Comparison of Photovoltaic Degradation Rates in Tropical Climate Derived from Different Calculation Methods

The degradation rate (DR) of different PV technologies installed in Thailand were estimated by using the statistical methods of linear regression and classical seasonal decomposition (CSD) over a five-year period. The selection of calculation method affects the resulting DR. Comparing the DR results in this work with other work which obtained in similar climate condition, same outdoor exposure duration and same calculation techniques, the DRs of Si wafer based PV were almost the same, while thin film type showed a wide range of variation. This indicates difficulty in comparing the DRs of thin film PV from many case studies.