Method and apparatus for assembling a plurality of floating wind turbines

Abstract

A method and installation for assembling a plurality of floating wind turbines (12). The method comprises establishing an installation by arranging an installation vessel (1) with a crane (4) at a sheltered site and mooring a barge (2) adjacent to the vessel (1). Further, a plurality of turbine blades (6), a plurality of tower segments (8) and a plurality of nacelles (10) are transported to the installation and hoisted onto the installation. Further, a first floating wind turbine foundation component (11a) is towed to the installation, a tower (8a) is erected on the first foundation component (11a) by assembling a set of the tower segments (8), a nacelle (10) is mounted on top of the tower (8a), a set of turbine blades (6) is mounted on the nacelle (10) to form a complete wind turbine (12a), and finally the first wind turbine (12a) is towed away.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method and an arrangement for assembling a wind turbine on a floating foundation as defined in the appended claims. BACKGROUND

[0002] In the prior art, wind turbines are either assembled individually at the installation site, or assembled at a quay and transported to the installation site. In the case where the wind turbines are assembled at a quay and transported to the installation site, a plurality of wind turbines can be transported to the installation site by the same ship.

[0003] An example of the first type of technology is shown in CN101429928B, where a barge is used to transport the wind turbine and a crane ship lifts the turbine from the barge onto the foundation.

[0004] An example of the latter type of technology is shown in WO2019100909A1, where a plurality of assembled turbines are arranged on a gantry of a ship and transported to the installation site, where they are lifted out to sea.

[0005] WO2019245366 describes an installation apparatus and method for installing a wind turbine at an installation site. This requires a ship to be designed for use at open sea, and such installation can only be performed during calm weather. These factors will increase the cost and shorten the weather window.

[0006] EP2597027 also describes an installation apparatus for assembling a wind turbine at an installation site. Since the wind turbine is a floating turbine, the installation ship is equipped with a gripping portion attached to the floating foundation.

[0007] Other prior art examples are in GB2225365B, CN101565091B, CB106014874B, JP1985208512A, CN110173397A, GB2479232A, JP5189050B2, CN102092645, WO2018074923, US2014317927, US2019186465, EP2724021, and CN104192272A.

[0008] The on-site individual assembly method is a slow and laborious process, and is not suitable for installing a plurality of wind turbines. The barge must travel back to the port to pick up the next turbine. At the same time, the crane ship will be idle, waiting for the barge to return.

[0009] Transporting a plurality of assembled wind turbines to the installation site or area is more efficient, but such transport requires a special ship capable of transporting assembled wind turbines.

[0010] With the increasing demand for renewable energy, ocean-based wind turbines have become an increasingly viable source of energy. It is therefore not feasible to build wind turbines one after the other today. This is too inefficient and expensive. There is therefore a need for new methods and devices that are both efficient and do not require specially constructed ships, but can use standard barges, transport ships and crane ships for the operation. SUMMARY

[0011] The main object of the present invention is to provide a method and device that allows for a continuous serial production of complete floating wind turbines.

[0012] Another object is to reduce the cost and construction time.

[0013] With the new method of the present invention, the serial production of wind turbines can take place without having to wait for any related ships for a large amount of time. BRIEF DESCRIPTION OF DRAWINGS

[0014] The present invention will now be described in connection with the illustrative and example embodiments shown in the drawings, in which:

[0015] Figure 1 An installation ship and a barge to be used as permanent installation devices during assembly of a wind turbine are shown,

[0016] Figure 2 A first feeding ship moored at the installation device is shown,

[0017] Figure 3 A wind turbine blade that has been loaded from the first feeding ship to the barge is shown,

[0018] Figure 4 A second heavy lift feeding ship that has arrived together with a tower section is shown,

[0019] Figure 5 A part of the tower section that has been lifted from the second feeding ship onto the installation ship is shown in the tower section,

[0020] Figure 6 A third feeding ship that has arrived together with a nacelle is shown,

[0021] Figure 7 The nacelle being unloaded is shown,

[0022] Figure 8 A first base part that has arrived at the installation device is shown,

[0023] Figure 9 a tower erected on the first foundation part is shown,

[0024] Figure 10 a further unloading of the tower segment is shown,

[0025] Figure 11 a nacelle already mounted on the first wind turbine is shown,

[0026] Figure 12 a blade mounted on the first wind turbine is shown,

[0027] Figure 13 a first wind turbine being towed away and a second foundation part arriving are shown,

[0028] Figure 14 a tower erected on the second foundation part is shown,

[0029] Figure 15 a second wind turbine already completed is shown,

[0030] Figure 16 a tower already erected on the third foundation part is shown,

[0031] Figure 17 a third wind turbine already completed is shown,

[0032] Figure 18 a tower already erected on the fourth foundation part is shown,

[0033] Figure 19 a fourth wind generator already completed is shown,

[0034] Figure 20 a first supply vessel returning to the installation site is shown,

[0035] Figure 21 a third supply vessel returning to the installation site is shown,

[0036] Figure 22 a second supply vessel returning to the installation site, and

[0037] Figure 23 a fifth wind turbine already completed is shown. DETAILED DESCRIPTION

[0038] The exemplary embodiments of the present invention are shown as a series in Figures 1 to 23 As a first step of the method, the installation vessel 1 and the barge 2 are brought to a sheltered area, such as a fjord or a bay having sufficient depth.

[0039] The barge 2 is moored using anchors (not shown) and the installation vessel 1 is positioned adjacent to the barge 2 as shown in Figure 1 The installation vessel 1 is preferably of the jack-up type, with jack-up legs 3. The jack-up legs 3 are lowered to the seabed to support the vessel 1 in a fixed position above the water surface.

[0040] The installation vessel is equipped with a crane 4 with sufficient lifting capacity to lift the heavy components of the wind turbine.

[0041] With the installation vessel 1 and the barge 2 in the fixed position, a first feeder vessel 5 arrives with a pile of turbine blades 6. The feeder vessel 5 is moved adjacent to the barge 2 and moors to this barge 2 at the opposite side of the installation vessel 1 as shown in Figure 2 The blades 6 are housed within frames, cages or boxes, so that the blades can be stacked on the deck of the feeder vessel 5. In the following, the frames, cages or boxes will be referred to as cages.

[0042] The crane 4 then lifts the blades 6 from the feeder vessel 5 and lifts them onto the barge 2 as shown in Figure 3 The barge can not have enough space for all the blades. In this case, some of the blades will remain on the feeder vessel until enough blades are assembled to the wind turbine to free up space. When all the blades have been unloaded from the first feeder vessel, the feeder vessel 5 is free to return to the harbour and pick up new items.

[0043] Next, a second heavy lift feeder vessel 7 arrives with tower sections 8. The heavy lift feeder vessel is moved adjacent to the installation vessel 1 and moors to this installation vessel 1 at the opposite side of the barge 2 as shown in Figure 4

[0044] The tower sections 8 are then lifted from the heavy lift feeder vessel 7 and lifted onto the deck of the installation vessel 1 as shown in Figure 5 The tower sections 8 can have different lengths depending on their position in the assembled tower. Since the installation vessel 1 can not have enough space to accommodate all the tower sections 8, some of the tower sections 8 can remain on the second heavy feeder vessel 7. During the transfer of the tower sections 8, a pair of towers 8a (this can range from one tower 8a to all towers 8a depending on the available space) is erected on the deck of the installation vessel in assembled state.

[0045] In a next step, a third feeder vessel 9 arrives with a load of nacelles 10. This can be done while the second heavy lift feeder vessel 7 is still moored adjacent to the installation vessel 1. As from Figure 6 ​As can be seen, the barge 2 is arranged slightly displaced along the installation vessel 1, leaving a gap at a part of the side of the installation vessel 1 for the third supply vessel 9 to dock and to moor adjacent to the installation vessel 1.

[0046] As shown in Figure 7 , the gondolas 10 are now lifted from the third supply vessel 9 and onto the deck of the installation vessel 1. Like the first and second supply vessels, there can not be enough space on the installation vessel 1 (or the barge 2) for all gondolas. In this case, some of the gondolas will remain on the supply vessel until enough space is freed on the installation vessel. Then, the third supply vessel is free to leave to pick up additional items.

[0047] With all parts of the wind turbine now arranged on the installation vessel 1, the barge 2 and possibly the second supply vessel 7, the first floating foundation part 11a is moved adjacent to the installation vessel 1. Preferably, this is done by two tug boats (not shown). Winches (not shown) on the installation vessel 1 are used to pull the foundation part 11a close to the installation vessel 1 and to hold it in place.

[0048] Now, the assembly of the wind turbine is ready to start. One of the assembled tower sections 8a is lifted by the crane 4 and onto the foundation part 11a where it is to be fixed, as shown in Figure 9 .

[0049] As the space for the first tower section 8a to be arranged on the installation vessel 1 is freed, further tower sections 8 can be lifted from the second supply vessel 7 to the free space on the installation vessel 1, as shown in Figure 10 .

[0050] Now, the gondolas 10 are mounted on top of the tower section 8a, as shown in Figure 11 . The crane 4 can continue to assemble tower sections into a new tower 8b, as long as this new tower 8b is not involved in the assembly operation of the wind turbine on the foundation part 11a, as shown in Figure 11 .

[0051] In a next step, blade grippers (not shown) are attached to the hooking part of the crane 4. Then, the first blade 6 is lifted directly from its cage on the barge 2 and attached to the gondola 10. The same steps are repeated for the next two blades 6.

[0052] When the crane is idle, it can be used to lift empty cages for the storage of blades 6 to the free space on the deck of the installation vessel 1.

[0053] After the functionality of the wind turbine has been tested, i.e. after the nacelle has been rotated, the first base part 11a with the assembled turbine 12a can be towed away and towed to the installation site or to an interim storage area to await installation.

[0054] The new base part 11b can now be towed to the place where the first base part 11a was, as shown in Figure 13 .

[0055] In Figure 14 , the second tower 8b has been lifted from the installation vessel 1 onto the second base part 11b and fixed to the second base part 11b. During the idle phase after the tower 8b has been removed from the installation vessel 1, the remaining tower segments 8 are lifted from the second feeding vessel 7 and assembled to the third tower 8c on the installation vessel 1. When the last tower segment 8 is removed from the feeding vessel 7, the feeding vessel 7 is free to leave and return to the harbour to pick up new items, see Figure 15 .

[0056] Now, the second turbine 12b is completed assembled in the same way as the first turbine 12a, and after testing, the turbine 12b will be towed to the installation site or to an interim storage area.

[0057] The third base part 11c is towed to a position adjacent to the installation vessel 7, and the third tower 8c is fixed on this third base part 11c, as shown in Figure 16 . Then, the nacelle 10 and the blades 6 are installed in the same way as described above, until the third turbine 12c is completed, as shown in Figure 17 .

[0058] During the idle phase, the crane 4 is used to assemble yet another tower 8d from the tower segments 8 that have been placed on the deck of the installation vessel 1.

[0059] Figure 18 The fourth base part 11d is shown, where the fourth tower 8d is fixed on the fourth base part 11d.

[0060] Figure 19 The completed fourth turbine 12d is shown. During the idle phase, the crane 4 builds a fifth tower 8e from the remaining tower segments 8 (see Figure 18 ).

[0061] The barge 2 is now empty, and the first feeding vessel 5 returns with new blades 6, as shown in Figure 20 . These new blades 6 are lifted onto the barge 2, while the empty blade cages are lifted from the installation vessel 1 to the first feeding vessel 5. Then, the first feeding vessel leaves. The fourth turbine 12d is now completed, and after testing will be towed to the installation site or to an interim storage location.

[0062] As Figure 21 shown in Fig. 6, the third feeder vessel 9 returns with new nacelles 10. These new nacelles 10 are hoisted onto the installation vessel 1, as shown in Fig. 7. After this, the third feeder vessel leaves. Figure 22

[0063] The fifth base part 11e is towed to the installation vessel 1 and moored thereto, and the fifth tower 8e is hoisted onto the fifth base part 11e and fixed thereto. At the same time, the second heavy-lift feeder vessel 7 returns with new tower segments 8. When the crane 4 is not busy assembling the fifth turbine 12e, some of the new tower segments are hoisted onto the installation vessel 1.

[0064] When the fifth turbine 12e is tested and found to be in working order, it is towed away, and the process continues so that further base parts are towed one after the other to a position adjacent to the installation vessel. The assembly and installation of further wind turbines takes place in the same way as described above until the desired number of complete wind turbines has been produced.

[0065] In the above-described method, a crane vessel is used which does not have sufficient deck space for all tower segments, so that some tower segments have to remain on the second feeder vessel. With a somewhat larger crane vessel, it is of course possible to unload all tower segments from the feeder vessel, and thus the feeder vessel can be vacated earlier.

[0066] An important result of the invention is that the installation equipment does not have to wait for new components to arrive, but can continuously assemble wind turbines. The feeder vessels should therefore be released from their load early enough to be able to turn again towards the port and return with new supply components in time for the needs of the feeder vessels.

[0067] In the above example, three feeder vessels are used. If the travel time between the port and the installation equipment is short, two feeder vessels can be sufficient.​

Claims

1. A method for assembling multiple floating wind turbines, the method comprising the following steps: a. An installation facility is established by deploying an installation vessel equipped with a crane in a concealed location and by mooring a barge adjacent to the installation vessel. b. Transporting multiple turbine blades to the installation equipment via a first delivery vessel. c. Using the crane to lift the turbine blades onto the mounting equipment. d. Multiple tower sections are transported to the installation equipment by a second heavy-duty lifting and feeding vessel. e. Using the crane to lift at least some of the plurality of tower sections onto the installation equipment. f. Transporting multiple pods to the installation equipment via a third delivery vessel. g. Using the crane to lift the pod onto the installation equipment. h. Towing the first floating wind turbine base component to the installation equipment. i. Using the crane, the tower, obtained by assembling a set of the tower sections, is erected on the first floating wind turbine base. j. Use the crane to install the pod on top of the tower. k. Using the crane, a set of turbine blades is installed on the pod to form a complete first wind turbine. l. Tow away the first wind turbine to provide space for the second floating base component at the location where the first wind turbine was assembled; The turbine blades are transported in a frame, cage, or box, and are then lifted onto the barge. The method further includes: when the decks of the barge and the installation vessel do not have sufficient space, lifting some turbine blades from the turbine blades onto the barge, lifting some tower sections from the tower sections onto the deck of the installation vessel, and lifting some pods from the pods onto the deck of the installation vessel, such that the remaining turbine blades from the turbine blades, the remaining tower sections from the tower sections, and the remaining pods from the pods are respectively retained on the first delivery vessel, the second heavy lifting delivery vessel, and the third delivery vessel.

2. The method according to claim 1, wherein, The installation vessel is a jack-up vessel, and the arrangement of the installation vessel includes using jack-up legs to lift the installation vessel from the sea surface.

3. The method according to claim 1 or 2, wherein, When the crane is not busy assembling the wind turbine onto the base components, it is used to erect the tower on the installation vessel.

4. A wind turbine installation apparatus comprising an installation vessel equipped with a crane and a barge, the installation vessel being a self-elevating vessel, wherein the installation vessel is raised from the sea surface and positioned in a concealed location by using its self-elevating legs, and the barge is moored atop the installation vessel, wherein... The installation equipment has deck space for receiving components sufficient to assemble multiple wind turbines, and is characterized by its ability to moor floating base components adjacent to the installation vessel, on which the wind turbines can be assembled. Turbine blades, tower sections, and pods are transported to the installation equipment via a first feeder, a second heavy-lift feeder, and a third feeder, respectively. In cases where the decks of the barge and the installation vessel lack sufficient space, some turbine blades are lifted onto the barge, some tower sections are lifted onto the deck of the installation vessel, and some pods are lifted onto the deck of the installation vessel, such that the remaining turbine blades, remaining tower sections, and remaining pods are retained on the first feeder, the second heavy-lift feeder, and the third feeder, respectively.

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