Identifying and Validating Root Causes of Glass Breakage in PV Modules
SUMMARY
A solar project developer engaged CEA to investigate widespread glass breakage across multiple PV sites. CEA conducted comprehensive on-site inspections and structural assessments, which pointed to possible issues related to module durability and mounting system compatibility.
Examples of glass breakage
APPROACH
To validate these concerns, CEA proposed laboratory testing that closely replicated actual field mounting conditions. Using the original purlins and clamps, CEA performed static load tests in accordance with IEC 61215-2 protocols. This setup allowed for a more accurate simulation of real-world torsional and bending stresses than conventional rigid lab fixtures.
“CEA’s investigation identified the likely root causes of breakage and provided the client with actionable evidence to hold responsible parties accountable.”
RESULTS
Field Investigation Findings:
Over 2,600 modules across multiple sites were found with glass breakage.
Breakage rates varied between the two module manufacturers.
While some failures were clearly linked to impact damage, structural concerns with the mounting system remained a leading suspect.
It was identified that mounting instructions required additional “bumpers” on some modules which were not present during the filed inspection.
Laboratory Testing Findings:
Static and dynamic mechanical load tests revealed weaknesses in the underlying racking design, which allowed excessive torsion on the modules.
Some modules failed due to electrical continuity loss or internal cell cracking under stress.
Although the glass did not break during testing, significant twisting and torsion were observed factors that, when combined with other field stressors, are likely contributors to glass breakage.
Glass surface tension was measured, and inherent stresses in some modules were identified.
CONCLUSION
CEA’s investigation identified the likely root causes of breakage and provided the client with actionable evidence to hold responsible parties accountable. A critical insight from this case was the value of replicating real-world conditions in laboratory testing. Unlike standard certification tests, which use rigid fixtures and uniform stress application, CEA’s approach mirrored the actual flexibility and torsion seen in field-mounted systems. This method uncovered failure modes that would likely remain hidden in conventional tests.
While dynamic mechanical load testing is typically part of CEA’s protocol, it was not applied in this project. However, it remains a valuable method for further assessing long-term risk—especially when using original mounting components to simulate true field behavior. Accurately replicating site conditions in testing is essential for understanding operational risk and improving system design.
