Quantifying PV Module Annual Degradation Rates: A Comparative Study Between Field Monitoring and Laboratory Results

Conference proceedings article

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Publication Details

Author list: Yaowanee Sangpongsanont, Manit Seapan, Tanokkorn Chenvidhya, Krissanapong Kirtikara, Dhirayut Chenvidhya, Ballang Muenpinij, Usman Yahaya, Surawut Chuangchote

Publication year: 2026

Title of series: PVSEC-36, 2025 PROCEEDINGS The 36th International Photovoltaic Science and Engineering Conference

Number in series: -

Volume number: -

Start page: 76

End page: 77

Number of pages: 2

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Abstract

This study assesses the yearly performance degradation of photovoltaic (PV) modules utilizing system monitoring data from Bangkok, Thailand, gathered from 2017 to 2022, in conjunction with laboratory tests at standard testing conditions (STC) from 2010. The data cleaning method involved filtering power rates based on irradiance and module temperature, utilizing a statistical technique to assure precision, resulting in a mean absolute error (MAE) of 0.07%. The annual degradation is determined using a modified performance ratio (PR) in accordance with IEC61724 standards, indicating that temperature and irradiance modifications should be omitted from total power calculations.

Keywords

Degradation kinetics, Long-Term Monitoring, Photovoltaic system, Solar photovoltaic