we hand wave that argument against the panels, many other components involved would have similar exposure.

Id be much more likely to point the blame to solder, interconnects, dirt, grime, power electronics, etc.

In power electronic circuits, one has to consider the DC losses and switching losses, losses in semiconductors and in high frequency transformers, etc. The losses in the circuit can then be calculated as the overall resistance between input and output of the circuit and the output current.

Its well understood that the on-state resistance of Silicon devices increase with temperature. For IGBTs (a core element of many power electronic converters), the resistance change is around 40% between 0-100C. Silicon Carbide devices have smaller losses, say 10% in that temperature range. This stuff needs to be kept clean and cool just like the panels.
 
Originally Posted By: Shannow
Originally Posted By: Vikas
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it!"


Ahhh...projection onto others usually means that it's a flaw that you observe in yourself.

Nope, I'm pretty cogniscent of what's out there...can't really comment on the projects that I've kicked off, completed, and had still born over the last 25 years.

But honestly, in your own engineering assessment, would you spend 20-30% more capital cost on cells then not use them today ?

Really ???

The only way projects like that fly is when you are spending handfuls of other people's money.


Let's face it, there is always margin built into a system design, to account for many things, component degradation being just one...

And there is a healthy tension between bean counters, designers and maintainers to define what is the right level of margin to ensure a system is useful across its lifecycle.

Im not saying things need to be x00% over designed, especially something that should be able to be dispatched like a solar power electronic converter, and which should be relatively low penetration compared to other generation.

It is disappointing if they are degrading faster than desired. Thing is, since these things aren't dispatched that Im aware of (for lack of better terms; told when and how much power to provide to the grid, they just output to the grid by frequency sync and an over potential), they are always putting out 100% of what they are capable of. Therefore, any excess capacity to make up for degradation would not be relative to installed capacity anyway... as excess capacity would always be putting out more, unless the conversion was undersized relative to the panel ratings, and why would anyone do that?
 
Originally Posted By: JHZR2
It is disappointing if they are degrading faster than desired. Thing is, since these things aren't dispatched that Im aware of (for lack of better terms; told when and how much power to provide to the grid, they just output to the grid by frequency sync and an over potential), they are always putting out 100% of what they are capable of. Therefore, any excess capacity to make up for degradation would not be relative to installed capacity anyway... as excess capacity would always be putting out more, unless the conversion was undersized relative to the panel ratings, and why would anyone do that?


Yep, the normal use of Solar and wind is that they harvest everything that they can at the time, it goes in first, and everything else has to dance around it...the solar wind then get paid the highest spot interval price called onto the market.

To date, that's been the model in Oz, but with the massive penetration in some states have lead to instability, volatile pricing, and the thermals exiting the market. Standards are being revised such that these systems MUST provide a reserve margin (like governor control on a thermal) so that they can bolster frequency and provide "virtual" inertia.

Short of reverting back to a centralised generating model it makes some sense.



edit, just to get a feel for the levels that are being used in Oz, here's what's happening at 12:00 on a cold, windy Sunday.

Numbers up the top are the price in $/MWh for the wholesale spot market in the different states. (divide by 10 to get the c/KWh)
 
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Originally Posted By: JHZR2


Which again is why without suitable assessment and resolution of many of the items I listed, the question will remain rhetorical.

Im curious what chemical phenomena can be well defined to justify performance loss beyond what the vendors claim and warranty to. Time at temperature affects everything, and so even if we hand wave that argument against the panels, many other components involved would have similar exposure.

Id be much more likely to point the blame to solder, interconnects, dirt, grime, power electronics, etc.

In power electronic circuits, one has to consider the DC losses and switching losses, losses in semiconductors and in high frequency transformers, etc. The losses in the circuit can then be calculated as the overall resistance between input and output of the circuit and the output current.

Its well understood that the on-state resistance of Silicon devices increase with temperature. For IGBTs (a core element of many power electronic converters), the resistance change is around 40% between 0-100C. Silicon Carbide devices have smaller losses, say 10% in that temperature range. This stuff needs to be kept clean and cool just like the panels.


I feel like we are watching these experiments slowly unfold in real-time due to the mass installation of all these huge industrial solar farms. Given this rather extensive list of other contributors to the overall decline in performance I think it will be interesting to see how it pans out for other installs as they age. Certainly this one example in Texas can't be the only one to be experiencing this trend.
 
Originally Posted By: turtlevette
I did some commissioning at a solar farm. It wasn't even on line yet and the panels were getting milky looking from water intrusion.




That's incredible
crazy2.gif
 
Originally Posted By: OVERKILL
Do you mind if I save those?


Send me an address and when I have a bit more bandwidth I'll email the originals.
 
Originally Posted By: JHZR2
Originally Posted By: OVERKILL
Do you mind if I save those?


Send me an address and when I have a bit more bandwidth I'll email the originals.


Sounds good!
 
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