A wave energy collection and conversion system that uses a compliant capture mechanism to enable the collection of wave energy over extensive distances without introducing damaging forces onto the collection structure. The system includes a flexible membrane in contact with or submerged under water, a plurality of power generation devices positioned on a sea floor, and lines that connect the flexible membrane to the power generation devices. The power generation devices each include a self-reeling mechanism and a turbine. As wave energy pushes the flexible membrane, the lines are reeled into and out of the corresponding power generation device(s). Rotation of the shaft, in turn, rotates a gear and rotator of the turbine, thus harnessing energy derived from the wave motion.

The wind or marine energy capture system uses paragliders, elliptical or rhomboidal kites that are rotated, twisted or with fins on portions of their trailing or leading edges of the major edges and held at their ends by cables or cords, which by the action of the wind or water rotate around its axis and apply the rotational movement to an electric generator or mechanical element to move to the ground. Paragliders or elliptical kites, etc. they are directed by the wind automatically without having to apply any energy to it.

A method of controlling an airborne object (2), such as a kite or a glider, is disclosed. The airborne object (2) may be an airborne energy generating system. The airborne object (2) is coupled to a part of a wind turbine (1), such as a nacelle (4), a tower (3) or a foundation, via a cable (7). At least one parameter related to movements (8) of the tower (3) of the wind turbine (1) is measured, and a cable force (9) of the cable (7) acting on the wind turbine (1) is adjusted, based on the at least one measured parameter. Thereby the tower movements (8) can be counteracted and fatigue can be reduced.

Methods, systems, and techniques for harnessing wind energy use a tethered airfoil and a digital hydraulic pump and motor, which may optionally be a combined pump/motor. During a traction phase, a wind powered airfoil is allowed to extend a tether and a portion of the wind energy harnessed through extension of the tether is stored prior to distributing the wind energy to an electrical service. During a retraction phase, the wind energy that is stored during the traction phase is used to retract the tether. The digital hydraulic pump and motor are mechanically coupled to the tether.

An underwater system for generating electricity can include a spool assembly configured to wind and unwind a retractable line. The system can include a controllable apparatus connected to the retractable line. The system can include a tension assembly connected to the spool assembly and configured to maintain a first tension in the retractable line. The system can include one or more surfaces connected to the apparatus and configured to produce a second tension in response to a current, the direction of the second tension being either opposite or equal to the direction of the first tension. The system can include an electrical generator assembly configured to generate electricity in response to unwinding the retractable line.

System for power generation from a flow of fluid, comprising a fluid driven device connected to a tether wherein the tether is coupled with a base station to convert energy from the flow of fluid into transportable energy, wherein the fluid driven device comprises a frame provided with adjustable vanes, and wherein the vanes are adjustable for setting into a predefine position relative to the flow of fluid. The fluid driven device comprises a working mode and a retraction mode, wherein in the working mode the vanes are set in a first predetermined position to generate a lift force from the flow of fluid, and wherein in the retraction mode the vanes are set in a second predetermined position to provide a low drag level to the flow of fluid, and wherein the work performed during working mode is larger than the work supplied during retraction mode.

A kite control system for controlling a kite which includes a plurality of rotators, a plurality of guiding elements locatable between each of the plurality of rotators and the kite, a plurality of adjustable deflectors, a plurality of deflector guides configured to adjust the operational length of the kite connecting line upon adjustment of the deflector, at least one invert correlator for, when in use, inversely correlate the adjustment of the operative length of the respective kite connecting lines, wherein the plurality of kite connecting lines includes the connection of at least one of the kite connecting lines at the kite biased towards the leading end region of the kite, and the connection of at least another kite connecting line biased towards the trailing end region of the kite.

An ocean wave energy absorbing kite system 200 captures an ocean wave's kinetic energy as a force on a submerged, reciprocating panel 202 that drives the panel back and forth in an oscillating motion. The force applied to the panel is transmitted to a power generator 244 through opposed flexible ropes or lines 214, 224 loaded in tension. Potential energy is captured from the wave as a vertical force when a buoyant volume attached to the energy absorbing panel or kite member 202 rises on a passing ocean wave's peak, and transmits the force through flexible ropes or lines in tension to a power generator. Optionally, the shape of the panel is configurable to limit or restrict absorbed wave energy, thereby preventing damage from larger storm-generated waves.

System for power generation from a flow of fluid, comprising a fluid driven device connected to a tether wherein the tether is coupled with a base station to convert energy from the flow of fluid into transportable energy, wherein the fluid driven device comprises a frame provided with adjustable vanes, and wherein the vanes are adjustable for setting into a predefine position relative to the flow of fluid. The fluid driven device comprises a working mode and a retraction mode, wherein in the working mode the vanes are set in a first predetermined position to generate a lift force from the flow of fluid, and wherein in the retraction mode the vanes are set in a second predetermined position to provide a low drag level to the flow of fluid, and wherein the work performed during working mode is larger than the work supplied during retraction mode.

An underwater system for generating electricity can include a spool assembly configured to wind and unwind a retractable line. The system can include a controllable apparatus connected to the retractable line. The system can include a tension assembly connected to the spool assembly and configured to maintain a first tension in the retractable line. The system can include one or more surfaces connected to the apparatus and configured to produce a second tension in response to a current, the direction of the second tension being either opposite or equal to the direction of the first tension. The system can include an electrical generator assembly configured to generate electricity in response to unwinding the retractable line.