Electrical safety qualifications of decommissioned PV modules for scalable second-life deployment

Abstract

Reuse of fully functional decommissioned crystalline silicon photovoltaic (PV) modules represents a high-value strategy for supporting circular economy. Large-scale deployment, however, remains limited by technical, economic and safety barriers. In practice, reuse qualification is often based solely on electrical performance, with electrical safety testing omitted, due to the lack of rapid and cost-effective methods. The risk to the industry with this approach is that acceptable power output (e.g ≥ 80% of nameplate power), alone does not guarantee insulation integrity and thus operational safety for field-aged modules. In this work, we address the electrical safety bottleneck in PV module reuse through two complementary pathways. First, we evaluate silicone-based backsheet coatings to restore and stabilise leakage resistance in glass/backsheet modules, potentially reducing the need for repeated wet leakage (WL) testing. Accelerated stress tests including extended soaking, elevated temperature, damp heat, and potential-induced degradation demonstrate that silicone-coated modules maintain insulation resistance well above the IEC 61215 threshold. Second, we develop and validate modified WL testing procedures including parallel module testing to enable higher-throughput safety screening compatible with field-based reuse operations. A two-module parallel WL test configuration was implemented during a mass-scale reuse pilot project in Queensland, Australia. Among more than 2200 modules that met electrical performance criteria, approximately 15% failed to meet the IEC WL threshold, providing quantitative field-scale evidence of the necessity of incorporating WL testing into reuse qualification protocols. Finally, an indicative comparative cost assessment of these two pathways is presented to evaluate their economic feasibility for mass-scale PV module reuse.