This book is designed to provide a fair and brief idea about the application of Fuzzy logic controller and optimization techniques in the power system to regulate the generation in different environments. In this book, an attempt has been made to unify the design of power system for different environments, fuzzy PID controller and hybridization of metaheuristics algorithms. The power system is designed in four different environments such as single area isolated thermal system, two area single unit thermal system, two area two units thermal system in conventional and deregulated power system. Fuzzy PID controller is validated as better controller over PID controller and the hybrid DEPSO algorithm is validated over DE and PSO algorithms to optimize the controllers in all environments. In this book, design of power system in different environments, design of fuzzy PID and hybridization of DE & PSO algorithms are described fairly with proper validation.