Investigation of Degradation in 20-Year-Field-Exposed PV Modules From India by Cross-Characterization Using Electroluminescence Imaging and Thermography




Field Exposed Photovoltaic Module, Degradations, Electroluminescence Imaging, Dark Lock-In Thermography


The reliability of photovoltaic (PV) modules is essential for ensuring a smooth operation over the anticipated timespan while operating outside. Examining the degradation in field-exposed photovoltaic (FEPV) modules will help to identify the possible degradation modes that can affect PV module performance and functioning. In this paper, to identify the major modes of degradation in Indian subtropical climate conditions, 20-year-old FEPV modules have been investigated by cross-characterization using dark lock-in thermography (DLIT) and electroluminescence (EL) imaging. Cross-characterization using EL and DLIT images has been helpful in investigation of various modes of degradations in FEPV modules in the presence of multiple degradations. Encapsulant and busbar ribbon interface degradations have been identified as the two main modes of degradation observed in Indian sub-tropical climate conditions. Minor degradations include finger interruptions and cell cracks. A major effect of degradation has been observed on the fill factor and short circuit current, which have decreased by up to 30% and 40%, respectively. The results presented in this paper can be used to understand degradation occurring in a sub-tropical climate and for the non-destructive analysis of degradations in the FEPV modules.


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M. Kumar, A. Kumar, Performance assessment and degradation analysis of solar photovoltaic technologies: A review, Renew. Sustain. Energy Rev., vol. 78, no. October, p. 554–587, 2017, doi:

C.M.S. Kumar, S. Singh, M.K. Gupta, Y.M. Nimdeo, R. Raushan, A. V. Deorankar, T.M.A. Kumar, P.K. Rout, C.S. Chanotiya, V.D. Pakhale, A.D. Nannaware, Solar energy: A promising renewable source for meeting energy demand in Indian agriculture applications, Sustain. Energy Technol. Assessments., vol. 55, no. February, p. 102905, 2023, doi:

A. Sinha, O.S. Sastry, R. Gupta, Nondestructive characterization of encapsulant discoloration effects in crystalline-silicon PV modules, Sol. Energy Mater. Sol. Cells., vol. 155, no. October, p. 234–242, 2016, doi:

A. Sinha, M. Bliss, X. Wu, S. Roy, R. Gottschalg, R. Gupta, Cross-characterization for imaging parasitic resistive losses in thin-film photovoltaic modules, J. Imaging. vol. 2, no. August, p. 1–19, 2016, doi:

A. Tummala, J. Oh, S. Tatapudi, G. TamizhMani, Degradation of Solder Bonds in Field Aged PV Modules: Correlation with Series Resistance Increase, In 2017 IEEE 44th Photovolt. Spec. Conf. (PVSC), p. 2912–2917, 2018, doi:

R. Meena, M. Kumar, R. Gupta, Investigation of dominant degradation mode in field-aged photovoltaic modules using novel differential current-voltage analysis approach, Progress in Photovoltaics: Research and Applications, vol. 30, no. November, p. 1312–1324, 2022, doi:

V. Gade, N. Shiradkar, M. Paggi, J. Opalewski, Predicting the long term power loss from cell cracks in PV modules, 2015 IEEE 42nd Photovolt. Spec. Conf. (PVSC), p. 2–7, 2015, doi:

I. Zafirovska, M.K. Juhl, J.W. Weber, J. Wong, T. Trupke, Detection of finger interruptions in silicon solar cells using photoluminescence imaging, Chinese Phys. B. vol. 27, no. November, p. 1496–1502, 2018, doi:

S. Kumar, R. Meena, R. Gupta, Finger and interconnect degradations in crystalline silicon photovoltaic modules: A review, Sol. Energy Mater. Sol. Cells. vol. 230 no. September, p. 111296, 2021




How to Cite

Pareek, A., Meena, R., & Gupta, R. (2024). Investigation of Degradation in 20-Year-Field-Exposed PV Modules From India by Cross-Characterization Using Electroluminescence Imaging and Thermography. SiliconPV Conference Proceedings, 1.

Conference Proceedings Volume


Module Characterization and Simulation