CN116648421A

CN116648421A - Offshore wind turbine assembly vessel

Info

Publication number: CN116648421A
Application number: CN202180086793.1A
Authority: CN
Inventors: D·B·维伊宁; J·鲁登伯格
Original assignee: Itrec BV
Current assignee: Huisman Equipment BV
Priority date: 2020-10-22
Filing date: 2021-10-19
Publication date: 2023-08-25
Also published as: CN116963990A

Abstract

The present invention relates to a crane for assembling and installing an offshore wind turbine at an offshore location, a vessel for assembling and installing an offshore wind turbine at an offshore location and a method for assembling and installing an offshore wind turbine at an offshore location. According to the invention, the crane is provided with a base section and a top section, wherein the top section is rotatably supported by bearings and is rotatable about a vertical axis with respect to the base section by means of a wind turbine lifting device, wherein a first trolley guide is mounted to the top section of the mounting crane for guiding the vertically movable wind turbine support trolley. According to the invention, the vessel is provided with one or more assembly tables at different sides of the mounting crane.

Description

Offshore wind turbine assembly vessel

Technical Field

The present invention relates generally to a crane for assembling and installing an offshore wind turbine at an offshore location, to a vessel for assembling and installing an offshore wind turbine at an offshore location, and to a method for assembling and installing an offshore wind turbine at an offshore location.

Background

Currently, many offshore wind turbine wind farms are planned to allow for large amounts of electricity production. Wind turbines have an ever increasing capacity and size for efficiency reasons. Now, 5MW and 8MW turbines are being planned. In the future even 14MW turbines are envisaged. In a known design, an 8MW turbine has a hub diameter (the hub can have 160 meters of blades), and She Gugao degrees at about 120 meters above sea level. The proposed 14MW turbine has a blade diameter of 220 meters and a hub at about 160 meters above sea level.

At least in future designs, wind turbines including towers, nacelles and blades may weigh well in excess of 1000 tons. The base itself may weigh several hundred tons, depending on the type of base, for example. Many types of susceptors are discussed in US 2007/243063. For example, JP2018053899 and EP3153398 relate to floating foundations.

It has been proposed to build the entire wind turbine onshore. In particular, the installation and testing of the nacelle, hub and blades on the tower is done onshore, which is much less costly than performing these operations offshore. This approach allows for reducing offshore installations and commissioning to compact operations, including installation of complete wind turbines. In this method, a foundation based on the sea floor or floating type may be pre-installed, and a tower with nacelle, hub and blades is fastened to the foundation.

In the field of floating base wind turbines it is currently generally understood that the assembly of the entire floating base wind turbine, i.e. the combination of floating base and wind turbine, is done remotely from the actual wind farm. For example, the assembly is done at a port-based site. The entire floating base wind turbine is then towed from the assembly location to a remote offshore wind farm location.

For example, hywind scotland is a wind farm using floating base wind turbines. These wind turbines have a tower 120 meters high mounted on a spar type floating foundation. The installation of the wind turbine on the spar type floating foundation is done in Fjord in norway using a saimem 7000 floating crane. The assembly is then towed through the north sea to scotland near the coast of peter black. In a wind farm, three suction anchors anchor the floating base to the sea floor.

To date, several installation vessels and methods have been proposed that are dedicated to offshore wind turbine installations.

The vessel MV Resolution is such a dedicated wind turbine assembly vessel. It is a jack-up vessel with six jack-up legs for raising the hull (at least partly) above the water surface to stabilize the hull for mounting the wind turbine. The vessel is equipped with a main foundation mounted boom crane at the stern of the vessel, which crane has a pivotable and tiltable boom. The existing MV Resolution vessel has a crane capacity of 300 tons and a new structure plan of the same design has a crane capacity of 1000 tons.

In US2010/0293781 a jack-up vessel is disclosed, which vessel is configured for mounting blades to a nacelle. The jack-up vessel is provided with a rail mounted nacelle support structure for temporarily supporting the nacelle so that the blades may be mounted to the nacelle. The jack-up vessel is also provided with a crane for mounting the wind turbine tower on a ducted foundation. I.e. on the type of foundation that is tethered to the sea floor. Once assembled with the blades, the rail mounted nacelle support is used to move the nacelle from an above deck position to an outboard position. The nacelle support is then used to lower the nacelle onto a wind turbine tower located near the vessel. Furthermore, the nacelle support structure is capable of lifting the assembled wind turbine from a barge positioned adjacent to the jack-up vessel and of lowering the assembled wind turbine onto a ducted foundation positioned adjacent to the jack-up vessel.

An alternative design is proposed in WO2011028102 which relates to an offshore wind turbine assembly vessel, wherein the vessel comprises a non-jack-up floating hull and a crane structure extending upwardly from the hull. The crane structure is provided with lifting means having one or more wind turbine suspension elements and wind turbine engagement means supported by the one or more suspension elements and adapted to engage with a wind turbine. Thus, the lifting device is adapted to support at least the tower of the wind turbine when the tower is in a vertical orientation and to raise and lower the at least the tower of the wind turbine in a controllable manner; preferably together with the nacelle and preferably also with the hub and blades mounted on top of the tower. Furthermore, the vessel enables transportation of the wind turbine between an onshore location and a mounted location, wherein the nacelle, hub and blades are mounted on top of the tower. This is not only useful when installing a wind turbine, but also allows for efficient replacement of an installed wind turbine, for example when the wind turbine is no longer operational and requires major repairs.

Other non-jack-up type vessels are disclosed in EP2473400 and EP 2952426. These types of vessels are configured to transport pre-assembled wind turbines between an assembly position and an operational position.

In WO2019/245366, a floating vessel is disclosed, which is configured to fit blades to a nacelle. The vessel is provided with a deck mounted nacelle supporting structure for temporarily supporting the nacelle such that the blades can be mounted to the nacelle. The vessel is also provided with two cranes. A crane is used to mount the wind turbine tower on the ducted foundation. I.e. on the type of foundation that is tethered to the sea floor. Another crane is used to lift the nacelle onto the nacelle support structure and once the blades are fitted to the nacelle, the nacelle is lifted onto a wind turbine tower located near the vessel.

Disclosure of Invention

The present invention aims to provide an alternative method for assembling and installing wind turbines and/or for creating a wind farm, for example a wind farm with one or more floating base wind turbines.

The present invention provides a mounting crane to be mounted on a floating hull of a vessel for assembling and mounting an offshore wind turbine according to claim 1,

The wind turbine mounting crane to be mounted on the floating hull of the vessel according to the invention has at least one assembly side facing the wind turbine assembly table and has a mounting side.

The mounting side of the crane is also referred to herein as the first vertical side of the wind turbine mounting crane or as the side for mounting the assembled wind turbine on the foundation using the mounting crane.

The mounting crane is configured to perform one or more wind turbine assembly steps, such as erecting a wind turbine tower, and the mounting crane is configured for arranging the assembled wind turbine from the at least one wind turbine assembly station into a mounting position above the wind turbine foundation adjacent the vessel at the mounting side of the mounting crane, and lowering the assembled wind turbine onto the foundation.

The mounting crane is provided with a wind turbine lifting device, a base section and a top section, and a first trolley guide with a first wind turbine support trolley.

The wind turbine lifting device has one or more wind turbine suspension elements, such as cables, and is adapted to support the assembled wind turbine and to raise and lower the assembled wind turbine in a controllable manner, the assembled wind turbine comprising a tower and assembled blades in combination with a nacelle.

The top section is rotatably supported by bearings and is rotatable about a vertical axis with respect to the base section by means of a wind turbine lifting device, and the lifting device is thus capable of transferring at least an upper tower component between the assembly table and the mounting side.

The first cart guide is mounted to a top section of the mounting crane. The first wind turbine support cart is vertically movable along the first cart guide and supports the wind turbine engagement device.

The invention thus allows a compact configuration of the installation process and thus allows the method according to the invention to be implemented on a compact vessel. It is believed that to date, assembly of wind turbines on vessels has only been proposed in the case of very large vessels. Typically, these types of vessels are so sized that they cannot be used to navigate wind farm locations, or even effectively for transfer between locations. The mounting crane according to the invention allows to use the vessel for assembling the wind turbine and to mount the assembled wind turbine on the foundation. Furthermore, when used in combination with a compact vessel, such as a semi-submersible vessel, the vessel may also be used to mount the assembled wind turbine on a floating base.

In an embodiment, an active horizontal movement device is mounted between the trolley and the wind turbine engagement device, the active horizontal movement device being adapted to actively compensate for horizontal displacement of the wind turbine engagement device relative to the base in at least one horizontal direction, possibly in two non-parallel horizontal directions, e.g. in an orthogonal horizontal direction, caused by sea conditions when the wind turbine is supported by the wind turbine engagement device.

In an embodiment, the installation crane, e.g. the first lifting device of the installation crane, is provided with heave compensation means adapted to compensate for heave motions caused by sea conditions of a wind turbine tower supported by the installation crane relative to a tower mounting structure of the foundation (e.g. a floating foundation).

Heave compensation devices are well known in the art in passive and active embodiments or mixed embodiments thereof. For example, the hoisting device may comprise one or more winches and one or more hoisting ropes, the heave compensation being formed by suitable operation of the (electric) winch and/or by one or more heave compensation cylinders carrying one or more rope pulleys over which the hoisting ropes are passed.

In an embodiment, the base section of the mounting crane is provided with a second trolley guide and a second wind turbine support trolley which is vertically movable along the second trolley guide on the mounting side of the mounting crane.

In another embodiment, the second cart supports a wind turbine engagement device. Preferably, an active horizontal movement device is mounted between the trolley and the wind turbine engagement device, the active horizontal movement device being adapted to actively compensate for horizontal displacement of the wind turbine engagement device relative to the base in at least one horizontal direction, possibly in two non-parallel horizontal directions, e.g. in an orthogonal horizontal direction, caused by sea conditions when the wind turbine is supported by the wind turbine engagement device.

The first cart and optionally the second cart may be arranged in an active position for supporting a wind turbine (e.g. a tower or upper tower part of a wind turbine) and in an inactive position for moving along the tower or upper tower part of a wind turbine supported by a wind turbine mounting crane, e.g. at least one wind turbine assembly station.

In an embodiment, the lifting device comprises two spaced apart cantilevers, which support one or more suspension elements. One or more suspension elements are connected to the first cart or to the wind turbine engagement means.

In another embodiment, the two booms may be arranged in an active position, in which the two booms are used to support the first cart and the first wind turbine engagement means, and in an inactive position, in which the two booms are used to move along the nacelle or blade of the partially or fully assembled wind turbine at the at least one wind turbine assembly station.

In an embodiment, the wind turbine mounting crane is configured such that when the assembled wind turbine is supported by the mounting crane, the cantilever arms extend above the nacelle of the wind turbine, and when seen in front view the nacelle of the supported wind turbine is located between the cantilever arms.

In another embodiment, the wind turbine mounting crane is configured such that when the assembled wind turbine is supported by the mounting crane, the cantilever arms extend above the nacelle of the wind turbine, and when seen in front view the nacelle of the supported wind turbine is located between the cantilever arms.

In an embodiment, the mounting crane is a double sided mounting crane with a wind turbine lifting device as a first lifting device on a first side of the crane and a second lifting device on an opposite second side of the mounting crane, such that the crane is able to perform lifting actions simultaneously on opposite sides of the mounting crane.

In an embodiment, the mounting crane is provided with one or more foundation pile supports for supporting the foundation piles in an upright position adjacent the mounting crane. The one or more foundation pile supports are movable between an active position in which the at least one foundation pile support extends in a direction away from the mounting crane and a passive position in which the at least one foundation pile support is retracted into or folded against the wind turbine mounting crane.

The invention also provides a method for assembling a wind turbine on a vessel, preferably in a floating state. Preferably, the vessel is also used for installing an assembled wind turbine, preferably at an offshore wind farm site. It will be appreciated that this allows avoiding long distance transport (e.g. by towing a complete wind turbine) from shore-based (e.g. peri-dock) locations to the wind farm. This transportation takes considerable effort, wastes time, and may be affected by weather conditions.

The present invention provides a method for assembling and installing an offshore wind turbine according to claim 16.

The method allows assembling the wind turbine offshore, in particular at the location where the wind turbine has to be installed. Thus, there is no need to transport the fully assembled wind turbine, which is a slow process, and it is difficult to transport the fully assembled wind turbine due to the size of the assembled wind turbine. Transporting the disassembled wind turbines facilitates transporting multiple wind turbines on a single vessel.

The invention thus allows the assembled wind turbine to be mounted on an already anchored floating foundation at the wind farm location. Thus, the floating foundation may be transported and anchored without supporting the assembled wind turbine. This significantly aids in the transportation and anchoring process. Furthermore, the invention allows for assembling wind turbines at or near a wind farm location.

Furthermore, the method allows for a compact configuration of the installation process and thus allows the method to be implemented on a compact vessel. It is believed that to date, assembly of wind turbines on vessels has only been proposed in the case of very large vessels. Typically, these types of vessels are so sized that they cannot be used to navigate wind farm locations, or even effectively for transfer between locations. The method according to the invention allows to use the vessel for assembling the wind turbine and to mount the assembled wind turbine on a foundation. Furthermore, when used in combination with a compact vessel, such as a semi-submersible vessel, the vessel may also be used to mount the assembled wind turbine on a floating base.

The invention thus provides an alternative method for assembly and for mounting a wind turbine.

In a method according to the invention for assembling a wind turbine on a wind turbine assembly vessel (e.g. a semi-submersible crane vessel), preferably for mounting an assembled wind turbine on a foundation (e.g. a subsea mounting foundation or a floating foundation) using a wind turbine assembly vessel, the wind turbine assembly vessel comprises:

-a floating hull;

a wind turbine component storage deck for storing components of a wind turbine, such as a tower, a lower tower component, an upper tower component, a rotor assembly, such as a nacelle with a hub, and blades;

preferably, the blade handling device is adapted to transfer the blade between a horizontal supply position and a fastening position adjacent the nacelle;

-at least one wind turbine assembly station;

a mounting crane mounted on the floating hull, for example on the deck of the floating hull, wherein the mounting crane has at least one assembly side facing the at least one wind turbine assembly station and has a mounting side,

the method comprises the following steps:

-moving one or more wind turbine components from the wind turbine component storage deck to at least one wind turbine assembly station; and

-using a mounting crane to:

-performing one or more assembly steps, for example by inverting the wind turbine tower or by lifting the nacelle onto the top of the tower or onto an upper tower part;

-supporting the assembled wind turbine on an assembly side and arranging the assembled wind turbine from the assembly station to an installation position on an installation side of the installation crane, the installation position being above a wind turbine foundation adjacent the vessel;

-lowering the assembled wind turbine onto the foundation.

In an embodiment, the method further comprises lifting the nacelle and lifting the nacelle onto the tower or upper tower component, preferably using a wind turbine installation crane, and installing the nacelle on the tower or upper tower component.

In an embodiment, the method further comprises the following wind turbine assembly steps: before or after mounting the nacelle on the tower or upper tower part, the section of the tower or upper tower part is lowered into a tower receiving well, preferably using a wind turbine mounting crane, which is submerged into or through the hull and is configured to receive at least a portion of the tower of the wind turbine therein such that the distance between the nacelle and the storage deck is reduced, preferably less than the length of a wind turbine blade, more preferably less than four fifths of the length of the blade.

In an embodiment, the method further comprises a wind turbine assembly step of arranging the tower or upper tower part in an upright mounting position, wherein the nacelle is mounted on the tower or upper tower part, wherein the nacelle, in particular a hub of the nacelle, is in a mounting position for mounting the blades to the nacelle, preferably in a horizontal position.

In another embodiment, the hub of the nacelle is positioned, more particularly rotated into position about a horizontal pivot axis, to mount the blades to the nacelle, which are supported in a horizontal position, preferably by the blade handling equipment.

In another embodiment the nacelle is positioned, more particularly rotated in position about a vertical pivot axis, to mount to the nacelle the blades supported in a vertical position above the deck, while the blades that have been mounted to the nacelle are supported mainly vertically above the sea surface, i.e. mainly outside the contour of the vessel when seen in top view.

In an embodiment, the method further comprises a blade mounting process of mounting the blade to the nacelle, preferably using a blade handling device, the blade mounting process comprising one or more, preferably all, of the following steps;

Lifting the first blade to a secured position adjacent the nacelle, mounting the first blade to the nacelle, and rotating the nacelle to a successive mounting position,

-lifting the second blade to a fastening position adjacent to the nacelle, mounting the second blade to the nacelle, and rotating the nacelle to a successive mounting position; and

-lifting the third blade to a fastening position adjacent to the nacelle and mounting the third blade to the nacelle.

In another embodiment, the tower or an upper tower part supporting the nacelle is received in a tower receiving well in the deck of the vessel such that the distance between the nacelle and the deck is reduced, preferably less than the length of the turbine blades, more preferably less than four fifths of the length of the blades.

In a further alternative embodiment, the nacelle is mounted on a nacelle support fixed to the deck of the vessel such that the nacelle is supported by the nacelle support at a distance above the deck, which distance is preferably less than the length of the turbine blades, more preferably less than four fifths of the length of the blades.

In an embodiment, the method further comprises a wind turbine assembly step of arranging the upper tower part on the lower tower part using the mounting crane, preferably after mounting the nacelle on the upper tower part, in case the tower consists of the lower tower part and the upper tower part.

In an embodiment, the method further comprises erecting a tower or upper tower part of the wind turbine from a horizontal storage position to an upright mounting position using the wind turbine mounting crane.

In an embodiment, the at least one wind turbine assembly rig is a first wind turbine assembly rig on a first side of the installation crane, the first side preferably being opposite to the installation side of the installation crane, and the vessel further comprises a second wind turbine assembly rig on a second side of the installation crane, and wherein

-a first assembly rig for erecting a tower or a top section of a tower and/or for mounting a nacelle on a tower or a top section of a tower, preferably using a mounting crane; and

a second assembly station for completing the assembly of the wind turbine, preferably with a mounting crane, e.g. for arranging the upper tower part on the lower tower part with the mounting crane if the tower consists of the lower tower part and the upper tower part, and/or for mounting the blade to the nacelle; and wherein

A mounting crane for arranging the tower or the top section of the tower from the first assembly station to the second assembly station, preferably the nacelle is mounted on top of the tower or the top section of the tower, the mounting crane for arranging the assembled wind turbine from the second assembly station to the mounting side of the mounting crane, and for lowering the assembled wind turbine onto the foundation.

In a further alternative embodiment, the at least one wind turbine assembly station is a first wind turbine assembly station located on a first side of the installation crane, the first side preferably being opposite to the installation side of the installation crane, the vessel further comprises a second wind turbine assembly station located on a second side of the installation crane, the vessel further comprises a third wind turbine assembly station located on a third side of the installation crane, the third side preferably being opposite to the second side of the installation crane, and wherein

-a first assembly table for lifting the nacelle and/or for lifting the nacelle mounted on a top section of the tower;

-a second assembly station for mounting the blade to the nacelle; and

a third assembly station for completing the assembly of the wind turbine, e.g. arranging an upper tower part provided with nacelle and blades on the lower tower part if the tower consists of the lower tower part and the upper tower part, and/or for mounting the nacelle provided with blades on the tower; and wherein

The mounting crane is used for arranging the assembled wind turbine from the third assembly station to the mounting side of the mounting crane and for lowering the assembled wind turbine onto the foundation.

In an embodiment, the wind turbine mounting crane is configured to actively compensate for sea state induced movements, such as horizontal displacements, of the assembled wind turbine relative to the foundation to which the wind turbine is to be lowered, in particular the floating foundation, the method comprising

Preferably the wind turbine is moved relative to the vessel using a wind turbine mounting crane as it is lowered onto the floating base to compensate for the sea-state induced motion of the vessel relative to the floating base and thereby maintain the wind turbine substantially aligned with the floating base.

In an embodiment, a vessel is provided with a base restraint system, the method comprising:

-engaging the floating base with a base restraint system;

preferably reducing the movement of the floating base relative to the vessel when the wind turbine is lowered onto the base, more particularly reducing the movement of the floating base relative to the assembled wind turbine to be mounted on the floating base, and/or monitoring the movement of the floating base relative to the vessel, more particularly monitoring the movement of the floating base relative to the assembled wind turbine to be mounted on the floating base.

The invention also provides an embodiment for assembling a wind turbine on a wind turbine assembly vessel, preferably for mounting an assembled wind turbine using a wind turbine assembly vessel,

Wherein the wind turbine assembly vessel comprises:

-a floating hull;

-a wind turbine component storage deck, wherein the storage deck preferably comprises a lower tower component storage area, an upper tower component storage area, a nacelle storage area and a blade storage area;

-a first assembly station, a second assembly station and a third assembly station;

-a handling crane and an installation crane, wherein the installation crane has an installation side, the installation crane being configured for supporting the assembled wind turbine at its installation side in an installation position above the base and for lowering the wind turbine onto the base, and wherein preferably the first assembly station is located on a first side of the installation crane, the second assembly station is located on a second side of the installation crane, the third assembly station is located on a third side of the installation crane, and the installation side is located on a fourth side of the crane;

preferably, the blade handling device is adapted to transfer the blade between a horizontal supply position and a fastening position;

the method comprises the following steps:

-storing wind turbine components, such as wind turbine upper tower components, wind turbine lower tower components, nacelle and blades, on a wind turbine component storage deck, preferably at a wind turbine component storage deck of a wind turbine component storage area;

-arranging the upper tower part into the first assembly station, preferably using a handling crane, and supporting the upper tower part in an upright mounting position;

in the first assembly station, the nacelle is lifted onto the upper tower part, preferably using a handling crane, and the nacelle is mounted,

-arranging the combined upper tower part and nacelle from the first assembly station to the second assembly station, preferably using a mounting crane, and supporting the wind turbine upper tower part in an upright mounting position, wherein the nacelle is in a mounting position for mounting the blade onto the nacelle;

-mounting the blade to the nacelle, preferably using a blade handling device, the blade mounting process comprising;

lifting the first blade to a fastening position adjacent to the nacelle, mounting the first blade to the nacelle, and rotating the nacelle to a successive mounting position, preferably using a blade handling device,

-lifting the second blade to a fastening position adjacent to the nacelle, mounting the second blade to the nacelle, and rotating the nacelle to a successive mounting position, preferably using a blade handling device; and

-lifting the third blade to a fastening position adjacent to the nacelle, preferably using a blade handling device, and mounting the third blade to the nacelle; and

-arranging the lower tower component into the third assembly station, preferably using a handling crane, and supporting the lower tower component in an upright mounting position;

-lifting the combined upper tower part, nacelle and blade, preferably using a mounting crane, and mounting the upper tower part to the lower tower part in a third assembly station to provide an assembled wind turbine; and

-lifting the wind turbine to a mounting position on a fourth side of the mounting crane using the mounting crane; and lowering the wind turbine onto the foundation.

The invention also provides a method for assembling a wind turbine on a wind turbine assembly vessel, preferably for mounting an assembled wind turbine using a wind turbine assembly vessel,

wherein the wind turbine assembly vessel comprises:

-a floating hull;

-a wind turbine component storage deck for storing components of a wind turbine, such as towers, nacelle and blades;

the method comprises the following steps:

-storing wind turbine components, preferably all wind turbine components, on a wind turbine component storage deck;

-arranging the tower into the first assembly station, preferably using a wind turbine mounting crane, and supporting the upper tower in an upright mounting position; optionally before this: erecting a tower of the wind turbine from a horizontal storage position to an upright mounting position, preferably using a wind turbine mounting crane;

in the first assembly station, the nacelle is lifted and lifted onto the tower, preferably using a wind turbine mounting crane, and mounted on the tower;

-arranging the combined tower and nacelle from the first assembly station to the second assembly station using a mounting crane, lowering a base section of the tower into the deck recess and supporting the tower components in an upright mounting position, and wherein the nacelle, in particular a hub of the nacelle, is in a mounting position for mounting the blades to the nacelle;

-mounting the blade to the nacelle, preferably using a blade handling device, to provide an assembled wind turbine, the blade mounting process comprising;

-arranging the assembled wind turbine from the second assembly station into a mounting position on a fourth side of the mounting crane using the mounting crane; and lowering the wind turbine onto the foundation.

The invention also provides a method for assembling a wind turbine and for mounting the assembled wind turbine on a foundation, such as a seabed-mounted foundation or a floating foundation, wherein a semi-submersible crane vessel is used, wherein the vessel comprises:

-a floating hull having:

-a deckbox structure;

two pontoons in parallel and one with each other,

-a row of support columns extending upwardly from each of the two pontoons, the support columns supporting a deck box structure thereon;

Wherein the deck box structure has a deck and a box bottom,

a mounting crane mounted on the deckbox structure and configured to mount the assembled wind turbine on a base, for example a tub crane, for example a crane mounted above a support column at the end of a row of columns,

wherein, at the assembly station, the hull of the vessel is provided with a tower receiving well sunk into or through the hull, preferably a well extending into or through the support column of the hull, the well being configured to receive at least a part of the tower of the wind turbine therein,

wherein the assembled wind turbine to be mounted comprises at least a part of a wind turbine tower and a rotor assembly mounted on the tower, e.g. a nacelle with a hub, the rotor assembly optionally being provided with one or more (e.g. all) rotor blades,

in the method, at least a portion of the tower is arranged in the tower receiving well during an assembly step of the wind turbine, e.g. during mounting of the rotor assembly on the tower and/or during assembly of one or more (e.g. all) rotor blades to the rotor assembly.

The invention also provides a method of assembling a wind turbine using a tower coupling mounted to a nacelle to enable handling of the nacelle with a mounting crane. The tower coupling is a short tubular section, one end of which may be fixed to the nacelle and the opposite end may be fixed to the top of the tower. In this method, the nacelle is mounted on top of the tower by means of a tower coupling during the assembly process, preferably after the nacelle has been provided with blades.

The tower coupling is much shorter than the upper tower part. Providing the nacelle with a tower coupling enables a wind turbine assembly process similar to a wind turbine assembly process comprising an upper tower part and a lower tower part. In this approach, the assembly process is completed by mounting the nacelle in combination with the blade and tower coupling on top of the full length tower, rather than mounting the nacelle in combination with the blade and upper tower components on top of the lower tower components.

The invention also provides a method of assembling a wind turbine using a tower. In such an embodiment, the nacelle is mounted on top of the complete tower during the assembly process, preferably before the nacelle is provided with blades.

In a method for assembling a wind turbine on a wind turbine assembly vessel, such as a semi-submersible crane vessel, and for mounting the assembled wind turbine on a foundation, such as a subsea installation foundation or a floating foundation, using a wind turbine assembly vessel, the wind turbine assembly vessel comprising:

-a floating hull;

-a wind turbine component storage deck for storing components of a wind turbine, such as a tower, a rotor assembly, such as a nacelle with a hub, and blades;

-a blade handling device for transferring blades between a horizontal supply position on a wind turbine storage deck and a fastening position adjacent to the nacelle;

-a first wind turbine assembly bench, a second wind turbine assembly bench, and preferably a third wind turbine assembly bench;

wherein the first wind turbine assembly stand is located on a first side of the mounting crane, the first side being opposite to the mounting side of the mounting crane,

Wherein the second wind turbine assembly station is located on a second side of the mounting crane, and

wherein preferably the third wind turbine assembly station is located on a third side of the mounting crane, the third side being opposite to the second side of the mounting crane,

the method comprises the following steps:

-moving one or more wind turbine components from the wind turbine component storage deck to one or more wind turbine assembly tables, e.g. positioning the tower in a top horizontal orientation at a first wind turbine assembly table enabling erection of the tower using a wind turbine mounting crane, and/or moving the nacelle to a third wind turbine assembly table enabling the wind turbine mounting crane to lift the nacelle at the first wind turbine assembly table and mount the nacelle on top of the tower;

-erecting a tower of the wind turbine from a horizontal storage position to an upright mounting position using a wind turbine mounting crane at a first wind turbine assembly station;

-picking up the nacelle, preferably using a wind turbine mounting crane, preferably at a third wind turbine assembly station;

-at a first wind turbine assembly station, mounting the nacelle on top of an erected tower using a wind turbine mounting crane;

-arranging the tower and the nacelle mounted on top of the tower from a first wind turbine assembly station to a second wind turbine assembly station using a mounting crane;

-at a second assembly station, completing the assembly of the wind turbine by mounting the blades to the nacelle; preferably, a blade mounting procedure is used to mount the blade to the nacelle using the blade handling equipment, the blade mounting procedure comprising the steps of;

-supporting the assembled wind turbine at a second wind turbine assembly station using a mounting crane, and arranging the assembled wind turbine from the second wind turbine assembly station at a mounting side of the mounting crane to a mounting position, the mounting position being above a wind turbine foundation adjacent the vessel;

-lowering the assembled wind turbine onto the foundation using the mounting crane.

In an embodiment of the method according to the invention, the wind turbine mounting crane is configured to actively compensate for movements, such as horizontal displacements, caused by sea conditions of the assembled wind turbine relative to the foundation, in particular the floating foundation, to which the wind turbine is to be lowered. For example, the wind turbine mounting crane may be provided with one or more trolleys that support and/or engage the wind turbine and may be moved in a horizontal direction to move the wind turbine relative to the floating vessel to maintain the wind turbine in alignment with the movement of the floating base as the floating base is lowered.

In another embodiment of the method according to the invention for mounting a wind turbine on a floating base, the method comprises, before lowering the assembled wind turbine onto the floating base, engaging the floating base with a base restraint system, wherein the base restraint system is configured to reduce the movement of the floating base relative to the vessel, more particularly to reduce the movement of the floating base relative to the assembled wind turbine to be mounted on the floating base, and/or to monitor the movement of the floating base relative to the vessel, more particularly to monitor the movement of the floating base relative to the assembled wind turbine to be mounted on the floating base.

wherein the wind turbine assembly vessel comprises:

-a floating hull;

The method comprises the following steps:

In an alternative method according to the invention only two assembly tables are provided and the combined upper tower part, nacelle and blade is lifted from the second assembly table to the fourth side of the mounting crane by the mounting crane and lowered and mounted onto a lower tower section that has been mounted on or as part of the foundation.

In such an embodiment, the third assembly station may be used as a storage station to store the combined upper tower component, nacelle and blade before being lifted from the storage station to a fourth side of the installation crane by the installation crane in order to lower and mount the combined upper tower component onto a lower tower section that has been mounted on or is part of the foundation.

The invention also provides a vessel for assembling and installing an offshore wind turbine according to claim 7.

According to the invention, a vessel for assembling a wind turbine and for mounting the assembled wind turbine on a foundation, such as a semi-submersible crane vessel, such as a subsea mounting foundation or a floating foundation, comprises a floating hull, a wind turbine component storage deck, at least one wind turbine assembly rig, and a wind turbine mounting crane.

The wind turbine component storage deck for storing components of the wind turbine (e.g., the tower, rotor assembly, and blades) preferably includes dedicated storage areas, such as a tower storage area, a nacelle storage area, and/or a blade storage area.

The mounting crane is configured to perform one or more wind turbine assembly steps (e.g., erecting a wind turbine tower) and has at least one assembly side facing the at least one wind turbine assembly stand and has a mounting side.

The mounting crane is provided with a wind turbine lifting device with one or more wind turbine suspension elements. The wind turbine lifting device is adapted to support an assembled wind turbine and to raise and lower the assembled wind turbine in a controllable manner, the assembled wind turbine comprising a tower and assembled blades in combination with a nacelle.

The installation crane has a base section and a top section. The top section is rotatably supported by bearings and is rotatable about a vertical axis with respect to the base section using wind turbine lifting means. Thus, the lifting device is able to transfer at least the upper tower part between the assembly table and the mounting side.

The mounting crane is configured for arranging the assembled wind turbine from the at least one wind turbine assembly station at a mounting side of the mounting crane into a mounting position above a wind turbine foundation adjacent the vessel, in a mounting position for supporting the assembled wind turbine at the mounting side above the foundation, and for lowering the wind turbine onto the foundation.

The invention thus allows assembling wind turbines offshore, in particular at locations where wind turbines have to be installed, i.e. at or near a wind farm location. Thus, there is no need to transport the fully assembled wind turbine, which is a slow process, and it is difficult to transport the fully assembled wind turbine due to the size of the assembled wind turbine. Transporting the disassembled wind turbines facilitates transporting multiple wind turbines on a single vessel.

The invention also allows the assembled wind turbine to be mounted on a foundation, such as a floating foundation that has been anchored, at the wind farm location. Thus, the floating foundation may be transported and anchored without supporting the assembled wind turbine. This significantly aids in the transportation and anchoring process.

It will be appreciated that this allows avoiding long distance transport (e.g. by towing a complete wind turbine) from shore-based (e.g. peri-dock) locations to the wind farm. This transportation takes considerable effort, wastes time, and may be affected by weather conditions.

In an embodiment, the at least one wind turbine assembly rig is a first wind turbine assembly rig, and the vessel further comprises a second wind turbine assembly rig, and preferably a third wind turbine assembly rig. The first assembly station is configured for supporting the tower in an upright mounting position. The second assembly table is configured for supporting the tower in an upright mounting position with the nacelle in a mounting position for mounting the blade to the nacelle. Preferably, the third assembly station is configured for presenting a nacelle to be lifted by a wind turbine mounting crane.

The first wind turbine assembly station is located on a first side of the mounting crane, the second assembly station is located on a second side of the mounting crane, and preferably the third assembly station is located on a third side of the mounting crane. The mounting side is on the fourth side of the crane.

In an embodiment, the second and third wind turbine assembly stations are located on opposite sides of the mounting crane and the first assembly station is located opposite a first vertical side of the wind turbine mounting crane, i.e. the mounting side of the crane, i.e. the side for mounting the assembled wind turbine on the foundation using the mounting crane.

In an embodiment, the first assembly station is configured for supporting the upper tower part in an upright mounting position, the second assembly station is configured for supporting the wind turbine upper tower part in an upright mounting position with the nacelle in a mounting position for mounting the blade to the nacelle, and the third assembly station is configured for supporting the lower tower part in an upright mounting position, such that the combined upper tower part, nacelle and blade can be lifted and lowered, preferably using a mounting crane, and the upper tower part is mounted to the lower tower part in the third assembly station to provide the assembled wind turbine.

In an embodiment, the vessel further comprises a blade handling device, preferably located near the second wind turbine assembly station, e.g. at the base of the mounting crane, for transferring the blade between a horizontal supply position and a fastening position adjacent to the nacelle on the tower top or upper tower section, preferably supported in the second assembly station.

In an embodiment, the vessel comprises a base restraint system, preferably when the wind turbine is lowered onto the base, the base restraint system being configured for engaging the floating base and being configured to reduce movement of the floating base relative to the vessel, more particularly to reduce movement of the floating base relative to an assembled wind turbine to be mounted on the floating base, and/or to monitor movement of the floating base relative to the vessel, more particularly to monitor movement of the floating base relative to an assembled wind turbine to be mounted on the floating base.

In an embodiment, the wind turbine mounting crane is configured to actively compensate for sea-state induced movements, such as horizontal displacements, of the assembled wind turbine relative to the foundation to which the wind turbine is to be lowered, in particular the floating foundation.

In an embodiment, the vessel further comprises a tower receiving well, which is preferably sunk into or through the hull at the at least one wind turbine assembly station or alternatively the wind turbine assembly station. The tower receiving well is configured to receive at least a portion of a tower of a wind turbine therein, preferably using a wind turbine mounting crane, such that a distance between the nacelle and the storage deck is reduced, preferably less than a length of a turbine blade, more preferably less than four fifths of the blade length, to facilitate mounting the blade to the nacelle.

In an embodiment, the vessel comprises a nacelle support fixed to the deck of the vessel such that the nacelle can be supported by the nacelle support at a distance above the deck, preferably less than the length of the turbine blades, more preferably less than four fifths of the length of the blades, to enable the blades to be mounted to the nacelle, preferably by using the blade handling equipment.

In an embodiment, the vessel is further provided with a handling crane.

In an embodiment, the storage deck comprises dedicated storage areas, such as a tower storage area, a lower tower component storage area, an upper tower component storage area, a nacelle storage area and/or a blade storage area.

The invention also provides a vessel for assembling a wind turbine and for mounting the assembled wind turbine on a foundation, such as a semi-submersible crane vessel, such as a subsea installation foundation or a floating foundation, the vessel comprising:

-a floating hull;

-preferably, a handling crane;

-at least one wind turbine assembly station;

wherein the wind turbine mounting crane is configured to perform one or more wind turbine assembly steps, e.g. erecting a wind turbine tower, lifting an upper tower part onto the top of a lower tower part, lifting a nacelle onto the top of the tower or the upper tower part, and for arranging the assembled wind turbine from the at least one wind turbine assembly station to a mounting position above the wind turbine foundation near the vessel mounting the mounting side of the mounting crane, and lowering the assembled wind turbine onto the foundation.

The present invention provides a vessel for assembling a wind turbine offshore, in particular at a location where the wind turbine has to be installed. Thus, there is no need to transport the fully assembled wind turbine, which is a slow process, and it is difficult to transport the fully assembled wind turbine due to the size of the assembled wind turbine. Transporting the disassembled wind turbines facilitates transporting multiple wind turbines on a single vessel.

The construction of a vessel, in particular a vessel with a plurality of assembly stations located around the installation crane, enables a compact vessel and an efficient installation process. It is believed that to date, assembly of wind turbines on vessels has only been proposed in the case of very large vessels. Typically, these types of vessels are so sized that they cannot be used to navigate wind farm locations, or even effectively for transfer between locations. The present invention provides a vessel for both assembling a wind turbine and mounting the assembled wind turbine on a foundation. Furthermore, when used in combination with a compact vessel, such as a semi-submersible vessel, the vessel may also be used to mount the assembled wind turbine on a floating base.

The present invention thus does provide an improved vessel for assembly and for mounting a wind turbine.

The invention also provides a vessel for assembling and installing an offshore wind turbine, comprising:

-a floating hull;

-a handling crane; and

-installing a crane in the vicinity of the crane,

wherein the mounting crane has a mounting side, the mounting crane being configured for supporting the assembled wind turbine at its mounting side in a mounting position above the base and for lowering the wind turbine onto the base, and wherein the first assembly station is located on a first side of the mounting crane, the second assembly station is located on a second side of the mounting crane, the third assembly station is located on a third side of the mounting crane, and the mounting side is located on a fourth side of the crane; and

wherein the mounting crane is provided with a wind turbine lifting device having one or more wind turbine suspension elements, the wind turbine lifting device being adapted to support at least an upper tower part of the wind turbine and to controllably raise and lower at least the upper tower part of the wind turbine when the upper tower part is in a vertical orientation; preferably, the nacelle and the blades are mounted on an upper tower member; and

Wherein the mounting crane has a base section and a top section, wherein the top section is rotatably supported by bearings and is rotatable about a vertical axis with respect to the base section by means of a lifting device, and the lifting device is thus capable of transferring at least an upper tower component between the mounting table and the mounting position.

In an embodiment, the first mounting position is configured for supporting the upper tower component in an upright mounting position, and preferably the handling crane is configured for lifting the nacelle on the upper tower section;

wherein the second mounting position is configured to support the wind turbine upper tower component in an upright mounting position with the nacelle in a mounting position for mounting the blade to the nacelle;

wherein the third mounting position is configured for supporting the lower tower part in an upright mounting position to enable lifting of the combined upper tower part, nacelle and blade, preferably using a mounting crane, and mounting the upper tower part to the lower tower part in a third assembly station to provide an assembled wind turbine.

In an embodiment, the second and third assembly stations are located on opposite sides of the mounting crane, and the first assembly station is located opposite a first vertical side of the crane, i.e. the side for mounting the assembled wind turbine on the foundation using the mounting crane.

In an embodiment, the vessel further comprises a blade handling device located near the second installation position for transferring the blade between a horizontal supply position and a fastening position adjacent the nacelle on top of the upper tower section supported in the second installation position.

In an embodiment, the lifting device comprises a first trolley guide mounted to the top section of the mounting crane, and a first wind turbine mounting trolley vertically movable along said first trolley guide,

wherein the first trolley supports the wind turbine engagement means, and wherein preferably an active horizontal movement means is mounted between the trolley and the wind turbine engagement means, the active horizontal movement means being adapted to actively compensate for horizontal displacement of the wind turbine engagement means relative to the base in at least one horizontal direction, possibly in two non-parallel horizontal directions, e.g. sea conditions in orthogonal horizontal directions,

wherein the first cart and the wind turbine engagement device are supported by one or more suspension elements, the suspension elements being connected to the first cart or the wind turbine engagement device.

In another embodiment, the base section of the mounting crane is provided with a second trolley guide and a second wind turbine mounting trolley, which is vertically movable along the second trolley guide on the first vertical side of the mounting crane,

wherein the second cart supports a wind turbine engagement device, and

wherein preferably an active horizontal movement means is mounted between the trolley and the wind turbine engagement means, the active horizontal movement means being adapted to actively compensate for horizontal displacement of the wind turbine engagement means relative to the base in at least one horizontal direction, possibly in two non-parallel horizontal directions, e.g. in an orthogonal horizontal direction, caused by sea conditions when the wind turbine is supported by the wind turbine engagement means.

In another embodiment, the first and optionally the second trolley may be arranged in an active position for supporting the upper tower part and in an inactive position for moving along the upper tower part supported in the assembly station.

In an embodiment, the lifting device comprises two spaced apart cantilever arms, which preferably support one or more suspension elements, which are connected to the first cart or the wind turbine engagement device.

In another embodiment, the two booms may be arranged in an active position, in which the two booms are used to support the first trolley and the first wind turbine engagement means in an active position, and in an inactive position, in which the two booms are used to move along the nacelle or blade of the partially or fully assembled wind turbine in the assembly station.

In another embodiment, the mounting cranes are configured such that when the assembled mounting cranes are supported by the mounting cranes, the booms extend above the nacelle of the wind turbine, and when seen in front view, the nacelle of the wind turbine is located between the booms.

The invention also provides an alternative wind turbine assembly vessel comprising only two assembly tables. In such an embodiment, the vessel is configured to lift the combined upper tower component, nacelle and blade from the second assembly station to the fourth side of the mounting crane and lower them onto and to a lower tower section already mounted on or as part of the base.

In such an embodiment, the third assembly station may be used as a storage station to store the combined upper tower component, nacelle and blade prior to lifting the combined upper tower component, nacelle and blade from the storage station to the fourth side of the installation crane by the installation crane, in order to lower and mount the combined upper tower component onto a lower tower section that has been mounted on or as part of the foundation.

The invention also provides a wind turbine assembly vessel comprising:

-a floating hull;

preferably, a handling crane for lifting and lowering a wind turbine component stored on the wind turbine component storage deck;

a mounting crane, wherein the mounting crane has a first side, a second side, a third side opposite the second side and a fourth side opposite the first side, the fourth side being a mounting side, and wherein the mounting crane is configured for supporting the assembled wind turbine in a mounting position above the base at the mounting side and for lowering the wind turbine onto the base,

a first assembly bench or nacelle mounting bench for mounting the nacelle on a wind turbine tower or a wind turbine tower section, and a second assembly bench or blade mounting bench for mounting the wind turbine blade on a nacelle mounted on a wind turbine tower or a wind turbine tower section, wherein the first assembly bench is located on a first side of the mounting crane, the second assembly bench is located on a second side of the mounting crane, the mounting side is located on a fourth side of the mounting crane,

Wherein the mounting crane has a lifting device comprising at least one lifting winch with an associated lifting cable, at least one trolley, such as a wind turbine support trolley, supported by the lifting cable for supporting a tower or tower section of the wind turbine, and a trolley guide for guiding the trolley in a vertical direction along the mounting crane, and wherein the trolley is configured to engage the tower or tower section of the wind turbine between a bottom end and a top end of the tower or tower section for supporting the tower or tower section in a lateral direction,

wherein the mounting crane has a base section and a top section, wherein the top section is rotatably supported by a bearing, the bearing is supported by the base section, and the top section is thus rotatable about a vertical axis with respect to the base section by means of a lifting device, and

wherein the trolley guide comprises a first trolley guide or top trolley guide mounted to the top section of the mounting crane and at least one second trolley guide or bottom trolley guide mounted to the base section of the mounting crane at one of the first assembly side, the second assembly side or the mounting side, preferably with a second trolley guide mounted to the base section of the mounting crane at each of the first assembly side, the second assembly side and the mounting side, and the trolley of the lifting device is thus movable along the top section and the base section of the mounting crane at least one assembly station (preferably at each assembly station) and at the mounting side.

In an embodiment of the vessel according to the invention, the vessel according to the invention comprises a single main deck, and the single main deck is a storage deck, and the installation crane extends upwards relative to the main deck.

In an embodiment, on the mounting side of the crane, the main deck extends on the opposite side of the mounting crane. Thus, when the mounting crane supports the assembled wind turbine above the base, the base is partly surrounded by the vessel on three sides.

Additionally or alternatively, the vessel comprises a catamaran hull having two main floats extending along opposite sides of the vessel and on the mounting side of the crane, the hull extends on opposite sides of the mounting crane, more specifically the main floats of the hull extend on opposite sides of the mounting crane. Thus, when the mounting crane supports the assembled wind turbine above the base, the base is partly surrounded on three sides by the hull of the vessel. Thus, the hull provides optimal stability on the mounting side of the crane during mounting and dismounting of the assembled wind turbine to and from the foundation, respectively.

In an embodiment, the main deck is provided with an upright rail. In order to be able to erect, for example, a wind turbine tower or foundation pile, the main deck is provided with rails for supporting an erection truck. During erection, the erection truck supports the bottom end of the pile or tower, while the top end of the pile or tower is lifted by the mounting crane. Thus, the bottom end of the pile or tower is guided along the deck on rails towards the installation crane.

In another embodiment, the upright rail is located on the opposite side of the mounting crane from the mounting side. Thus, when the vessel is in a mounting position for mounting the wind turbine on the foundation, the mounting crane is located between the upright rail and the foundation.

In an embodiment, the erection rail and the mounting crane are established on a centre line of the vessel, and the erection rail extends in a longitudinal direction of the vessel. For example, when the vessel is a semi-submersible vessel having two main floats, i.e. a hull similar to a catamaran type, the mounting crane and the erection track are mounted on deck, between the two main floats, and the erection track extends parallel to the main floats.

Thus, the erection rail and the mounting crane are arranged on the central axis of the vessel such that the centre of gravity is not greatly shifted during the erection process and the roll of the vessel is minimized.

In an embodiment of the vessel according to the invention, the vessel is provided with a ballast system configured to compensate for a shift in weight due to the installation crane moving the load (e.g. the assembled wind turbine or foundation pile). For example, a ballast system may be provided to reduce roll of the vessel when the crane moves the assembled wind turbine from a second assembly station located away from the centre line of the vessel to an installation position above the base in which the assembled wind turbine is supported on the centre line of the vessel. In yet another embodiment, the ballasted base system may be configured to reduce pitching of the vessel when the assembled wind turbine is lowered onto the base, and the weight of the wind turbine is transferred from the crane to the floating base.

In an embodiment, the vessel has a ballast tank for holding ballast (e.g., ballast liquid, such as ballast water). In an embodiment, a ballast control system is provided that is configured for moving ballast liquid between ballast tanks. In addition, the vessel may comprise a ballast system comprising rail mounted weights which are moved along the rails by a ballast control system to compensate for load variations due to the mounting crane moving the load between the assembly station and/or the base.

In an embodiment, the vessel comprises a tower receiving well, which is preferably sunk into or through the hull at least one wind turbine assembly station or alternatively a wind turbine assembly station. The tower receiving well is configured to receive at least a portion of a tower of a wind turbine therein, preferably using a wind turbine mounting crane, such that a distance between the nacelle and the main or storage deck is reduced, preferably less than a length of a turbine blade, more preferably less than four fifths of the length of the blade, in order to facilitate mounting the blade to the nacelle.

In an embodiment, the mounting crane comprises a vertical crane structure. The vertical crane structure comprises a base section and a top section of the mounting crane, wherein the base section is fixed to the hull of the vessel and the top section is pivotable about a vertical axis relative to the base section. In another embodiment, at least the top section of the crane structure is a frame or truss construction.

In an embodiment, the crane structure has a rectangular cross section, providing four different sides for the crane. In another embodiment, the vertical rails on one or more sides of the crane for moving the cart up and down are mounted at or near the corners of the vertical crane structure. In an embodiment, the crane, more particularly the top section of the crane, is mounted with a rectangular cross section and the crane is provided with three assembly stations on the vessel and the crane may be positioned such that three sides of the crane top section each face the assembly stations.

In alternative embodiments, the vertical crane structure, in particular the top section, may comprise a triangular cross section, a hexagonal cross section or a circular cross section. Preferably, the crane comprises at least two sides provided with vertical rails for moving the trolley up and down along the vertical crane structure, the at least two sides being opposite sides of the mounting crane.

In an embodiment of the mounting crane, the top section has a height compared to the height of the base section, for example having twice or three times the height of the base section. In this embodiment, the swivel bearing is thus located, for example, at one third or one fourth of the total height of the installation crane, which height is measured from the deck of the vessel. Preferably, the mounting crane is provided with a track for moving the trolley up and down along the crane structure, the track extending along the base section and the top section of the crane.

In the embodiment shown, the base section of the crane is a closed structure, accommodating the cab and crew dormitory, while the top section is an open truss construction.

In an embodiment, the mounting crane is configured to support an elongated load, such as a wind turbine tower or foundation pile, in close proximity to a top section of the crane. In an embodiment, the lifting device of the mounting crane is configured to move the guided trolley in a vertical direction along the vertical crane structure, the guided trolley being configured to engage the tower or the foundation pile. Thus, the installation crane is configured to support a tower or pile immediately adjacent to the vertical crane structure.

The invention also provides a method for assembling and installing a wind turbine using a vessel according to the preceding claim, wherein the method comprises:

-storing the wind turbine component on a wind turbine component storage deck;

-arranging a tower of a wind turbine into the first assembly station, preferably using a wind turbine mounting crane, and supporting the tower in an upright mounting position, optionally before: erecting a tower of the wind turbine from a horizontal storage position to an upright mounting position, preferably using a wind turbine mounting crane;

In the first assembly station, lifting the nacelle and lifting the nacelle onto the tower, preferably using a wind turbine mounting crane, and mounting the nacelle on the tower;

-arranging the combined tower and nacelle from the first assembly station to the second assembly station using a mounting crane and supporting the tower in an upright mounting position, preferably the nacelle, in particular a hub of the nacelle, in a mounting position for mounting the blades to the nacelle;

lifting the first blade to a fastening position adjacent to the nacelle, mounting the first blade to the nacelle, and rotating the nacelle, in particular a hub of the nacelle, to a successive mounting position, preferably using a blade handling device,

lifting the second blade to a fastening position adjacent the nacelle, mounting the second blade to the nacelle, and rotating the nacelle, in particular the hub of nacelle 416, to a successive mounting position, preferably using a blade handling device; and

-lifting the third blade to a fastening position adjacent to the nacelle, preferably using a blade handling device, and mounting the third blade to the nacelle;

-arranging the assembled wind turbine from the second assembly station into a mounting position at a fourth or mounting side of the mounting crane; and

The invention also provides for the use of a vessel according to the invention, preferably for performing the method according to the invention, for assembling and installing wind turbines, preferably for assembling and installing a plurality of wind turbines to provide a wind park.

In this context, the term wind turbine assembly rig is used to refer to a wind turbine mounting crane adjacent to and within reach of the wind turbine mounting crane in order to perform one or more wind turbine assembly steps, such as lifting the nacelle, erecting the tower, mounting the blade to the nacelle, preferably using the wind turbine mounting crane. As an alternative wind turbine mounting location, the term mounting location may be used. Thus, the mounting crane may be provided with three wind turbine mounting locations located at three sides of the crane on the vessel for performing wind turbine assembly steps.

In the field of offshore construction, semi-submersible crane vessels are known as heavy duty machines for (heavy) hoisting operations. These lifting vessels are now also used for mounting wind turbines on a foundation. Typically, such semi-submersible crane vessels comprise:

-a floating hull having:

-a deck-box structure,

two pontoons in parallel and one with each other,

a row of support columns extending upwardly from each of the two pontoons, the support columns supporting a deck box structure thereon,

wherein the deck box structure has a deck and a box bottom, and

-a mounting crane mounted on the deckbox structure and configured to mount the assembled wind turbine on the base.

In the art, many vessels have a basin-based crane, wherein the rotatable superstructure of the crane is mounted via bearings (e.g. roller bearings or an arrangement of bogies) directly above the basin in one piece with the deckbox structure, e.g. above the support columns at the ends of a row of columns. In other known embodiments, the crane is a tower crane.

The invention also aims to provide an improved semi-submersible crane vessel for wind turbine installation, for example, allowing for more efficient assembly of (a part of) a wind turbine on the vessel of the crane vessel.

The present invention provides a semi-submersible crane vessel for assembling a wind turbine and for mounting the assembled wind turbine on a foundation, such as a seabed mounted foundation or a floating foundation, by a crane of the vessel, wherein the assembled wind turbine to be mounted comprises at least a part of a wind turbine tower and a rotor assembly, such as a nacelle with a hub, mounted on the tower, optionally provided with one or more (e.g. all) rotor blades,

wherein the ship comprises:

-a floating hull having:

-a deck-box structure,

two pontoons in parallel and one with each other,

wherein the deck box structure has a deck and a box bottom,

wherein, at the assembly station, the hull of the vessel is provided with a tower receiving well sunk into or through the hull, preferably a well extending into or through the support columns of the hull, the well being configured to receive at least a part of the tower of the wind turbine therein during an assembly step of the wind turbine, e.g. during mounting of the rotor assembly on the tower and/or during assembly of one or more (e.g. all) rotor blades to the rotor assembly.

-a floating hull having:

-a deckbox structure;

two pontoons in parallel and one with each other,

wherein the deck box structure has a deck and a box bottom,

In the method, during an assembly step of the wind turbine, for example during mounting of the rotor assembly on the tower and/or during assembly of one or more (e.g. all) rotor blades to the rotor assembly, at least a portion of the tower is arranged in the tower receiving well.

The invention is based on the insight that a semi-submersible vessel is well suited to be provided with a tower receiving well sunk into the hull or even through the hull, which well is configured to receive at least a part of the tower of the wind turbine therein during assembly of the wind turbine.

In a preferred embodiment, the tower receiving well extends into the support column, optionally even into the buoy. Preferably, the well has a floor configured for the tower to stand on, e.g. integrated with the pontoons and/or with the lower portion of the support columns.

It will be appreciated that the tower containment well may be retrofitted in existing semi-submersible vessels.

Preferably, the tower containment well is arranged within reach of the installation crane, allowing the crane to be used to place the tower or a part thereof in the well, and subsequently the assembled or partially assembled wind turbine is removed from the well, which is then placed on the foundation by the crane.

For example, the installation crane is mounted directly above the support columns at the ends of a row of columns, thus in effect at the corners of the deckbox structure, and the tower receiving wells are provided in adjacent support columns of the same row of columns on the pontoons. In another embodiment, for example when the vessel has one installation crane above the support columns at the ends of a row of columns on one pontoon at one corner of the deck box structure, the tower receiving well is arranged into or through the support corner at the end of a row of columns on the other pontoon, for example both the crane and the well are located at the stern of the vessel, for example the crane and the well are each in fact located at a corner of the deck box structure.

In an embodiment, the vessel has two, possibly identical, cranes, each of which is fitted at a respective corner of the deckbox structure, for example at the stern, as is known in the art.

In an embodiment, the well is assembled and the vessel has one tower-receiving well, the tower-receiving wells being disposed in the same row of adjacent support columns on the pontoon.

For example, the well has a depth of at least 15 meters, such as at least 30 meters, as measured from the deck of the deckbox structure. For example, the well has a depth of more than 40 meters, which is for example possible in vessels like the recently launched Sleipnir vessel, because the total height is about 50 meters.

For example, embodiments of a well having a depth of at least 30 meters (e.g., over 40 meters) allow for a substantial portion of the entire tower of a wind turbine to be housed in the well, e.g., because the tower height may vary between 75 meters and 110 meters in practical embodiments. By being placed in the well, the top of the tower is closer to the deck, which facilitates operations like mounting the nacelle on top of the tower, mounting one or more (e.g. all blades) on the nacelle, etc.

Considering the advantages of the tower height and having the top end relatively close to the deck to perform some assembly steps, such as installing the nacelle and/or installing one or more (e.g. all blades), it is contemplated that in embodiments the well extends through the hull, e.g. through the support columns, and further down through the pontoons. In the latter form, the well resembles a moonpool or shaft that passes completely through the hull, for example, to allow the tower to extend below the bottom of the pontoon of the vessel. In such open-bottomed wells, the tower or a portion thereof may be suspended, for example, by winch-driven cables, for example, which engage at the lower end of the tower.

The open-bottomed well may allow a tower (or tower component) to be disposed (e.g., suspended) therein such that its top is proximate the deck. This allows the nacelle to be slidingly moved substantially horizontally on the deck, e.g. by one or more vehicles or by a trolley, e.g. by a rail mounted on the deck, e.g. by a sliding trolley, so that the nacelle is positioned above and connected to the tower top. For example, the tower is then lifted a portion of its height to a height suitable for mounting one or more blades to the nacelle.

The above operations may be combined with a closed-bottom well such that the well extends into the hull but does not pass through the hull, which may also be performed when using a tower for the two components of the wind turbine. Here, the upper part of the tower is placed in the well and then the nacelle is mounted on top of it.

Those skilled in the art will appreciate that the features disclosed herein as needed or discussed in terms of optional ways with respect to one embodiment of the invention may be equally applied to one or more other embodiments described herein, wherein the features perform their specified functions. All such combinations are contemplated herein unless the combination would result in a technically impossible solution and/or would not meet the required functionality.

In the drawings, corresponding parts in terms or construction and/or function have the last two digits of the same reference numerals.

Drawings

In the accompanying drawings

FIG. 1 shows a side view of a wind turbine assembly and installation vessel according to the present invention, the vessel comprising a floating hull, a wind turbine component storage deck, an installation crane and a handling crane;

FIG. 2 shows another partial side view of the wind turbine assembly and mounting vessel of FIG. 1, with the handling crane not shown;

FIG. 3 illustrates a top view of the wind turbine assembly and mounting vessel of FIG. 1, wherein the handling crane is not shown, and wherein a portion of the lifting device of the mounting crane is shown lifting the upper tower member in a first mounting position and engaging the upper tower member in the first mounting position;

FIG. 4 shows a side view of the wind turbine assembly and mounting vessel of FIG. 1 with a blade handling apparatus supporting the blades in a horizontal supply position;

FIG. 5 shows a side view of the wind turbine assembly and mounting vessel of FIG. 1 with a blade handling device supporting the blade in a secured position;

FIG. 6 shows a side view of the wind turbine assembly and mounting vessel of FIG. 1 with a handling crane lifting lower tower components into a third assembly station;

FIG. 7 shows a close-up side view of a mounting crane of the vessel of FIG. 1 supporting an assembled wind turbine in a mounted position;

FIG. 8 shows a close-up elevation of a mounting crane of the vessel of FIG. 1 supporting an assembled wind turbine in a mounted position;

FIGS. 9 and 10 show close-up side and elevation views of a mounting crane of the vessel of FIG. 1 supporting the assembled wind turbine in a mounted position and compensating for wave induced movement of the wind turbine relative to the base;

Fig. 11 and 12 show an installation crane according to the invention, wherein the first trolley is in an active position and an inactive position, respectively;

FIG. 13 shows a side view of a mounting crane according to the invention with a first cart in an active position and a second cart in an inactive position, the mounting crane lifting an object using the first cart;

FIG. 14 shows a side view of a vessel according to the invention, wherein a mounting crane stands up a tower for a wind turbine at a first wind turbine assembly station on one side and supports the assembled wind turbine at the mounting side of the wind turbine mounting crane;

FIG. 15 shows a partial side view of the vessel of FIG. 14 with the tower erected in an upright mounting position at the first wind turbine assembly stand;

FIG. 16 shows a partial front view of the vessel of FIG. 14; wherein the nacelle in the third wind turbine assembly station is ready to be lifted by a wind turbine mounting crane;

FIG. 17 shows a partial elevation view of the vessel of FIG. 14, with the nacelle lifted by a mounting crane at a third wind turbine assembly station;

FIG. 18 shows a partial side view of the vessel of FIG. 14 with the nacelle lowered onto top of the erected tower at the first wind turbine assembly table;

FIG. 19 shows a front view of the vessel of FIG. 14, wherein the tower and nacelle of FIG. 20 are fitted with blades at a second wind turbine assembly station;

FIG. 20 shows a side view of the vessel of FIG. 14 with the mounting crane supporting an assembled wind turbine including the blade-equipped tower and nacelle of FIG. 20 supported by the mounting crane;

FIG. 21 shows a partial side view of a vessel according to the invention, wherein a wind turbine mounting crane supports an assembled wind turbine above a base;

FIG. 22 shows a front view of the vessel of FIG. 21 supporting a wind turbine;

FIG. 23 shows three trolleys of the wind turbine mounting crane of FIG. 21 in isolation;

FIG. 24 shows a partial top view of a vessel according to the invention, wherein the wind turbine at the second wind turbine assembly station is equipped with blades;

FIG. 25 shows a partial side view of a vessel according to the invention, wherein the wind turbine at the second wind turbine assembly station is equipped with blades;

FIG. 26 shows a front view of the vessel of FIG. 25;

FIG. 27 shows an exemplary embodiment of a wind turbine assembly and a mounting vessel according to the invention, the vessel comprising a mounting crane with a first lifting device comprising two carts for lifting an assembled wind turbine and a second lifting device for lifting a nacelle;

FIG. 28 shows the vessel of FIG. 27 with the lifting device in a position facing the assembled wind turbine at the second assembly station;

FIG. 29 shows the vessel of FIG. 27 with the two carts of the lifting device lowered into position for engaging the assembled wind turbine;

FIG. 30 shows the vessel of FIG. 27, wherein two carts of the lifting device engage the assembled wind turbine;

FIG. 31 shows the vessel of FIG. 27 with the lifting device supporting the assembled wind turbine above a floating base;

FIG. 32 shows the vessel of FIG. 27 during a pile erection process;

FIG. 33 shows a semi-submersible vessel with an installation crane and a tower containment well;

FIG. 34 shows a cross section of a vessel having a tower containment well;

FIG. 35 shows the vessel of FIG. 33 with the tower disposed in the tower receiving well;

FIG. 36 shows the vessel of FIG. 35 with the nacelle mounted on top of the tower;

FIG. 37 illustrates mounting a first blade to a nacelle using blade handling equipment on a vessel; and

FIG. 38 shows the wind turbine fully assembled.

Detailed Description

Further objects, embodiments and detailed description of the device and method according to the invention will become apparent from the following description, wherein the invention is further illustrated and described on the basis of a number of exemplary embodiments with reference to the accompanying drawings.

In fig. 1, a wind turbine assembly and installation vessel 1 is shown, comprising a floating hull 2, a wind turbine component storage deck 3, a handling crane 10 and an installation crane 20.

The mounting crane 20 is arranged near one side of the vessel hull, preferably at the front or stern side of the vessel, to be able to lower the wind turbine from the vessel onto the foundation. The transfer crane 10 is disposed near the mounting crane 20 at a more central position of the hull of the ship and thus away from the side of the hull of the ship.

The wind turbine component storage deck 3 shown comprises different storage areas for different wind turbine components. In particular, in the top view of fig. 3, it can be seen that the lower tower component storage area 3a is arranged adjacent to the upper tower component storage area 3b, both storage areas being arranged at the same side of the vessel, remote from the mounting crane 20 and within reach of the handling crane 10.

Furthermore, a nacelle storage area 3c and a blade storage area 3d are provided. The blade storage areas 3d are arranged on opposite sides of the lower tower part storage area 3a and the upper tower part storage area 3b of the vessel 1. The cabin storage area 3c is arranged centrally between them. In the illustrated configuration, six cabins, six lower tower components, and six upper tower components may be clearly distinguished.

The wind turbine assembly and installation vessel 1 further comprises a first assembly station 4, a second assembly station 5 and a third assembly station 6.

These assembly stations are disposed adjacent to the mounting crane 20. The mounting crane 20 has a mounting side 7 and is configured for supporting the assembled wind turbine at its mounting side in a mounting position above the foundation and for lowering the wind turbine onto the foundation. With the mounting crane 20 in the center, the mounting side 7 is set at the 6 o' clock position in top view.

In the embodiment shown, the first assembly station 4 is located on a first side of the installation crane opposite the lowered side, in the 12 o ' clock position in fig. 4, the second assembly station 5 is located on a second side of the installation crane, in the 9 o ' clock position, and the third assembly station 6 is located on a third side of the installation crane opposite the second assembly station 5, in the 3 o ' clock position.

In the embodiment shown, the upper tower component storage area 3a and the lower tower component storage area 3b are located near the first 4 and third 6 assembly stations, the nacelle storage area 3c is located near the first assembly station 4 and the blade storage area 3d is arranged near the second assembly station 5.

The illustrated construction allows arranging the upper tower part 31 from the upper tower part storage area 3b into the first assembly station 4, preferably using the handling crane 10, and supporting the upper tower part in an upright mounting position.

Subsequently, in the first assembly station 4, the nacelle 32 is lifted from the nacelle storage area 3c on the upper tower member 31, preferably using the handling crane 10. Nacelle 32 is mounted to upper tower member 31.

In a subsequent step, the combined upper tower part 31 and nacelle 32 is arranged from the first assembly station 4 to the second assembly station 5, preferably using the mounting crane 20. The wind turbine upper tower member 31 is supported in an upright mounting position by the nacelle 32 for mounting the blades to the nacelle.

In fig. 2 a blade handling device 8 is schematically visible for transferring a blade 33 between a horizontal supply position and a fastening position.

The blades 33 are preferably mounted to the nacelle 32 using the blade handling apparatus 8.

The blade mounting process comprises the following steps:

lifting the third blade to a secured position adjacent the nacelle, preferably using a blade handling device, and mounting the third blade to the nacelle.

The assembly method comprises the subsequent step of arranging the lower tower member 34 from the lower tower member storage area 3a into the third assembly station 6 and supporting the lower tower member 34 in an upright mounting position, preferably using the handling crane 10.

The combined upper tower part 31, nacelle 32 and blades 33 are preferably lifted towards the third assembly station 6 using a mounting crane 20, and the upper tower part 31 is mounted to the lower tower part 34 in the third assembly station 6 to provide an assembled wind turbine.

Finally, lifting the assembled wind turbine to the installation position of the installation side 7 of the installation crane 20; and lowered onto the base using the mounting crane 20.

Fig. 1 shows a side view of a wind turbine assembly and a mounting vessel 101 according to the invention, which vessel comprises a floating hull 102, a wind turbine component storage deck 103, a mounting crane 104 and a handling crane 105.

In the exemplary embodiment shown in FIG. 1, wind turbine component storage deck 103 includes a lower tower component storage area, an upper tower component storage area, a nacelle storage area, and a blade storage area.

In FIG. 1, a lower tower member storage area 106 is shown having a plurality of lower tower members 107.

Furthermore, in fig. 1, the assembled wind turbine 108 is shown in a third assembly station 115 in a position adjacent to the installation crane 104 and in a position above the floating base 109 supported by the installation crane 104 at the installation side 119 of the installation crane 104. The floating base 109 is only partially depicted.

Fig. 2 shows another partial side view of the wind turbine assembly and the mounting vessel 101. In this figure, the handling crane 105 is not shown. A blade storage area 110 having a plurality of blades 111 is shown.

Furthermore, in fig. 2, the assembled wind turbine 108 is shown in a position supported above the floating base 109 by the mounting crane 104. The floating base 109 is only partially depicted.

Further, FIG. 2 shows upper tower component 112 provided with nacelle 116, and the blades are shown in a position adjacent to mounting crane 104 in second assembly station 114. Furthermore, in the first assembly station 113, the upper tower part 112 provided with the nacelle 116 without blades is shown in a position adjacent to the mounting crane 104.

FIG. 3 shows a top view of the wind turbine assembly and mounting vessel of FIG. 1 showing the lower tower component storage area 106 adjacent to the upper tower component storage area 117, on the opposite side of the handling crane 105, only the base of which is shown. Also shown are a blade storage area 110 and a nacelle storage area 118 having a plurality of nacelles 116.

A first assembly station 113, a second assembly station 114, and a third assembly station 115 are shown adjacent to the mounting crane 104.

Note that in fig. 3, the upper tower part with nacelle is shown in a first assembly station 113, the upper tower part with nacelle and blades is shown in a second assembly station, and the assembled wind turbine 108 is shown supported by the mounting crane 104, which comprises a lower tower part 107, an upper tower part 112, a nacelle 116 and blades 111.

With respect to fig. 1-3, it is noted that the figures show a plurality of assembly stations occupied by a partially or fully assembled wind turbine. In practice, the upper tower sections are transported along successive assembly stations to assemble the wind turbine. Preferably, a new upper tower section is arranged in the first assembly station to start a new assembly process only after the assembled wind turbine has been installed. Thus, typically only one assembly station is occupied at a time. However, the lower tower section may already be arranged at the third assembly station when the upper tower section is transferred in or between the other assembly stations. Furthermore, a new lower tower section may be arranged in the first assembly station when assembling or installing the wind turbine.

The mounting crane 104 is provided with a wind turbine lifting device 120 having one wind turbine suspension element 121. The wind turbine lifting device 120 is adapted to support at least an upper tower component of the wind turbine when the upper tower component is in a vertical orientation and to raise and lower the upper tower component of the at least wind turbine in a controllable manner, e.g. for moving the upper tower component provided with the nacelle from the first assembly station to the second assembly station.

The installation crane 104 has a base section 122 and a top section 123. The top section 123 is rotatably supported by bearings 124 and can be rotated about a vertical axis with respect to the base section 122 using the lifting device 120. Thus, the lifting device may transfer the upper tower part between the mounting table and the mounting position.

In the illustrated embodiment, wind turbine lifting device 120 is adapted to support an upper tower component that is part of an assembled wind turbine and to raise and lower it in a controllable manner to move the assembled wind turbine from a third assembly position to a mounting position above the base.

In the illustrated embodiment, the first mounting location 113 is configured for supporting the upper tower component in an upright mounting position, see fig. 2, and the handling crane 105 is configured for lifting the nacelle onto the upper tower section in the assembly station.

The second mounting position 114 is configured for supporting the wind turbine upper tower component in an upright mounting position with the nacelle in a mounting position for mounting the blade to the nacelle, see e.g. fig. 2.

The third mounting position 115 is configured for supporting the lower tower component in an upright mounting position to enable lifting of the combined upper tower section, nacelle and blade, preferably using a mounting crane, and mounting the upper tower component to the lower tower component in a third assembly station to provide an assembled wind turbine, see for example fig. 1.

The second and third assembly stations 114, 115 are located on opposite sides of the mounting crane 104 and the first assembly station 113 is located opposite a first vertical side 125 of the mounting crane, the first vertical side 125 being the side of the mounting crane for mounting the assembled wind turbine on a foundation using the mounting crane.

In the exemplary embodiment shown, wind turbine lifting device 120 includes a first cart guide 126 mounted to top section 123 of mounting crane 104, and a first wind turbine mounting cart 127 vertically movable along the first cart guide 126.

The first cart 127 supports a wind turbine engagement device 128. An active horizontal movement device 129 is mounted between the trolley and the wind turbine engagement device, the active horizontal movement device 129 being adapted to actively compensate for horizontal displacement of the wind turbine engagement device relative to the base in at least one horizontal direction, possibly in two non-parallel horizontal directions, e.g. in an orthogonal horizontal direction, caused by sea conditions when the wind turbine is supported by the wind turbine engagement device.

The first cart 127 and the wind turbine engagement device 128 are supported by a plurality of suspension elements 130, which in the illustrated exemplary embodiment are connected to the wind turbine engagement device 128.

In the particular embodiment shown, the suspension element is a lifting cable attached to an associated winch. A winch may be used to lower and raise the first cart.

In the exemplary embodiment shown, the base section 122 of the mounting crane 104 is provided with a second trolley guide 131 and a second wind turbine mounting trolley 132, the second wind turbine mounting trolley 132 being vertically movable along the second trolley guide on a first vertical side of the mounting crane.

The second cart supports a wind turbine engagement device 133 and an active horizontal movement device 134 is mounted between the second cart 132 and the wind turbine engagement device. The active horizontal movement means are adapted to actively compensate for horizontal displacement of the wind turbine engagement means in at least one horizontal direction, possibly in two non-parallel horizontal directions, e.g. in an orthogonal horizontal direction, caused by sea conditions, relative to the foundation when the wind turbine is supported by the wind turbine engagement means.

In the exemplary embodiment shown, the first cart 127 and the second cart 132 may be arranged in an active position for supporting the upper tower component (see, e.g., fig. 7-10) and in an inactive position for movement along the upper tower component supported in the assembly station. The first cart 127 is shown in its active position in fig. 11 and in its inactive position in fig. 12.

In the exemplary embodiment shown, the lifting device 120 includes two spaced apart cantilevers 135 that support a suspension element 130 that is connected to a wind turbine engagement device on the first cart.

The two cantilevers 135 may be arranged in an active position shown in fig. 11 for supporting the first trolley 127 and the first wind turbine engagement device 128 in an active position for movement along the nacelle or blade of the partially or fully assembled wind turbine in the assembly station, and in an inactive position shown in fig. 12.

Furthermore, the mounting cranes 104 are configured such that when the assembled mounting cranes are supported by the mounting cranes, see fig. 7 and 8, the booms extend above the nacelle of the wind turbine, and when seen in front view, the nacelle of the wind turbine is located between the booms.

Fig. 11 shows the mounting crane 104 according to the invention, wherein the first wind turbine mounting trolley 127 is in an active position, i.e. a position in which the trolley is able to support a load, such as a wind turbine. Fig. 12 shows the same mounting crane with the first trolley in an inactive position. With the trolley in the inactive position, the top section of the mounting crane may be turned as the first trolley passes an assembled wind turbine, e.g. standing in a first wind turbine assembly station located near one side of the crane.

Fig. 13 shows a side view of a wind turbine mounting crane 204 according to the invention, wherein a first trolley 227 is in an active position and a second wind turbine mounting trolley 232 is in an inactive position, the mounting crane lifting an object 200 using the first trolley 227.

Fig. 14-20 show subsequent assembly steps of the wind turbine assembly and installation process according to the invention. The process includes a plurality of wind turbine assembly steps.

The method involves a wind turbine comprising a tower 235. In such an embodiment, nacelle 216 is mounted atop tower 235 during the assembly process, preferably prior to providing nacelle 216 with blades 211.

The wind turbine mounting vessel 201 shown in fig. 14-20 comprises a floating hull 202, a wind turbine component storage deck 203, a wind turbine mounting crane 204, a blade handling equipment 236, a first wind turbine assembly rig 213, a second wind turbine assembly rig 214, and a third wind turbine assembly rig 215. The wind turbine assembly tables, and in particular their position relative to the wind turbine mounting crane, are also shown in fig. 24.

A wind turbine mounting crane 204 is mounted on the floating hull 202, in the embodiment shown on the deck of the floating hull. In the illustrated embodiment, the mounting crane 204 has first, second and third assembly sides facing the first, second and third wind turbine assembly stations. Furthermore, the mounting crane 204 has a mounting side 219.

Thus, the first wind turbine assembly stand 213 is located on a first side of the mounting crane 204. It is also opposite the mounting side 219 of the mounting crane 204. The third wind turbine assembly stand 215 is located opposite the second wind turbine assembly stand.

In the illustrated embodiment, the wind turbine component storage deck 203 is provided with a blade storage area 210, a tower storage area 217, and a nacelle storage area, as shown in the partial top view of FIG. 24.

The vessel further comprises a blade handling device 236 for transferring blades between a horizontal supply position and a raised blade securing position adjacent to the nacelle 216 of the wind turbine being assembled. In the preferred embodiment shown, the blade handling apparatus 236 is located at the second wind turbine assembly station 214.

The method comprises a plurality of wind turbine assembly steps.

The method begins by moving one or more wind turbine components from the wind turbine component storage deck 203 to one or more wind turbine assembly tables. In the particular embodiment shown, the horizontally oriented tower 235 has a top end located at the first wind turbine assembly stand 213 to enable erection of the tower 235 using the wind turbine mounting crane 204. The tower in the horizontal storage position is shown erected in an upright mounting position in fig. 14, with the tower 235 shown in a plurality of successive positions during the erection process. Fig. 15 shows tower 235 erected in an upright mounting position at first wind turbine assembly stand 213.

Note that in the particular embodiment shown, wind turbine mounting crane 204 is a double sided crane having a first lifting device on a first side of the crane and a second lifting device on an opposite second side of the crane, such that the cranes are able to simultaneously perform lifting actions on opposite sides of the crane. In fig. 15, the mounting crane supports the assembled wind turbine on the mounting side of the crane while erecting the tower on the first wind turbine assembly stand.

The method further comprises an assembly step of moving the nacelle 216 to a third wind turbine assembly station 215 to enable the wind turbine mounting crane 204 to lift the nacelle 216 and mount the nacelle on top of the tower 235 at the first wind turbine assembly station.

Fig. 16 shows a nacelle 216 in a third wind turbine assembly stand 215 ready to be lifted by the wind turbine mounting crane 204. Fig. 17 shows nacelle 216 lifted by a mounting crane at a third wind turbine assembly station. FIG. 18 shows nacelle 216 lowered atop an erected tower 235 at first wind turbine assembly table 214.

The method further comprises an assembly step of arranging a tower 235 and a nacelle 216 mounted on top of the tower from a first wind turbine assembly stand 213 shown in fig. 18 to a second wind turbine assembly stand 214 shown in fig. 19 using a mounting crane 204.

The method further includes completing an assembly step of wind turbine 208 by mounting blade 211 to nacelle 216 at second assembly station 214.

In the preferred embodiment shown, the blade handling apparatus 236 is used to mount blades. In the particular embodiment shown, the blade handling apparatus comprises a gripper portion for engaging and supporting the blade, a base and an arm between the base and the gripper portion, the blade handling apparatus being mounted to the vessel via the base, in the embodiment shown to a wind turbine mounting crane.

The blade mounting process comprises the following steps

In the preferred method shown, see fig. 24, the nacelle 216 is positioned (more specifically, rotated about a vertical pivot axis) in a position for mounting to the nacelle the blade 211a supported above the deck in a vertical position, while the blade 211b already mounted to the nacelle is supported mainly vertically above the sea surface, i.e. mainly outside the contour of the vessel when seen in top view.

Once the assembly is completed by mounting the blades to the nacelle, the assembled wind turbine is picked up by the wind turbine mounting crane and can be lowered onto the base at the mounting side of the mounting crane. Alternatively, the assembled wind turbine may be stored in a third assembly station, for example when the vessel is moved to the base where the wind turbine is to be installed. Temporary storage of wind turbines at a third wind turbine assembly station also allows for another wind turbine to be assembled and thus allows for two assembled wind turbines to be ready for installation.

The method further comprises, after supporting the assembled wind turbine at the second wind turbine assembly station, arranging the assembled wind turbine from the second wind turbine assembly station into a mounting position above the wind turbine foundation of the adjacent vessel at the mounting side of the mounting crane. This is shown in fig. 20, after which a crane is installed for lowering the assembled wind turbine onto the foundation.

In a preferred method according to the invention for mounting a wind turbine on a floating base, the method comprises, before lowering the assembled wind turbine onto the floating base, engaging the floating base with a base restraint system, wherein the base restraint system is configured to reduce the movement of the floating base relative to the vessel, more particularly relative to the assembled wind turbine to be mounted on the floating base, and/or to monitor the movement of the floating base relative to the vessel, more particularly relative to the assembled wind turbine to be mounted on the floating base. Fig. 21 shows a wind turbine mounting crane 204 supporting an assembled wind turbine 208 above a floating base 209. The vessel is provided with a base restraint system 237 that engages the floating base 209.

Fig. 27 shows another exemplary embodiment of a wind turbine assembly vessel 401 according to the present invention. Vessel 401 is similar to vessel 101 shown in fig. 1 and is also similar to the vessel shown in fig. 14 and the vessel shown in fig. 25.

Vessel 401 is positioned along floating base 409. More specifically, the vessel is positioned with the bow of the vessel facing the floating base, such that the mounting crane is able to support the assembled wind turbine in a mounting position above the base on the mounting side of the crane and lower the wind turbine onto the base.

In the illustrated embodiment, the floating base 409 comprises three stabilizing columns interconnected by a triangularly arranged beam when seen from above. One of the stabilizing columns of the floating base is implemented as a tower mounting structure configured to mount a tower of a wind turbine thereon.

The floating base, e.g., each buoyancy column of the floating base, is provided with a ballast tank for holding ballast (e.g., ballast liquid, such as ballast water). In an embodiment, a ballast control system is provided that is configured for moving ballast between ballast tanks, e.g., at least three stabilizing columns, to adjust the vertical orientation of an upwardly directed mounting axis. Further, the floating base comprises a water retention plate, wherein the water retention plate is attached to the lower end of the stabilizing column.

Wind turbine assembly vessel 401 includes a floating hull 402, a wind turbine component storage deck 403, an installation crane 404, and a handling crane 405.

In the illustrated embodiment, vessel 401 is of the type known as a semi-submersible vessel having a pair of generally parallel, laterally spaced apart buoyant pontoons, for example, having ballast water tanks that permit movement of the pontoons between a submerged condition and a surface floating condition, and having a row of a plurality of columns supported by and extending upwardly from each pontoon, and a deck structure supported by the upper ends of the columns. The crane is mounted on the deck structure of the hull.

The semi-submersible vessel 401 has a bow and a stern and the crane is mounted at the bow, for example on a deck structure between two pontoons (seen from above), for example the deck structure has a bow end located behind the bow of the pontoons.

The transfer crane 405 is also provided near one side of the hull of the ship 401. In the embodiment shown, the handling crane is located near the port side (also called port side) of the vessel.

In the illustrated embodiment, the ship's steering deck and crew's dormitory are included in the installation crane 404. The integration of the steering deck and the crew's dormitory in the crane allows providing the vessel with a deck covering almost the entire vessel.

In the embodiment shown, the vessel is provided with a handling crane and a mounting crane, both mounted on the hull of the vessel and extending upwards from the deck. The deck is devoid of any other major structure extending above the deck. The deck is thus free to be used for storing and moving wind turbine components along the deck, and for providing an assembly station adjacent to the mounting crane.

The main part of the vessel deck is a wind turbine component storage deck 403, which comprises different storage areas for different wind turbine components. In the particular embodiment shown, wind turbine component storage deck 403 includes a tower storage area 403a, a nacelle storage area 403c, and a blade storage area 403d.

Vessel 401 carries a plurality of wind turbine towers at tower storage area 403 a. In contrast to the vessel 101 shown in fig. 1, the wind turbine tower is a full length wind turbine tower. The vessel 101 shown in fig. 1 carries a lower tower part and an upper tower part to be combined in a full length wind turbine tower. Furthermore, the vessel 401 carries the wind turbine tower in a horizontal storage position. The horizontal storage position provides a lower center of gravity for the vessel than transporting the tower in an upright position. The horizontal transport position is such that the tower must be erected to be able to assemble the wind turbine. In the embodiment shown, the deck of the installation crane and the vessel is configured for erecting the wind turbine tower and thus achieving a horizontal transport position.

Blade storage areas 403d are disposed on opposite sides of tower storage area 403a of vessel 401. The cabin storage area 403c is more or less arranged near the mounting crane 404.

In a preferred embodiment of wind turbine installation vessel 401, the reach of handling crane 405 is such that the installation crane can lift and lower wind turbine components, such as blades or cabins, stored on wind turbine storage deck 403.

The wind turbine assembly and mounting vessel 401 further comprises a first assembly station 413, a second assembly station 414 and a third assembly station 415.

The first assembly station is located on a first side of the installation crane, the second assembly station is located on a second side of the installation crane, the third assembly station is located on a third side of the installation crane, and the installation side is located on a fourth side of the crane and at the bow of the vessel.

The first wind turbine assembly table 413 is located opposite the mounting side 419 of the mounting crane 404. The second wind turbine assembly stand 414 is located opposite the third wind turbine assembly stand 415.

Note that, similar to the ship 201 shown in fig. 19, for example, the third assembly station 415 is configured for storing the nacelle. Thus, in the embodiment shown, the mounting crane 404 is effectively provided with two assembly stations, namely a first assembly station 413 for mounting the nacelle on the tower of the wind turbine and a second assembly station 414 for mounting the blade on the nacelle.

Hereinafter, the first assembly station will also be referred to as nacelle mounting station 413, the second assembly station will also be referred to as blade mounting station 414, and the third assembly station will also be referred to as nacelle pickup station 415.

Note that in the particular embodiment shown, wind turbine mounting crane 204 is a double sided crane having first and second lifting devices 420a, 420b on opposite sides of the crane. Providing the crane with lifting means on opposite sides of the crane enables the crane to perform lifting actions simultaneously on opposite sides of the crane. For example, the nacelle is lifted at the nacelle pickup tower 415 while the wind turbine tower with the nacelle is lifted or lowered at the blade mounting tower 414, or the nacelle is lowered onto the wind turbine tower at the nacelle mounting tower 413 while the assembled wind turbine is supported above the foundation at the mounting side 419 of the vessel.

In the embodiment shown in fig. 27, the mounting crane is provided with a first lifting device for lifting and mounting the assembled wind turbine, in particular for lifting and supporting the tower of the wind turbine, and a second lifting device configured for lifting a wind turbine component, in particular the nacelle, and for erecting the pile.

Similar to the mounting cranes shown in the other figures, the mounting crane 404 has a base section 422 and a top section 423. The top section 423 is rotatably supported by a bearing 424 supported by the base section 422. Thus, the top section 243 comprising the two lifting devices may be turned about a vertical axis with respect to the base section 422, and the crane may thus transfer at least the wind turbine component or the assembled wind turbine between the assembly station and the mounting side with the lifting devices.

In the illustrated embodiment, the base section 422 of the crane is a closed structure to accommodate the cab and crew dormitory, while the top section 423 is an open truss construction.

In the illustrated embodiment, wind turbine mounting crane 204 is a double sided crane having two lifting devices 420a, 420b located on opposite sides of the crane. Each lifting device 420 includes at least one lifting winch 439 with an associated lifting cable 440, a trolley 441 supported by the lifting cable (e.g., a wind turbine support trolley), and a trolley guide 442 guiding the trolley in a vertical direction along the crane.

In the exemplary embodiment shown in the figures, the cart guide comprises a first cart guide 426 mounted to the top section 423 of the mounting crane and a second cart guide 431 mounted to the base section 422 of the mounting crane. Thus, the trolley 441 of the lifting device can move along both the top section and the base section of the crane. More specifically, the second cart guide 431 enables the cart to be lowered close to the deck, while the first cart guide 426 enables the cart to rotate with the top section 432 of the crane.

Thus, fig. 27 shows a wind turbine assembly and installation vessel 401 according to the invention, comprising:

-a floating hull 402;

a wind turbine component storage deck 403 for storing components of the wind turbine, such as the tower 435, nacelle 416 and blades 411;

preferably a handling crane 405 for lifting and lowering wind turbine components stored on the wind turbine component storage deck 403;

a mounting crane 404, wherein the mounting crane has a first side, a second side, a third side opposite the second side and a fourth side opposite the first side, the fourth side being a mounting side 419, and wherein the mounting crane 404 is configured for supporting the assembled wind turbine 408 in a mounting position above the base 409 at the mounting side 419 and for lowering the assembled wind turbine 408 onto the base 409,

a first assembly stand 413 or nacelle mounting stand for mounting the nacelle 416 on a wind turbine tower 435 or a wind turbine tower section, and a second assembly stand 414 or blade mounting stand for mounting the wind turbine blade 411 to a nacelle 416 mounted on the wind turbine tower 435 or a wind turbine tower section, wherein the first assembly stand 413 is located on a first side of the mounting crane 404, the second assembly stand 414 is located on a second side of the mounting crane 404, and the mounting side 419 is located on a fourth side of the mounting crane 404,

Wherein the mounting crane 404 has a lifting device 420, the lifting device 420 comprising at least one lifting winch 439 with an associated lifting cable 440, at least one trolley 441 supported by the lifting cable 440 to support a tower 435 or tower section of the wind turbine, such as a first wind turbine support trolley 427, and a trolley guide 442 for guiding the trolley 441 in a vertical direction along the mounting crane 404, and wherein the trolley 441 is configured to engage the tower 435 or tower section of the wind turbine between a bottom end and a top end of the tower 435 or tower section to support the tower 435 or tower section in a lateral direction,

wherein the mounting crane 404 has a base section 422 and a top section 423, wherein the top section 423 is rotatably supported by a bearing 424, the bearing 424 being supported by the base section 422, and the top section 423 is thus rotatable about a vertical axis with respect to the base section 422 by means of the lifting device 420, and

wherein the trolley guide 442 comprises a first trolley guide 426 or a top trolley guide mounted to the top section 423 of the mounting crane 404 and at least one second trolley guide 431 or a base section trolley guide mounted to the base section 422 of the mounting crane 404 at one of the first assembly side, the second assembly side or the mounting side, preferably with the second trolley guide 431 mounted to the base section 422 of the mounting crane 404 at each of the first assembly side, the second assembly side and the mounting side, and the trolley 427 of the lifting device 420 is thus movable along the top section 423 and the base section 422 of the mounting crane 404 at least one assembly station (preferably at each assembly station) and at the mounting side.

Wind turbine assembly vessel 401 implements a method for assembling and installing a wind turbine according to the present invention. The method comprises, for example:

storing the wind turbine components on a wind turbine component storage deck 403, which in the illustrated embodiment are a tower 435, a nacelle 416 and a blade 411;

arranging a tower 435 of a wind turbine into the first assembly station 413, preferably using a wind turbine mounting crane 404, and supporting the tower 435 in an upright mounting position, optionally before: wind turbine tower 435 is preferably erected from a horizontal storage position to an upright mounting position using wind turbine mounting crane 404;

lifting the nacelle 416 in the first assembly table 413 and lifting the nacelle 416 onto the tower 435, preferably using the wind turbine mounting crane 404, and mounting the nacelle 416 on the tower 435;

arranging the combined tower 435 and nacelle 416 from the first assembly station 413 to the second assembly station 414 using the mounting crane 404, and supporting the tower 435 in an upright mounting position, preferably with the nacelle 416 (in particular the hub of the nacelle 416) in a mounting position for mounting the blade 411 to the nacelle 416;

Mounting the blade 411 to the nacelle 416, preferably using blade handling equipment, to provide an assembled wind turbine 408, the blade mounting process comprising;

lifting the first blade to a secured position adjacent to the nacelle 416, mounting the first blade to the nacelle 416, and rotating the nacelle 416 (in particular the hub of the nacelle 416) to a successive mounting position, preferably using a blade handling device,

lifting the second blade to a secured position adjacent to the nacelle 416, mounting the second blade to the nacelle 416, and rotating the nacelle (in particular the hub of the nacelle 416) to a successive mounting position 416, preferably using a blade handling device; and

lifting the third blade to a secured position adjacent to the nacelle 416, preferably using a blade handling device, and mounting the third blade to the nacelle 416;

-arranging the assembled wind turbine 408 from the second assembly station 414 to a mounting position of a fourth side (i.e. a mounting side 419) of the mounting crane 404; and

lowering the assembled wind turbine 408 onto a base 409 using the mounting crane 404.

In the method, arranging the combined tower and nacelle from the first assembly station to the second assembly station includes lifting the combined tower and nacelle at the first assembly station using a lifting device of the mounting crane and lowering the combined tower and nacelle at the second assembly station, and rotating a top section of the mounting crane relative to a base section of the mounting crane to move the combined tower and nacelle from the first assembly station to the second assembly station.

Further, in the method, arranging the assembled wind turbine from the second assembly station to the mounting position at the fourth side of the mounting crane comprises lifting the assembled wind turbine at the second assembly station using a lifting device of the mounting crane, and rotating a top section of the mounting crane relative to a base section of the mounting crane to move the assembled wind turbine from the second assembly station to the mounting side of the mounting crane.

The mounting crane 404 is arranged near one side of the hull of the vessel 401, in the embodiment shown the front side of the vessel. The mounting crane 404 has a mounting side at the bow. The mounting crane 404 is configured for supporting the assembled wind turbine at its mounting side in a mounting position above the base and for lowering the wind turbine onto the base. The base may be a seabed-mounted base or may be a floating base.

The mounting crane 404 has a vertical crane structure erected on the hull of the ship 401. The vertical crane structure includes a base section 422 and a top section 423 of the mounting crane. The vertical crane structure has a base section of the crane structure fixed to the hull and a pivotable top section of the crane structure, wherein the lifting means comprises one or more winch drive cables suspended from one or more pulley blocks arranged on the pivotable top section (e.g. on a pivoting cantilever of the pivotable top section). The gyration of the top section may be used to pick up the assembled wind turbine from the deck of the vessel by means of a lifting device and bring the wind turbine together with its tower over the tower mounting structure of the floating foundation.

The vertical crane structure includes a pivoting cantilever 535 for each of the first wind turbine lift 420a and the second wind turbine lift 420 b. In the embodiment shown, the lifting booms are arranged on opposite sides and at the top of the crane structure such that the W-shaped lifting cable is suspended from a pulley block arranged on the respective pivoting boom.

The mounting crane is provided with a first wind turbine mounting trolley 427 or an upper wind turbine mounting trolley and a second wind turbine mounting trolley 432 or a lower wind turbine mounting trolley. The trolley supports a tower engagement device 428, 432 and an actively controlled movement mechanism or active horizontal movement device 428, 434, respectively, which is configured and operable to provide controlled movement of the respective tower engagement device in a horizontal plane in order to align and maintain alignment of the tower of the suspended wind turbine with the mounting axis of the floating base. The tower engagement device is configured to actively force the suspended wind turbine to be oriented away from its plumb line and aligned with the mounting axis.

Providing the crane with a first wind turbine mounting trolley 427 or an upper wind turbine mounting trolley and a second wind turbine mounting trolley 432 or a lower wind turbine mounting trolley enables the tower engagement means of the respective upper and lower wind turbine mounting trolleys to act on the tower of the supported wind turbine at different heights, e.g. the lower wind turbine mounting trolley is located below the centre of gravity of the wind turbine to be mounted, the upper wind turbine mounting trolley is located above said centre of gravity. When the assembled wind turbine is mounted on the foundation, the actively controlled horizontal movement means 429, 434 are operated to align the tower 435 of the suspended wind turbine with the mounting axis of the floating foundation. For example, the upper tower engaging means and the lower tower engaging means are separated in a vertical direction by at least 20 meters.

In the illustrated embodiment, the actively controlled horizontal movement devices 428, 434 each include a first set of horizontal rails extending in a first horizontal direction that supports a first carrier and that supports a second set of one or more horizontal rails extending in a second horizontal direction different from the first direction, e.g., the first and second directions are orthogonal directions. A second set of horizontal rails supports a second carrier, and a further second carrier supports the tower engaging means.

In addition, actively controlled horizontal movement devices include horizontal displacement actuators (e.g., hydraulic cylinders or an assembly of one or more cables and associated (electric) winches) or rack and pinion drives.

In the embodiment shown in FIG. 31, the assembled wind turbine 408 is received in an upper wind turbine mounting cart 427 and a lower wind turbine mounting cart 432. The upper wind turbine mounting trolley 427 is supported via an upper trolley suspension element 130 (in the embodiment shown, a lifting cable 440 of a lifting winch 439). The lower wind turbine mounting cart 432 is supported by the upper wind turbine mounting cart via a lower cart suspension element (in the illustrated embodiment, cart suspension cable 446). The assembled wind turbine is supported via wind turbine suspension elements (wind turbine suspension cables 447 in the illustrated embodiment) that are connected to the tower engaging means of the lower wind turbine support cart.

The wind turbine suspension cables extend between attachment elements fitted (e.g. temporarily fitted) on the wind turbine tower at a level below the upper tower engagement means.

The mounting crane is provided with horizontally spaced apart first and second upper pulley blocks and the upper wind turbine support trolley is provided with horizontally spaced apart first and second lower pulley blocks. A first multi-drop cable arrangement of the hoisting cable extends between the first upper and lower pulley blocks, and a second multi-drop cable arrangement of the hoisting cable extends between the second upper and lower pulley blocks. The arrangement is such that in use, the nacelle and one of the blades of the wind turbine pointing upwards are located between the drop cable arrangements without these cable arrangements being in contact with any of the blades and nacelle.

Note that in the particular embodiment shown, wind turbine mounting crane 204 is a double sided crane having first and second lifting devices 420a, 420b on opposite sides of the crane.

In the embodiment shown, the first lifting device is adapted to support an assembled wind turbine and to raise and lower the assembled wind turbine in a controllable manner, the assembled wind turbine comprising a tower in combination with a nacelle and being fitted with blades. Thus, the first lifting device is provided with a first wind turbine installation trolley 427 or an upper wind turbine installation trolley, and a second wind turbine installation trolley 432 or a lower wind turbine installation trolley

In the shown embodiment, the second lifting device is configured for lifting the nacelle, more particularly for lifting the nacelle located at the third assembly station or nacelle storage location, and for lowering the nacelle onto the top of a tower set up in the first wind turbine assembly station. Furthermore, the lifting device is configured for erecting a wind turbine tower or pile. Thus, in the embodiment shown, the second lifting device is provided with a trolley configured to engage the nacelle and can also be configured to pivotably engage the top end of the pile or tower.

Fig. 25 shows a second lifting device 420b for erecting a pile 448, while a first lifting device 420a supports a hammering device 449 for driving another pile into the sea floor to provide a foundation for the wind turbine. In the embodiment shown, the vessel is adapted to erect the pile, lower the pile towards the sea floor, and split the pile into the sea floor.

These piles are stored on deck for transport to a wind farm, for example from a pile plant located on shore. Once the vessel arrives at the wind farm, the piles may be erected so that they may be engaged by the crane and lowered into the sea. In the embodiment shown, the vessel is provided with temporary pile set-up positions on opposite sides and adjacent to the installation crane. Thus, after erection and before being lowered into the sea, the pile may be set up adjacent to the installation crane. In the embodiment shown, two piles are set up adjacent to the mounting crane.

In the embodiment shown, the vessel 401 is provided with a transom 438 extending in line with the mounting crane 404. The tail plate 438 is provided to enable the erection of a pile or foundation pile for the installation of the wind turbine. These piles have a considerable length, which is longer than the length of the wind turbine tower. In order to be able to erect the pile section, the deck comprising the rear deck is provided with rails for supporting the erecting vehicles. During erection, the erection truck supports the bottom end of the pile or tower, while the top end of the pile or tower is lifted by the mounting crane. Thus, the bottom end of the pile or tower is guided along the deck on rails towards the installation crane.

It has been proposed that the process of erecting piles, lowering piles and driving piles into the sea floor can also be performed by means of an installation crane according to the invention with a single lifting device.

In order to be able to erect the pile and the wind turbine tower, the base section 422 of the mounting crane is provided with a trolley guide on one side of the deck (i.e. the side of the mounting crane facing the first wind turbine assembly station) for guiding the trolley in a vertical direction along the crane, in particular the trolley is a trolley for erecting the tower or pile. The top section of the crane is provided with two first or top trolley guides 426, one at each wind turbine lifting device. In addition, the exemplary embodiment shown is provided with a plurality of second or base trolley guides 431 mounted to the base section 422 of the mounting crane.

In the embodiment shown, the mounting crane is further provided with two pile engaging means 451. The pile engaging means is mounted to the top of the mounting crane and is aligned with the second lifting means to engage a pile being erected using the second lifting means. The pile engaging means is arranged to engage the pile being erected and secure the pile in position whilst moving the pile by the swivel of the top section. The pile engaging means prevents swinging of the pile, in particular when the rotation of the top section of the mounting crane starts or stops. Moreover, they can prevent the swing of the pile caused by the movement of the ship.

The pile engaging means is mounted between the two rails of the trolley guide and is hingeable between an inactive position in which the pile engaging means is folded against the top section of the mounting crane to allow the trolley to pass, and an active position in which the pile engaging means extends outwardly from the top section of the mounting crane to engage a pile supported by the second wind turbine lifting device. In fig. 32, the lower of the two pile engaging devices is hinged to the active position, while the upper pile engaging device is still in the inactive position.

In the embodiment shown, the mounting crane is at each side of the crane, and thus at the first and second wind turbine assembly stations, at the mounting side of the mounting crane and at the nacelle storage side of the mounting crane, a base trolley guide is provided. Thus, at all sides, the trolley can be lowered along the base section of the crane.

Providing a base cart guide at the first wind turbine assembly station enables the cart to be lowered close to the deck. This is beneficial for the erection process. Lowering the cart close to the deck allows the cart to be coupled with the top end of a tower or pile supported on the deck in a horizontal configuration and thus enables the pile to be erected using a mounting crane.

Furthermore, in order to enable the pile to be turned over, in the embodiment shown comprising a rear deck, the deck is provided with rails for supporting the upright carrier 450. During erection, the erection truck supports the bottom end of the pile or tower, while the top end of the pile or tower is lifted by the mounting crane. Thus, the bottom end of the pile or tower is guided along the deck on rails towards the installation crane.

It has been proposed that the trolley of the first lifting device and the trolley of the second lifting device may be arranged in an active position for supporting the wind turbine or wind turbine component and in an inactive position for moving along the tower or upper tower component of the wind turbine supported by the wind turbine mounting crane, for example at the at least one wind turbine assembly station. Fig. 27 to 29 show the trolley of the first lifting device in the inactive position, while fig. 30 shows the trolley of the first lifting device in the active position.

In the particular embodiment shown, the wind turbine mounting assembly and mounting vessel 401 is provided with a foundation restraint system 445 on the mounting side of the mounting crane 404 for engaging the foundation 409 and enabling the assembled wind turbine 408 supported by the mounting crane 404 to be aligned with a floating foundation, see for example fig. 31. The constraint system is configured to at least to some extent constrain movement of the tower-mounting structure relative to the vessel in a horizontal plane.

The floating base (e.g., each buoyancy column of the floating base) is provided with a ballast tank for holding ballast (e.g., ballast liquid, such as ballast water). In an embodiment, a ballast control system is provided that is configured for moving ballast between ballast tanks, e.g., at least three stabilizing columns, to adjust the vertical orientation of an upwardly directed mounting axis. Further, the floating base comprises a water retention plate, wherein the water retention plate is attached to the lower end of the stabilizing column.

In the illustrated embodiment, the base restraint system 445 includes a trolley guide or track-mounted trolley 443 provided with engagement members in the form of gripping devices 444 for engaging the tower-mounted structure of the floating base. The base restraint system also has an actively controlled motion mechanism configured and operable to provide controlled motion of the engagement member relative to the hull of the vessel, thereby providing controlled restraint of the engaged floating base relative to the hull of the vessel. The actively controlled motion mechanism is implemented to actively constrain the engaged floating base relative to the hull of the vessel in two non-parallel horizontal directions (e.g., in orthogonal horizontal directions).

The wind turbine assembly and mounting vessel further comprises an alignment system comprising a base restraint system 445 and a first wind turbine mounting cart 427 (or upper wind turbine mounting cart) and a second wind turbine mounting cart 432 (or lower wind turbine mounting cart). The trolley supports a tower engagement device 428, 432 and an actively controlled movement mechanism or active horizontal movement device 428, 434, respectively, which is configured and operable to provide controlled movement of the respective tower engagement device in a horizontal plane in order to align and maintain alignment of the tower of the suspended wind turbine with the mounting axis of the floating base. The tower engagement device is configured to actively force the suspended wind turbine to be oriented away from its plumb line and aligned with the mounting axis.

In an embodiment, one or more sensors are used for monitoring the movement of the tower mounting structure in one or more directions relative to the lower end of the tower floating base during installation. Preferably, these one or more sensors are linked to a controller, such as a computerized controller, which is configured and operative to cause automatic operation of the heave compensation apparatus and/or the alignment system. For example, one or more sensors are implemented as cameras, radars, displacement sensors, and the like.

For example, one or more motion monitoring sensors are combined with a restraint system as discussed herein.

For example, the one or more motion monitoring sensors are configured to monitor a tilt of the tower mounting structure relative to the hull of the vessel, such as relative to the restraint system.

In an embodiment, the restraint system comprises at least three mooring lines securing the floating base to the vessel, e.g. to the bow of the vessel, said mooring lines extending in different directions, e.g. mainly in the horizontal plane. This allows for example to maintain a substantially fixed relative horizontal position of the vessel and the floating base. Preferably, in this arrangement, the base is anchored to the seabed.

In an embodiment, in addition to a portion of the vessel being coupled to the anchored floating base via a restraint system, the vessel is anchored to the seabed via a plurality of anchor lines. For example, the restraint system couples, for example, the bow of a semi-submersible vessel to a floating base (e.g., a stabilizing column thereof), and one or more anchor lines extend from the stern of the vessel during installation.

In an embodiment, the restraint system further comprises, for example, one or more tensioning line assemblies disposed on the vessel, each tensioning line assembly comprising one or more tensioning lines connected to the floating base and one or more respective tensioners providing controlled tension to the tensioning lines, and the tensioning line assemblies are configured and operable to tension the one or more lines so as to restrain the floating base with respect to the vessel primarily in the heave direction.

The installation crane, in the shown embodiment the first lifting device of the installation crane, is provided with heave compensation means adapted to compensate for sea-state induced heave movements of the wind turbine tower supported by the installation crane relative to the tower mounting structure of the floating foundation.

In particular for lifting devices having one or more lifting winches and lifting cables, as preferred herein, suitable heave compensation devices are well known in the art in embodiments of both passive and active embodiments or a mixture thereof. For example, the hoisting device comprises one or more winches and one or more hoisting ropes, which are heave compensated by a suitable operation of the (electric) winch and/or by one or more heave compensation cylinders carrying one or more rope pulleys over which the hoisting ropes are passed.

In the method, a tower alignment system is used that is configured to engage on the suspended wind turbine, e.g., on a tower of the suspended wind turbine, and align and maintain the tower of the suspended wind turbine in alignment with the mounting axis of the floating base so as to compensate for sea state induced motion of the wind turbine tower relative to the mounting axis of the floating base, including at least tilting motion in one or more vertical planes.

The method comprises-in the case where the hull of the vessel is in a floating state and the floating base is in a floating state-the steps of:

suspending the wind turbine from the crane by means of a lifting system,

positioning the lower end of the tower of the suspended wind turbine above the tower mounting structure of the floating foundation,

operating a heave compensation apparatus to compensate for heave motions caused by sea-state of the wind turbine tower relative to the tower mounting structure of the floating foundation,

operating a tower alignment system to align and maintain alignment of the tower of the wind turbine with the mounting axis of the floating base so as to compensate for sea-state induced tilting movements of the wind turbine tower relative to the mounting axis of the floating base,

operating the lifting system while the heave compensation apparatus and the tower alignment system are in operation, thereby lowering the suspended wind turbine together with the lower end of the tower onto the tower mounting structure of the floating foundation,

-a tower mounting structure securing the tower with its lower end to the floating foundation.

Thus, the method contemplates providing and operating a tower alignment system to allow the lower end of the tower to properly drop onto the tower mounting structure of the floating foundation. In general, tower alignment systems are used to force a suspended wind turbine out of its plumb line orientation in order to align and maintain its tower with a mounting axis that is at least continuously subject to tilting movements relative to the tower due to sea conditions acting on the floating hull and on the floating foundation of the vessel.

The invention allows for example to anchor a plurality of floating foundations at their final position in an offshore wind farm, all without wind turbines, and then sailing the vessel to the wind farm and subsequently mounting the wind turbines on the floating foundations. This approach enables a more cost-effective approach to establishing a floating base offshore wind farm than the above approach (cost-effective) in which fully assembled floating wind turbines must be towed a relatively long distance to their location in the wind farm. In embodiments, the floating bases of a wind farm are installed in one calendar year, and the associated wind turbines are installed on these bases in a later calendar year.

For example, the present invention allows the use of deep draft floating foundations, such as spar-type foundations, without the need for deep draft installation locations near the coast, such as FJord, described above.

In embodiments, lowering the tower onto the tower mounting structure may have caused or subsequently caused a preliminary fastening to be established between the tower and the base, such that the wind turbine is stabilized relative to the base, e.g. to allow operation of the alignment system to be stopped, e.g. to allow disengagement of the alignment system.

For example, the lower end of the tower is configured for penetration into or onto a tower mounting structure of the floating foundation, said penetration connection providing a stable preliminary fastening between the tower and the foundation.

In an example, one or more preliminary fastening means are provided on the lower end and/or the tower mounting structure, which establish a preliminary fastening between the tower and the foundation, e.g. automatically or on command. Final fastening of the lower end portion to the tower mounting structure may then be performed, e.g. providing a connection by bolts, welding, grouting etc.

In an embodiment, the lower end of the tower and the tower mounting structure are provided with cooperating self-actuating fastening members, such as e.g. automatic latches or the like, fastening the tower to the foundation.

In an embodiment, at least the tower alignment system remains operational during part or all of the fastening steps, e.g. the system is used or aids in stabilizing the wind turbine relative to the foundation during this step.

In an embodiment, at least the heave compensation apparatus remains operational during part or all of the fastening step, e.g. the apparatus is also used or assisted to support at least a part of the weight of the wind turbine relative to the foundation during this step. In another embodiment, the weight of the wind turbine is transferred from the crane to the floating base once the lower end of the tower has been lowered onto the tower mounting structure of the floating base. This may be done, for example, by a suitable operation of the hoisting system and/or the heave compensation apparatus.

In a preferred method of installation, at least during the step of lowering the tower onto the foundation, the vessel faces the wave with its bow or stern. Most preferably, the vessel is implemented with the wind turbine suspended at the bow or stern of the vessel, preferably in the mid-plane of the vessel.

Preferably, during installation of the wind turbine, the floating base is restrained, at least to some extent, by the restraining system, at least or only at a level relative to the vessel. For example, the constraint may involve a plurality of mooring lines extending in different directions arranged between the floating base on the one hand and the hull of the vessel on the other hand, so as to provide coupling of the floating base and the hull at least or only in the horizontal plane.

In an embodiment, the restraint system is disposed at the bow of the semi-submersible vessel.

The mounting crane 404 is provided with a boom for each of the two lifting devices. The lifting device thus comprises two spaced apart booms, which preferably support one or more suspension elements, which are connected to the first trolley or the wind turbine engaging means.

The two cantilevers may be arranged in an active position for supporting the first trolley and the first wind turbine engagement means in an active position and in an inactive position for moving along the nacelle or the blade of the partially or fully assembled wind turbine in the assembly table.

The mounting cranes are configured such that when the assembled mounting cranes are supported by the mounting cranes, the booms extend above the nacelle of the wind turbine and the nacelle of the wind turbine is located between the booms when seen in elevation.

Referring to fig. 28, vessel 401 further comprises a tower receiving well 452, which is submerged into the hull at a second wind turbine assembly station, which is an assembly station configured for mounting the blade to the nacelle of the wind turbine using a blade manipulator (not shown in the figures), and wherein the tower receiving well is configured to receive at least a portion of the tower of the wind turbine therein, preferably using a wind turbine mounting crane, such that the distance between the nacelle and the storage deck is reduced, preferably less than the length of the turbine blade, more preferably less than four fifths of the length of the blade, in order to facilitate mounting the blade to the nacelle.

It has been proposed that semi-submersible vessels are well suited to be provided with a tower receiving well sunk into or even through the hull, the well being configured to receive at least a portion of the tower of a wind turbine therein during assembly of the wind turbine.

In the preferred embodiment shown, the tower receiving well extends into the support column, optionally even into the buoy. The well has a floor configured for the tower to stand on, e.g., integrated with the pontoons and/or with the lower portion of the support columns.

The tower containment well is placed within reach of the installation crane, allowing the crane to be used to place the tower or a portion thereof in the well, and then the assembled or partially assembled wind turbine is removed from the well, which is then placed on the base by the crane.

The installation crane is mounted directly above the support columns at the ends of a row of columns, thus in practice at the corners of the deckbox structure, and the tower receiving wells are provided in adjacent support columns of the same row of columns on the pontoons. In another embodiment, for example when the vessel has one installation crane above the support columns at the ends of a row of columns on one pontoon at one corner of the deck box structure, the tower receiving well is arranged into or through the support corner at the end of a row of columns on the other pontoon, for example both the crane and the well are located at the stern of the vessel, for example the crane and the well are each in fact located at a corner of the deck box structure.

For example, embodiments of a well having a depth of at least 30 meters (e.g., over 40 meters) allow for a substantial portion of the entire tower of a wind turbine to be housed in the well, e.g., because the tower height may vary between 75 meters and 110 meters in practical embodiments. By being placed in the well, the top of the tower is closer to the deck, which facilitates operations like mounting the nacelle on top of the tower, mounting one or more (e.g. all) blades on the nacelle, etc.

Considering the advantages of the tower height and having the tip relatively close to the deck to perform some assembly steps, such as installing the nacelle and/or installing one or more (e.g. all) of the blades, it is contemplated that in embodiments the well extends through the hull, e.g. through the support columns, and further down through the pontoons. In the latter form, the well resembles a moonpool or shaft that passes completely through the hull, for example, to allow the tower to extend below the bottom of the pontoon of the vessel. In such open-bottomed wells, the tower or a portion thereof may be suspended, for example, by winch-driven cables, for example, which engage at the lower end of the tower.

33-38, the use of the semi-submersible vessel in a shipboard assembly of wind turbines and the mounting of the assembled wind turbines on a foundation by the crane of the vessel will be discussed.

Fig. 33-38 illustrate a semi-submersible vessel 1000 that includes a dual pontoon floating hull having:

-a deckbox structure 1001;

two parallel pontoons 1002, 1003,

for each of the two pontoons 1002, 1003, an associated row (here four, three or two in other known embodiments) supports columns 1010-1013, 1014. Each of these columns extends upwardly from a respective pontoon. The deckbox structure 1001 is supported on all support columns. The columns together with the pontoons contribute to the buoyancy of the vessel.

Reference numeral 1004 denotes the bow of the ship, and 1005 denotes the stern.

The deckbox structure 1001 has a deck 1006 and a box bottom 1007 above the waterline.

The vessel 1000 is provided with a mounting crane 1100 mounted on the deckbox structure and configured to mount the assembled wind turbine on a base (not shown) located within reach of the crane 1100.

The base may be a seabed-mounted or fixed base, such as a mono-pile base or a ducted base, as is known in the art. In another embodiment, for example for deeper waters, the base is a floating base, for example a spar-type base (e.g. as in hybond engineering), or as disclosed in WO 2009/131826.

The depicted crane 1100 is a basin-mounted crane, wherein a rotatable superstructure 1101 of the crane is mounted via bearings, such as roller bearings or an arrangement of bogies, on a basin 1102 integral with the deckbox structure 1001. As shown and preferably, the crane 1100 is disposed directly above the support columns 1010 at the ends of a row of columns.

The crane 1100 has a pivoting boom 1103 that pivots up and down by a pitch mechanism where the pitch mechanism includes a winch-driven pitch cable 1104 extending between the boom 1103 and the mast structure of the superstructure 1101.

Crane 1100 has the ability to independently maneuver a fully assembled wind turbine, as will be explained herein.

In other embodiments, the crane is a tower crane.

Generally, as known in the art, a fully assembled wind turbine to be mounted on an offshore foundation comprises at least a part of a wind turbine tower, preferably the entire tower, and a rotor assembly mounted on the tower (typically a nacelle with a hub), which rotor assembly is preferably provided with one or more (e.g. all) rotor blades before being mounted on the foundation.

It is contemplated that the assembly of the wind turbine is at least partially completed on the vessel 1000.

Preferably, even when the foundation is a floating foundation, the vessel 1000 is located at an offshore wind farm, e.g. moored near the foundation at a final position in the wind farm, when one or more assembly steps for assembling the wind turbine are performed.

33-38, at the ship's 1000 shipboard assembly station, the ship's hull is provided with a tower-receiving well 1040 sunk into or through the hull.

As best shown in fig. 33 and 34, in an embodiment, the well 1040 extends from its top opening 1041 (e.g., the top opening 1041 is flush with the deck of the vessel) into the support column 1011 of the hull.

The well 1040 is configured to house at least a portion of a tower of a wind turbine therein during an assembly step of the wind turbine, such as during installation of a rotor assembly (here a nacelle) on the tower and/or during assembly of one or more (e.g., all) rotor blades to the rotor assembly.

As an example, the depicted vessel 1000 has a width of 100 meters, a length of 180 meters of deckbox, a height of 12 meters of deckbox, a height of 24 meters of columns, and a height of 14 meters of pontoons. The uprights have a horizontal cross section of at least 20 x 20 meters.

In this example, the total height between the deck and the bottom of the pontoon is 50 meters. This height, as well as the structural strength and integration of the columns in the hull, allows for efficient implementation of the wells 1040 in the columns.

The available height in the hull of the semi-submersible vessel allows the well 1040 to be implemented to accommodate a substantial portion of the entire tower of the wind turbine therein during assembly of the wind turbine.

The well 1040 may extend to the bottom end or floor of a well located in the column. As shown, in another embodiment, the tower receiving well extends through the entire height of the support column, even into the pontoon under the column.

As shown, the well 1040 has a floor 1050 that is preferably configured to have a tower erected thereon. The floor 1050 is shown here as being integrated with a structure such as a bulkhead, wall (wall), and/or with a support column, for example with a lower portion of a support column.

It will be appreciated that the tower containment well 1040 may be retrofitted into existing semi-submersible (heavy-crane) vessels.

As shown, tower containment well 1040 is preferably disposed within reach of installation crane 1100.

The installation crane 1100 is shown installed directly above the support columns 1010 at the ends of a row of columns, and thus in fact at the corners of the deckbox structure 1001, and the tower receiving wells 1040 are provided in the adjacent support columns 1011 of the same row of columns on pontoons.

Crane 1100 preferably has sufficient lifting capacity to use crane 1100 to place the entire wind turbine tower 1200 or an upper portion thereof (e.g., between 40-65% of the entire tower length) in well 1040, and then remove the assembled or partially assembled wind turbine from the well, which is then placed on a base by crane 1100.

In an embodiment, as known in the art, the vessel has two, possibly identical, cranes 1100, each mounted at a respective corner of the deckbox structure, for example at the stern.

In an embodiment, the vessel 1000 has, in addition to a crane 1100 configured to mount an assembled or partially assembled wind turbine on an offshore foundation, another crane mounted to the hull with lower lifting capacity than the crane 1100. For example, additional cranes are provided for handling wind turbine components (e.g., towers or tower components) and/or cabins between storage locations on the deck of the vessel and one or more assembly stations disposed within reach of the crane 1100.

As described herein, embodiments of the well 1040 having a depth of at least 30 meters (e.g., greater than 40 meters) allow for a substantial portion of the entire tower of the wind turbine to be housed in the well, e.g., as the tower height may vary between 75 meters and 110 meters in practical embodiments for offshore wind turbines.

FIG. 35 shows that the entire wind turbine tower 1200 has been placed in a well 1040, in this example, the tower has a height between 75 meters and 110 meters. It can be seen that due to the placement of the tower 1200 in the well, the top of the tower is closer to the deck, which facilitates operations like mounting the nacelle on top of the tower, mounting one or more (e.g., all) blades on the nacelle, etc.

Fig. 36 shows that the nacelle 1250 has been lifted onto top of the tower 1200, here by means of a crane 1100. The nacelle 1250 may already be stored in a storage area on the deck of the vessel.

In an embodiment, this subassembly of tower 1200 and nacelle 1250 without any blades is lifted out of well 1040 by crane 1100, and then crane 1100 is swung into position with the tower above the offshore foundation. The partially assembled wind turbine is then placed on the base and secured to the base. In a further assembly step, for example using the crane 1100, the blades 1275, 1276, 1277 are assembled to the nacelle.

In another approach, the nacelle 1250 has been provided with two blades, for example, onshore, before placing the nacelle on top of the tower. This method is known in the art as the rabbit ear method. Then, once the wind turbine has been placed on the foundation, only the other blade is mounted. This may be done, for example, with crane 1100.

Preferably, one or more blades 1275, 1276, 1277 are mounted to nacelle 1250 while simultaneously being mounted to tower 1200, wherein the tower is at least partially housed in well 1040.

FIG. 37 shows the blades 1275, 1276, 1277 mounted to the nacelle 1250 one after the other. Once all of the blades, here three blades, are installed, the wind turbine is fully assembled and ready for lifting from the well 1040 and placement on the base with the crane 1100.

Fig. 37 shows that instead of mounting the blade to the nacelle using a mounting crane 1100, a blade handling apparatus 1300 is used that is configured for transporting the blade between a horizontal supply position and a fastening position (e.g., a tilted or horizontal fastening position).

Fig. 37 shows the blade handling device 1300 placed on the deck of a vessel.

For example, as schematically shown, the apparatus 1300 is configured to bring a blade into a secured position in which a root end of the blade is aligned with a blade mounting structure, wherein the blade handling apparatus comprises:

-a blade holder adapted to hold a blade;

-a base;

a pivoting boom, for example a hinged boom, to which one or more blade holders are attached, the boom being movable between a lowered position for holding a blade in a horizontal supply position and a raised position in which the blade has a fastening orientation;

Preferably, one or more actuators, for example on a boom, for maneuvering the blade into a secured position.

Fig. 37 shows an embodiment wherein the horizontally turned hub is provided with three blade mounting structures spaced apart by 120 ° and wherein the fastening orientation is a tilted orientation, preferably for each blade mounted using the blade handling device 1300, the fastening orientation corresponding to about four o 'clock or about eight o' clock positions of the nacelle as seen in a front view, e.g. wherein the blade is 30 ° to 40 ° from the horizontal.

Fig. 37 shows that in an embodiment, the oblique orientation is the same for each of the three blades associated with the hub, which is rotated 120 ° between each installation of the blades.

Fig. 38 shows the completed assembly, all steps being performed at a single assembly station on the vessel 1000, here at well 1040.

The figures show that in an embodiment, the nacelle 1250 is mounted on the tower 1200 such that the front of the nacelle (to which the blades are mounted to the hub of the nacelle) faces outward relative to the long side of the hull of the vessel. As is preferred, and as shown, the axis of the hub is not perpendicular to the long side of the hull of the vessel, but is at an angle between the vertical line and the side of the hull (when viewed from above).

Fig. 38 illustrates the benefit of this arrangement of the hubs of the nacelle and the arrangement of the wells 1040 into or through the support columns, in that one blade of a fully assembled wind turbine may extend outside the hull rather than near the deckbox and crane 1100.

The apparatus 1300 may (not shown) have an articulating boom that allows the blade to be brought to a horizontal securing position to secure the blade to the hub of the nacelle.

In another approach, not shown, it is contemplated that the well 1040 extends completely through the hull, such as through the support columns, and then further down through the pontoons. In the latter form, the well resembles a moonpool or shaft that passes completely through the hull, e.g., to allow operation of the tower of the wind turbine to extend below the bottom of the pontoon of the vessel. In such open-bottomed wells, the tower or a part thereof may be suspended, for example by winch-driven cables, for example engaged on the lower end of the tower.

In embodiments, extending the well through the hull may allow the nacelle 1250 to be mounted on top of the tower without the use of a crane. For example, a tower (or tower component) is suspended in the well such that its top is near the deck. This allows the nacelle to be moved substantially horizontally (e.g., slid by a sliding truck) on the deck (e.g., on rails mounted on the deck), such as by one or more vehicles or by a truck, for example, so that the nacelle is positioned above and connected to the tower top. For example, the tower is then lifted a portion of its height, e.g., using crane 1100 or a suspension device suspending the tower in well 1040, to a height suitable for mounting one or more blades to the nacelle, e.g., as discussed above.

In embodiments, the well 1040 extends through the deckbox structure at a location remote from any support column of the hull, such as in the space between two support columns. For example, additional well side walls (e.g., tubular side walls) are then assembled between the deckbox structure and the pontoons to provide a dry well in which the tower or tower components are to be placed.

Claims

1. A wind turbine mounting crane to be mounted on a floating hull of a vessel,

wherein the mounting crane has at least one assembly side for facing the wind turbine assembly table and has a mounting side,

wherein the mounting crane is configured to perform one or more wind turbine assembly steps, e.g. erecting a wind turbine tower, and the mounting crane is configured for arranging the assembled wind turbine from the at least one wind turbine assembly station into a mounting position above a wind turbine foundation adjacent the vessel at a mounting side of the mounting crane, and lowering the assembled wind turbine onto the foundation,

wherein, the installation hoist is provided with:

a wind turbine lifting device having one or more wind turbine suspension elements, such as cables, adapted to support an assembled wind turbine and to raise and lower the assembled wind turbine in a controllable manner, the assembled wind turbine comprising a tower in combination with a nacelle and an assembled blade,

A foundation section and a top section, wherein the top section is rotatably supported by bearings and is rotatable about a vertical axis with respect to the foundation section with a wind turbine lifting device, and the lifting device is thus capable of transferring at least an upper tower part between the assembly table and the mounting side, and

-a first trolley guide mounted to the top section of the mounting crane and a first wind turbine support trolley vertically movable along said first trolley guide, wherein the first trolley supports the wind turbine engagement means.

2. The mounting crane according to claim 1, wherein the base section of the mounting crane is provided with a second trolley guide and a second wind turbine support trolley, the second wind turbine support trolley being vertically movable along the second trolley guide on the mounting side of the mounting crane.

3. The mounting crane according to claim 2, wherein the second trolley supports a wind turbine engagement device, and wherein preferably an active horizontal movement device is mounted between the trolley and the wind turbine engagement device, the active horizontal movement device being adapted to actively compensate for horizontal displacement of the wind turbine engagement device relative to the base in at least one horizontal direction, possibly in two non-parallel horizontal directions, e.g. sea conditions in orthogonal horizontal directions, when the wind turbine is supported by said wind turbine engagement device.

4. The installation crane according to one or more of the preceding claims, wherein the lifting device comprises two spaced apart booms supporting one or more suspension elements, one or more suspension elements being connected to the first trolley or to the wind turbine engagement device.

5. The mounting crane according to one or more of the preceding claims, wherein the wind turbine mounting crane is configured such that when the assembled wind turbine is supported by the mounting crane, the cantilever arms extend above the nacelle of the wind turbine and when seen in front view the nacelle of the supported wind turbine is located between the cantilever arms.

6. The mounting crane according to one or more of the preceding claims, wherein the mounting crane is a double-sided mounting crane having wind turbine lifting means as first lifting means on a first side of the crane and second lifting means on an opposite second side of the mounting crane, such that the crane can perform lifting actions simultaneously on opposite sides of the mounting crane.

7. A vessel for assembling a wind turbine and for mounting the assembled wind turbine on a foundation, such as a semi-submersible crane vessel, such as a seabed-mounted foundation or a floating foundation, the vessel comprising:

-a floating hull;

-a wind turbine component storage deck for storing components of a wind turbine, such as towers, rotor assemblies and blades, wherein the storage deck preferably comprises a dedicated storage area, such as a tower storage area, a nacelle storage area and/or a blade storage area;

-at least one wind turbine assembly station; and

wind turbine installation crane, preferably according to one or more of the preceding claims, mounted on a floating hull,

wherein the mounting crane is configured to perform one or more wind turbine assembly steps, such as erecting a wind turbine tower,

wherein the mounting crane has at least one assembly side facing the at least one wind turbine assembly table and has a mounting side,

wherein the mounting crane is provided with a wind turbine lifting device having one or more wind turbine suspension elements, said wind turbine lifting device being adapted to support an assembled wind turbine and to controllably raise and lower the assembled wind turbine, the assembled wind turbine comprising a tower in combination with a nacelle and an assembled blade,

Wherein the mounting crane has a base section and a top section, wherein the top section is rotatably supported by bearings, and wherein the top section is rotatable about a vertical axis with respect to the base section with a wind turbine lifting device, and wherein the lifting device is thus capable of transferring at least an upper tower part between the assembly table and the mounting side,

wherein the mounting crane is configured for arranging the assembled wind turbine from the at least one wind turbine assembly station at the mounting side of the mounting crane into a mounting position above the wind turbine foundation adjacent the vessel, for supporting the assembled wind turbine at the mounting side in the mounting position above the foundation, and for lowering the wind turbine onto the foundation.

8. Vessel according to claim 7, wherein at least one wind turbine assembly rig is a first wind turbine assembly rig, and wherein the vessel further comprises a second wind turbine assembly rig, and preferably a third wind turbine assembly rig, wherein the first assembly rig is configured to support the tower in an upright mounting position, wherein the second assembly rig is configured to support the tower in an upright mounting position with the nacelle in a mounting position for mounting the blade to the nacelle, and wherein preferably the third assembly rig is configured to present the nacelle to be lifted by a wind turbine mounting crane,

Wherein the first wind turbine assembly station is located on a first side of the installation crane, the second assembly station is located on a second side of the installation crane, and preferably the third assembly station is located on a third side of the installation crane, and wherein the installation side is located on a fourth side of the crane.

9. Vessel according to one or more of the claims 7-8, wherein the second wind turbine assembly station and the third wind turbine assembly station are located on opposite sides of the mounting crane and the first assembly station is located opposite a first vertical side of the wind turbine mounting crane, i.e. the mounting side of the crane, i.e. the side for mounting the assembled wind turbine on the foundation using the mounting crane.

10. A vessel according to claim 8 or 9, wherein the first assembly station is configured for supporting the upper tower part in an upright mounting position, the second assembly station is configured for supporting the wind turbine upper tower part in an upright mounting position with the nacelle in a mounting position for mounting the blades to the nacelle, and the third assembly station is configured for supporting the lower tower part in an upright mounting position, such that the combined upper tower part, nacelle and blades can be lifted and lowered, preferably using a mounting crane, and the upper tower part is mounted to the lower tower part in the third assembly station to provide an assembled wind turbine.

11. Vessel according to one or more of the claims 7-10, wherein the vessel further comprises a blade handling device, preferably located near the second wind turbine assembly station, e.g. at the base of a mounting crane, for transporting the blades between a horizontal supply position and a fastening position adjacent to the nacelle on a tower top or upper tower section, preferably supported in the second assembly station.

12. Vessel according to one or more of claims 7-11, wherein the vessel comprises a base restraint system, preferably when the wind turbine is lowered onto the base, the base restraint system being configured for engaging the floating base to reduce the movement of the floating base relative to the vessel, more particularly to reduce the movement of the floating base relative to an assembled wind turbine to be mounted on the floating base, and/or to monitor the movement of the floating base relative to the vessel, more particularly to monitor the movement of the floating base relative to an assembled wind turbine to be mounted on the floating base.

13. Vessel according to one or more of claims 7-12, wherein the wind turbine mounting crane is configured to actively compensate for sea-state induced movements, such as horizontal displacements, of the assembled wind turbine relative to the foundation, in particular the floating foundation, to which the wind turbine is to be lowered.

14. Vessel according to one or more of claims 7-13, wherein the vessel further comprises a tower receiving well, preferably sunk into or through the hull at least one wind turbine assembly station or alternatively a wind turbine assembly station, and wherein the tower receiving well is configured to receive at least a part of the tower of the wind turbine therein, preferably using a wind turbine mounting crane, such that the distance between the nacelle and the storage deck is reduced, preferably less than the length of a wind turbine blade, more preferably less than four fifths of the length of the blade, in order to facilitate mounting the blade to the nacelle.

15. Vessel according to one or more of the claims 7-14, wherein the vessel comprises a nacelle support, which is fixed to the deck of the vessel such that the nacelle can be supported by the nacelle support at a distance above the deck, preferably a distance of less than the length of a turbine blade, more preferably less than four fifths of the length of a blade, such that the blade can be mounted to the nacelle, preferably by using a blade handling device.

16. Method for assembling a wind turbine on a wind turbine assembly vessel, preferably for mounting an assembled wind turbine on a foundation, such as a semi-submersible crane vessel, using a wind turbine assembly vessel, such as a subsea installation foundation or a floating foundation, and preferably using a wind turbine installation vessel according to one or more of claims 7-15,

Wherein the wind turbine assembly vessel comprises:

-a floating hull;

-at least one wind turbine assembly station;

the method comprises the following steps:

-using a mounting crane to:

-performing one or more assembly steps, for example by erecting a wind turbine tower or by lifting a nacelle onto the top of the tower or onto an upper tower part;

-supporting the assembled wind turbine on an assembly side and arranging the assembled wind turbine from the assembly station to a mounting position above the wind turbine foundation adjacent the vessel on a mounting side of the mounting crane;

-lowering the assembled wind turbine onto the foundation.

17. A method according to claim 16, wherein the method further comprises a wind turbine assembly step of lifting the nacelle and lifting the nacelle onto the tower or upper tower part using a wind turbine mounting crane, and mounting the nacelle on the tower or upper tower part.

18. A method according to claim 16 or 17, wherein the method further comprises the following wind turbine assembly steps: before or after mounting the nacelle on the tower or upper tower part, the section of the tower or upper tower part is lowered into a tower receiving well using a wind turbine mounting crane, the tower receiving well being submerged into or through the hull and configured to receive at least a portion of the tower of the wind turbine therein such that the distance between the nacelle and the storage deck is reduced, preferably less than the length of a wind turbine blade, more preferably less than four fifths of the length of the blade.

19. Method according to one or more of claims 16-18, wherein the method further comprises a wind turbine assembly step of arranging the tower or upper tower part in an upright mounting position, wherein the nacelle is mounted on the tower or upper tower part, wherein the nacelle, in particular a hub of the nacelle, is in a mounting position for mounting the blade to the nacelle, preferably in a horizontal position.

20. Method according to one or more of claims 16-19, wherein the method further comprises a blade mounting procedure for mounting the blade to the nacelle, preferably using a blade handling device, the blade mounting procedure comprising one or more, preferably all, of the following steps;

21. A method according to claim 20, the nacelle being mounted on a nacelle support fixed to the deck of the vessel such that the nacelle is supported by the nacelle support at a distance above the deck, preferably less than the length of the turbine blades, more preferably less than four fifths of the length of the blades.

22. A method according to one or more of claims 16-21, wherein the method further comprises a wind turbine assembly step of arranging the upper tower part on the lower tower part using a mounting crane, preferably after mounting the nacelle on the upper tower part, in case the tower consists of the lower tower part and the upper tower part.

23. The method of one or more of claims 16-22, wherein the method further comprises erecting a tower or upper tower component of the wind turbine from a horizontal storage position to an upright installation position using a wind turbine installation crane.

24. Method according to one or more of claims 16-23, wherein at least one wind turbine assembly rig is a first wind turbine assembly rig on a first side of the installation crane, preferably opposite the installation side of the installation crane, and the vessel further comprises a second wind turbine assembly rig on a second side of the installation crane, and wherein

the second assembly station is used for completing the assembly of the wind turbine, preferably with a mounting crane, e.g. in case the tower consists of a lower tower part and an upper tower part, arranging the upper tower part on the lower tower part with the mounting crane, and/or for mounting the blade to the nacelle; and wherein

25. Method according to one or more of claims 16-24, wherein at least one wind turbine assembly station is a first wind turbine assembly station located on a first side of the installation crane, preferably opposite the installation side of the installation crane, the vessel further comprising a second wind turbine assembly station located on a second side of the installation crane, and the vessel further comprising a third wind turbine assembly station located on a third side of the installation crane, preferably opposite the second side of the installation crane, and wherein

-a second assembly station for mounting the blade to the nacelle; and

a third assembly station for completing the assembly of the wind turbine, e.g. arranging an upper tower part provided with nacelle and blades on the lower tower part in case the tower consists of the lower tower part and the upper tower part, and/or for mounting the nacelle provided with blades on the tower; and wherein

26. Method according to one or more of claims 16-25, wherein the wind turbine mounting crane is configured to actively compensate for sea-state induced movements, such as horizontal displacements, of the assembled wind turbine relative to a foundation, in particular a floating foundation, to which the wind turbine is to be lowered, the method comprising

27. The method according to one or more of claims 16-26, wherein the vessel is provided with a base restraint system, the method comprising:

-engaging the floating base with a base restraint system;

28. Method for assembling a wind turbine on a wind turbine assembly vessel, preferably for installing an assembled wind turbine using a wind turbine assembly vessel, preferably according to one or more of claims 16-27,

wherein the wind turbine assembly vessel comprises:

-a floating hull;

the method comprises the following steps:

-storing wind turbine components, such as wind turbine upper tower components, wind turbine lower tower components, nacelle and blades, on a wind turbine component storage deck, preferably on a wind turbine component storage deck of a wind turbine component storage area;

in the first assembly station, the nacelle is lifted onto said upper tower part, preferably using a handling crane, and the nacelle is mounted,

29. Method for assembling a wind turbine on a wind turbine assembly vessel, preferably for installing an assembled wind turbine using a wind turbine assembly vessel, preferably according to one or more of claims 16-27,

Wherein the wind turbine assembly vessel comprises:

-a floating hull;

the method comprises the following steps:

30. Method for assembling a wind turbine and for mounting an assembled wind turbine on a foundation, preferably a method according to one or more of claims 16-27, such as a foundation mounted on the seabed or a floating foundation, wherein a semi-submersible crane vessel is used, wherein the vessel comprises:

-a floating hull having:

-a deckbox structure;

two pontoons in parallel and one with each other,

wherein the deck box structure is provided with a deck and a box bottom,

Wherein the assembled wind turbine to be mounted comprises at least a part of a wind turbine tower and a rotor assembly mounted on the tower, e.g. a nacelle with a hub, the rotor assembly optionally being provided with one or more, e.g. all, rotor blades,

in the method, at least a portion of the tower is arranged in the tower receiving well during an assembly step of the wind turbine, e.g. during mounting of the rotor assembly on the tower and/or during assembly of one or more, e.g. all, rotor blades to the rotor assembly.

31. Use of a vessel according to one or more of claims 7-15, preferably for performing the method according to one or more of claims 16-30, for assembling and installing a wind turbine, preferably for assembling and installing a plurality of wind turbines to provide a wind farm.