Over the past 30 years, wind energy has evolved from a small industry active in a few countries to a large international industry involving major players in the manufacturing, development, and utility sectors. Coinciding with the industry growth, significant innovation in the technology has resulted in larger sized turbines with lower associated costs of energy and more complex designs in all subsystems, from the rotor to the drivetrain to the electronics and control systems. However, as deployment of the technology grows and its role within the electricity sector has become more prominent, so have the expectations of the technology in terms of performance, reliability, and cost. This book surveys the landscape of systems engineering methods and catalogues the various existing modelling tools that relate to the design of wind energy systems from components to entire plants.