Method for the mass production of floats for offshore wind turbines

Abstract

A method for the mass production of floats (2) for offshore wind turbines each consisting of the assembly of two to six unit mega-blocks (B-1, B-2) made of steel, the method comprising, in succession, manufacturing mega-blocks on a dedicated construction zone, transporting the mega-blocks produced by the construction zone by sea and storing them in storage zones (Z-1, Z-2) of a production zone (10) distinct from the construction zone, the same mega-blocks being stored in one and the same storage zone, and finally mass-production of floats, this comprising, for each float, a step of preparing the mega-blocks, a step of assembling and primary-welding of the mega-blocks at an assembly and primary-welding zone (Z-3) distinct from the storage zones and adjacent thereto, followed by a step of final-welding of the mega-blocks at a final-welding zone (Z-4), followed by a step of completing the float at a completion zone (Z-5), the float mega-blocks and the floats in the process of being manufactured being moved between the different manufacturing zones using translational movements.

Description

Description Title of the invention: Method for mass production of floats for offshore wind turbines Technical Field

[0001] The invention relates to the general field of floats for offshore wind turbines. More specifically, it relates to a method for mass producing such floats. Prior art

[0002] An offshore wind turbine uses wind energy to generate electricity using a turbine and an electric generator. There are two main types of offshore wind turbines: fixed wind turbines, which are installed on the seabed (at shallow depths, typically less than 50m), and floating wind turbines, which offer the advantage of being able to be built on land and installed in areas where the seabed depth typically exceeds 50m.

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

[0004] The lower end of the mast is mounted on a floating support structure (called a "float"). There are different types of floats, namely semi-submersible floats (with or without pendulum counterweight), submerged floats with tensioned cables (or "TLP" platforms for "Tension-Leg Platform" in English), "SPAR" type floats (for "Single Point Anchor Reservoir"), semi-submersible "barge" type floats, etc. For example, we can refer to the publication WO 2019 / 106283 which describes a floating support structure whose main structure has a toroidal or polygonal shape.

[0005] Offshore wind turbines are most often grouped together in a "wind park" or "wind farm" generally comprising between 20 and 50 wind turbines with a unit power of several megawatts.

[0006] In floating offshore wind farm development projects, the floater delivery schedule is a key parameter for the successful delivery of large offshore wind farms within tight installation windows. Furthermore, the ability to secure local floater production is of utmost importance, but land space available for floater assembly is usually a major obstacle. Statement of the invention

[0007] There is therefore a need for a mass production process for floats for offshore wind turbines that requires only a small land area.

[0008] According to the invention, this aim is achieved by means of a method for the mass production of floats for offshore wind turbines, each consisting of the assembly of two to six individual steel mega-blocks, the method successively comprising: - the manufacture of a plurality of steel mega-blocks on a dedicated construction surface equipped with a loading dock; - the transport by sea of ​​mega-blocks from the construction area and their storage in different storage areas of a production area separate from the construction area and equipped with an unloading dock, the same mega-blocks of floats being stored in the same storage area of ​​the production area; - the final production line of floats comprising successively for each float, a stage of preparation of the mega-blocks at their level storage area, a step of assembly and primary welding of the float megablocks together at a primary assembly and welding area of ​​the production surface separate from the storage areas and adjacent to them, followed by a step of final welding of the megablocks together at a final welding area of ​​the production surface separate from the other areas of the production surface, followed by a step of completion of the float at a completion area of ​​the production surface separate from the other areas of the production surface; - the mega-blocks of floats and the floats being manufactured being moved on the production surface between the different zones of the latter mainly according to translational movements.

[0009] This process is remarkable in that it allows floats for offshore wind turbines to be manufactured in series on a very limited land area from mega-blocks prefabricated on a construction area separate (and possibly remote) from the production area. Indeed, the arrangement of the different areas of the production area in relation to each other and the sequence of successive stages of float manufacturing make it possible to considerably limit the footprint of the manufacturing process while allowing a high production rate linked to at least two operations of assembling mega-blocks together.Furthermore, because the movements of the various float elements are carried out mainly by translational movements (and not by lifting), the method according to the invention is very easy to implement with the use of standard handling means (without heavy lifting means) and a limited need for specialized labor.

[0010] Furthermore, due to its great simplicity of implementation, the method according to the invention makes it possible both to maximize local resources with the use of rapid staff training sessions, and to minimize the carbon impact on the environment with mobile / reusable assets and a selected energy supply. The method according to the invention can be implemented temporarily anywhere near wind farms, and be moved to other areas depending on the location of the projects.

[0011] Preferably, the final production line of floats further comprises loading the completed float onto a transport barge moored at the loading dock by means of transport or by launching the completed float into the water by sliding it onto an inclined plane. In this case, the method may further comprise, following the loading of the float onto the transport barge, integrating a mast and a wind turbine onto the float.

[0012] The step of transporting mega-blocks from the construction area to the storage areas of the production area can be carried out by means of transport vessels.

[0013] Also preferably, the step of completing the floats is followed by a step of removing and repairing a float that has been identified as having manufacturing defects, this step of removing and repairing being carried out at a buffer zone of the production area distinct from other areas of the production area and adjacent to the completion zone.

[0014] The assembly and primary welding, final welding and completion areas are advantageously located between two lateral storage areas of the production surface.

[0015] The primary welding, final welding, and completion assembly and welding areas are preferably spaced longitudinally from each other, with the completion area adjacent to the production floor loading dock.

[0016] Mega float blocks and floats being manufactured can be moved between different areas of the construction surface by multi-wheeled transport vehicles or by skidding.

[0017] The various stages of the production process are advantageously monitored (for example using video surveillance cameras, scanners, etc.).

[0018] More preferably, the method further comprises the establishment of traceability of the mega-blocks of floats and of the various equipment used for the manufacture of the floats.

[0019] Each float may be formed by assembling three unitary steel mega-blocks, namely: a first unitary mega-block comprising a central column intended to receive a wind turbine mast, an outer column and a lower pontoon between the central column and the outer column; and two second identical unitary mega-blocks each comprising an outer column and a lower pontoon. Brief description of the drawings

[0020] [Fig. 1] Figure 1 shows an example of different unit mega-blocks of a semi-submersible float to which the production method according to the invention is applied.

[0021] [Fig. 2] to [Fig. 13] Figures 2 to 13 represent different stages of a process for mass production of semi-submersible floats according to the invention.

[0022] [Fig. 14] Figure 14 is a schematic perspective view of the installation for implementing the production method according to the invention. Description of the embodiments

[0023] The invention relates to the mass and chain production of floats for offshore wind turbines, in particular semi-submersible type floats.

[0024] The floats to which the present invention applies have the particularity of being able to be manufactured by assembling two to six individual steel mega-blocks.

[0025] In the application example described below, each float 2 comprises, as shown in Figure 1, four columns including a central column 4 which is intended to receive a wind turbine mast and three external columns 6 which are connected to the central column by lower pontoons 8.

[0026] In practice, such floats 2 can each be formed by assembling three steel mega-blocks, namely: a first mega-block Bl comprising the central column 4, an outer column 6 and a lower pontoon 8, and two second identical mega-blocks B-2 each comprising an outer column 6 and a lower pontoon 8.

[0027] For example, for a 15 Megawatt wind turbine, the Bl mega-blocks can have a minimum length of 50m for a minimum height of 25m, and the B-2 mega-blocks can have a minimum length of 25m for a minimum height of 25m.

[0028] Of course, the invention applies to other types and other forms of floats, the latter having to be formed by the assembly of two (minimum) to six (maximum) unitary mega-blocks made of steel.

[0029] The preliminary step in the mass production process of such floats consists of manufacturing the various mega-blocks Bl, B-2 then required for the production of the floats. This manufacturing is carried out on a dedicated construction surface (not shown in the figures) which is equipped with a loading dock and which is separate (and can be remote) from the production surface on which the floats are produced. This mass production of mega-blocks consists of assembling and welding steel sheets to form the various unit mega-blocks required for the manufacture of the floats.

[0030] The mass production process for the floats requires a land-based production area 10 capable of accommodating the various components and equipment required for the manufacture of the floats. This production area 10 is separate from the construction area on which the steel mega-blocks are manufactured.

[0031] Advantageously, this production land area 10 may be relatively compact (typically not exceeding 100 m) and be provided with a loading dock 12 (typically having a length of between 300 and 800 m).

[0032] The initial step of the series production method according to the invention (figure 2) consists of transporting different unit mega-blocks B1, B-2 from the construction surface to the production surface by means of transport ships 14 which come to dock at the loading dock 12.

[0033] The mega-blocks Bl, B-2 are unloaded from the transport barges 14 preferably by multi-wheeled transport vehicles 16 pre-positioned for this purpose on the production surface 10 (figure 3).

[0034] Alternatively, the mega-blocks could be unloaded by skidding, i.e. by sliding (by pulling or pushing them onto concrete mega-blocks for example).

[0035] The mega-blocks of floats belonging to the same category are stored in the same storage area. Thus, as represented by Figure 4, the mega-blocks Bl are transported and stored in the same first storage area Zl of the production surface, while the mega-blocks B-2 are transported and stored in a second storage area Z-2 of the production surface separate from the first storage area Zl.

[0036] Advantageously, the storage areas Z1, Z-2 are located along two opposite lateral edges 18a, 18b of the production surface 10, so as to provide a central assembly surface between them.

[0037] The final production line of floats can then begin with a preliminary stage consisting of preparing the individual mega-blocks of floats, i.e. by carrying out machining, surfacing, geometric measurement operations, etc. on them. This preparation stage is carried out at the level of storage areas Z1, Z-2.

[0038] For each float, the final manufacturing continues with a step of assembly and primary welding of the different mega-blocks Bl, B-2 constituting the same float between them. This step of assembly and primary welding consists of ensuring a connection of the mega-blocks between them. It is carried out using specific work tools (not shown) and at the level of an assembly and primary welding zone Z-3 of the surface of production which is separate from and adjacent to storage areas Zl, Z-2.

[0039] In practice, and as shown by way of example in Figures 5 to 7, the first mega-block Bl of the float is brought to the primary assembly and welding zone Z-3 by means of multi-wheeled transport vehicles 16 or by skidding (Figure 5), then a first mega-block block B-2 of the float is also brought to the primary assembly and welding zone (Figure 6), followed by a second mega-block block B-2 identical to the first (Figure 7). The mega-blocks are then assembled on top of each other and then a first welding pass is carried out in order to ensure their connection.

[0040] The float thus assembled by primary welding is then moved from the primary assembly and welding zone Z-3 to an adjacent final welding zone Z-4 ​​which is separate from the other zones Z1 to Z-3. This movement is carried out by means of multi-wheeled transport vehicles 16 or by skidding (figure 8).

[0041] At this final welding zone Z-4, the various mega-blocks constituting the float undergo a new welding pass (figure 9) using specific working tools (not shown).

[0042] In parallel with this final welding stage, other mega-blocks Bl, B-2 constituting another float are brought to the assembly and primary welding zone Z-3 left free.

[0043] In the next step (Figure 10), the float thus assembled and whose constituent mega-blocks have been welded together is transported (by multi-wheeled transport vehicles or by skidding) to another completion zone Z-5 which is separate from the other zones of the production surface while being adjacent to the final welding zone Z-4.

[0044] This stage of float completion consists of finalizing the float by a final inspection of the welds, the installation of anti-corrosion coatings on the welded areas, the installation and removal of various equipment on the float, the final closure of the various accesses, etc.

[0045] In parallel with this completion stage, the float assembled in the primary assembly and welding zone Z-3 is transported to the final welding zone Z-4 ​​left free, while other mega-blocks Bl, B-2 constituting another float are brought to the primary assembly and welding zone Z-3 also left free.

[0046] 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.

[0047] This withdrawal and repair step is carried out at a buffer zone Z-6 of the production surface which is distinct from the other zones Z-1 to Z-5 and which is adjacent to the completion zone Z-5 (figure 11).

[0048] For example, advantageously, the primary assembly and welding zones Z-3, final welding Z-4 and completion Z-5 are located longitudinally one behind the other between the two storage zones Z1, Z-2 with the completion zone Z-5 located in the immediate vicinity of the loading dock 12 of the production surface. With such a spatial configuration, the buffer zone Z-6 is advantageously located along one of the lateral edges of the production surface 10 (namely the lateral edge 18a in the example illustrated by FIG. 11) and in the immediate vicinity of the loading dock 12.

[0049] It should be noted that buffer zones could also be set up next to the primary assembly and welding zone Z-3 and / or the final welding zone Z-4, these buffer zones serving to separate the float under construction if assembly defects are identified in order to repair them without slowing down the production rate of the floats.

[0050] As shown in Figure 12 (and Figure 14 in perspective), a transport barge 20 is moored at the loading dock 12 of the production area. The float 2 located in the completion zone Z-5 is then loaded onto the transport barge by means of transport (by shifting or by lifting and rolling using multi-wheel platforms). Alternatively, the float could be launched by sliding on an inclined plane.

[0051] In Figure 13, float 2 which is loaded onto the transport barge 20 has cleared the completion zone Z-5. If float 2' which is located in buffer zone Z-6 has been repaired, it can be transported to this completion zone Z-5 left free. If the repairs have not been completed on this float 2', then it is the float located in final welding zone Z-4 ​​which is transported to completion zone Z-5 (with the movement of the other floats upstream of the production line).

[0052] Following the loading of the float 2 onto the transport barge 20, an additional step of integrating a mast and a wind turbine (not shown in the figures) onto the float can be envisaged.

[0053] It will be noted that the mega-blocks of floats and the floats being manufactured are moved between the different areas of the construction surface by multi-wheeled transport vehicles or by skidding, i.e. mainly by following translational movements. In particular, the method according to the invention does not implement any lifting operation of the mega-blocks or floats being manufactured.

[0054] It should also be noted that the various stages of the production process are advantageously monitored in real time, for example using video surveillance cameras and scanners.

[0055] It should also be noted that the production method according to the invention can advantageously also include the establishment of traceability of the mega-blocks of floats and the various equipment used for the manufacture of the floats.

Claims

Claims 1. Method for mass production of floats (2) for offshore wind turbines, each consisting of the assembly of two to six unit mega-blocks (Bl, B-2) made of steel, the method successively comprising: - the manufacture of a plurality of steel mega-blocks on a dedicated construction surface equipped with a loading dock; - the transport by sea of ​​mega-blocks (Bl, B-2) coming from the construction area and their storage in different storage areas (Zl, Z-2) of a production area (10) separate from the construction area and provided with an unloading dock (12), the same mega-blocks of floats being stored in the same storage area of ​​the production area; and - the final production line of floats comprising successively for each float, a step of preparing the mega-blocks at their storage area, a step of assembling and primary welding the float mega-blocks together at a primary assembly and welding area (Z-3) of the production surface separate from the storage areas and adjacent to them, followed by a step of final welding of the mega-blocks together at a final welding area (Z-4) of the production surface separate from the other areas of the production surface, followed by a step of completing the float at a completion area (Z-5) of the production surface separate from the other areas of the production surface; - the mega-blocks of floats and the floats being manufactured being moved on the production surface between the different zones of the latter mainly according to translational movements.

2. The method of claim 1, wherein the final production line of floats further comprises loading the completed float onto a transport barge (20) moored at the loading dock (12) by means of transport or by launching the completed float by sliding it on an inclined plane.

3. Method according to claim 2, further comprising, following the loading of the float onto the transport barge, the integration on the float of a mast and a wind turbine.

4. Method according to any one of claims 1 to 3, wherein the step of transporting the mega-blocks from the construction surface to the storage areas of the production surface is carried out by means of transport vessels (14).

5. Method according to any one of claims 1 to 4, in which the step of completing the floats is followed by a step of removing and repairing a float having been identified as having manufacturing defects, this step of removing and repairing being carried out at a buffer zone (Z-6) of the production surface distinct from the other zones of the production surface and adjacent to the completion zone (Z-5).

6. Method according to any one of claims 1 to 5, in which the assembly and primary welding zones (Z-3), final welding zones (Z-4) and completion zones (Z-5) are located between two lateral storage zones (Z1, Z-2) of the production surface.

7. A method according to claim 5, wherein the primary, final and completion welding and assembly zones are longitudinally spaced from each other, the completion zone (Z-5) being adjacent to the loading dock (12) of the production area.

8. A method according to any one of claims 1 to 7, wherein the float mega-blocks and the floats being manufactured are moved between the different zones (Zl to Z-6) of the construction surface by multi-wheeled transport vehicles (16) or by skidding.

9. Method according to any one of claims 1 to 8, in which the different stages of the production process are monitored.

10. Method according to any one of claims 1 to 9, further comprising the establishment of traceability of the mega-blocks of floats and of the different equipment used for the manufacture of the floats.

11. Method according to any one of claims 1 to 10, in which each float is formed by the assembly of three unitary mega-blocks made of steel, namely: a first unitary mega-block (B1) comprising a central column (4) intended to receive a wind turbine mast, an outer column (6) and a lower pontoon (8) between the central column and the outer column; and two second identical unitary mega-blocks (B-2) each comprising an outer column (6) and a lower pontoon (8).

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