Construction method and floating guidance unit for floating wind power generation facilities

Abstract

This invention provides a construction method for floating offshore wind power generation facilities that allows for efficient movement and fixed-point maintenance of the floating structures without requiring the connection of numerous tugboats to the floating structures that make up the floating offshore wind power generation facility. [Solution] A method for constructing a floating wind power generation facility having a floating body moored in a target water area and a wind power generation device erected on the floating body, wherein a floating body guidance unit is installed on the floating body, the unit comprising a main body that is detachable from the floating body and a plurality of propulsion devices installed on the main body at a distance from each other, and the floating body is maintained at a fixed point or moved by driving the plurality of propulsion devices.

Description

Technical Field

[0001] The present invention relates to a construction method for a floating wind power generation facility. More specifically, it relates to a construction method for a floating wind power generation facility that can efficiently move and hold a floating body in a fixed position without connecting the floating body constituting the floating wind power generation facility to a large number of towing vessels. Further, the present invention relates to a construction method for floating wind power generation equipment and a floating body guiding unit.

Background Art

[0002] Floating wind power generation facilities with a structure in which a wind power generation device is erected on a floating body moored in a sea area are classified into semi-submersible type, TLP (Tension Leg Platform) type, barge type, etc., according to the structure of the floating body. Conventionally, the floating body was moved by connecting the floating body and a large number of towing vessels with ropes respectively and towing the floating body with a large number of towing vessels (see, for example, Patent Document 1). When holding the floating body in a fixed position, the floating body was held in a state at the target position by pushing and pulling the floating body from a plurality of directions by a large number of towing vessels and winches (power winches), and the floating body was moored using mooring ropes and anchors extending in a plurality of directions to hold the floating body in a fixed position. In this conventional method, a large number of towing vessels were required for moving and holding the floating body in a fixed position, and the number of required workers was also large. Further, for holding the floating body in a fixed position, since it was necessary to moor the floating body by pulling it from multiple directions by a large number of towing vessels with mooring means, it was necessary to secure a relatively wide space around the floating body.

[0003] For example, one possible method for efficiently constructing multiple floating wind power generation facilities is to build a floating structure in the water where multiple wind power generation unit assembly parts can be temporarily stored, and then arrange multiple floating bodies around this floating structure. Then, using a self-elevating barge, the wind power generation unit assembly parts temporarily stored on the floating structure are installed on each floating body, thereby efficiently assembling the wind power generation unit assembly (integrated unit) on the floating body. However, in the conventional method of using many tugboats to move and maintain the floating bodies in fixed positions, it is not possible to place the floating bodies in close proximity, and a long distance must be maintained between them. Therefore, when setting up bases for wind power generation unit assembly work on multiple floating bodies, it is necessary to secure a large space for temporarily storing the wind power generation unit assembly parts, and a vast space must also be secured in the surrounding water. Thus, there are various challenges and room for improvement in the methods of moving and maintaining the floating bodies in the construction of floating wind power generation facilities. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 7202551 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The object of the present invention is to provide a construction method for a floating wind power generation facility that allows for efficient movement and fixed-point maintenance of the floating structures without having to connect the floating structures to a large number of towboats. [Means for solving the problem]

[0006] To achieve the above objective, the present invention provides a method for constructing a floating wind power generation facility comprising a floating body moored in a target water area and a wind power generation device erected on the floating body, wherein a floating body guidance unit comprising a main body detachable from the floating body and a plurality of propulsion devices installed on the main body at a distance from each other is installed on the floating body, and the floating body is held in a fixed position or moved by driving the plurality of propulsion devices. [Effects of the Invention]

[0007] In this invention, by preparing a floating guidance unit equipped with a frame, multiple propulsion devices, position information acquisition means, and a control device in advance, multiple propulsion devices and control devices that enable at least one of either movement control or fixed-point holding control of the floating body can be easily and quickly installed on the floating body. Furthermore, by controlling the multiple propulsion devices with the control device based on position information input from the position information acquisition means, it becomes possible to efficiently perform at least one of either movement control or fixed-point holding control of the floating body without connecting a large number of tugboats to the floating body. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram illustrating a semi-submersible floating offshore wind power generation facility constructed according to the present invention, viewed from the front. [Figure 2] This is an explanatory diagram illustrating, from a front view, a situation in which a semi-submersible floating body is floating in the sea in a semi-submersible state, and a floating body guidance unit is being lifted from above by a crane ship. [Figure 3] Figure 2 is an explanatory diagram illustrating a floating object in a semi-submerged state in the sea area shown in Figure 2, viewed from a plan perspective. [Figure 4] Figure 2 is an explanatory diagram illustrating a floating guidance unit in a plan view. [Figure 5] This is an explanatory diagram illustrating, from a front view, the floating guidance unit shown in Figure 2, mounted on a support platform attached to a crane ship. [Figure 6] This is an explanatory diagram illustrating, in cross-sectional view, the state in which a floating body guide unit is installed on a floating body that is floating in a semi-submerged state in the sea area, as shown in Figure 2. [Figure 7] Figure 6 is an explanatory diagram illustrating a floating structure with the floating guidance unit installed, shown in a plan view. [Figure 8] This is a diagram illustrating, in plan view, a configuration in which a floating structure equipped with a floating guidance unit and a self-elevating barge are positioned in the assembly work area near a floating structure where assembly parts for a wind power generation device are temporarily placed. [Figure 9] Figure 8 is an explanatory diagram illustrating, in cross-sectional view, an example of a floating structure and a self-elevating barge on which assembled components of a wind turbine are temporarily placed. [Figure 10] This is an explanatory diagram illustrating, from a front view, a floating structure with a floating guidance unit installed on a mound on the seabed of the assembly work area, in a state where it has settled on the seabed. [Figure 11] Figure 10 is an explanatory diagram illustrating a floating body with a floating guidance unit installed, in a state where it is resting on the mound, as shown in a plan view. [Figure 12] This is an explanatory diagram illustrating, in cross-sectional view, the situation in which assembly components of a wind turbine are installed using a self-elevating barge on a floating body equipped with a floating guidance unit that has been grounded on a mound, as shown in Figure 9. [Figure 13] This is an explanatory diagram illustrating, in a plan view, the situation after the installation of the wind power generation equipment assembly parts on the floating body with the floating guidance unit installed has been completed, and the self-elevating barge has been moved to another work area, starting from the state shown in Figure 12. [Figure 14] This is an explanatory diagram illustrating, from a front view, the situation in which, starting from the state shown in Figure 13, a floating structure (assembly) on which a wind power generation device is erected is moved to the target sea area using a floating structure guidance unit, and the assembly is moored while the floating structure guidance unit controls its fixed position within the target sea area. [Figure 15] This is a diagram illustrating, in plan view, a floating structure equipped with a floating guidance unit positioned in the assembly work area near a quay where assembly parts for a wind power generation device have been temporarily placed. [Figure 16] This diagram illustrates, in cross-sectional view, the situation in which a floating structure is being controlled to maintain a fixed position while floating in a semi-submerged state using a floating structure guidance unit installed on the floating structure, and where assembly parts for a wind turbine are being installed on the floating structure using a crane positioned on the quay shown in Figure 15. [Figure 17] FIG. 1 is an explanatory view illustrating, in a front view, a state in which a floating body guiding unit of another embodiment is installed on a TLP type floating body. [Figure 18] FIG. 2 is an explanatory view illustrating, in a front view, a state in which a floating body guiding unit of another embodiment is installed on a spar type floating body. [Figure 19] FIG. 3 is a diagram for explaining a position information acquisition means in a floating body guiding unit. [Figure 20] FIG. 4 is a diagram for explaining a control device in a floating body guiding unit. BEST MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, a construction method of the floating wind power generation facility of the present invention will be described based on the embodiments shown in the drawings.

[0010] As illustrated in FIG. 1, the floating offshore wind power generation facility 1 includes a floating body 2 moored in the installation target sea area IA and a wind power generation device 3 erected on the floating body 2. In the installation target sea area IA, the floating body 2 is moored to the seabed SB using mooring means 8 such as mooring cables 8a and anchors 8b. In the following examples, the floating offshore wind power generation facility 1 will be described, but the floating offshore wind power generation facility may be a floating wind power generation facility in a lake, pond, river, etc., not limited to the ocean. Further, the floating body 2 is not limited to being moored to the seabed SB and may be moored to the water bottom.

[0011] This construction method targets the floating offshore wind power generation facility 1 provided with the floating body 2 in a semi-submerged state while the floating body 2 as illustrated in FIG. 1 is moored in the installation target sea area IA. Specifically, this construction method can be adopted for the construction of floating offshore wind power generation facilities 1 of other types (semi-sub type, TLP type, spar type, etc.) excluding the spar type. In the following description, an integrated object of the floating body 2 and the wind power generation device 3 before being moored in the installation target sea area IA is defined as an assembly 7, and the assembly 7 moored by the mooring means 8 in the installation target sea area IA is defined as the floating offshore wind power generation facility 1.

[0012] This embodiment illustrates the construction of a semi-submersible floating offshore wind power generation facility 1. As illustrated in Figure 1, the semi-submersible floating body 2 is submerged in the sea to a predetermined draft and moored in a semi-submersible state. The wind power generation device 3 has a nacelle hub (a single unit of nacelle and hub) 5 installed on top of a tower 4 that extends in the vertical direction, and multiple blades 6 are arranged radially on the nacelle hub 5. Electrical equipment such as a generator, brakes, and gearbox are built into the nacelle hub 5, and the power cables connected to the generator are routed inside the tower 4.

[0013] This embodiment illustrates a wind turbine 3 having three blades 6 and a tower 4 composed of three segmented members 4a. The number of blades 6 and the structure of the blades 6, as well as the number of segmented members 4a constituting the tower 4, are not limited to this embodiment. For example, the blades 6 may be made up of multiple connected members, or the tower 4 may be made up of a single long member.

[0014] As illustrated in Figures 2 and 3, the semi-submersible floating body 2 has a floating body body 2a and a plurality of column-shaped columns 2b erected on the floating body body 2a. In this embodiment, the floating body body 2a has a cross-shaped (X-shaped) central part in plan view and polygonal support parts in plan view joined to four ends of the central part. Columns 2b are erected on each of the four support parts. A tower fixing part 2c is provided on one of the columns 2b to which the lower end of the tower 4 can be fixed, and a wind power generation device 3 is erected on that one column 2b. At the tower fixing part 2c, the upper end of the column 2b and the lower end of the tower 4 (divided member 4a) are joined, for example, by bolting or welding.

[0015] The floating body 2 has a structure that allows it to store (fill) ballast water internally, and the draft and attitude of the floating body 2 can be adjusted by adjusting the amount of ballast water stored by the ballast system. The floating body 2 is equipped with a control unit 2d for controlling the ballast system. The ballast system is controlled by the control unit 2d. Note that the control unit 2d is not shown in figures other than Figure 1. As illustrated in Figure 2, the vertical distance (thickness) H1 from the upper end to the lower end of the floating body 2a is, for example, about 3m to 10m. As illustrated in Figure 3, the vertical length L1 and horizontal width L2 of the semi-submersible floating body 2 (floating body 2a) in a plan view are about 60m to 100m, respectively. In this embodiment, the center of gravity G1 of the floating body 2 is located in the center of the floating body 2 in a plan view.

[0016] The shape and structure of the floating body 2 (for example, the shape and structure of the floating body main body 2a and columns 2b, the number and arrangement of columns 2b, etc.) are not limited to the configuration of this embodiment, and various other configurations of the floating body 2 can be used. In this embodiment, a semi-submersible type floating body 2 is shown as an example, but when constructing a TLP type floating offshore wind power generation facility 1, a known TLP type floating body 2 is used, and when constructing a barge type floating offshore wind power generation facility 1, a known barge type floating body 2 is used.

[0017] As illustrated in Figures 4 and 5, this construction method uses a floating guidance unit 10 for controlling the movement and maintaining a fixed point of the floating body 2. As illustrated in Figures 6 and 7, the floating guidance unit 10 is installed on the floating body 2 for use. As illustrated in Figure 6, when the floating body 2 with the floating guidance unit 10 installed is floating in the sea in a semi-submerged state, the floating guidance unit 10 makes it possible to propel the floating body 2 on its own.

[0018] As illustrated in Figures 4 and 5, the floating guidance unit 10 comprises a frame 11 that can be attached to and detached from the floating body 2, a plurality of propulsion devices 12 installed on the frame 11 at a distance from each other, a position information acquisition means 13 that acquires position information of a predetermined position on the frame 11, and a control device 14. The floating guidance unit 10 in this embodiment further includes a drive source supply means 15 that supplies a drive source (electricity or hydraulics) to each device that requires one, and a control room 16 used by an administrator who manages (monitors) the construction of the floating body 2.

[0019] The frame structure 11 has a mounting section 11a that is placed on the floating body 2 and a support section 11b erected on the mounting section 11a. The mounting section 11a is formed by combining a plurality of horizontally extending metal frame materials in a grid pattern in plan view. For example, structural steel or square steel pipes can be used for the aforementioned metal frame materials. In this embodiment, the outer shape of the mounting section 11a is formed in a square shape in plan view, and the support section 11b is positioned in the center of the mounting section 11a. The vertical length L3 and horizontal width L4 of the mounting section 11a in plan view can be appropriately determined according to the size of the floating body 2, but are set to, for example, 10m or more and 70m or less. Propulsion devices 12 are arranged at each of the four corners of the mounting section 11a.

[0020] As illustrated in Figure 5, the frame section 11b is composed of a plurality of columns erected on the mounting section 11a, a plurality of beams connecting the upper parts of adjacent columns, and a top plate fixed to the upper parts of the columns and beams. The vertical distance H2 from the lower end of the frame structure 11 to the upper end of the frame section 11b is set to, for example, 5m or more and 15m or less. A position information acquisition means 13, a control device 14, a drive source supply means 15, and a control room 16 are arranged on the frame section 11b (top plate).

[0021] The frame structure 11 is further provided with multiple connecting parts 17 to which the suspension device 21 (wire rope) can be attached. In this embodiment, connecting parts 17 are provided at each of the four corners of the support base 11b (top plate). The number and arrangement of connecting parts 17 provided on the frame structure 11 are not limited to this embodiment and can be appropriately determined according to the shape and size of the frame structure 11. For example, connecting parts 17 can also be provided on the mounting part 11a.

[0022] As illustrated in Figures 2 and 3, the floating body 2 (floating body main body 2a) is provided with fixing means 18 used to fix the frame assembly 11 to the floating body 2. In this embodiment, a plurality of guide members 18a are arranged on the floating body main body 2a as fixing means 18. As illustrated in Figures 6 and 7, when the mounting portion 11a of the frame assembly 11 is placed on the floating body 2, the frame members constituting the mounting portion 11a fit between the guide members 18a, thereby fixing the frame assembly 11 to the floating body 2 in a detachable manner. In this embodiment, the four frame members constituting the outer frame of the mounting portion 11a are each fixed by a plurality of guide members 18a provided on the mounting portion 11a. The upper surface of the guide members 18a is provided with an inclined surface that guides the frame members of the mounting portion 11a between the guide members 18a. With the frame structure 11 placed on the floating body 2, the propulsion devices 12 are positioned to avoid the floating body 2 (outside the floating body 2).

[0023] As illustrated in Figures 4 and 5, the propulsion system 12 includes a thruster 12a that generates thrust, a support shaft 12b that supports the thruster 12a, and a drive unit 12c that rotatably supports the support shaft 12b. The thruster 12a is preferably composed of a thruster (propeller and motor), but it can also be composed of other thrusters, such as a water jet thruster. The thruster 12a is connected to the tip of the support shaft 12b. The rear of the support shaft 12b is supported by the drive unit 12c. The drive unit 12c is fixed to the frame 11 (mounting part 11a).

[0024] The drive unit 12c rotates the support shaft 12b, allowing the support shaft 12b to be switched between a state where it extends downwards below the frame assembly 11 and a state where it extends laterally outwards from the frame assembly 11. When the support shaft 12b is extended downwards, the thruster 12a is positioned below the lower end of the frame assembly 11. By rotating the thruster 12a itself (the propeller and motor unit) horizontally while the support shaft 12b is extended downwards, the direction of the thrust generated by the thruster 12a can be changed.

[0025] As illustrated in Figure 4, with the support shaft 12b extending downward, the planar separation distances D1 and D2 between adjacent propulsion devices 12 (centers of thrusters 12a) are set to, for example, 10m or more and 50m or less. As illustrated in Figure 5, with the support shaft 12b extending downward, the vertical distance H3 from the lower end of the frame 11 (mounting section 11a) to the lower end of the thruster 12a is set to, for example, 4m or more and 14m or less. As illustrated in Figure 6, with the frame 11 mounted on the floating body 2, with the support shaft 12b extending downward, the thruster 12a protrudes below the lower end of the floating body 2. In the above state, the vertical distance H4 from the lower end of the floating body 2 to the lower end of the thruster 12a is set to, for example, 1m or more and 4m or less.

[0026] The position information acquisition means 13 is composed of, for example, a GNSS (Global Navigation Satellite System) receiving device that acquires position coordinate data from the Global Positioning System. The position information acquisition means 13 is, for example, a positioning system using GNSS (Global Navigation Satellite System). The position information acquisition means 13 acquires position information of a predetermined position in the floating guidance unit 10. Figure 19 is a diagram illustrating the position information acquisition means 13 in the floating guidance unit 10. The position information acquisition means 13 comprises a receiving unit 13a and a conversion unit 13b. The receiving unit 13a receives transmitted radio waves GS transmitted from multiple satellites S. The receiving unit 13a includes an antenna for receiving transmitted radio waves GS. The number of antennas included in the receiving unit 13a may be one or two or more. In this embodiment, the receiving unit 13a of the position information acquisition means 13 (GNSS receiver) is positioned at a predetermined location on the floating guidance unit 10, for example, at the center (center) in a plan view on the frame structure 11 (on the mounting base 11b). The receiving unit 13a can be located at any position on the floating guidance unit 10 (either on the frame structure 11 or on the propulsion device 12). The conversion unit 13b measures the time it takes for radio waves from multiple satellites to reach the receiver. The conversion unit 13b converts these measured time differences into distance and calculates the position based on the distance from each satellite. The position information acquisition means 13 is not limited to a GNSS receiver; other positioning devices and positioning systems can be used as long as they are configured to acquire position information from a predetermined location on the frame structure 11. The predetermined location from which position information is acquired by the position information acquisition means 13 is not particularly limited and can be set to any other location. In the drawing, the position information acquisition means 13 is shown by the receiving unit 13a.

[0027] Alternatively, instead of the conversion unit 13b, a control device inside the control room 16 on the floating guidance unit 10 may perform the above-mentioned time measurement, time difference distance conversion, and satellite position calculation using the reception results from the receiver. Furthermore, the reception results from the receiver may be transmitted via wired or wireless communication to a computer located at a distance from the floating guidance unit 10, such as a floating body, a water structure, or a quay, for example, a server, a mobile PC, or a smartphone. In addition, instead of the conversion unit 13b, the above-mentioned time measurement, time difference distance conversion, and satellite position calculation may be performed by a computer located at a distance from the floating guidance unit 10. In other words, a part of the position information acquisition means 13 may be located at a distance from the main body of the floating guidance unit 10 to remotely control the fixed-point holding or movement of the floating body 10.

[0028] The control device 14 is composed of a computer or the like. Based on the position information input from the position information acquisition means 13, the control device 14 controls each of the multiple propulsion devices 12 to perform at least one of either movement control or fixed-point holding control of the floating body 2. It is preferable that the control device 14 is configured to perform both movement control and fixed-point holding control of the floating body 2. The propulsion devices 12 and the position information acquisition means 13 may communicate with the control device 14 via wired communication cables, or they may communicate via wireless communication.

[0029] The control device 14 (control means) will be described in more detail. Figure 20 is a diagram illustrating the control device 14 (control means) in the floating guidance unit 10. The control device 14 comprises a controller 14a and a driver 14b. The controller 14a generates a control signal for controlling the fixed-point holding or movement of the floating body 2 based on position information input from the position information acquisition means 13. The driver 14b generates a drive signal for driving the drive source supply means 15, which supplies power to operate the propulsion device 12, based on the control signal from the controller 14a. The drive source supply means 15 supplies a drive source to the propulsion device 12 based on the drive signal from the driver 14b. Alternatively, a part of the control device 14 (control means) may be located away from the main body of the floating guidance unit 10 to remotely control the fixed-point holding or movement of the floating body 10.

[0030] The control room 16 is, for example, constructed as a prefabricated house (a so-called prefabricated building). Inside the control room 16 are a control device (computer and input means) that is communicatively connected to the position information acquisition means 13 and the control device 14, a monitor connected to the control device, and a control means used when manually operating the floating guidance unit 10. When the administrator inputs position information (coordinate information) of the target position to which the floating body 2 will be moved, target path information of the floating body 2 to the target position, and position information of the target position for holding the floating body 2 at a fixed point into the control device, the input position information of the target position and target path information are transmitted to the control device 14.

[0031] In this embodiment, the control device 14 is configured to switch between an automatic control mode and a manual control mode via a management device. In automatic control mode, the control device 14 automatically performs movement control to move the floating body 2 to the target position and fixed-point holding control to keep the floating body 2 at the target position by controlling each of the multiple propulsion devices 12 based on the coordinate information of the target position input from the management device and the position information input from the position information acquisition means 13. When target path information for the floating body 2 to the target position is input from the management device, the control device 14 performs movement control to move the floating body 2 along the target path to the target position by controlling each of the multiple propulsion devices 12 based on the input target path information and the position information input from the position information acquisition means 13. In movement control, the speed at which the floating body 2 is moved by the floating body guidance unit 10 can be changed and adjusted by inputting a numerical value for the floating body 2's movement speed to the management device.

[0032] In manual control mode, the control device 14 controls each of the multiple propulsion devices 12 so that the floating body 2 moves in the direction input by the control means. When the direction of movement is set to neutral (center) by the control means, the control device 14 controls each of the multiple propulsion devices 12 so that the floating body 2 is held in place at a fixed point. The speed at which the floating body guidance unit 10 moves the floating body 2 can also be changed and adjusted by the operation of the control means (for example, the degree to which the control lever is tilted). The control device 14 is configured to automatically switch from automatic control mode to manual control mode when the control means is operated while it is set to automatic control mode.

[0033] The monitor located in the control room 16 displays information necessary for managing (monitoring) the guidance of the floating body 2 by the floating body guidance unit 10. Specifically, the monitor displays coordinate information of the target position and target route information entered by the administrator into the management device, position information entered into the management device from the position information acquisition means 13, nautical chart information of the sea area in which the floating body 2 is guided, and the control status of each propulsion device 12 entered from the control device 14. The monitor displays a nautical chart of the sea area in which the floating body 2 is guided, and the current position of the floating body 2 acquired by the position information acquisition means 13, the target position for moving or holding the floating body 2 at a fixed point, and the target route of the floating body 2 are displayed on the nautical chart as needed.

[0034] Furthermore, in this embodiment, the management device is configured to communicate with the ballast system, and the amount of ballast water stored in the floating body 2 can be adjusted by operating the ballast system via the management device. For example, the management device controls the ballast system via the control unit 2d. The monitor is configured to also display the amount of ballast water stored in the floating body 2. The position information acquisition means 13, the control device 14, and the ballast system may each communicate with the management device via a wired communication cable, or they may communicate via wireless communication.

[0035] The power source supply means 15 is composed of, for example, a power generator and a hydraulic system. In this embodiment, the propulsion device 12, position information acquisition means 13, control device 14, and control room 16 are each connected to the power generator that constitutes the power source supply means 15 via power cables. In addition, the propulsion device 12 (drive unit 12c) is connected to the hydraulic system that constitutes the power source supply means 15 via hydraulic piping. Note that the control device, monitor, control means, ballast device, power cables, hydraulic piping, and communication cables mentioned above are omitted from the figures. As illustrated in Figure 4, the components constituting the floating guidance unit 10 should be laid out so that the center of gravity G2 of the floating guidance unit 10 is located in the center (preferably the center) of the floating guidance unit 10 in a plan view.

[0036] The construction method for a floating offshore wind power generation facility 1 using a floating guidance unit 10 is described below.

[0037] As illustrated in Figures 4 and 5, a floating guidance unit 10, comprising a frame 11, multiple propulsion devices 12, position information acquisition means 13, and control device 14, is assembled in advance on land or on a ship and prepared beforehand. In this embodiment, a drive source supply means 15 and a control room 16 (management device, monitor, and control means) are also mounted on the frame 11. As illustrated in Figure 5, when assembling the floating guidance unit 10 on land or on a ship, or when transporting the assembled floating guidance unit 10 by crane ship or the like, it is preferable to prepare a support base 22 that is higher than the vertical distance H3 from the lower end of the frame 11 to the lower end of the propulsion device 12a, and place the floating guidance unit 10 (frame 11) on the support base 22. Alternatively, the propulsion device 12 can be rotated horizontally by rotating the propulsion device 12a itself (propeller and motor unit) horizontally while the support shaft 12b extends downward to change the orientation of the propulsion device 12a.

[0038] Then, as illustrated in Figure 2, the installation of the floating body guidance unit 10 on the floating body 2 is carried out in a calm sea area where the influence of waves is small. Preferably, the aforementioned installation work is carried out in the sea area inside a breakwater installed in a bay or the like. In this embodiment, an example is given of installing the floating body guidance unit 10 on the floating body 2 which is floating in a semi-submerged state in a calm sea area. For example, a mound can be made on the seabed SB, and the floating body guidance unit 10 can be installed on the floating body 2 which is resting on the mound.

[0039] As illustrated in Figure 2, when installing the floating body guidance unit 10 on the floating body 2, it is preferable to adjust the amount of ballast water stored in the floating body 2 so that the fixing means 18 (guide member 18a) is positioned on the water surface and the floating body 2 floats in the sea in a semi-submerged state. If the floating body 2 is swaying due to the effects of waves, the floating body 2 may be simply moored to the seabed SB. Then, the floating body guidance unit 10 is lifted above the floating body 2 using a crane such as a crane ship. In this embodiment, the lifting device 21 is connected to the wire rope 20 of the crane of the crane ship, and the wire rope of the lifting device 21 is connected to the connecting part 17 provided on the frame structure 11 (support structure 11b). If the floating body 2 is located in a position close to land, such as a quay, the floating body guidance unit 10 can also be lifted onto the floating body 2 using a crane or the like located on land.

[0040] Next, the floating guidance unit 10, which is suspended by the crane, is gradually lowered from above the floating body 2. Then, as illustrated in Figures 6 and 7, the frame assembly 11 (mounting section 11a) is placed on the floating body 2, and the frame assembly 11 is fixed to the floating body 2 by the fixing means 18. In this embodiment, the frame assembly 11 can be easily fixed to the floating body 2 by fitting the frame material constituting the frame assembly 11 (mounting section 11a) between the guide members 18a provided on the floating body body 2a. Then, by releasing the suspension of the floating guidance unit 10 by the crane of the crane ship, the installation work of the floating guidance unit 10 to the floating body 2 is completed. The statement that the floating guidance unit 10 is detachable from the floating body 2 does not mean that the floating guidance unit 10 is detachable from the floating body 2, as long as it is detachable from the floating body 2, as described above, by suspending the floating guidance unit 10 with a crane or the like. For example, the floating guidance unit may have a submersible function, with a part of it submerging below the water surface before attaching to the floating body 2, and then submerging again after moving to a predetermined water area to detach from the floating body 2. Alternatively, the floating guidance unit may self-propel on the water surface, ride up onto the floating body 2, be placed on the floating body 2, and then detach after moving to a predetermined water area to detach from the floating body 2.

[0041] As illustrated in Figure 7, preferably, the floating guidance unit 10 is installed relative to the floating body 2 such that the distance between the center of gravity G1 of the floating body 2 and the center of gravity G2 of the floating guidance unit 10 in a plan view is, for example, 10 m or less, more preferably 3 m or less, and even more preferably the center of gravity G1 of the floating body 2 and the center of gravity G2 of the floating guidance unit 10 coincide. In other words, when the floating guidance unit 10 is installed relative to the floating body 2, it is preferable to lay it out such that the distance between the center of gravity G2 of the floating body 2 and the center of gravity G2 of the floating guidance unit 10 in a plan view is 10 m or less, more preferably 3 m or less, and even more preferably the center of gravity positions G1 and G2 coincide. By designing both the floating body 2 and the floating guidance unit 10 so that their center of gravity positions coincide or are in close proximity, the oscillations caused by wind and waves can be reduced, improving capsizing resistance and propulsion performance by the propulsion device.

[0042] Next, as illustrated in Figure 8, the floating body 2 is moved using the floating body guidance unit 10 installed on the floating body 2 to the assembly work area OA (assembly work water area) near the floating structure 30 on which the assembled components constituting the wind power generation device 3 are placed and temporarily stored.

[0043] The floating structure 30 is designed to be large enough to temporarily store multiple sets of assembled components for the wind turbine 3, including the nacelle hub 5, blades 6, and tower 4 (divided member 4a), and to be structurally capable of withstanding the weight of the multiple sets of assembled components. In this embodiment, a rectangular floating structure 30 in plan view is shown as an example. The length of the floating structure 30 in the longitudinal direction in plan view is set to be, for example, 150m to 450m, and the width is set to be, for example, 80m to 120m.

[0044] As illustrated in Figure 9, in this embodiment, a pier is constructed in the sea as the floating structure 30. The floating structure 30 is preferably constructed in a sea area where the water depth DW (depth from the sea surface position WL to the seabed SB) is 8m or more and 20m or less. The components used to construct the floating structure 30 are transported to the construction area of ​​the floating structure 30 using a transport ship or the like, and the floating structure 30 is constructed in the sea area using a known method. For example, a floating structure can also be constructed in the sea area as the floating structure 30. It is preferable to construct the floating structure 30 in a calm sea area where the influence of waves is small. The assembled components that make up the wind power generation device 3 are transported using a transport ship (specifically, for example, a LOLO ship, etc.) and temporarily placed on the floating structure 30 using the crane on the transport ship.

[0045] As illustrated in Figure 8, in this embodiment, multiple work areas WA are provided in the sea area adjacent to the floating structure 30 for assembly work on the assembly 7 and subsequent additional work. The size and shape of the floating structure 30, and the number of work areas WA provided in the sea area adjacent to the floating structure 30, can be appropriately determined according to the number of floating offshore wind power generation facilities 1 to be constructed.

[0046] Each work area WA is large enough to accommodate the floating body 2 and the self-elevating barge 50 (hereinafter referred to as SEP vessel 50), and each work area WA includes a bottoming area BA for resting the floating body 2 and a mooring area SA for mooring the SEP vessel 50. In Figure 8, the virtual outer frame of each work area WA is shown by a dashed line, and the virtual outer frame of the bottoming area BA and mooring area SA is shown by a dashed line. Each bottoming area BA is provided with a mound M for resting the floating body 2. It should be noted that the extent and boundaries of each work area WA only need to be known by the workers and managers involved in the construction, and it is not necessary to visualize the extent of each work area WA in the sea area.

[0047] In the movement control that moves the floating body 2 to the bottoming area BA using the floating body guidance unit 10, target path information from the position where the floating body guidance unit 10 is installed on the floating body 2 to the target position T set in the bottoming area BA is input to the management device, and the control device 14 is set to automatic control mode. When the target path information of the floating body 2 is input to the management device, that target path information is transmitted to the control device 14. The control device 14, set to automatic control mode, controls the multiple propulsion devices 12 based on the input target path information and the position information input from the position information acquisition means 13, thereby performing movement control to move the floating body 2 along the target path to the target position T, for example, by the shortest possible path as shown as RT1. Alternatively, movement control may be performed to move to the target position T by a detour path, for example, as shown as RT2. The movement path to the target position T is not limited to the above example, and may be moved by a different path. Furthermore, if the floating body deviates from the target movement path due to wind, waves, etc., it may be controlled to move along the target movement path as appropriate.

[0048] When the control device 14 controls the movement of the floating body 2 by the floating body guidance unit 10, it sets the direction in which each thruster 12a generates thrust to move the floating body 2 along the target path toward the target position T and to suppress the floating body 2 from deviating from the target path, and sets the magnitude of the thrust of each thruster 12a appropriately according to the set target movement speed.

[0049] Then, based on the target path information and the position information input from the position information acquisition means 13, the control device 14 controls the thrust of the thrusters 12a that are generating thrust in the direction of moving the floating body 2 closer to the target path to be relatively larger than the thrust of the thrusters 12a that are generating thrust in the direction of moving the floating body 2 away from the target path if the floating body 2 deviates from the target path due to the influence of waves, water currents, etc. Alternatively, the control device 14 controls the thrust of the thrusters 12a that are generating thrust in the direction of moving the floating body 2 away from the target path to be relatively smaller than the thrust of the thrusters 12a that are generating thrust in the direction of moving the floating body 2 closer to the target path. Alternatively, the control device 14 increases the thrust in the direction of moving the floating body 2 closer to the target path by changing the direction in which thrust is generated by one or more thrusters 12a.

[0050] The control device 14 returns the floating body 2, which has deviated from the target path, to the target path by performing at least one of the aforementioned controls. The control device 14 performs movement control to move the floating body 2 along the target path to the target position T by continuously and repeatedly performing such controls.

[0051] The sea area in which the floating body 2 is being moved may have other vessels navigating it or obstacles such as driftwood. Therefore, when the control device 14, which is set to automatic control mode, is moving the floating body 2 along the target path, if there is a risk of the floating body 2 colliding with another vessel or an obstacle, the administrator will operate the steering means to switch the control device 14 to manual control mode. The administrator will then operate the steering means to move the floating body 2 in a direction that avoids collision with the other vessel or obstacle. Alternatively, the administrator will change or adjust the speed of the floating body 2 to a speed that avoids collision with the other vessel or obstacle. After avoiding a collision between the floating body 2 and the other vessel or obstacle, the control device 14 will be switched back to automatic control mode and the floating body 2 will be returned to the target path.

[0052] For example, the floating guidance unit 10 can be equipped with a monitoring system that automatically detects other ships and obstacles in the surrounding area using a 360-degree camera or LiDAR sensor. In that case, the control device 14, which is set to automatic control mode, can be configured to perform hazard avoidance control by temporarily changing the direction of movement of the floating body 2 in a direction that avoids collision with the detected other ships or obstacles, based on the detection results of the monitoring system.

[0053] After moving the floating body 2 to the target position T in the work area WA (settling area BA), the floating body guidance unit 10 installed on the floating body 2 is used to perform fixed-point holding control to keep the floating body 2 at the target position T. Then, while performing fixed-point holding control of the floating body 2 with the floating body guidance unit 10, the ballast device is operated to increase the amount of ballast water stored in the floating body 2, causing the floating body 2 to gradually sink at the target position T. Finally, the floating body 2 is brought to the bottom on the mound M located on the seabed SB in the work area WA (settling area BA).

[0054] When the floating body guidance unit 10 performs fixed-point holding control of the floating body 2, the control device 14 sets the direction in which each thruster 12a generates thrust toward the center (or outward) of the floating body 2, and sets the thrust of each thruster 12a to the same magnitude. In other words, each thruster 12a generates a water flow with the same force toward the outside (or inside) of the floating body 2. Then, based on the position information input from the position information acquisition means 13, if the floating body 2 moves (shifts) from the target position T for fixed-point holding due to the influence of waves, water currents, etc., the control device 14 controls the thrust of the thruster 12a that is generating thrust in the direction of bringing the floating body 2 closer to the target position T (returning it) to be relatively larger than the thrust of the other thrusters 12a. Alternatively, the control device 14 controls the thrust of the thruster 12a that is generating thrust in the direction of moving the floating body 2 away from the target position T, making it relatively smaller than the thrust of the other thrusters 12a. The control device 14 returns the floating body 2 to the target position T by performing at least one of the above controls. The control device 14 performs fixed-point holding control to keep the floating body 2 at the target position T by continuously and repeatedly performing such control.

[0055] As illustrated in Figures 10 and 11, the mound M is shaped such that the thrusters 12a constituting each propulsion device 12 do not interfere with each other when the floating body 2 on which the floating guidance unit 10 is installed is brought to the bottom. In other words, the mound M is shaped by cutting out the area where the thrusters 12a are placed, or by creating a recess in the area where the thrusters 12a are placed. The mound M is formed, for example, by arranging stones or sandbags on the seabed SB. In this embodiment, a cross-shaped (X-shaped) mound M is provided in plan view, and a floating body 2, which is cross-shaped (X-shaped) in plan view, is brought to the bottom on the mound M.

[0056] As illustrated in Figure 10, with the support shaft 12b extending downwards, the height H5 of the mound M is set higher than the vertical distance H4 from the lower end of the floating body 2 to the lower end of the thruster 12a so that the thruster 12a does not come into contact with the seabed SB. Furthermore, the height H5 of the mound M should be set so that the upper end of the support base 11b is above the sea surface position WL when the floating body guidance unit 10 is installed on the floating body 2. Specifically, the height H5 of the mound M should be set to, for example, 2m or more and 5m or less. The shape of the mound M is not limited to this embodiment and can be appropriately determined according to the shape of the floating body 2 and the arrangement of the propulsion device 12.

[0057] As illustrated in Figure 10, when the floating body 2 is set afloat on the mound M, the propulsion device 12 located on the mounting section 11a and the lower part of the support section 11b become submerged, but the upper part of the support section 11b is positioned higher than the sea surface level WL. As a result, the area on the support section 11b becomes a dry area, and the submersion of the position information acquisition means 13, control device 14, drive source supply means 15, and control room 16 located on the support section 11b is avoided. It is preferable to position the floating body 2 such that the column 2b having the tower fixing section 2c is oriented toward the water structure 30 side and the mooring area SA side.

[0058] Using the method described above, as illustrated in Figure 8, the floating bodies 2, each equipped with a floating guidance unit 10, are sequentially lowered to the bottom of the mound M in each work area WA. Then, the SEP vessel 50 is positioned to rest in the mooring area SA of any of the work areas WA.

[0059] As in this embodiment, when the floating structure 30 is constructed in a sea area with a water depth DW of 8m or more and 20m or less, the floating body 2 and the SEP vessel 50 can be safely moved to the work area WA near the floating structure 30. Also, in a sea area with a water depth DW of 8m or more and 20m or less, the floating body 2 can be easily settled on a mound M provided on the seabed SB, and the assembly parts of the wind power generation device 3 can be installed on the floating body 2 while it is settled on the mound M. In other words, in a sea area with a water depth DW of less than 8m, the water depth DW is too shallow, making it difficult to move the floating body 2 and the SEP vessel 50 to the vicinity of the floating structure 30. In a sea area with a water depth DW of more than 20m, the water depth DW is too deep, making it difficult to install the assembly parts of the wind power generation device 3 on the floating body 2 while it is settled on the seabed SB.

[0060] As illustrated in Figures 8 and 9, the SEP vessel 50 comprises a mobile barge body (platform) 51, a plurality of lifting legs 52 that are vertically movable relative to the barge body 51, and a large crane 53 mounted on the barge body 51. The SEP vessel 50 is moored so that the bow or stern side, where the crane 53 is mounted, is aligned with the side of the water structure 30.

[0061] When stopping the SEP vessel 50, the lifting legs 52 are moved downward relative to the floating barge body 51 in the sea area, so that the lower ends of each lifting leg 52 touch the seabed SB. From that state, the barge body 51 is moved upward relative to each lifting leg 52, so that the barge body 51 is raised to a position above the sea surface, and the barge body 51 is supported in mid-air by the lifting legs 52. By raising the barge body 51 to a height where it is not reached by waves, the barge body 51 becomes unaffected by waves. The water depth at which the SEP vessel 50 can be stopped by the lifting legs 52 is generally 40m or less. By constructing a floating structure 30 in a sea area with a water depth DW of 8m or more and 20m or less, the SEP vessel 50 can be stopped in a stable state in the work area WA near the floating structure 30.

[0062] Subsequently, using the crane 53 of the SEP vessel 50, which is moored in the work area WA (mooring area SA), an assembly operation is carried out to install a set of assembly parts onto the floating body 2, which is resting on the mound M in the bottoming area BA, thereby assembling the assembly 7 on which the wind power generation device 3 is constructed.

[0063] Specifically, first, the crane 53 of the SEP vessel 50 is used to install the segmented member 4a, which forms the base of the tower 4 temporarily placed on the floating structure 30, onto the tower fixing part 2c of one column 2b of the floating body 2. Next, the crane 53 of the SEP vessel 50 is used to connect the segmented member 4a, which forms the middle section of the tower 4 temporarily placed on the floating structure 30, onto the segmented member 4a that forms the base of the tower 4. Then, similarly, the segmented member 4a that forms the upper end of the tower 4 is connected onto the segmented member 4a that forms the middle section of the tower 4, thereby erecting the tower 4 on the column 2b. Next, as illustrated in Figure 12, the crane 53 is used to install the nacelle hub 5, which is temporarily placed on the floating structure 30, onto the top of the tower 4. After that, the crane 53 is used to attach the three blades 6, which are temporarily placed on the floating structure 30, to the nacelle hub 5. By performing the above operations, the assembly of the assembly body 7 is completed in one work area WA, as illustrated in Figure 13.

[0064] Subsequently, as illustrated in Figure 13, the SEP vessel 50 moves from the work area WA where the assembly work has been completed to another work area WA and stops. Then, using the crane 53 of the SEP vessel 50, the same assembly work is performed on the floating body 2 which is resting on the mound M in that work area WA. In parallel with this, additional work, including adjustment work, is performed on the assembly 7 which has already been assembled. Additional work is preparatory work performed on the assembly 7 before it is transported to the installation area, and specifically includes pre-commissioning work. Pre-commissioning work involves setting up, testing, and adjusting the electrical equipment of the assembly 7. In this embodiment, additional work is performed on the assembly 7 which has already been assembled in the work area WA where the assembly work has been completed.

[0065] After completing the additional work and confirming that there are no abnormalities in the wind power generation device 3, the assembly 7 sequentially uses the floating guidance unit 10 to control the floating body 2's fixed position and reduces the amount of ballast water stored in the floating body 2 using the ballast device, thereby causing it to float away from the mound M. The floating body 2 with the floating guidance unit 10 installed is then floated in the sea area in a semi-submerged state. When raising the floating body 2 with the floating guidance unit 10 installed, each propulsion device 12 is activated to generate thrust in each thruster 12a. Then, based on the position information input from the position information acquisition means 13, the control device 14 controls the multiple propulsion devices 12 to gradually raise the floating body 2 while performing fixed-point control to keep it at the target position T when it was resting on the mound M.

[0066] Then, with the floating body 2 of the assembly 7 floating in the sea area in a semi-submerged state, the assembly 7 with the wind turbine 3 erected on the floating body 2 is moved to the installation area IA (the target water area). By using the floating guidance unit 10, it is also possible to propel the assembly 7 with the floating guidance unit 10 installed from the assembly work area OA to the installation area IA, but the distance to travel from the assembly work area OA to the installation area IA may be long. In such cases, it is preferable to connect one or two towboats to the floating body 2 with the floating guidance unit 10 installed, and while controlling the movement of the floating body 2 with the floating guidance unit 10, tow the floating body 2 with a small number of towboats to the vicinity of the target position set in the installation area IA.

[0067] Specifically, target path information is input to the control device from the position where the assembly 7 has been attached to the floating body 2 to the position where the connection with the tugboat is released near the target position set in the target sea area IA, and the control device 14 is set to automatic control mode. Once the target path information is input and the control device 14 is set to automatic control mode, it controls the multiple propulsion devices 12 based on the input target path information and the position information input from the position information acquisition means 13 to move the floating body 2 along the target path to the position where the connection with the tugboat is released. By controlling the movement of the assembly 7 (floating body 2) with the floating body guidance unit 10, it becomes possible to move the assembly 7 along the target path more stably even when the assembly 7 is towed by a small number of tugboats.

[0068] Then, after moving the assembly 7 to the vicinity of the target position in the sea area IA where it will be installed, the floating guidance unit 10 controls the fixed position of the assembly 7 (floating body 2) in the sea area near the target position, while disconnecting the floating body 2 from the tugboat. After that, the floating guidance unit 10 controls the movement, allowing the assembly 9 to self-propel to the target position in the sea area IA where it will be installed.

[0069] As illustrated in Figure 14, at the target location in the sea area IA where the installation will take place, the floating guidance unit 10 installed on the floating body 2 is used to maintain the assembly 7 (floating body 2) at a fixed point at the target location while performing the mooring operation of the assembly 7. In this embodiment, the floating body 2 is moored to the seabed SB using a mooring rope 8a and an anchor 8b as the mooring means 8. After that, a seabed cable is connected to the wind turbine 3, and the final operational check (so-called final commissioning) of the floating offshore wind power generation facility 1 is performed. With this, the construction of the floating offshore wind power generation facility 1 is completed.

[0070] After the construction of the floating offshore wind power generation facility 1 is completed, the floating guidance unit 10 is removed from the floating body 2. Specifically, the floating guidance unit 10 is separated from the floating body 2 by lifting it using a crane on a crane ship or the like. Separating the floating guidance unit 10 from the floating body 2 by lifting is easy because the process can be carried out while visually monitoring the crane operation. In particular, in wind power generation facilities where the wind power generation device 3, after the blades 6 are attached, is located far from the center of gravity G1 of the floating body 2, in other words, wind power generation facilities where the wind power generation device 3 is located near the periphery rather than in the center of the floating body 2 (floating offshore wind power generation facility 1 in this embodiment and the floating offshore wind power generation facilities shown in Figures 17 and 18), there is an advantage that space can be secured above the floating guidance unit 10 for the crane to access, and isolation from above can be carried out while preventing collision with the blades. In other words, the method of attaching and detaching the suspended / lifted floating guidance unit has the advantage of being easy and safe to perform during the isolation process of the floating guidance unit after the wind power generation facility has been installed on the floating body. After isolation, the floating guidance unit 10 can be reused by installing it on another floating body 2.

[0071] As described above, in this construction method, by preparing a floating guidance unit 10 in advance, which includes a frame 11, multiple propulsion devices 12, position information acquisition means 13, and control device 14, multiple propulsion devices 12 and control device 14 that enable at least one of either movement control or fixed-point holding control of the floating body 2 can be easily and quickly installed on the floating body 2.

[0072] Because the floating bodies 2 that make up the floating offshore wind power generation facility 1 are large in size and heavy, multiple relatively large propulsion devices 12 are required to move and maintain the floating bodies 2 in a fixed position. For example, if multiple propulsion devices 12, position information acquisition means 13, control devices 14, etc. are installed separately on the floating bodies 2 without preparing a floating body guidance unit 10, the installation work using a crane will require a lot of manpower and time. In contrast, with this construction method, by preparing the floating body guidance unit 10 in advance, it is possible to mount various equipment necessary for controlling the movement and fixed position of the floating bodies 2 onto the floating bodies 2 in a single installation operation using a crane.

[0073] After installing the floating body guidance unit 10 on the floating body 2, the control device 14 controls multiple propulsion devices 12 based on the position information input from the position information acquisition means 13. This makes it possible to efficiently control the movement or fixed-point maintenance of the floating body 2 without connecting a large number of tugboats to the floating body 2. In other words, by installing the floating body guidance unit 10 on the floating body 2, the floating body 2 can be made self-propelled. In conventional methods that use a large number of tugboats to move or maintain the floating body 2, a manager responsible for managing (monitoring) the floating body 2 needs to send instructions to the operators of each tugboat, which requires relatively complicated management. However, with this construction method, by using the floating body guidance unit 10, such complicated management becomes unnecessary. Furthermore, if tugboats are not used, a separate operator for each tugboat is not required. Even when connecting a small number of tugboats, such as one or two, to the floating body 2 (assembly 7) on which the floating guidance unit 10 is installed, the number of operators for the tugboats can be reduced, making it possible to move and maintain the floating body 2 with fewer workers.

[0074] Furthermore, this construction method eliminates the need to connect numerous towboats to the floating bodies 2, making it possible to position the floating bodies 2 closer together. Therefore, as illustrated in Figure 9, even when constructing a base (floating structure 30) for assembling the wind turbines 3 for multiple floating bodies 2, it becomes unnecessary to secure a vast space for temporarily storing the assembly parts of the wind turbines 3, as in conventional methods, and also eliminates the need to secure a vast space in the surrounding water. For example, even when using a small number of towboats, the connection between the floating bodies 2 and the towboats can be released at a certain distance from the assembly base, and the floating bodies 2 can be moved to the target position of the assembly base using movement control by the floating body guidance unit 10, thereby making it possible to position the floating bodies 2 closer together. In addition, since the floating bodies 2 can be positioned closer to the floating structure 30, the work of installing the assembly parts of the wind turbines 3 that have been temporarily placed on the floating structure 30 onto the floating bodies 2 becomes easier, and the assembly work of the assembly 7 can be carried out more efficiently. Therefore, this construction method is also advantageous for improving the construction efficiency of floating offshore wind power generation facilities. Furthermore, the floating guidance unit 10 can be reused. For this reason, this construction method is very beneficial to those skilled in the art.

[0075] As in this embodiment, configuring the floating guidance unit 10 to have four or more propulsion devices 12 is advantageous for accurately controlling the movement and maintaining a fixed point of the floating body 2 using the floating guidance unit 10. The floating guidance unit 10 only needs to have at least three propulsion devices 12. If the floating body 2 is large, five or more propulsion devices 12 can be provided, but providing five or more propulsion devices 12 increases the weight of the floating guidance unit 10. Therefore, considering the installation work of the floating guidance unit 10 on the floating body 2, it is preferable to provide four propulsion devices 12.

[0076] As illustrated in Figure 4, setting the separation distance (interval distance) D1 and D2 between adjacent propulsion devices 12 (centers of thrusters 12a) in a plan view to 10m or more and 50m or less, more preferably 15m or more and 45m or less, and even more preferably 20m or more and 40m or less, is advantageous for accurately controlling the movement and maintaining a fixed point of the floating body 2 using multiple propulsion devices 12. If the aforementioned separation distance (interval distance) D1 and D2 is less than 10m, adjacent propulsion devices 12 are close together, and multiple propulsion devices 12 will generate thrust near the center of the floating body 2, which is disadvantageous for accurately controlling the movement and maintaining a fixed point of the floating body 2. If the aforementioned separation distance (interval distance) D1 and D2 is greater than 50m, the frame 11 becomes excessively large relative to the floating body 2, which has the disadvantage of increasing the weight of the floating body guidance unit 10.

[0077] As illustrated in Figure 6, when the frame 11 is placed on the floating body 2 and the support shaft 12b extends downward, setting the vertical distance H4 from the lower end of the floating body 2 to the lower end of the thruster 12a to 1m or more and 4m or less, more preferably 1.5m or more and 3.5m or less, and even more preferably 2m or more and 3m or less is advantageous for accurately controlling the movement and maintaining a fixed point of the floating body 2 by the multiple thrusters 12. Setting the aforementioned vertical distance H4 to 1m or more makes it less likely for the water flow generated by the thruster 12a to hit the floating body 2, which is advantageous in avoiding the generation of thrust in an unintended direction by the thruster 12a. Setting the aforementioned vertical distance H4 to more than 4m has the disadvantage that the height H5 of the mound M on which the floating body 2 rests becomes excessively large.

[0078] If the frame structure 11 has a support base 11b erected on the mounting section 11a, the upper part of the support base 11b can be kept dry even when the mounting section 11a is submerged in water along with the floating body 2. Therefore, providing the support base 11b is advantageous in avoiding malfunctions of control devices 14 and other components that would be undesirable to be submerged in water. Placing the position information acquisition means 13 on the support base 11b is advantageous in avoiding a situation where the position information acquisition means 13 is submerged in water and unable to communicate.

[0079] As illustrated in Figure 7, when the floating guidance unit 10 is installed on the floating body 2 with the distance between the center of gravity G1 of the floating body 2 and the center of gravity G2 of the floating guidance unit 10 being 10m or less, more preferably 3m or less, and even more preferably with the center of gravity G1 of the floating body 2 and the center of gravity G2 of the floating guidance unit 10 coinciding, the balance between the floating body 2 and the floating guidance unit 10 becomes less likely to be disrupted when the floating guidance unit 10 is placed on the floating body 2. Therefore, this is advantageous for stably performing the installation work of the floating guidance unit 10 on the floating body 2. In addition, the balance of the floating body 2 with the floating guidance unit 10 installed also becomes less likely to be disrupted, which is advantageous for stably performing movement control and fixed-point holding control of the floating body 2 using the floating guidance unit 10.

[0080] By using the floating body guidance unit 10 installed on the floating body 2 to control its fixed position while sinking it, the floating body 2 can be brought to the bottom of the mound M, allowing it to sink to the mound M in a very stable state. Furthermore, by performing fixed-point control, the oscillation of the sinking floating body 2 can be reduced, which is advantageous for accurately aligning the floating body 2 with the mound M.

[0081] In another embodiment illustrated in Figures 15 and 16, a temporary storage base for the assembly components of the wind turbine 3 is provided on the quay 40, and multiple work areas WA are provided in the assembly work area OA near the quay 40 for assembling the assemblies 7 and subsequent additional work. The number and arrangement of work areas WA in the assembly work area OA can be appropriately determined according to the number of floating offshore wind turbines 1 to be constructed.

[0082] In this embodiment, a crane 60 (for example, a ring lift crane) for assembling the wind turbine 3 onto the floating body 2 is positioned on the quay 40, and multiple sets of assembly parts for the wind turbine 3 (divided members 4a of the tower 4, nacelle hub 5, and blades 6) are temporarily placed on the quay 40. In this embodiment, a floating body guidance unit 10 installed on the floating body 2 is used to control the movement of the floating body 2 to the assembly work area OA near the quay 40. Then, as illustrated in Figure 16, in the assembly work area OA near the quay 40, the floating body guidance unit 10 installed on the floating body 2 is used to control the floating body 2's fixed position, and the assembly parts for the wind turbine 3 are placed on the floating body 2, which is floating in a semi-submerged state, to assemble an assembly 7 with the wind turbine 3 erected on the floating body 2.

[0083] As in this embodiment, even when installing assembly parts of the wind power generation device 3 on a floating body 2 that is floating in a semi-submerged state, the floating body guidance unit 10 is used to control the floating body 2's fixed position, allowing the assembly parts to be installed on the floating body 2 in a stable state. This method causes the floating body 2 to sway slightly during the assembly work compared to the method of resting the floating body 2 on a mound M, but it can be used even when the water depth of the assembly work area OA is relatively deep, and it also has the advantage of not requiring the construction of a mound M on the seabed SB.

[0084] This construction method allows the floating bodies 2 to be positioned close together by using the floating body guidance unit 10. Therefore, even when setting up a base on the quay 40 for assembling wind power generation equipment 3 on multiple floating bodies 2, it is no longer necessary to secure a vast space on the quay 40 as in the conventional method, nor is it necessary to secure a vast space in the surrounding waters. Furthermore, because the floating bodies 2 can be positioned close to the quay 40, assembly work using a crane 60 positioned on the quay 40 becomes easier. By positioning the floating bodies 2 close together, for example, even when using a crane 60 fixed to the quay 40, it becomes possible to perform assembly work and additional work on, for example, two floating bodies 2. Note that the number of floating bodies 2 to be positioned is not limited to the example above, and may be three or more.

[0085] Furthermore, even when establishing an assembly base at the quay 40, for example, a mound M can be set up in the waters surrounding the quay 40, and the floating body 2 can be lowered onto the mound M using the floating body guidance unit 10, after which assembly and additional work can be performed on the floating body 2 that has settled on the mound M using the crane 60. Alternatively, even when establishing an assembly base at the quay 40, the SEP vessel 50 can be moored in the waters surrounding the quay 40, and assembly and additional work can be performed on the floating body 2 using the crane 53 mounted on the SEP vessel 50. For example, a movable crane 60 can also be installed at the quay 40.

[0086] In yet another embodiment illustrated in Figure 17, a floating guidance unit 10 applied to a TLP (Tension Leg Platform) type floating body 2 is illustrated. In the target sea area IA, the TLP type floating body 2 is forcibly fixed to the seabed SB in a semi-submerged state by tension mooring. As illustrated in Figure 17, the TLP type floating body 2 of this embodiment has a floating body body 2a that is substantially triangular in shape in plan view, and columnar columns 2b provided at each of the three corners of the floating body body 2a. A tower fixing part 2c to which the lower end of the tower 4 can be fixed is provided on one of the columns 2b. Multiple guide members 18a are arranged on the floating body body 2a as fixing means 18.

[0087] In this embodiment, the frame 11 constituting the floating guidance unit 10 has a mounting section 11a that is roughly hexagonal in plan view, with a support section 11b positioned in the center of the mounting section 11a. Three propulsion devices 12 are arranged between adjacent columns 2b. The thrusters 12a of each propulsion device 12 are positioned on the outside of the floating body 2a. The other configurations of the floating guidance unit 10 are the same as those of the floating guidance unit 10 of the previous embodiment illustrated in Figures 1 to 14.

[0088] As in this embodiment, even when the floating guidance unit 10 is applied to a TLP-type floating body 2, the same effects and advantages can be achieved using the same construction method as the floating guidance unit 10 of the previous embodiment illustrated in Figures 1 to 14. Similarly, even when the floating guidance unit 10 has three propulsion devices 12, it is possible to perform movement control and fixed-point holding control of the floating body 2 using the floating guidance unit 10.

[0089] In yet another embodiment illustrated in Figure 18, a floating guidance unit 10 applied to a barge-type floating body 2 is illustrated. The barge-type floating body 2 has a flat floating body body 2a, like an ark. As illustrated in Figure 18, the barge-type floating body 2 of this embodiment has a floating body body 2a that is substantially octagonal in shape in plan view, and a tower fixing part 2c provided at one location on the floating body body 2a. A plurality of guide members 18a are arranged on the floating body body 2a as fixing means 18.

[0090] In this embodiment, the frame 11 constituting the floating guidance unit 10 has a mounting section 11a that is rectangular in shape when viewed from above, with a support section 11b positioned in the center of the mounting section 11a. Four propulsion devices 12 are arranged on the outside of the floating body 2a at intervals from each other. The thrusters 12a of each propulsion device 12 are positioned on the outside of the floating body 2a. The other configurations of the floating guidance unit 10 are the same as those of the floating guidance unit 10 of the previous embodiment illustrated in Figures 1 to 14.

[0091] As in this embodiment, even when the floating guidance unit 10 is applied to a barge-type floating body 2, the same effects and advantages can be achieved using the same construction method as the floating guidance unit 10 of the previous embodiment illustrated in Figures 1 to 14.

[0092] Thus, the floating guidance unit 10 used in this construction method is highly versatile as it can be used in the construction of various floating offshore wind power generation facilities 1, such as semi-submersible, TLP, and barge types. The shape and structure of the frame 11 constituting the floating guidance unit 10, the number and arrangement of the propulsion devices 12, etc. are not limited to the embodiments exemplified above, and can be appropriately determined according to the shape and size of the floating body 2 used. For example, the propulsion devices 12 can be placed in the opening inside the floating body 2a of the TLP type floating body 2 exemplified in Figure 17, or in the opening inside the floating body 2a of the barge type floating body 2 exemplified in Figure 18.

[0093] As illustrated in the above embodiment, if the fixing means 18 is configured with multiple guide members 18a arranged on the floating body 2a, the work of fixing the frame assembly 11 to the floating body 2 and the work of removing the frame assembly 11 from the floating body 2 can be performed very easily. However, the fixing means 18 is not limited to the case where multiple guide members 18a are used, and can be configured in various other ways. For example, as the fixing means 18, insertion parts that protrude downward are provided at multiple locations on the frame assembly 11, and insertion holes into which the aforementioned insertion parts can be inserted are provided at multiple locations on the floating body 2 (floating body 2a). Then, when placing the frame assembly 11 on the floating body 2, the frame assembly 11 can be fixed to the floating body 2 by fitting each insertion part provided on the frame assembly 11 into each insertion hole provided on the floating body 2.

[0094] The embodiments disclosed above include, for example, the following aspects: [Note 1] In a construction method for a floating offshore wind power generation facility having a floating body moored in the sea area to be installed and a wind power generation device erected on the floating body, A floating guidance unit is prepared in advance, comprising a frame assembly that is detachable from the floating body, a plurality of propulsion devices installed on the frame assembly at intervals from each other, a position information acquisition means for acquiring position information of a predetermined position on the frame assembly, and a control device. A method for constructing a floating offshore wind power generation facility, characterized by placing the frame structure on the floating body to install the floating body guidance unit on the floating body, and controlling the plurality of propulsion devices by the control device based on the position information input from the position information acquisition means to perform at least one of the following: movement control of the floating body or fixed-point holding control. [Note 2] A method for constructing a floating offshore wind power generation facility as described in Appendix 1, wherein the floating body is moved to an assembly work area near a floating structure or quay where the assembled components constituting the wind power generation device are temporarily placed, using the floating body guidance unit installed on the floating body. [Note 3] A method for constructing a floating offshore wind power generation facility according to Appendix 1 or 2, wherein the floating body guidance unit installed on the floating body is used to perform the fixed-point holding control of the floating body in an assembly work area near a floating structure or quay where the assembled components constituting the wind power generation device are temporarily placed. [Note 4] The construction method for a floating offshore wind power generation facility as described in Appendix 3, wherein, while performing the fixed-point holding control of the floating body, the assembly components are installed on the floating body which is floating in a semi-submerged state, and an assembly in which the wind power generation device is erected on the floating body is assembled. [Note 5] The construction method for a floating offshore wind power generation facility as described in Appendix 3, wherein the floating body is lowered while maintaining the floating body at a fixed point, the floating body is brought to rest on a mound provided on the seabed of the assembly work area, and the assembly components are installed on the settled floating body to assemble an assembly in which the wind power generation device is erected on the floating body. [Note 6] A method for constructing a floating offshore wind power generation facility according to Appendix 1 or 2, wherein the movement control is performed to move an assembly on which a wind power generation device is erected on the floating body to the target sea area, using the floating body guidance unit installed on the floating body. [Note 7] A method for constructing a floating offshore wind power generation facility according to Appendix 1 or 2, wherein, in the sea area to be installed, the floating guidance unit installed on the floating body is used to control the fixed-point holding of the floating body, while mooring work is performed on the assembly on which the wind power generation device is erected on the floating body. [Explanation of Symbols]

[0095] 1. Floating offshore wind power generation facility 2 Floating bodies 2a Floating body 2b Column 2c Tower mounting section 3. Wind power generation equipment 4 Towers 4a Divided member 5 Nasel Hub 6 blades 7 Assembly 8. Mooring means 8a Mooring line 8b Anchor 10 Floating guidance unit 11. Framework 11a Mounting section 11b Base section 12 Propulsion device 12a thruster 12b Support shaft 12c drive unit 13 Location information acquisition means 14 Control device 15. Power source supply means 16 Management room 17 Connecting part 18 Fixing means 18a Guide member 20 (Wire ropes of the crane on the crane ship) 21 Hanging equipment 22 Support stand 30 Floating structures 40 Wharf 50 Self-elevating barge (SEP vessel) 51 Barge body 52 Lifting Legs 53. Crane (mounted on a self-elevating barge) 60 (cranes positioned on the quay) SB Undersea WL sea level position IA installation target sea area OA assembly work area WA work area BA bottom contact area SA docking area T target position M Mound G1 (Center of gravity of the floating object) G2 (Center of gravity of the floating guidance unit)

Claims

1. In a construction method for a floating wind power generation facility having a floating body moored in the target water area and a wind power generation device erected on the floating body, A floating guidance unit is installed on the floating body, comprising a main body that is detachable from the floating body and a plurality of propulsion devices installed on the main body at a distance from each other. By driving the aforementioned multiple propulsion devices, the floating body is maintained at a fixed point or moved. Construction methods for floating wind power generation facilities.

2. The floating guidance unit comprises a position information acquisition means for acquiring position information of a predetermined position of the floating guidance unit and a control means for controlling the drive of the plurality of propulsion devices based on the position information. A method for constructing a floating wind power generation facility as described in claim 1.

3. In the assembly work area near a floating structure or quay on which the assembled components constituting the wind power generation device are placed, While maintaining the fixed position of the floating body, the assembly components are installed on the floating body which is floating in a semi-submerged state, thereby assembling an assembly in which the wind power generation device is erected on the floating body. A method for constructing a floating wind power generation facility according to either claim 1 or claim 2.

4. In the assembly work area near a floating structure or quay on which the assembled components constituting the wind power generation device are placed, While maintaining the floating body at the fixed point, the floating body is lowered so that it settles on a mound provided on the seabed of the assembly work area, and the assembly components are installed on the settled floating body to assemble the assembly on which the wind power generation device is erected. A method for constructing a floating wind power generation facility according to either claim 1 or claim 2.

5. The movement of the floating body is performed by using the floating body guidance unit installed on the floating body to move the assembly on which the wind power generation device is erected to the target water area. A method for constructing a floating wind power generation facility according to either claim 1 or claim 2.

6. In the water area where the installation is to take place, the floating body guidance unit installed on the floating body is used to maintain the floating body at a fixed point while the mooring operation of the assembly on which the wind power generation device is erected on the floating body is performed. A method for constructing a floating wind power generation facility according to either claim 1 or claim 2.

7. The floating body is equipped with fixing means for fixing the main body, The main body is fixed to the floating body by the fixing means, and the floating body guidance unit is installed on the floating body. A method for constructing a floating wind power generation facility according to either claim 1 or claim 2.

8. A floating guidance unit for maintaining a fixed position or moving a floating body on which a wind power generation device is erected on the water, A main body that is detachable from the aforementioned floating body, Multiple propulsion devices are installed on the main body at a distance from each other, Equipped with, Floating guidance unit.

9. A position information acquisition means for acquiring position information of a predetermined position in the main body, A control means for controlling the plurality of propulsion devices based on the position information, Equipped with, The floating guidance unit according to claim 8.

10. The main body comprises the position information acquisition means and the control means, A floating guidance unit according to claim 9.

11. The position information acquisition means and a portion of the control means are provided at a location separate from the main body, and the fixed point holding or movement of the floating body is controlled remotely. A floating guidance unit according to claim 9.

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