In an installation of a wind turbine on a floating foundation in floating condition and subject to sea-state induced motions, e.g. at the site of an offshore windfarm, use is made of a vessel with a crane arranged on the hull and provided with a hoisting system adapted to support the weight of the wind turbine and suspend the wind turbine from the crane. A heave compensation device compensates for sea-state induced heave motion of the wind turbine mast relative to the mast mounting structure of the floating foundation. Use is made of a mast alignment system configured to engage on the suspended wind turbine, e.g. on the mast of the suspended wind turbine, and to bring and maintain the mast of the wind turbine in alignment with the mounting axis of the floating foundation in order to compensate for sea-state induced motions, at least including tilt motions in one or more vertical planes, of the wind turbine mast relative to the mounting axis of the floating foundation.

A semi-submersible crane vessel for use in assembling a wind turbine and for installation by means of a crane of the vessel of the assembled wind turbine on a foundation. At an assembly station, the hull of the vessel is provided with a mast-receiving well that is sunk into, or through, the hull, preferably a well that extends into, or through a support column of the hull, which well is configured to receive therein at least a portion of the mast of the wind turbine during an assembly step of the wind turbine. For example, the mast-receiving well has a depth of at least 15 meters, e.g. at least 30 meters, measured from the deck of the deckbox structure.

An offshore wind turbine includes a ballast adjustable hull. In addition, the offshore wind turbine includes a telescopic tower movably coupled to the hull. The tower has a central axis and comprises a plurality of nested concentrically arranged elongate tubulars. Further, the offshore wind turbine includes a ballast adjustable elevator disposed about the telescopic tower and movably coupled to the hull. The elevator is configured to lift one or more of the plurality of tubulars of the tower axially upward relative to the hull. Still further, the offshore wind turbine includes a nacelle coupled to an upper end of one of the plurality of tubulars of the tower. Moreover, the offshore wind turbine includes a rotor assembly coupled to the nacelle.

Semi-submersible offshore support structure for a wind turbine comprising three semi-submersible columns that are connected to each other by a connection structure, wherein the connection structure defines three sides of the support structure, wherein the support structure further comprises a wind turbine receiving element for receiving a wind turbine tower, wherein the wind turbine receiving element is positioned on a side of the support structure between two semi-submersible columns.

An adjustable platform for installing a wind turbine generator comprises an adjustable platform shell, the adjustable platform shell is installed on a hull, pile legs are connected vertically in the adjustable platform shell in a sliding way, a plurality of adjusting jacks are arranged on the pile legs, an electric plug-in component is arranged in the adjustable platform shell and used for fitting with the adjusting jacks. The fitting of electric plug-in component with the adjusting jacks of the pile legs replaces the bolted connection between the installation platform and the pile legs, and the electric power is used to replace the manual operation, solving the technical problems in the prior art that bolted connection is required between the installation platform and the pile legs, bolts are required to be removed manually before the pile legs sink, and the labor cost is greatly consumed.

A pile displacement system includes a first subsystem, and a second subsystem arranged adjacent to the first subsystem along a longitudinal axis of the monopile. Each of the first and the second subsystems includes a height adjustable support, and a pile support unit arranged on the height adjustable support such that the pile support unit is movable along the monopile's longitudinal axis. A method for displacing a horizontally oriented monopile for an off-shore wind turbine parallel to a base floor by use of the pile displacement system includes arranging the monopile onto the monopile support units of the first and second subsystems; lowering the height adjustable support of at least the first subsystem towards the base floor until the weight of the monopile is transferred from at least the first subsystem to an external support structure aligned along the monopile's longitudinal axis, adjacent to the first subsystem; moving the pile support unit of the first subsystem a distance in direction away from the external support structure; raising the height adjustable support of the first subsystem away from the base floor until the weight of the monopile is transferred from the external support structure to the first subsystem; and moving the pile support units of the first and the second subsystems a distance in direction towards the external support structure.

A method for assembling a floating offshore wind farm, including: arranging at least N floating structures on a body of water; providing mast sections for assembling at least N masts; providing turbines and blades for at least N wind turbines; selecting at least one floating structure referred to as the mounting floating structure, the other floating structures being receiving floating structures; fastening a lifting device to the mounting floating structure; moving the mounting floating structure up to a receiving floating structure, and using the lifting device to lift and mount at least one constituent element of a wind turbine on the receiving floating structure; repeating the preceding step for the other receiving floating structures.

There provides an auxiliary structure for floating and sinking the whole offshore wind turbine with suction bucket foundation(s), which includes an upper bracket floated on water and a lower bracket sunk synchronously with a support structure. The upper bracket includes upper floating boxes; upper cross-connectors each of which is fixedly connected to the upper hoop and a corresponding upper floating box; and an upper hoop configured to sleeve on an outer side of the support structure. The upper bracket and the support structure are relatively moved in an up and down direction, and are connected in a manner of limiting position. The lower bracket includes lower floating boxes, a bottom of each of which is adjustable in height; lower cross-connectors each of which is fixedly connected to the lower hoop and a corresponding lower floating box; and a lower hoop that holds the support structure tightly.

A floating body (4) for a spar-type offshore wind power generation facility floating sideways is raised by injecting ballast water at sea, by steps including a first step of decentering a center of gravity of the floating body for the spar-type offshore wind power generation facility by means of a center-of-gravity decentering device, and a second step of injecting the ballast water to raise upright the floating body for the spar-type offshore wind power generation facility. The center-of-gravity decentering device may be a weight (2) attached to an outer surface of the floating body, or a solid ballast (34) introduced in the floating body.

Disclosed is an offshore wind turbine, comprising: a base configured to be submerged when the turbine is in an upright generating position in open water; and, a tower attached to the base and having a longitudinal axis, wherein the tower and base are movable between a horizontal towing position in which the turbine is towable through a body of water, and an upright generating position in which the turbine is vertically orientated for use in the body of water. Also disclosed herein is a method of deploying a wind turbine comprising the steps of assembling the wind turbine in a horizontal or near horizontal orientation prior to deploying to an installation location, towing the assembled wind turbine in a horizontal or near horizontal position to the installation location and up righting the assembled wind turbine in the installation location.