Key takeaways:
Kiwa PVEL’s 2026 Module Reliability Scorecard featured 43 manufacturers as top performers across various reliability test categories
Mechanical stress sequence (MSS) and hail stress sequence (HSS) tests accounted for a large share of module failures, particularly in thinner frame and glass designs
Delamination rates increased significantly this year, highlighting the importance of encapsulation quality, BOM selection, and lamination processes
Reliability is an important consideration when choosing modules, given the environment they must survive in over their lifetime. With many issues cropping up in the field, the industry’s focus on reliability is also increasing. These issues are attributed not only to the bill of materials (BOM) but also to the processes. We detail some of the key issues observed in PV manufacturing in 2025 in this article titled Real-Time QA Insights From Global PV Module Manufacturing.
Kiwa PVEL, an independent laboratory for reliability and performance testing of PV modules, has released its 12th edition of Module Reliability Scorecard. This edition features 43 manufacturers as ‘top performers’.
A series of destructive and non-destructive tests is performed on modules, and manufacturers are rated as top performers in one or more of these tests. The lab introduced a new test sequence for ultraviolet-induced degradation (UVID) for the 2026 edition. Other tests include thermal cycling (TC), damp heat (DH), mechanical stress sequence (MSS), hail stress sequence (HSS), potential-induced degradation (PID), light and elevated temperature induced degradation (LID + LeTID), and PAN performance.
One of the most important observations was that none of the manufacturers was a ‘top performer’ in every test sequence. This year’s list features 13 first-time top performers and 20 dropouts from the previous year.
Module energy yields continue to increase due to bifaciality and improved temperature coefficient. However, LID and LeTID performance continue to remain a concern, even for mainstream n-type TOPCon modules. The median LID power loss for TOPCon was 0.4%, compared with around 0.6% for PERC, 0.7% for HJT, and 0.6% for xBC. In the case of LeTID, the median power loss was 0.1% for TOPCon, xBC, and PERC, while HJT showed 0.4%. The overall worsening of LID this year is attributed to the increase in the number of new cell factories.
Another concern is breakage under mechanical and hail stress. About 30% of BOMs have MSS failure. More than half (62%) of these failures were due to frame stiffness, which transfers the stress from bends or twists to the glass via pinch points. The breakage rate also doubled when the frame thickness was reduced below 35 mm. With respect to HSS, thicker front glass (3.2 mm) is less susceptible to breakage with 45 mm hail, accounting for 7% of breakage among thicker glass. Modules with 2 mm glass on both sides accounted for 61% of breakages with 45 mm hail.
Although UVID results were not included in the 2025 scorecard, the current edition shows a 3% median power loss from UVID in TOPCon, lower than the 4.2% in the past year. This is likely due to improvements in module BOMs and also the process and quality control at the cell level.
Module delamination has increased 3 times since last year, with about 45% of models experiencing this failure after DH, TC, MSS, PID, and UVID. Encapsulation quality, thickness, and lamination process are critical to this failure.
The failure rate has increased to a record high compared to the last edition, with about 87% of manufacturers and 61% of BOMs experiencing at least one failure. MSS and HSS are the top contributors to these high failures.
Tristan Erion-Lorico, VP of Sales and Marketing, said, “We’re seeing reductions in power loss for some tests and increased energy yields in our PAN testing. At the same time, failure rates, particularly delamination and mechanical breakage, have reached new highs. These results underscore that innovation and cost cutting measures must be matched with consistent quality and robust design to ensure long-term field reliability in an increasingly cost-conscious industry.”