Long-term Performance Analysis of CdTe PV module in real operating conditions

Solar photovoltaic (PV) technology has gained ample attention with the continuously increasing electricity demand and climate concerns. The Cadmium Telluride (CdTe) based PV technology is the leading and foremost technology among rapidly growing thin film PV industry because of its lower energy and economic payback period and energy efficiency competitive to the wafer based technology. Although, these modules undergo a series of indoor qualification tests specified by IEC61646, the long-term performance analysis in real operation conditions is essential in order to ensure long term stability, robustness and reliability. In this paper, performance analysis of 80WP CdTe PV module has been carried out on the basis of long term time series data of short circuit current (ISC) and open circuit voltage (VOC) measured in outdoor conditions. The measured electrical parameters has been translated to alternate reporting conditions i.e. 800W/m2 irradiance over the module surface and 40°C module temperature. The monthly averaged and normalized VOC and ISC of the module is found to be degraded by 2.86% and 2.29% after 23 months of outdoor exposure. The parameters are translated to standard test conditions for diurnal analysis which shows the degradation of 2.91% for VOC while no deviation in the value of ISC.