The impact of environmental conditions on CIGS device stability must be understood and minimized in order to gain widespread acceptance among users. The stability of CIGS-based PV coatings, cells and modules has been evaluated at Global Solar Energy (GSE) by accelerated and real-time testing. Several failure modes have been identified and addressed. New packaging designs and materials have extended the durability of flexible modules. Glass-based CIGS modules have been found to be especially robust and capable of meeting extended product warranties required for power modules