Design of photovoltaic Wind Energy System Hybrid Electric Power System (PV/WES HEPS) has many issues if we take all economical and technical parameters into account. The Book presents a complete design and simulation of a PV/WES HEPS to be interconnected with utility grid, UG. The proposed design of PV/WES HEPS is based on energy balance, minimum price of gener-ated kilo watt hour (kWh), maximum power point tracking for PV and WES by using an artificial intelligence technique. This Book presents also a possible circuit topology and controller design for a grid- connected DC-AC power converter. In this Book we present a study, describe a control strategy for interconnection of hybrid system with electric utility accompanied with or without battery storage using artificial intelligence techniques and also a fuzzy logic technique to calculate and assess the reliability index for each HEPS configuration under study."