Water Solubility of Cadmium Telluride in a Glass-to-Glass Sealed PV Module

Abstract

Cadmium Telluride (CdTe) is gaining a substantially increased role in the world’s energy mix. The environmental safety concern of cadmium leaching out of CdTe solar panels has become a very important issue. Our recent study shows that naturally occurring groundwater and rainwater dissolve CdTe at a very fast rate, allowing cadmium to enter the groundwater at concentrations at least four orders of magnitude greater than the EPA allowed limits for drinking water. The study also demonstrates that water travels by capillary action between the various layers in a typical PV module structure, thus leading to delamination and hence contamination by cadmium at an even faster rate than otherwise anticipated. The behavior of the cadmium leaching out of CdTe solar panels makes it imperative not to discard rejected CdTe modules/panels in dumps or landfills.