Slashdot Mirror
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.
Violence is the last refuge of the incompetent. Polar Scope Align for iOS
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.
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.