Method for mass producing floaters for offshore wind turbines

Abstract

The method of the present invention comprises the continuous production of floats on a final assembly line, including the manufacturing of mega-blocks on a dedicated construction area, the transport of the mega-blocks (B-1, B-2) by sea and their storage in different storage zones (Z-1, Z-2) of a production area (10) separate from the construction area and equipped with a loading dock (12), and the preparation of the mega-blocks for each float in their storage zones, the assembly and primary welding of the float's mega-blocks in an assembly and primary welding zone (Z-3) of the production area separate from and adjacent to the storage zones, the final welding of the mega-blocks in a final welding zone (Z-4) of the production area, and the completion of the float in a completion zone (Z-5) of the production area separate from the other zones of the production area. The mega-blocks and floats of the floats being manufactured are moved between the various zones on the production area, mainly by translational movements.

Description

[Technical Field]

[0001] The present invention relates to the general field of floaters for offshore wind turbines, and more particularly to a method for mass producing such floaters. [Background technology]

[0002] The purpose of an offshore wind turbine is to harness the energy of the wind to generate electricity through a turbine and generator. There are two main types of offshore wind turbines: bottom-fixed wind turbines, which are installed on the seabed (typically at shallow depths of less than 50 m), and floating wind turbines, which have the advantage that they can be constructed on land and installed in areas where the seabed depth is typically greater than 50 m.

[0003] The floating wind turbine to which the present invention relates comprises a turbine generally formed by a motor having several rotating blades with a horizontal axis and a generator coupled to the motor, the motor and generator being fixed to the upper end of a vertical mast (or pylon).

[0004] The lower end of the mast is attached to a floating support structure (hereinafter referred to as a float). There are various types of floats, such as semi-submersible floats (with or without a pendulum counterweight), submersible floats with tension cables ("tension leg platforms (TLPs)"), SPAR (single point anchor reservoir) floats, and "barge" type semi-submersible floats. For example, Patent Document 1 describes a floating support structure whose main structure has a toroidal or polygonal shape. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 106283 Summary of the Invention [Problem to be solved by the invention]

[0006] Offshore wind turbines are usually grouped into "wind parks" (parc eolien) or "wind farms" (ferme eolienne), which typically consist of 20 to 50 turbines of several megawatts each.

[0007] In floating offshore wind park development projects, the delivery schedule of the floaters is a key factor for successfully delivering a large-scale offshore wind park within the limited installation period. In addition, the ability to guarantee local production of the floaters is of utmost importance, but the available land area for assembly of the floaters is generally a major obstacle.

[0008] Therefore, there is a need for a method for mass-producing floaters for offshore wind turbines that requires only a small land area. [Means for solving the problem]

[0009] According to the invention, this object is achieved by a method for mass-producing floating bodies for offshore wind turbines, in which each floating body consists of an assembly of 2 to 6 unit megablocks made of steel, the method comprising: fabricating a plurality of steel mega blocks on a dedicated construction area with a loading dock; transporting megablocks coming from the construction area by sea and storing them in a different storage zone in the production area with a loading dock, separate from the construction area, and storing megablocks of the same floating body in the same storage zone in the production area; and manufacturing the floats in a final assembly line, the manufacturing process comprising the steps of: for each float, preparing mega-blocks in their storage zone; assembling and primarily welding the mega-blocks of the float in an assembly and primary welding zone in a production area separate from and adjacent to the storage zone; followed by final welding of the mega-blocks in a final welding zone in the production area separate from other zones in the production area; followed by completing the float in a completion zone in the production area separate from other zones in the production area; The floating megablocks and floating bodies under construction are moved between the various zones on the production area, mainly by translational movements.

[0010] This method is noteworthy in that it allows for the assembly-line production of floaters for offshore wind turbines on a very limited land area from prefabricated mega-blocks on a construction area different from (possibly remote from) the production area. Indeed, the arrangement of the different zones of the production area relative to each other and the sequence of the successive floater production steps make it possible to significantly limit the footprint of the production process while enabling a high production rate for at least two mega-block assembly operations. Furthermore, since the movement of the different floater elements occurs mainly by translational movements (rather than by lifting), the method according to the invention is very easy to carry out using standard handling means (without heavy lifting means) and requires only a limited number of skilled workers.

[0011] In addition, being very easy to implement, the method according to the invention allows both maximizing the use of local resources with short staff training sessions and minimizing the carbon impact on the environment with mobile / reusable assets and selected energy supplies. The method according to the invention can be implemented temporarily at any location near the wind park and moved to other areas depending on the project location.

[0012] Preferably, manufacturing the float body on a final assembly line further comprises loading the completed float body onto a transport barge moored at the loading dock by transport means or by launching the completed float body by sliding it down an inclined plane, in which case the method may further comprise integrating a wind turbine mast and turbine with the float body following loading of the float body onto the transport barge.

[0013] The step of transporting the megablocks from the construction area to a storage zone in the production area may be performed by a transport vessel. Also preferably, the step of completing the float is followed by a step of removing and repairing any float identified as having a manufacturing defect, the removal and repair step being carried out in a buffer zone of the production area adjacent to the completion zone and separate from other zones of the production area.

[0014] The assembly and primary welding zone, the final welding zone and the completion zone are advantageously located between two storage zones to the side of the production area. The assembly and primary welding zone, the final welding zone, and the completion zone are preferably longitudinally spaced from one another, with the completion zone adjacent to an input dock of the production area.

[0015] Float megablocks and floats in production may be moved between various zones of the construction area by multi-wheeled transport vehicles or slides. The various steps of the production method are advantageously monitored (eg, using video surveillance cameras, scanners, etc.).

[0016] More preferably, the method further comprises establishing traceability of the megablocks of the float and the various equipment used to manufacture the float. Each float may be formed by assembling three unit mega-blocks made of steel: a first unit mega-block comprising a central strut intended to receive the mast of a wind turbine, outer struts and a lower pontoon between the central and outer struts, and two second identical unit mega-blocks each comprising an outer strut and a lower pontoon. [Brief explanation of the drawings]

[0017] [Figure 1] 1 shows an example of various unit megablocks of a semi-submersible floating body to which the production method according to the present invention is applied. [Figure 2] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 3] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 4] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 5] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 6] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 7] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 8] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 9] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 10] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 11] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 12] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 13] 1 illustrates steps in a method for mass producing a semi-submersible floating body according to the present invention. [Figure 14]1 is a schematic perspective view of an installation for carrying out the production method according to the invention; DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention relates to mass assembly line production of floaters, particularly semi-submersible floaters, for offshore wind turbines. The floating structure to which the present invention is applied has the feature that it can be manufactured by assembling two to six steel unit mega-blocks.

[0019] In the application example described below, as shown in Figure 1, each floating body 2 comprises four struts, including a central strut 4 intended to receive a wind turbine mast, and three outer struts 6 connected to the central strut by lower pontoons 8.

[0020] In practice, each such floating body 2 may be formed by assembling three steel mega-blocks, namely a first mega-block B-1 comprising a central strut 4, outer struts 6 and lower pontoons 8, and two identical mega-blocks B-2 each comprising an outer strut 6 and lower pontoons 8.

[0021] For example, for a 15 megawatt wind turbine, a B-1 megablock may have a minimum length of 50m and a minimum height of 25m, and a B-2 megablock may have a minimum length of 25m and a minimum height of 25m.

[0022] Of course, the invention also applies to other types and shapes of floating bodies, which are formed by assembling two (minimum) to six (maximum) steel unit megablocks. A preliminary step in the method for mass-producing such floating bodies consists of manufacturing the various mega-blocks B-1, B-2 that will be required for the subsequent production of the floating bodies. This manufacturing takes place in a dedicated construction area (not shown), which is equipped with a loading dock and which is separate (possibly remote) from the production area where the floating bodies are produced. This mass manufacturing of mega-blocks consists of assembling and welding steel plates to form the various mega-blocks required for the production of the floating bodies.

[0023] The method for mass-producing floating bodies requires a land-based production area 10 that can accommodate the various elements and equipment required for the construction of the floating bodies. This production area 10 is separate from the construction area where the steel mega-blocks are manufactured.

[0024] Advantageously, this onshore production area 10 can be relatively compact (typically not exceeding 100,000 square metres (10 ha)) and can include a loading dock 12 (typically having a length of 300-800 m).

[0025] The initial step of the mass production method according to the invention (FIG. 2) consists of transporting the various unit mega-blocks B-1, B-2 from the construction area to the production area by means of a transport ship 14 docked at the loading dock 12.

[0026] The mega-blocks B-1, B-2 are preferably unloaded from the transport barge 14 into the production area 10 (FIG. 3) by a multi-wheeled transport vehicle 16 pre-positioned for this purpose. Alternatively, the mega-blocks may be unloaded by ripage, ie, sliding (eg, pulling or pushing a concrete mega-block).

[0027] Floating megablocks belonging to the same category are stored in the same storage zone. Thus, as shown in Figure 4, megablock B-1 is transported and stored in the same first storage zone Zl in the production area, and megablock B-2 is transported and stored in a second storage zone Z-2 in the production area, which is different from the first storage zone Zl.

[0028] Advantageously, the storage zones Z1, Z-2 are arranged along two opposite side edges 18a, 18b of the production area 10, forming a central assembly zone between them. The assembly line production of the final float may begin with a preliminary step consisting of preparing the float unit megablocks, i.e. performing machining, surface finishing, geometric measurements, etc. on the floats. This preparation step takes place in storage zones Z1 and Z-2.

[0029] The final production of each floater continues with the step of assembly and primary welding of the various mega-blocks B-1, B-2 that make up the same floater. This step of assembly and primary welding consists of securely connecting the mega-blocks to one another. This operation is carried out using specific work tools (not shown) and is carried out in an assembly and primary welding zone Z-3 in a production area separate from but adjacent to the storage zones Z-1, Z-2.

[0030] In practice, as shown by way of example in Figures 5 to 7, a first megablock B-1 of the float is transported by a multi-wheeled transport vehicle 16 or a slide to the assembly and primary welding zone Z-3 (Figure 5). Then, a first megablock B-2 of the float is transported to the assembly and primary welding zone (Figure 6), followed by a second megablock B-2 identical to the first megablock B-2 (Figure 7). The megablocks are then assembled together, followed by a first welding pass to secure their connection.

[0031] The float assembled by the primary welding is then moved from the assembly and primary welding zone Z-3 to the adjacent final welding zone Z-4, which is separate from the other zones Z1 to Z-3. This movement is carried out by a multi-wheeled transport vehicle 16 or by sliding (Fig. 8).

[0032] In this final welding zone Z-4, the various megablocks that make up the floating body undergo a new welding pass (Fig. 9) using specific work tools (not shown). In parallel with this final welding step, other mega-blocks B-1 and B-2 that will constitute another floating body are transported to the vacant assembly and primary welding zone Z-3.

[0033] In the next step (Fig. 10), the float thus assembled and with the megablocks welded together is transported (by multi-wheeled transport vehicle or by sliding) to a separate completion zone Z-5, adjacent to the final welding zone Z-4, separate from the other zones in the production area.

[0034] The completion step of this floater consists of finishing the floater by final inspection of the welds, application of anti-corrosion coatings to the welds, installation and removal of various equipment on the floater, final closure of the various access points, etc.

[0035] In parallel with this completion step, the float assembled in the assembly and primary welding zone Z-3 is transported to the vacant final welding zone Z-4, while the other mega-blocks B-1 and B-2 that will make up another float are transported to the vacant assembly and primary welding zone Z-3.

[0036] Advantageously, if the completion step reveals that the float has manufacturing defects, this step can be followed by a step of removing and repairing the float. This removal and repair step takes place in a buffer zone Z-6 in the production area, separate from the other zones Z-1 to Z-5 and adjacent to the completion zone Z-5 (Figure 11).

[0037] For example, advantageously, an assembly and primary welding zone Z-3, a final welding zone Z-4, and a completion zone Z-5, which is located in close proximity to the loading dock 12 of the production area, are arranged between the two zones Z1 and Z-2, in that order from the deepest to the deepest in the longitudinal direction. With such a spatial configuration, the buffer zone Z-6 is advantageously arranged along one of the side edges of the production area 10 (i.e., side edge 18a in the example shown in FIG. 11) and in close proximity to the loading dock 12.

[0038] It should be noted that buffer zones may be installed next to the assembly and primary welding zone Z-3 and / or the final welding zone Z-4, and these buffer zones are used to isolate the floater under construction in case of identified assembly defects so that repairs can be made without slowing down the floater's production speed.

[0039] As shown in Figure 12 (and in the perspective view of Figure 14), a transport barge 20 is moored at the loading dock 12 of the production area. The floats 2 placed in the completion zone Z-5 are then loaded onto the transport barge by transport means (sliding or lifting and rolling using multi-wheel trays). Alternatively, the floats may be launched by sliding down an inclined plane.

[0040] In Figure 13, the float 2 is loaded onto the transport barge 20, and the completion zone Z-5 is vacant. If the float 2' located in the buffer zone Z-6 has already been repaired, the float 2' may be transported to this completion zone Z-5. If the repair of this float 2' is not yet complete, the float located in the final welding zone Z-4 ​​is transported to the finishing zone Z-5 (at this time, other floats upstream in the production line will also be moved).

[0041] Following loading of the floating body 2 onto the transport barge 20, an additional step may be envisaged of integrating a wind turbine and mast (not shown) with the floating body. It should be noted that the floating mega-blocks and floating bodies under construction are moved between different zones of the construction area by multi-wheeled transport vehicles or slides, i.e. mainly following a translational movement. In particular, the method according to the invention does not involve any lifting operations of the floating mega-blocks or floating bodies under construction.

[0042] It should also be noted that the various steps of the production method are advantageously monitored in real time, for example using video surveillance cameras or scanners. It is also noted that the production method according to the invention advantageously includes establishing traceability of the floating body megablocks and the various pieces of equipment used in the manufacture of the floating body.

Claims

1. A method for mass-producing floating bodies (2) for offshore wind turbines, each of said floating bodies consisting of an assembly of 2 to 6 unit mega-blocks (B-1, B-2) made of steel, said method comprising the steps of: fabricating a plurality of steel mega blocks on a dedicated construction area with a loading dock; transporting by sea megablocks (B-1, B-2) coming from the construction area and storing them in different storage zones (Z-1, Z-2) of a production area (10) separate from the construction area and equipped with a loading dock (12), and storing megablocks of the same floating body in the same storage zone of the production area; manufacturing floats in a final assembly line, the manufacturing process comprising the steps of: for each float, preparing the mega-blocks in their storage zone; assembling and primarily welding the mega-blocks of the float in an assembly and primary welding zone (Z-3) of the production area, separate from and adjacent to the storage zone; followed by final welding of the mega-blocks in a final welding zone (Z-4) of the production area, separate from the other zones of the production area; followed by completing the float in a completion zone (Z-5) of the production area, separate from the other zones of the production area; A method in which the floating megablocks and floating bodies under construction are moved between various zones on the production area primarily by translational movements.

2. 10. The method of claim 1, wherein fabricating the float on a final assembly line further comprises loading the completed float onto a transport barge (20) moored to the loading dock (12) by means of transportation or by sliding the completed float down an inclined surface and launching it.

3. The method of claim 2 , further comprising integrating a wind turbine mast and turbine to the floating body subsequent to loading the floating body onto the transport barge.

4. The method according to any one of claims 1 to 3, wherein the step of transporting the mega-blocks from the construction area to the storage zone of the production area is performed by a transport ship (14).

5. 5. The method according to any one of claims 1 to 4, wherein the step of completing the floaters is followed by a step of removing and repairing floaters identified as having manufacturing defects, the removal and repair step being carried out in a buffer zone (Z-6) of the production area, separate from other zones of the production area and adjacent to the completion zone (Z-5).

6. 6. The method according to any one of claims 1 to 5, wherein the assembly and primary welding zone (Z-3), the final welding zone (Z-4) and the completion zone (Z-5) are located between two storage zones (Z-1, Z-2) on the sides of the production area.

7. 6. The method of claim 5, wherein the assembly and primary welding zone, the final welding zone, and the completion zone are longitudinally spaced apart from one another, and the completion zone (Z-5) is adjacent to the loading dock (12) of the production area.

8. The method according to any one of claims 1 to 7, wherein the floating megablocks and the floating bodies under construction are moved between the various zones (Z-1 to Z-6) of the construction area by means of a multi-wheeled transport vehicle (16) or by means of a slip.

9. The method according to any one of claims 1 to 8, wherein the various steps of the production method are monitored.

10. The method according to any one of claims 1 to 9, further comprising establishing traceability of the floating body megablocks and the various equipment used to manufacture the floating body.

11. 11. The method according to any one of claims 1 to 10, wherein each floating body is formed by assembling three unit mega-blocks made of steel: a first unit mega-block (B-1) comprising a central strut (4) intended to receive the mast of a wind turbine, outer struts (6) and a lower pontoon (8) between said central and outer struts, and two second identical unit mega-blocks (B-2), each comprising an outer strut (6) and a lower pontoon (8).

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