Mid-life degradation evaluation of polycrystalline Si solar photovoltaic modules in a 100 kWp grid-tied system in east-central India

Abstract

This study presents the mid-life degradation evaluation of a 100 kWp grid-tied solar photovoltaic (PV) power plant which is in the eleventh year of its operation. The field evaluation includes the visual inspections to identify the extent of degradation present in the PV modules, and the measurement of field current-voltage (I–V) data for maximum power deviation of the operational PV modules. Significant visual degradations were observed in many PV modules like encapsulant discoloration, snail tracks and cell cracks, burn marks on the surface of the PV module, shattering of front PV glass due to lightning strike, discoloration on metallization, corroded metal frame and hot spots. The PV module having heavy snail tracks, visible cracks and burn marks on the surface showed the highest power reduction of 95.9 W with respect to the reference module. The power degradation rate of the reference PV modules, which had no apparent visible degradation, over a period of ten years, was found to be varying between 0.16%/year to 1.72%/year. This study would be helpful in better understanding of the various types of degradations affecting the PV modules operating in the composite climate regions of east-central India.