The basics of wind energy conversion, the evolution of today’s giant wind turbines and many key decisions about the design concepts (number of blades, upwind or downwind etc.) are explained. Rotor design, direct drive and the increasing diversity of drive train options are examined. Permanent magnet generators and general electrical design issues are addressed. The evolution of larger wind turbines and the challenges of further upscaling especially in the context of the expanding offshore market are also discussed. The design process, the importance of accurate design loads prediction and effective control of the wind turbine are highlighted. How design options may affect cost of energy is illustrated and future trends are reviewed.The course offers a significant depth of understanding of the technology background but does not assume any prior knowledge of wind energy.