When a utility selects a solar project, it is essentially committing to a fuel still good after twenty or thirty years out in the sun and the rain. How to be sure it has lasting value, and that if it fails; that it won’t hurt the entire industry?
While most manufacturers continue to employ best practices, any slip-ups could end up costing the industry as a whole. As the battle to the bottom continues in the price wars, how is long term quality weighted? A broken quality chain would have very negative consequences not just for the project, but also for the whole industry.
If investor confidence is damaged by field issues, that will lead to higher costs of capital or limited capital availability. These are the troubling issues that worry Dissigno CEO David Williams, whose real-world experience in solar development led to concerns about long term quality blowback from the price wars.
He serves on the merit review committees for the DOE Sunshot program, and on the technical review committee for the national labs which are working on improving certification models, to ensure that the exposure the panels are getting is really analogous to stresses they will see in real life.
“I don’t want to sound like I’m fear-mongering,” Williams tells PV Insider. “But some manufacturers may be driven to making decisions - even if they’re unsure of the consequences of making them - because they’re going bankrupt. They are making very hard choices about how to shave those pennies off.”
A lot can go wrong when corners are cut. Output degradation of more than five or even ten percent a year is possible. Junction boxes can catch on fire, or fall off, badly soutered joints can cause fires, there can be hot spots where a lot of current is going into the same single cell and getting very hot.
Fire is a reality with solar panels that go bad. “That’s why I’m so passionate about it” he said. In view of the dangers, “I don’t want people to feel comfortable.”
“It’s a very big concern,” agrees Martin Plass, VP and General Manager of the cutting edge solar testing lab CFV, part-owned by Germany’s Fraunhofer ISE (Instituts für Solare Energiesysteme).
“You cannot take 80% out of the cost of a product and expect it to have the same quality any more,” he says. “So I do think we will see modules with problems popping up in the field.”
Imperfect basic testing protocols
“There’s no formula that says that if you do this much testing then it guarantees your modules will last this long,” Plass tells PV Insider. A lot the initial testing of today has a very low bar for initial certification. That’s where CFV comes in as an independent lab with follow-up.
“Liability testing or for quality control often comes from the manufacturers when they want proof of bankability,” he says. “Say if they want to convince a bank that their modules are better or will last longer or have less degradation over time.”
But even top notch testing can be compromised, because in the current cut-throat competition, the manufacturer can choose the best test to ace. “The manufacturer can say I want to do this specific test or test sequence,” Plass explains.
“Someone can request say 400 hundred cycles of temperature cycling and 2,000 hours of damp heat; believing that that is a good representation of a 25 year stress out in the field. But someone else might then choose to do 400 cycles and 1,500 hours. So those results are not comparable,” he says.
Add self-inflicted wounds
An additional very big problem for quality assurance has been the “self inflicted” wound of the U.S. solar tariff war against China, that indirectly has hobbled quality control by creating artificial disruptions in tested supply lines and production.
“Under U.S. pressure to change to non-Chinese-made cells, manufacturers are starting to make changes, like sourcing different cells made in Taiwan,” says Williams. “And there’s been no oversight into that.That’s kind of like replacing the engine of a car and not going through all the same crash testing.”
While the module manufacturing remains in China, and the factory is still abiding by its same quality standards, now it has switched to an unknown quantity in a cell that has perhaps not been tested.
Already tough business
Humidity is a problem, but more for crystalline PV. Thin film tends to be better protected against degradation than crystalline solar, simply by its airtight construction, First Solar’s Alan Bernheimer tells PV Insider in a recent interview.
“Ours for example, is a very thin coating of cadmium telluride that’s applied to the back of glass, and sandwiched between two layers of glass, laminated so it’s water tight and air tight,” Bernheimer said. “It’s a very stable and robust material that looks more like traditional silicon based panels.”
However, the technology has a high bar. “The cocktail to make thin film panels work is harder to keep stable than crystalline,” Williams cautions.
“Cadmium, telluride or CIGS technologies are cocktails of metals that don’t necessarily want to work together. While some companies like First Solar have done a lot of work making them stable, it’s not an easy process, and so it’s not impossible that some modules are degrading faster than expected,” says Williams.
Also, with the exponential growth of the industry, some new manufacturing techniques are so new that its hard to determine if what they are doing is cutting the quality.
“I do think that most panel manufacturers are in fact making all the right decisions,” he adds, emphasising that there is a need for the solar industry to defend the good quality manufacturers who “just because they could make poor choices - since nobody’s really overseeing - doesn’t mean they are.”
“And there’s extremely brilliant material scientists that are solving the problems. But this is not an overnight exercise," he concludes. "It’s a many year effort.”
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