Diffuser-augmented wind turbines can include a first diffuser ring arranged to form a turbine rotor cowling, the diffuser being fixed to and rotatable with the turbine rotor about the horizontal axis of the wind turbine. The first diffuser ring may have one or more dynamic, aero-elastic, vortex entrainment devices attached to a trailing edge of the diffuser. The first diffuser ring may include one or more slot gaps arranged within its body, each slot gap creating a channel between the interior and exterior surfaces of the first diffuser ring. In some embodiments the diffuser may optionally further include one or more further diffuser rings, the one or more further diffuser rings being static rings (e.g. non-rotatable about the horizontal axis) or dynamic diffuser rings (e.g. rotatable around the horizontal axis).

A wind turbine having one or more magnets for reducing friction between the turbine support and a turbine rotor. The reduction of friction between the turbine rotor and the turbine support allows for an increase in energy production and scale of the wind turbines. The magnet configuration employs a ring of cylindrically-shaped magnets at the bottom and opposed by a corresponding number of generally rectangular-shaped magnets. Bearing magnets are also employed for axial stabilization.

The application relates to unidirectional hydrokinetic turbines having an improved flow acceleration system that uses asymmetrical hydrofoil shapes on some or all of the key components of the turbine. These components that may be hydrofoil shaped include, e.g., the rotor blades (34), the center hub (36), the rotor blade shroud (38), the accelerator shroud (20), annular diffuser(s) (40), the wildlife and debris excluder (10, 18) and the tail rudder (60). The fabrication method designs various components to cooperate in optimizing the extraction of energy, while other components reduce or eliminate turbulence that could negatively affect other component(s).