Method for constructing floating wind power generation equipment

Abstract

The purpose of the present invention is to provide a method for constructing floating wind power generation equipment which is less susceptible to the effects of wind and waves when towed. A provisional assembly (1a) is assembled on the ground. The provisional assembly (1a) includes: a base part (8) of a floating body (2); and provisionally mounted members (6, 13, 16) disposed at positions different from the positions at the time of completion. After assembling the provisional assembly (1a), the provisional assembly (1a) is launched. After being launched, the floating wind power generation equipment under construction is towed to an installation position, and the provisionally mounted members (6, 13, 16) are deployed to the positions at the time of completion. Since the vertical length of the provisional assembly (1a) is shorter than the floating wind power generation equipment at the time of completion, the provisional assembly (1a) is less likely to be affected by wind and waves when towed.

Description

How to build a floating wind turbine

[0001] The present invention relates to a method for constructing a floating wind power generation facility.

[0002] Wind power generation is a renewable energy source. Floating wind turbines can be installed in deep waters where fixed-bottom offshore wind turbines are difficult to install, so the area in which they can be installed is wide. For this reason, the demand for floating wind turbines is increasing.

[0003] Patent Document 1 discloses a construction method for constructing a floating wind power generation facility, in which a float is transported to an offshore work area, sunk, and secured to a bottom-mounted platform installed on the seabed. The tower, nacelle, and blades are then attached to the float secured to the bottom-mounted platform, and the float is then floated and towed to the installation area. With this method, because the float is secured to the bottom-mounted platform during assembly, the bottom of the tower is located underwater, reducing the height of the tower above the water surface. This prevents the need for a large crane ship.

[0004] Furthermore, Patent Documents 2 and 3 disclose that the main body of a floating wind power generation facility assembled on land is towed to an installation position.

[0005] Japanese Patent Application Laid-Open No. 2015-155655 Japanese Patent Application Laid-Open No. 2016-529430 Japanese Patent Application Laid-Open No. 2018-507135

[0006] However, while the method described in Patent Document 1 prevents the crane vessel from becoming larger, it requires the installation of a bottom-mounted platform and the work of fastening and detaching the floating body to the bottom-mounted platform on the seabed, which increases costs. Also, when towing the equipment from the offshore work area to the installation area, the equipment is almost completed and has a large height, so it is greatly affected by wind and waves.

[0007] In the methods described in Patent Documents 2 and 3, the main body of the floating wind power generation facility is towed in a nearly completed state with a large height, so it is greatly affected by wind and waves. Furthermore, in the methods described in Patent Documents 2 and 3, if some components are to be attached at sea to reduce the effects of wind and waves, a large crane ship is required.

[0008] In view of the above background, an object of the present invention is to provide a method for constructing a floating wind power generation facility that is less susceptible to the effects of wind and waves during towing. Another object of one aspect of the present invention is to provide a method for constructing a floating wind power generation facility that can build a tall tower without using a large crane ship.

[0009] In order to solve the above-mentioned problems, one aspect of the present invention is a method for constructing a floating wind power generation facility (1) comprising a float (2) including a base (8), a tower (3) installed on the base, a nacelle (4) attached to the upper end of the tower, a hub (5) rotatably attached to the nacelle around a rotor axis (X), and a plurality of blades (6) attached to the hub, the method comprising the following steps: a temporary placement step of assembling, on ground, a temporary assembly (1a) including the base and the temporary mounting members so that at least one temporary mounting member (6, 13, 16) constituting a part of the floating wind power generation facility is positioned closer to the base than its position at the time of completion; a launching step of launching the temporary assembly; and a final placement step of towing the floating wind power generation facility under construction to its installation position and placing the temporary mounting member in its position at the time of completion after the launching step. It is preferable that the floating body (2) further includes an underwater portion (9) extending downward from the base (8), the tower (3) includes a lower tower portion (15) installed on the base (8) and an upper tower portion (16), and the temporary attachment member includes the lower end portion (13) of the underwater portion, the upper tower portion (16), and / or the blade (6).

[0010] According to this aspect, the floating wind power generation facility in the temporary arrangement state has a shorter vertical length than that of the completed state, so that the effects of wind and waves during towing are reduced.

[0011] In the above aspect, the temporary assembly (1a) assembled in the temporary placement step may include the base (8), the underwater part (9), the tower lower part (15), the tower upper part (16), the nacelle (4), the hub (5), and the blades (6).

[0012] Attaching heavy main components on water requires the use of a large crane vessel, but with this configuration, the main components are attached to each other on land, eliminating the need for a large crane vessel.

[0013] In the above aspect, the temporary mounting member includes a plurality of the blades (6), and the temporary placement step includes removably mounting the plurality of blades to the tower so that one end to be attached to the hub (5) faces upward and the blades are shifted from one another in the circumferential direction about a tower axis (Z), which is the central axis of the tower (3) extending in the vertical direction; attaching the hub to the nacelle (4); and attaching the nacelle to an upper end of the tower upper part (16) via a support member (20) that enables the nacelle to rotate about the tower axis; and the actual placement step may include rotating the hub about the rotor axis (X) and rotating the nacelle about the tower axis, to sequentially align each of the blades with the portion of the hub where the blade is to be attached.

[0014] According to this aspect, the support member allows the portion of the hub where the blade is to be attached to be close to the blade, making it easier to attach the blade.

[0015] In the above aspect, the support member (20) may be configured to enable the nacelle (4) to tilt within a predetermined range around a tilt axis (Y) perpendicular to the tower axis (Z) and the rotor axis (X).

[0016] According to this aspect, the support member allows the nacelle to be tilted around the tilt axis, so that the blades can be brought closer to the tower during maintenance, facilitating maintenance of the blades.

[0017] In the above aspect, the temporary mounting member may include a lower end (13) of the underwater part (9), the temporary placement step may include temporarily fixing the underwater part to the base (8), and the actual placement step may include releasing the temporary fixation of the underwater part to the base and moving the underwater part downward.

[0018] According to this aspect, since the underwater section is positioned higher than when completed during land work, the amount of ground excavation required to create a trench or hole to accommodate the underwater section can be reduced, and the temporary assembly is stable, facilitating launching work. Furthermore, the vessel can be launched into shallow water, and if there are any legal restrictions on transportation regarding the vertical dimensions of the equipment to be launched, these restrictions can be complied with.

[0019] In the above aspect, the lower tower part (15) is installed on the base part (8) and includes at least three legs (17) that support the upper tower part (16) at their upper ends, the upper tower part is positioned in the center of the at least three legs in a plan view and is supported at its lower end by the upper ends of the at least three legs when completed, the temporary mounting member further includes the upper tower part, the temporary placement step includes placing the upper tower part on the upper end of the underwater part (9) so that the outer peripheral surface of the middle part in the vertical direction abuts or faces the upper ends of the at least three legs, and the actual placement step may include moving the upper tower part upward.

[0020] According to this aspect, the upper part of the tower is placed underwater during launching, so that the upper part of the tower is stable.

[0021] In the above aspect, the placement step may further include towing the floating wind power generation facility under construction to an installation position after the underwater section (9) has been moved downward and before the upper part of the tower has been moved upward.

[0022] According to this aspect, when the floating wind power generation facility is towed to the installation site, the height from the base is lower than when the facility is completed, and the facility is therefore less susceptible to the effects of wind and waves.

[0023] In the above aspect, the temporary placement step includes attaching a temporary ring material (25) extending circumferentially relative to a tower axis (Z), which is the central axis of the tower (3) extending in the vertical direction, to the upper end of the leg (17), placing a lifting cable (23) passing under the tower upper part (16), and attaching a lifting device (24) that pulls up the lifting cable to the temporary ring material, and the upward movement of the tower upper part in the actual placement step may be performed by pulling up the lifting cable that supports the bottom of the tower upper part with the lifting device (24).

[0024] According to this aspect, the upper part of the tower can be moved upward using the lifting cable and the lifting device attached to the upper end of the leg, so there is no need to use a crane ship to move the upper part of the tower. Also, while the upper limit of the tower height was conventionally determined by the height of the crane of the crane ship, according to this aspect, the tower height can be determined without such restrictions.

[0025] In the above aspect, the underwater portion (9) may include a rod portion (12) extending downward from the base portion (8), and a mass portion (13) that forms the lower end of the underwater portion, is connected to the lower end of the rod portion, and has a diameter larger than that of the rod portion.

[0026] According to this aspect, since the rod portion is thinner than the mass portion, even if the rod portion is positioned so as to protrude upward from the base portion (8) in a floating wind power generation facility in a temporary arrangement state, it does not hinder the arrangement of other components.

[0027] According to the above aspect, it is possible to provide a method for constructing a floating wind power generation facility that is less susceptible to the effects of wind and waves when towing.

[0028] 3. Side view of the main part of the floating wind power generation facility according to the embodiment. 4. Perspective view of a part of the floating wind power generation facility according to the embodiment. 5. Explanatory diagram showing the construction method of the floating wind power generation facility according to the embodiment (ground work). 6. Cross-sectional view along line IV-IV in FIG. 3. 7. Explanatory diagram showing the construction method of the floating wind power generation facility according to the embodiment (after launching). 8. Explanatory diagram showing the construction method of the floating wind power generation facility according to the embodiment (towing to the installation position). 9. Explanatory diagram showing the construction method of the floating wind power generation facility according to the embodiment (enlarged view of the area surrounded by the two-dot chain line in FIG. 6). 10. Explanatory diagram showing the construction method of the floating wind power generation facility according to the embodiment (after the tower is deployed).

[0029] Hereinafter, a floating wind power generation facility 1 and a method for constructing the same according to an embodiment of the present invention will be described with reference to the drawings.

[0030] As shown in Figures 1 and 2, the floating wind power generation facility 1 comprises a float 2, a tower 3 installed on the float 2, a nacelle 4 attached to the upper end of the upper part of the tower 3, a hub 5 attached to the nacelle 4 so as to be rotatable around the rotor axis X, a plurality of blades 6 attached to the hub 5, and mooring lines 7 (see Figure 8) for mooring the float 2 (the mooring lines 7 are not shown in Figure 1, and the nacelle 4, hub 5, blades 6, and mooring lines 7 are not shown in Figure 2).

[0031] The float 2 includes a base 8 and an underwater section 9 extending downward from the base 8. The base 8 includes a ring section 10 having an annular shape in a plan view, and three support sections 11 extending radially inward from positions 120° apart from each other in the circumferential direction on the inner peripheral surface of the ring section 10 and connected to each other at the center of the ring section 10. The upper and lower surfaces of the base 8 are preferably flush with the ring section 10 and the support sections 11. The underwater section 9 includes a cylindrical rod section 12 extending downward from a center section 11a where the three support sections 11 are connected, and a bottomed cylindrical mass section 13 connected to the lower end of the rod section 12. The cylindrical axes of the rod section 12 and the mass section 13 coincide with the tower axis Z, which passes through the center of the ring section 10 and extends in the vertical direction. The mass portion 13 forms the lower end of the underwater portion 9 and has a diameter larger than that of the rod portion 12 and smaller than the inner diameter of the ring portion 10. A through-hole 14 through which the rod portion 12 can be inserted is provided in the center portion 11a where the three support portions 11 are connected. The ring portion 10, support portions 11, rod portions 12, and mass portion 13 have a hollow structure and are made of, for example, steel. The floating wind turbine power generation facility 1 is configured so that most of the base 8 and the underwater portion 9 are located underwater in the sea, lake, etc., and the upper surface of the base 8 is located slightly above the water surface W (see FIG. 8 ).

[0032] The tower 3 includes a lower tower portion 15 supported at its lower end by the base portion 8 and an upper tower portion 16 supported at its lower end by the upper end of the lower tower portion 15 .

[0033] The tower lower portion 15 includes three legs 17 whose lower ends are supported by different supports 11 and whose upper ends are inclined so as to approach each other. The legs 17 have a hollow structure with a hollow portion 17b (see FIG. 4) extending in the extension direction of the legs 17, and are made of, for example, reinforced concrete. The lower ends of the three legs 17 are arranged on a single circumference centered at the center 11a in a plan view, and have pin joints 17a so that the legs are supported by the supports 11 so as to be tiltable about an axis extending tangentially to the circle.

[0034] The tower upper part 16 includes a first upper part 18 supported at its lower end by three legs 17, and a second upper part 19 supported at its lower end by the upper end of the first upper part 18. The tower upper part 16 extends along the tower axis Z, and is disposed in the center of the three legs 17 in a plan view.

[0035] The first upper portion 18 has a generally truncated cone-shaped outer shape and is a hollow structure with a hollow portion (not shown) extending in the vertical direction. The first upper portion 18 is made of, for example, reinforced concrete. The outer peripheral surface of the lower end of the first upper portion 18 abuts against the inner surface of the upper end of the leg portion 17 via a joint material (not shown) or the like, and is fixed by a tension member (not shown). It is preferable that the abutting portions of the outer peripheral surface of the lower end of the first upper portion 18 and the inner surface of the upper end of the leg portion 17 are each flat.

[0036] The second upper portion 19 has a cylindrical shape and is formed of, for example, a steel pipe. The hollow portion of the first upper portion 18 is open at the top, and the lower end of the second upper portion 19 is inserted into the hollow portion of the first upper portion 18 and fixed to the first upper portion 18.

[0037] The nacelle 4 includes a generator that generates electricity through rotation of the hub 5 and blades 6, and a gearbox (not shown), and is attached to the upper end of the second upper part 19 via a bearing member 20. The bearing member 20 is configured to enable the nacelle 4 to rotate 360° around the tower axis Z relative to the second upper part 19, and to enable it to tilt within a predetermined range around a tilting axis Y that is perpendicular to the rotor axis X and the tower axis Z. The bearing member 20 has a structure similar to that of a spherical sliding bearing, for example, and includes a concave spherical base 20a (see FIG. 8) and a slider 20b (see FIG. 8) that slides on the spherical base.

[0038] The hub 5 and the blades 6 constitute a rotor. When the blades 6 catch wind, they rotate together with the hub 5 around the rotor axis X. The rotation is accelerated by the gearbox in the nacelle 4, and the accelerated rotation is transmitted to a generator that generates electricity.

[0039] A method for constructing the floating wind power generation facility 1 will be described with reference to FIGS. 3 to 8 and FIG.

[0040] 3 and 4, workers assemble a temporary assembly 1a on the ground, in which some components of the floating wind power generation facility 1 (see FIG. 1) are temporarily positioned in positions different from the positions at the time of completion. In the temporary assembly 1a, temporary attachment members are positioned closer to the base 8 than at the time of completion so that the vertical length of the temporary assembly 1a is shorter than at the time of completion. The temporary attachment members include the mass portion 13, the tower upper portion 16, and the blades 6.

[0041] As shown in Figure 3, in the temporary assembly 1a, the underwater section 9 of the float 2 is positioned higher relative to the base 8 than its completed position. The rod section 12 is inserted into the through-hole 14 (see Figure 2), with the upper portion of the rod section 12 protruding upward from the upper surface of the base 8, and the mass section 13 is positioned higher than its completed position. It is preferable that the upper surface of the mass section 13 abuts against the lower surface of the base 8. The underwater section 9 is temporarily fixed to the base 8 by fasteners, wires, etc. (not shown). When the temporary fixation is released, the rod section 12 slides along the inner surface of the through-hole 14, allowing the underwater section 9 to move downward. The base 8 is supported on its lower surface near its outer periphery by the ground G, and an excavation section Ga is provided in the ground G to receive the mass section 13.

[0042] 3 and 4 , in the temporary assembly 1a, the tower upper portion 16 is positioned lower than its completed position relative to the tower lower portion 15 and is placed on the upper end surface of the temporarily fixed rod portion 12. The vertically intermediate portion of the outer circumferential surface of the first upper portion 18 of the tower upper portion 16 faces the radially inner surface of the upper end of the leg portion 17 with a predetermined gap therebetween. Circular temporary ring members 25 extending circumferentially about the tower axis Z are temporarily fixed to the upper ends of the three legs 17, thereby maintaining the radially inner surface of the upper end of the leg portion 17 spaced apart from the outer circumferential surface of the tower upper portion 16. The temporary ring members 25 are, for example, hollow steel members. The temporary assembly 1a includes three lifting cables 23 arranged to pass below the bottom of the tower upper portion 16 and six lifting devices 24, such as jacks, attached to the upper surfaces of the temporary ring members 25 and used to lift the lifting cables 23. At the locations of the temporary ring material 25 where the lifting devices 24 are arranged, through-holes 25a are provided that extend in the vertical direction and allow the lifting cables 23 to pass through. Two lifting devices 24 are provided for each leg 17, and are arranged at positions offset in the circumferential direction on opposite sides of the leg 17. Both ends of the three lifting cables 23 are attached to different lifting devices 24 so that the lifting cables 23 push up the bottom of the tower upper portion 16 when pulled up by the lifting devices 24.

[0043] In the temporary assembly 1a, each blade 6 is temporarily fixed to the first upper portion 18 of the tower upper portion 16 by a mounting bracket 22 or the like. The mounting bracket 22 includes, for example, a bracket embedded in the first upper portion 18 or wound around the outer circumferential surface of the first upper portion 18, and a bracket attached to the blade 6. The blade 6 is temporarily fixed to the first upper portion 18 by fastening the two brackets together with a fastener (not shown) or the like. The blades 6 are disposed at positions offset from each other by approximately 120° in the circumferential direction about the tower axis Z and offset by approximately 60° from the leg 17. Each blade 6 is temporarily fixed so that one end to be attached to the hub 5 faces upward and is disposed substantially at the same height as or lower than the lower surface of the hub 5, and the other end faces downward and is disposed higher than the base 8.

[0044] The lower ends of the legs 17 are joined to the base 8 via pin joints 17a, just as in the completed assembly, and the upper ends of the legs 17 are temporarily fixed to temporary ring materials 25 and are positioned at approximately the same positions as in the completed assembly or at a position radially outward from the completed assembly. The second upper portion 19, support member 20, nacelle 4, and hub 5 of the tower upper portion 16 are attached to their direct attachment target members (first upper portion 18, second upper portion 19, support member 20, and nacelle 4) in the same manner as in the completed assembly, but are positioned lower than in the completed assembly because the first upper portion 18 is positioned lower than in the completed assembly.

[0045] Next, workers launch the temporary assembly 1a and tow it to a position deeper in water than the vertical length of the floating body 2, then release the temporarily fixed underwater section 9 and, as shown in Figure 5, move the underwater section 9 downward and fix the upper ends of the rod sections 12 to the support sections 11 (see Figure 2) of the base section 8 with fasteners (not shown) or the like. By moving the underwater section 9 downward in this manner, the temporary assembly 1a (see Figure 3) becomes the first deployable body 1b with the underwater section 9 arranged in the completed position. At this time, the tower upper section 16 is supported by the lifting cables 23.

[0046] Next, workers tow the first deployable body 1b to the installation position of the floating wind power generation facility 1 (see FIG. 1), install anchors (mooring) by attaching mooring lines 7 as shown in FIG. 6, and then move the tower upper part 16 upward to place it in its completed position. As shown in FIG. 7, the tower upper part 16 is moved upward using a lifting cable 23 that supports the bottom of the tower upper part 16 and a lifting device 24 such as a jack that pulls up the lifting cable 23. Workers then pull up the lifting cable 23 using the lifting device 24, place the tower upper part 16 in its completed position as shown in FIG. 8, and secure the first upper part 18 to the upper ends of the legs 17 with tension members (not shown) or the like. Through these operations, the first deployable body 1b (see FIG. 5) becomes the second deployable body 1c, with the tower upper part 16 placed in its completed position.

[0047] Next, the worker attaches the blades 6 to the hub 5. The hub 5 is rotatable 360° about the rotor axis X, and the nacelle 4 to which the hub 5 is attached is attached to the tower upper portion 16 via the support members 20, and is therefore rotatable 360° about the tower axis Z (see FIG. 4 ). The worker rotates the hub 5 about the rotor axis X so that one of the portions of the hub 5 where the blades 6 are to be attached faces downward, and further rotates the nacelle 4 about the tower axis Z so that this portion is vertically aligned with one of the blades 6 temporarily fixed to the first upper portion 18. After attaching the aligned blade 6 to that portion, the worker rotates the hub 5 120° about the rotor axis X and rotates the nacelle 4 120° about the tower axis Z, thereby attaching the second blade 6 in alignment with the portion of the hub 5 where the blade 6 is to be attached. Furthermore, the worker rotates the hub 5 by 120 degrees in the same direction about the rotor axis X, and rotates the nacelle 4 by 120 degrees in the same direction about the tower axis Z, thereby aligning and attaching the third blade 6 to the position on the hub 5 where that blade 6 is to be attached. After that, the worker rotates the nacelle 4 about the tower axis Z so that the hub 5 and blade 6 face upwind, and tilts it about the tilting axis Y so that the side where the hub 5 is attached is tilted slightly upward with respect to the horizontal. In this way, the floating wind turbine power generation facility 1 shown in Figure 1 is constructed.

[0048] The effects of the method for constructing the floating wind power generation facility 1 will now be described.

[0049] 3, during work on land, the underwater section 9 is positioned higher than its completed position, which allows the size of the excavation section Ga to be reduced and facilitates launching work. Furthermore, since the underwater section 9 includes the rod section 12 and the mass section 13, and the rod section 12 is thinner than the mass section 13, even if the upper part of the rod section 12 is positioned so as to protrude from the base section 8 in the temporary assembly 1a, this does not interfere with the placement of other components such as the legs 17.

[0050] In the temporary assembly 1a, the tower upper part 16 is placed on the upper surface of the rod part 12, which provides high stability to the tower upper part 16 when launched. In the temporary assembly 1a, the underwater part 9 is positioned higher than in the completed model, so the length of the part of the temporary assembly 1a below the base part 8 is shorter than in the completed model. This makes the temporary assembly 1a stable when launched, allowing it to be launched into shallow waters, and also enabling it to comply with any legal restrictions on transportation regarding the vertical dimensions of the equipment to be launched below the water surface.

[0051] The first deployable body 1b shown in Figure 5 is lower in height from the top surface of the base 8 than the completed floating wind turbine power generation facility 1 (see Figure 1). This reduces the effects of wind and waves when the first deployable body 1b is towed to the installation position.

[0052] As shown in Figures 4 and 6 to 8, the main components are towed to the installation location while temporarily secured to each other, eliminating the need to transport the main components separately. Furthermore, the temporarily secured tower upper portion 16 can be moved upward using a lifting cable 23 and a lifting device 24, which can be arranged on the first deployable body 1b, and the temporarily secured blades 6 can be attached to the hub 5 using support members 20. This allows the floating wind power generation facility 1 (see Figure 1) to be constructed without using a crane ship, or even if a crane ship is used, by using a relatively small crane ship. Furthermore, when the tower upper portion 16 is installed by a crane ship, the upper limit of the tower 3 height is determined by the height of the crane ship's crane. However, with this method, such limitations are not present, allowing for the construction of a taller tower 3.

[0053] As shown in Figures 1 and 4, the support members 20 allow the nacelle 4 to rotate 360° around the tower axis Z relative to the tower upper part 16. Therefore, even if the three blades 6 are temporarily fixed at positions offset by 120° from each other to avoid the legs 17, the hubs 5 can be brought close to each blade 6, making it easy to attach the blades 6 to the hubs 5. Furthermore, wind power generation equipment is generally used in a state in which the rotor axis X is slightly tilted relative to the horizontal so that the hub 5 points upward. However, because the support members 20 allow the nacelle 4 to tilt within a predetermined range around the tilt axis Y, the nacelle 4 can be tilted so that the blades 6 approach the tower upper part 16 during maintenance. This makes maintenance of the blades 6 easy.

[0054] Although the specific embodiments have been described above, the present invention is not limited to the above-described embodiments and modifications, and can be implemented in a wide variety of ways. Four or more legs may be provided. Blades may be attached to the hub before the upper tower is moved upward from the temporary fixed position. In this case, after one blade is attached to the hub, the hub may be rotated around the rotor axis to attach another blade to the hub. To prevent the attached blade from hitting the legs, the nacelle may be tilted so that the hub faces upward relative to the horizontal. The temporary attachment members may be one or two of the mass, the upper tower, and the blades, or other components such as the nacelle. Some components may be transported to the installation position after launching or towing, rather than on land, and then attached. The number of lifting cables and lifting devices may be changed. The lifting devices may be attached directly to the legs without using temporary rings. In the temporary assembly, the inner surface of the upper end of the leg is temporarily fixed by abutting against the middle part in the vertical direction of the outer surface of the upper part of the tower, and the temporary fixation can be released when the lifting cable is pulled up by the lifting device.

[0055] 1: Floating wind power generation facility 2: Floating body 3: Tower 4: Nacelle 5: Hub 6: Blades 8: Base 9: Underwater section 12: Rod section 13: Mass section 15: Tower lower section 16: Tower upper section 17: Leg section 17a: Pin joint section 20: Support member 23: Lifting cable 24: Lifting device X: Rotor axis Y: Tilting axis Z: Tower axis

Claims

1. A method for constructing a floating wind power generation facility comprising a float including a base, a tower installed on the base, a nacelle attached to the upper end of the tower, a hub rotatably attached to the nacelle around a rotor axis, and a number of blades attached to the hub, the method comprising: a temporary placement step of assembling a temporary assembly including the base and the temporary mounting members on ground so that at least one temporary mounting member constituting a part of the floating wind power generation facility is positioned closer to the base than its position at the time of completion; a launching step of launching the temporary assembly; and a final placement step of towing the floating wind power generation facility under construction to its installation position after the launching step, and placing the temporary mounting members in their positions at the time of completion.

2. The construction method of claim 1, wherein the floating body further includes an underwater portion extending downward from the base, the tower includes a lower tower portion and an upper tower portion installed on the base, and the temporary attachment member includes a lower end of the underwater portion, the upper tower portion, and / or the blade.

3. The construction method according to claim 2, wherein the temporary assembly assembled in the temporary placement step includes the base, the underwater portion, the tower lower portion, the tower upper portion, the nacelle, the hub and the blades.

4. The construction method according to claim 3, wherein the temporary mounting member includes a plurality of the blades, and the temporary positioning step includes removably mounting the plurality of blades to the tower so that one end of the blades to be attached to the hub faces upward and is offset from one another in the circumferential direction about a tower axis that is the central axis of the tower extending in the vertical direction, mounting the hub to the nacelle, and mounting the nacelle to the upper end of the upper part of the tower via a support member that enables the nacelle to rotate about the tower axis, and the final positioning step includes rotating the hub about the rotor axis and rotating the nacelle about the tower axis to sequentially align each of the blades with the portion of the hub where the blade is to be attached to each other.

5. The method of claim 4, wherein the support member is configured to allow the nacelle to tilt within a predetermined range about a tilt axis perpendicular to the tower axis and the rotor axis.

6. A construction method as described in claim 3, wherein the temporary mounting member includes the lower end of the underwater portion, the temporary positioning step includes temporarily fixing the underwater portion to the base, and the actual positioning step includes releasing the temporary fixation of the underwater portion to the base and moving the underwater portion downward.

7. The construction method described in claim 6, wherein the lower tower part is installed on the base and includes at least three legs supporting the upper tower part at their upper ends, the upper tower part is positioned in the center of the at least three legs in a plan view and is supported at its lower end by the upper ends of the at least three legs when completed, the temporary mounting member further includes the upper tower part, the temporary positioning step includes placing the upper tower part on the upper end of the underwater part so that the outer peripheral surface of the middle part in the vertical direction abuts or faces the upper ends of the at least three legs, and the actual positioning step includes moving the upper tower part upward.

8. The construction method of claim 7, wherein in the placement step, the floating wind power generation facility under construction is towed to the installation position after the underwater portion moves downward and before the tower upper portion moves upward.

9. A construction method as described in claim 7, wherein the temporary placement step includes attaching a temporary ring material extending circumferentially about the tower axis, which is the central axis of the tower extending in the vertical direction, to the upper end of the leg, placing a lifting cable passing under the upper part of the tower, and attaching a lifting device that pulls up the lifting cable to the temporary ring material, and the upward movement of the upper part of the tower in the actual placement step is achieved by pulling up the lifting cable supporting the bottom of the upper part of the tower with the lifting device.

10. The construction method of claim 6, wherein the underwater portion includes a rod portion extending downward from the base portion, and a mass portion that forms the lower end of the underwater portion, is connected to the lower end of the rod portion, and has a diameter larger than a diameter of the rod portion.

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