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SolarCity Pushing Industry To 40% Increase In Useful Lifetime of Solar Power Installations (electrek.co)
An anonymous reader writes: SolarCity released a new report that says solar power systems have a usable lifetime of at least 35 years, which is 40% longer than what the market expects. Electrek reports: "The key finding of the report is that power degradation (annual efficiency loss) of solar panels supplied to SolarCity is as much as 35% lower than for a comparable industry-wide selection of non-SolarCity panels, which are typically expected to last for 25 years. In the study here, SolarCity looked at greater than 11,000 panels to determine their data points and come to their conclusion that their solar panels are performing well beyond expected industry standards. Today, standard efficiency solar panels put out by Tier 1 suppliers are generally warranted to lose no more than 0.7% efficiency per year for the first 25 years -- this is the Power Production Warranty. The key finding in this study is that the annual 0.7% efficiency loss is too high an estimation -- and that the number ought be closer to 0.5%. While it might seem a small number -- a difference of 0.2% -- when applied over a multiple decades timeframe, it means that instead of the standard twenty five year assumed productive life, we can expect at least another ten years of production above 80% of the original system output. Large installers like SolarCity, able to do this type of wide-scale research -- and to also demand higher quality, are showing their ability to pull the manufacturers of the world upward. With SolarCity building their own solar panel Gigafactory we ought expect the quality levels to be even greater in the near future.
I get a 404 error on the first link. The actual report link is at : http://www.solarcity.com/sites/default/files/reports/SolarCity%20Photovoltaic%20Modules%20with%2035%20year%20Useful%20Life.pdf
As for the degradation of panels, I have a 10kW system made of relatively inexpensive Chinese Renesola Virtus II hybrid panels for over 3 years now and I have seen no measurable degradation in performance so far. And I even look at the peak days of month to avoid the issue of daily weather and still it seems the peak has not reduced (rather increased by 1% which should be within the margin of error) in these three years. So there goes two myths my installer told me "you need to pay me to service and wash them every year to maintain peak output" and "output will measurably drop yearly anyway though". No I haven't washed them. So, I don't know if they will continue this trend or will suddenly drop in efficiency, but at least for the first few years they seem stable.
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It's even simpler than that. How can any company, that has only existed for 9 years, have any proof their product lasts 35 years let alone even 10?
By using math.
What's the expected lifetime and warranty of the inverter? The cost of inverters seem to be about $0.40 per watt so for a 3,000 watt system it would cost ~$1,200. There surely are It looks like they are warranted for 5 years but one would hope they would last longer than that. And I'm sure there are service contracts with guaranteed replacement. How many would be needed over 35 years? Hopefully not too many.
In a time of universal deceit, telling the truth is a revolutionary act. George Orwell
Good for Solar City.
They're still not putting their panels on my roof and charging me money for the electricity they generate. They can lease the space from me, but if they retain full ownership interest in the panels, I'm not giving them anything for free, much less paying them for the privilege.
Solar city came around and handed out brochures, and I got an estimate from them.
Of their 3 plans in the estimate, none "charge me" for the electricity they produce. The three plans are three tiers representing the amount I pay up front, and the amount my electricity bill is reduced going forward.
So in other words, I could buy the panels outright ('sorta) and get a big reduction on my electricity consumption, or I could pay nothing and get a small reduction.
All of which was surveyed to my house, which accounted for the latitude, number of sunny days, estimated cost of electricity, and my average usage.
Putting up solar cells is a project that a lot of people don't have the skills or ambition for (especially older folks) - this is basically a turn-key solution. "Pay nothing, get a (small) decrease in electricity costs, and we'll maintain the system for 20 years".
For a lot of people, it's a good deal.
Just an anecdote, I lived in Brisbane Australia. We got some horrendous hail storms, my most memorable being one where the golfball - tennisball sized hail wasn't even round but rather had sharp edges.
I was wondering the same thing as you were one crazy storm we had so I went to watch my neighbours panels (my house was slightly taller than theirs). I was not so happily watching these huge hailstones deflect off their panels ... shatting the windows in my study. Zero damage to their panels. I had to replace windows on the side of my house deflected by their roof, and everyone in the street had the insurance company replace their cars as we didn't have car ports.
Sidenote: I've never seen so much damage to a 4-wheel drive. All windows completely missing except for the windscreen which shattered but didn't actually fall out due to being laminated.
But this is just an anecdote. These panels are super tough, and glass (well it's not actually glass) does incredibly well under compression loads with a lot of the force of impact absorbed by the various layers underneath like the substrate and metal backing.
So one witness in court claiming he saw the murderer is not proof but an anecdote?
Unless the testimony of that witness can be corroborated in some way then that is correct. By itself it is rarely sufficient because shockingly, people lie and are routinely wrong even when well intentioned. When it comes to science and engineering, eyewitness testimony is close to worthless and anecdotal evidence is generally considered dubious for good reason.
You americans are really quite dumb. Or your school system ... or what ever.
Really? You don't understand the difference between data and anecdotes and we are the dumb ones? Curious bit of logic you have there...
BTW: solar panels, as in photovoltaics, exist since over 50 years. We have a pretty good idea how long they last and degrade.
You do realize the panels we produced 20+ years ago are not identical to the panels we produce today, right? That's like claiming an 8086 chip from Intel should have the same failure modalities and rates as a modern Pentium chip. Your point is correct that we have a fairly good idea how they degrade but the reasons why are a lot more complicated than the fact that solar panels have been made for a long time.