The focus of this book is the application of Linguistic Weighted Average (LWA), where the weights are always words modeled as interval type 2 fuzzy sets (IT2FS) for reliability analysis of interconnected power systems. Reliability analysis has been considered as an important step in any system design process. A reliable electrical Power system means a System which has sufficient power to feed the load demand during a certain period. With the interconnection of Photovoltaic (PV) and Wind Energy System (WES) as a Hybrid Electrical Power System (HEPS)into the Utility Grid (UG), the fluctuating...