A method and a device for dampening movement in a multiple rotor (MR) wind turbine located at sea and comprising a tower (2) extending in an upwards direction, a load carrying structure (3, 4) forming a first section (3) and a second section (4), the first and second sections extending in different directions away from the tower (2). To provide efficient dampening of the movement, the method comprises tethering a first body (20) to the first section (3), the first body being at least partly submerged into the sea.

A wind turbine foundation structure comprising a hollow structural member having a longitudinally extending circumferential wall, the wall being bounded at the top by a top end face and bounded at the bottom by a bottom end face, wherein the wall is formed from a mineral building material and in that a wall thickness of the wall tapers from the top end face towards the bottom end face.

A multi-tank/vessel buoyancy system for use in deploying and connecting tendons or other elongate members between subsea anchors and floating/semi-submersible platforms. The vessels are interconnected at axially spaced locations toward their upper ends and lower ends, there being an equalizing system proximate the top ends of the vessels to permit ingress and egress of air into the vessels and a lower water equalizing system to permit free-flowing ingress and egress of water into the vessels. There is at least one clamping system operatively connected to the multi-vessel system, the clamping system, like the valving systems, being remotely, acoustically operable from a PLC on a work barge or the like.

Disclosed embodiments provide a renewable power generation apparatus. In embodiments, the renewable power generation apparatus is driven by wind. In other embodiments, the renewable power generation apparatus is driven by water. Disclosed embodiments utilize two cylindrical turbines placed adjacent to each other. A diverter directs wind towards both turbines, causing them to rotate about their respective longitudinal axis. The turbines are coupled to a driveshaft that drives a generator to generate power. Embodiments utilize an airfoil adjacent to each turbine. The airfoil causes air to move faster over the airfoil surface to create low pressure which increases the performance of the turbines. The renewable power generation apparatus of disclosed embodiments is relatively compact compared to a traditional wind turbine. This allows disclosed embodiments to have more flexibility in where they are installed, facilitating local power generation, off-grid applications, and other important environmental applications.

A system for maintaining buoyant, energy-capture devices in general relative position in water in the presence of surface waves allows heeling of the energy capture devices while preventing collision. The system includes a grid of structural members that resists compression while permitting limited relative surface displacement between the first and second energy-capture devices. The structural members may be partially compressible and provide a restoring force, and they may allow heeling. Electricity from wave energy capture devices is combined in a way that smoothes variations inherent in wave action. Electricity from wind energy capture devices is combined with energy from wave energy capture devices for transmission to shore.

A method for assembling a wind turbine, including: attaching an elevator carriage (27) to a nacelle (9) to form a carriage-nacelle assembly (27,9); and mounting the carriage-nacelle assembly (27,9) on to a tower (3) as a unit.

A method of fixing an offshore structure to a pre-piled foundation pile is provided. A tube is piled into the sea floor and the offshore structure includes a leg inserted into the foundation pile. Grout is applied to a first region between an end portion of the leg and the sea floor within the foundation pile. The grout is allowed to at least partially cure, and then grout is applied to a second region. The second region is an annular region between the leg and the foundation pile.

A floating platform for supporting generators of power derived from the wind, the waves and ocean currents, adopting an approximately disc-shaped general configuration with a circular or polygonal perimeter, which optimises its size and therefore minimises substantially its weight and likewise its production costs, as well as other associated complexities; which eliminates the possibility of entering into resonance with the movement of the ocean waves and thus not damaging the equipment installed, not overturning, and not surpassing the maximum list acceptable for wind power generators, nor wave power generators, nor ocean current generators; and which withstands the waves of the greatest size possible, all due to a ratio between its depth or height (13) and the diameter (14) thereof of between 0.06 and 0.35.

A blade pitch controller for a wind turbine includes a nominal control system and a tower feedback loop. The tower feedback loop includes a filtering system. The filtering system is arranged to control wind turbine blade pitch so as to provide additional effective stiffness to the wind turbine in response to motion of the wind turbine which is above a filter frequency of the filtering system.

An offshore wind turbine erected in a body of water includes a generator, a foundation, a nacelle, a tower having a first end mounted to the foundation and a second end supporting the nacelle, an electrolytic unit arranged above a water level and electrically powered by the generator to produce hydrogen from an input fluid, in particular water, and a fluid supply assembly for supplying the input fluid from a fluid inlet arranged below the water level to the electrolytic unit by means of a fluid connection, wherein the fluid supply assembly includes a cleaning unit configured to clean a build-up formed along an area extending through the inner part of at least a part of the fluid connection or formed at the fluid inlet.