Improvement in Reliability and Energy Yield Prediction of Thin-Film CdS/CdTe PV Modules

In this work, we illustrate improvement in thin-film PV module durability via process optimization. Data are presented from large installations, allowing accurate estimation of failure rates and distributions of failure modes. Improvement in product quality is also described; we show that recent thin-film products can meet industry expectations for consistent power output. In addition, results of product characterization performed at First Solar are presented. Dependence of module output on irradiance and temperature is illustrated, and we show that common assumptions about such dependence (based on experience with conventional PV technology) may not hold for thin-film modules. Predicted behavior of module output (as computed with PV system modeling software) and real-world data are compared. It is shown that adjustment of the parametric description of the module can be used to successfully reduce discrepancy between predicted and actual module behaviors