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.