A rotary connection for a rotor blade of a wind turbine. The rotary connection is used, for example, for adjusting a rotor blade of a wind turbine. The rotary connection according contains an outer ring and an inner ring. The inner ring has a contact surface in the direction of the rotor blade and a screw fixing surface in the direction of the rotor hub. The contact surface and the screw fixing surface are arranged parallel to each other and provided with passage holes, which each have a central axis. Rolling elements are arranged in at least two running rows located under each other between the outer ring and the inner ring, wherein the rolling elements each have a rolling element diameter. According to the invention, at least the lower running row is arranged with its rolling element centre underneath the screw fixing surface.

A buoy, preferably for a wave energy converter system, comprises a central portion; and one or a plurality of buoyancy blocks connected, directly or indirectly, to the central portion. By providing the central portion with a bell mouth opening and attachment means for a wire or rope, a buoy with improved characteristics is provided.

An arrangement for generating energy made up of at least two rotating bodies of revolution partially immersed in a dynamic fluid. The at least two rotating bodies of revolution have their longitudinal axis of rotation located perpendicularly to the flow of the fluid, and are further associated to support means and to drive means, being immersed about 30% of their diameter. One of the at least two rotating bodies of revolution is located upstream of said dynamic fluid with its longitudinal axis of rotation located in a longitudinal slider of the support means with the possibility of translation and variable rotation speed. The other of the at least two rotating bodies of revolution is located downstream of the dynamic fluid, with its longitudinal axis of rotation being attached to the support means, and with a rotation synchronized with the flow speed of the dynamic fluid.

A turbine, in particular for harvesting energy in flowing air or flowing water, is easily adaptable to different application conditions and facilitating a comparably high degree of efficiency. This is achieved in that the basic shape of the turbine is cylindrical and is provided with blades which are parallel to an axis of the turbine. The blades are pivotally arranged in joints on the outer circumference of at least one turbine wheel. The blades are substantially L-shaped. The longer limb of the blade is curved preferably in a manner corresponding to the radius of the turbine casing, and the shorter limb lies within the surface line of the turbine.

Systems and methods disclosed herein provide a tidal power generator including a first container, a second container coupled to the first container, a frame pivotably coupled to the second container, a first valve, associated with the second container, configured to selectively control ingress of a first volume of a fluid into the second container, and a second valve, associated with the second container, configured to selectively control egress of a second volume of the fluid out of the second container.

An axial impeller has a tubular housing mounted on bearings for rotation. The housing is capable of engaging a motor or generator directly or through a drive belt. Interior turbine blades are mounted on the housing wall. The blades may be hinged so they can rotate between a retracted position adjacent to the wall and an extended radial position. Rods penetrate the wall to position the blades between retracted and extended positions. When extended, the blades may be rotated to propel a fluid through the housing; and when retracted natural fluid flow is less restricted.

A gravity driven hydroelectric system, whereby hydroelectric power is developed from potential energy of dammed water driving a water turbine assembly. The hydroelectric power extracted from the water depends on volume and on a difference in height between a source and an outflow of the water. A penstock delivers the water to the water turbine assembly. The penstock has a housing secured by frame assemblies to a structure. The housing has electromagnetic coils that produce electricity from a rotation of turbine blades having magnets.

A hollow first housing with a rigid wall and a center of mass located on a portion of the rigid wall to which a weight is attached. When force is applied to tilt the apparatus then the center of mass is raised. When force is discharged, then a rocking motion of the hollow sphere device or housing will seek an equilibrium at the minimum gravitational potential energy. The rocking motion of the first housing activates a circular motion of a pendulum object. Motion of the pendulum object is passed to an electrical generator, which in turn produces electricity. The first housing may be a round circular hollow sphere, a circular cylinder, a cone, a frustrum, or may be configured in other shapes. A sail may be attached to an external surface of the first housing, at a location on the first housing furthest away from and opposite the weight.

A rotor hub for a wind power installation, with at least two flange portions each for receiving a rotor blade, wherein the rotor hub has a housing with a wall which is interrupted by the flange portions, wherein the housing has a wall region between two adjacent flange portions. A rotor arrangement for a wind power installation, and a wind power installation. A surface portion with cylindrical curvature is formed in the wall region.

A floating wave energy converter intended to be installed in an aquatic environment comprising a surface, water and a bed, realized by a cylinder including an energy-production device, and connectors connected to anchors, wherein the connectors intersect.