Oxidation Impact of CIGS Photovoltaic Modules Performance after 10 Years of Operation

Photovoltaic (PV) Modules, PV system reliability, Electroluminescence (EL), CIGS PV Module Oxidation

This paper analyzes the impact of the oxidation degradation on the CIGS solar modules performance and energy production. A series of tests performed in two laboratories, the SolarTechLAB of the Politecnico di Milano and the Kiwa Carnet Laboratory. Visual Inspection, Junction Box Analysis, Thermographic Analysis, I-V and P-V curves in Real Conditions, Energy Test, Maximum Power Determination and Electroluminescence Test for six CIGS photovoltaic (PV) modules were carried out. A power reduction up to 90% compared to the nominal power was observed.

The degradation analysis of the photovoltaic modules is crucial for the evaluation of their performance. While they are operating various downgrading phenomena may occur to the modules and the identification of their influence on the energy performance can increase the liability and the robustness of the photovoltaic systems.

In the presented study, a series of test was performed at two laboratories to analyse the performance of the degraded modules. Visual inspection, thermographic analysis and electroluminescence (EL) test was carried out, pointing out the similar results between the three tests for the behaviour of the modules. Additionally, a junction box analysis was performed with both visual and electrical inspection.

Furthermore, IV and PV curves were measured showing a considerable reduction of the indices of the most degraded modules. The same results were extracted from the flash test carried out, with a reduction of the power of 33.6% up to 90% compared with the datasheet values.

Lastly, the energy test was performed for a period of nine days for the five modules, while the module #1 did not present electrical connection. The results showed a significant reduction in the energy production for the most degraded modules compared with a healthy reference c-Si module.

This paper was published by researchers of the Politecnico di Milano.