RETC Report Shows Rising Reliability Risks in Solar Modules

Lab tests show rising failure rates that pose direct risks to the industry's ability to secure project financing.

Overview

RETC published its 2026 PV Module Index on Wednesday, June 3, 2026, reporting that extended lab tests found more than 10% of samples failed 2,000-hour damp heat testing and about 8.3% showed unacceptable UV-induced degradation.
The index is based on RETC’s Thresher extended protocols run between Q2 2025 and Q1 2026 and is designed to reveal wearout mechanisms that standard certification tests can miss.
RETC recorded year-over-year increases in red-flag results across damp heat, potential-induced degradation, mechanical load, and thermal cycling tests, which helps explain negative field-performance trends noted by technical-due-diligence teams.
The report recognized 19 manufacturers for high achievement and named 13 as Overall Highest Achievers while stressing that even top performers must be judged by extended-stress results for bankability decisions.
Independent labs including Kiwa PVEL have flagged similar markers, and stakeholders such as developers, financiers, insurers, and asset owners are likely to tighten procurement, warranty and due-diligence requirements because of these lab findings.