Inspections are revealing growing failures in modern glass solar panels as manufacturers respond to increasing demand for larger, thinner, and lighter panels.

“Broken glass seems to be more common than before,” the U.S. National Renewable Energy Laboratory (NREL), since renamed and refocused by the Trump administration as the Department of Energy’s National Laboratory of the Rockies, wrote [pdf] in a 2024 report. “In the past few years, our team has found power plants around the world where [solar] module glass has broken with no obvious cause.”

“We call this type of breakage spontaneous.”

The report identifies “big floppy modules” as the type of panel most prone to breakage.

These glass solar panels have decreased in thickness from 3.2 to 2 millimetres, but also grown in size from around two to three square metres to cover larger areas—and are usually installed with low-cost mounts.

The report finds that a combination of factors could lead to breakage. “We’re working on tests and characterization methods that can detect modules vulnerable to breakage at low loads,” the authors write.

Manufacturing errors have been identified by global quality inspection company Intertek CEA. They find cold soldering, grid breaks, and scratched cells in the manufacturing process among the top issues in 11 countries, with the U.S. recording the highest number of deficiencies. The trends are seen commonly in manufacturers that are ramping up production—rather than mature producers—most significantly in the U.S. as “capacity expansion exposes early-stage execution risks,” the Intertek report states [pdf].

Chinese manufacturers observed just over 20% minor or critical issues in the ramp-up process, while the U.S. sits at nearly 40%.

North American solar manufacturers stand to learn a thing or two from manufacturers in China, Mike Andrade, executive chair of Toronto-based Morgan Solar, told The Energy Mix, adding that the Chinese have been making them far longer than the U.S.

Manufacturers must now meet a need to increase the surface area of panels for increased energy output, all while keeping weight down to reduce installation costs.

“The labour associated with the construction of a solar field is now a bigger portion of the cost of the solar field,” Andrade said. So the trend is shifting toward bigger, more powerful panels that need less labour to install.

Solar manufacturing moves quickly as technology evolves, producing hundreds of thousands of parts and pieces compared to conventional energy infrastructure that can take years to complete and is not subject to the same external stressors as solar.

That list includes weather events, like heavy snow that puts stain on the panels, or human error if a panel wasn’t connected properly into the frame/ And yet, Andrade said, solar is on track to becoming more reliable than their conventional counterparts.

“[Solar is] incredibly reliable as a baseline, and is going to be far more reliable than any other electricity generation technology that would be compared to them,” he said. “There’s no moving parts, you don’t have any pumps or turbines or anything that lasts 30 years.”

Glass breakage is calling into question the longevity of panels, but Andrade said the problems are not unsolvable as the industry works to identify the root causes of breakages.

“If it’s a pervasive manufacturing problem across all thin glass things, that’s going to take longer,” he said. But fixing or changing clamps that mount thinner glass panels would be an easier solution.

“Electronic products get better by breaking—you do a root-cause analysis on figuring out why it broke, fix that thing, then do it again, and again, and again,” he said.

“Next thing you know, you’ve got a super-reliable product, and that’s why I’m very confident the industry will figure this out.”