From Guest Blogger Mathias: Kyocera's Solar Panels Seems to Degrade Slower
Solar panel systems from the Japanese manufacturer Kyocera that were installed in a small French near Lyon has been up and running for exactly two decades now.
This about how long the warranty for solar panels lasts. What is remarkable about the 20-year old solar panels is that they show much less degeneration than what is expected – 8.3% reduction in performance when output levels were measured and compared to original levels. In other words, these solar panels still performed at 91.7% of their original maximum power output!
Most solar panel manufacturers offer a full warranty of 25 years. The power output is guaranteed to not drop below 80% before the warranty expires. It is also common to receive a separate guarantee for 90% that is valid for the first decade.
Atomic Energy and Alternative Energies Commission (CEA) carried out the tests at the certification laboratory CERTISOLIS. Hespul, a French non-profit organization with focus on sustainability and renewable energy sources, funded the remarkable solar system consisting of 15 modules at 63 watts (945 watts in total).
That test results from reality (not just simulations in the lab) can show these results is good news for the solar industry in general. There has been many technological advancements since Hespul`s solar system in France, and if solar modules could be built this robust 20 years ago, chances are today`s solar panels will last a long time as well.
Kyocera was funded already back in 1959, at the time a ceramics producer, but since then has moved towards the photovoltaic industry. In the last year, the company has sold for more than 1.19 trillion yen (about $14.5 billion).
For more information on residential solar, check out best solar panels, how much they cost at Energy Informative.
Hmmmmm. Back in 2000 and 2001, Kyocera had a very bad run of their 120W modules (they had very poor solder joints). Very few of those modules still work at any where near their rated power; Kyocera, to their credit, stepped up to the plate and replaced any that could be documented as failed, literally thousands of modules. BP (back then Solarex) has also had a bad run of modules, and there have been others too. As the owner of a company that sells and installs solar modules, I am concerned about the number of cheaper modules out there now and wonder how many of those companies will be around in 10 or 20 years to deal with any warranty issues.
Unfortunate that you couldn’t show us a picture of the actual 15 modules. As I look at the photo I count seven columns and three rows or 21 modules. Not the 15 in the article???
“Solar panel systems from the Japanese manufacturer Kyocera that were installed in a small French near Lyon has been up and running for exactly two decades now.” In a small French WHAT? Field? Village? Valley? Lake? House?
Rock outcropping? Are we missing a word here??
Bit of a sarcastic SOB am I not?
Schott had a similar experience with an array they had installed at the Fraunhofer Institute, Schott PV solar panels maintained 90% of their original performance after a twenty-five year period of use.
http://www.pvpanelguide.co.uk/guides/schott-pv-photovoltaic-solar-panels/
As Chris says, there are concerns that not all panels will meet the expected durability standard, and this would appear to be being borne out by increasing numbers of failing panels as manufacturers are driven to ever more urgent pressures to cut costs.
Here are some tips for longer less troubled panel life
1. Look for panels made with Grade A cells by major manufacturers – preferably tier one i.e. manufacturers who’s panels are considered bankable by major institutional financiers and used in utility scale solar farms.
2. Look for those manufacturers with lower debts than their piers – they are more likely to stick around. (Nearly all manufacturers are in debt, some more than others, with most having made a loss over the last 1 to 2 years).
3. Consider panels with a non cancellable underwritten warranty. Ideally this warranty will be underwritten by a major insurance organisation covering both labour and materials as well as power output. (i.e. stepped or linear 80% of initial rated output for 25 years)
4. Look for panels certified for additional factors such as
a. Suitable for ammonia exposure i.e. livestock shelters / barns. These need a higher quality backsheet to prevent deterioration when exposed to corrosive chemicals.
b. Suitable for installation where exposed to salt spray i.e. windy coastal areas.
c. PID degradation resistant – able to tolerate use in long strings at near maximum rated voltage for long periods without loss of performance – these panels are more likely to be used in large commercial and institutional arrays.
d. Depending on your location, you might also consider panels rated as sand abrasion resistant. This applies mostly to areas prone to sand storms.
5. Pick panels with high rated output i.e. 260 Watts in preference to 240 Watts. These panels are more likely to have cells with fewer and less serious cracks and flaws.
6. Select panels with narrow positive binning. i.e. if you want 250 Watt panels, don’t buy panels rated at 250 Watts +/- 5% which have a flash test rating between 237.5 Watts and 262.5 Watts, rather select 250 Watts + (0 to 5 Watts) all of which fall in the range 250 Watts to 255 Watts.
Closely matched panels in a string will give higher annual yield, and are less likely to stress any less powerful panels by resistive heating. For large arrays, if each panel has an exact flash test reading, sub-bin the panels into narrower bands i.e.
If your panels are all declared as binning in the range 250 watts to 255 watts, then if you can, place all the panels which flash tested at 250 watts in one string, 251 watts in the second string etc.
7. If shade is likely to be a factor in the design of an array, select panels with more bypass diodes – less power will be lost if a small part of a panel is shaded. Also consider DC optimisers or micro inverters for this array to minimize shade related string output loss. (DC optimisers are likely to perform more reliably in very hot regions as they tend to have a higher rated operating temperature and less electronics to go wrong.
8. If you have the opportunity to select panels with better part load performance and or temperature coefficient do so.
9. A few panels operate at a slightly lower temperature as a result of better thermal conductivity back sheets. These should have a longer panel life other factors being equal.
10. A few manufacturers have experimented with encapsulating their cells in clear silicone. I am not sure if these panels are or are not in commercial production, however they should retain better performance over the long term especially in high temperature environments where other encapsulation materials may yellow as they age.
The more of these factors apply, the more likely the panels will be durable.
Often the wiring and junctions are the most failure-prone in a solar PV system, especially on rooftop. But the inverter is absolutely not going to last 20 years. When that fails the system output falls to nothing until it is replaced, which causes the average system output to fall noticeably.
I’m not intending to denigrate the accomplishment of Kyocera in putting out a very robust panel, I’m just saying that the panel degradation is only a small portion of the overall system degradation and maintenance issues involved with PV solar.