Solar panels start to break spontaneously more frequently

Experts point to the glass cover of PV modules getting worse.

The National Renewable Energy Laboratory (NREL) has observed an increase in spontaneous glass breakage in solar panels. The reason seems to be the declining quality of the glass cover.

Recent reports indicate a troubling rise in solar panel glass breaking spontaneously, sometimes even before the panels are commissioned. The Renewable Energy Test Center (RETC) investigates this and other glass-related trends in its annual PV Module Index. Generally, glass breakage is mostly due to sloppy operations and maintenance practices. However, recently NREL team has been regularly receiving reports of glass breakage in silicon modules that are not linked to direct damage from maintenance or storms. They found that the overall quality of solar glass seems to be declining over time.

NREL experts highlight that older modules would pass the IEC 61215 static load test with a big safety factor. More modern modules are either barely passing the base static load test or not passing at all with higher safety factors.

The NREL team hypothesizes that glass damage in solar panels might be similar to damage in a car windshield. A small star-shaped mark from impact can, over time and under extreme weather conditions, develop into a large crack across the surface.

Experts point out that this issue might be due to the trend of solar glass getting thinner over time. Thinner glass requires fewer defects to create strength-limiting flaws, which NREL is actively studying to understand the potential pitfalls of using thin glass in solar manufacturing. Multiple factors might be contributing to the increasing glass breakage threat. Modules are getting larger, frames are getting thinner, and mounting rails are getting closer together, creating “large, floppy modules” that put more pressure on the thinning glass.

Some researchers at NREL believe that climate-specific modules and testing are starting to look viable as emphasis on total system costs grows. It’s possible that there will be hail-hardened modules, especially in the U.S. market, where paying more upfront for hail resilience might be worthwhile.

Interested in what solar panels are worth picking for areas with harsh weather? At A1 SolarStore we would recommend brands like Panasonic, REC, Mission Solar and Silfab. Their panels are generally tested at higher standards than cheaper but lower-quality Chinese solar panels.