Performance Degradation of Various PV Module Technologies in Tropical Singapore

The performance of ten photovoltaic (PV) modules with nine different solar cell technologies (and one different module construction) is monitored in the tropical climate of Singapore. The types of modules included in this study are monocrystalline Si (glass-backsheet with frame and glass-glass without frame), heterojunction crystalline Si, monocrystalline Si back-contact, multicrystalline Si, double-junction “micromorph” Si, single-junction/double-junction amorphous Si, CdTe, and CIGS. Three years of outdoor monitoring data are used to extract degradation trends of the performance of the various modules. Statistical decomposition methods are used to extract trends for performance ratio (PR), short-circuit current (I_SC), open-circuit voltage (V_OC), and fill factor (FF). The degradation rates of the monocrystalline Si modules are found to be equal to or less than -0.8% per year, mainly contributed by the decrease in I_SC. The multicrystalline Si module shows a slightly higher degradation rate of -1.0% per year. The amorphous Si, micromorph Si, and CdTe modules show degradation rates of around -2% per year. The CIGS module showed an exceptionally high degradation rate of -6% per year. The decrease in FF and VOC is found to be significant for all the thin-film modules but not for the crystalline silicon modules.