• The study provides an experimental validation of second-life PV systems in Brazil, supporting circular economy strategies and demonstrating the potential of reuse to reduce waste and extend module lifetimes. • Second-life multicrystalline PV modules demonstrated stable and safe operation after more than 23 years in service, including their second installation phase. • The average annual degradation rates were 0.40%/yr and 0.44%/yr for individual modules, and 0.7%/yr at the system level, remaining below the typical 1%/yr warranty threshold. • The temperature-corrected Performance Ratio (PR) reached 85.3%, confirming satisfactory system efficiency and validating the technical feasibility of reuse. • Insulation resistance and thermographic inspections confirmed electrical safety, with no inverter alarms or severe defects identified during operation. The rapid growth of photovoltaic (PV) energy generation has raised concerns about premature module replacement and the resulting increase in waste with discarded modules. Circular economy strategies as reuse can extend module lifetimes, but their viability depends on verified safety and reliable performance. This study presents a technical characterization and experimental evaluation of multicrystalline silicon PV modules, originally installed in 2000, decommissioned after 22 years of off-grid operation on an island in Brazil, and screened for faults. After this screening, the modules were redeployed in southern Brazil in two independent experimental configurations: (i) two modules were monitored individually in an outdoor setup with continuous IV curve measurements, and (ii) a string of 14 modules was reinstalled in a grid-connected rooftop system. In the individual-module outdoor setup, after one year of second-life operation, the modules exhibited stable behavior, with performance consistent with annual degradation rates of 0.40–0.44%, well below the typical warranty value of 1%/year at the time of manufacturing. For the grid-connected rooftop system, after 23 years, the grid-connected PV string showed a total degradation of 14.0% and a weather-corrected Performance Ratio (PR) of 85.3%, exceeding the 80% threshold guaranteed by the manufacturer’s 20-year performance warranty. Insulation resistance and thermal inspections confirmed electrical safety, with only minor anomalies detected. The results demonstrate that second-life PV modules can operate safely and effectively after decommissioning and more than two decades after manufacture, highlighting their potential contribution to circular economy strategies in the solar sector.
Ebert et al. (Sun,) studied this question.