Floating offshore wind turbine system, transportation method of floating offshore wind turbine, and floating offshore wind turbine

Abstract

The purpose of this invention is to provide a floating offshore wind turbine system with a structure useful for replacing large components of a floating offshore wind turbine. The floating offshore wind turbine system of this invention is characterized by comprising a floating offshore wind turbine, a main float, and a mooring body. The floating offshore wind turbine includes: blades that withstand wind; a hub that secures the blades; a compartment housing a generator that converts the rotational energy of the hub into electricity; a tower that supports the compartment; a secondary float that supports the tower; and a secondary float connection that can be fitted with a transport vessel connection. The main float is moored on the seabed by the mooring body and has a secondary float insertion space for inserting the secondary float.

Description

[Technical Field]

[0001] This invention relates to a floating offshore wind turbine system with a decomposable floating structure, a method for transporting the floating offshore wind turbine, and the floating offshore wind turbine itself. [Previous Technology]

[0002] In recent years, wind power has been widely adopted worldwide as a countermeasure against global warming. The installation sites for wind power plants are expanding from land to sea, and at sea, they are gradually expanding from shallow waters with fixed offshore wind turbines to deep waters with floating offshore wind turbines. However, because it is impossible to use jack-up vessels (JUVs) in deep waters, it is difficult to replace large parts, such as those requiring large cranes on JUVs, when maintaining floating offshore wind turbines.

[0003] Therefore, in the wind power generation equipment of Patent Document 1, as described in the abstract, "A wind power generation equipment, characterized by comprising: a tower, which is installed on land or at sea and serves as a support for a generator; a cabin, which is installed on the tower and houses the generator; and a rotor, which is installed at one end of the cabin and includes a hub and blades that receive wind and convert wind energy into rotational energy; and, in the cabin, a winch for transporting replacement parts of the generator is provided between the land or sea and the cabin." Large parts inside the cabin can be replaced using the winch within the cabin. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2015-110927 [Summary of the Invention]

[0005] [Problem to be solved by the invention] However, the winch of Patent Document 1 is only for replacing parts inside the cabin and cannot handle the replacement of large parts outside the cabin, such as blades.

[0006] Therefore, the object of the present invention is to provide a floating offshore wind turbine system with a structure useful for replacing large components of a floating offshore wind turbine. [Technical Means for Solving the Problem]

[0007] To solve the above problems, the floating offshore windmill system of the present invention comprises a floating offshore windmill, a main float, and a mooring body. The floating offshore windmill includes: blades that withstand wind; a hub that fixes the blades; a compartment that houses a generator that converts the rotational energy of the hub into electricity; a tower that supports the compartment; a secondary float that supports the tower; and a secondary float coupling that can be fitted with a transport vessel coupling. The main float is moored on the seabed by the mooring body and has a secondary float insertion space for inserting the secondary float. [Effects of the Invention]

[0008] According to the floating body type offshore wind turbine system of the present invention, the auxiliary floating body can be miniaturized, thereby realizing economic advantages.

Implementation Method

[0010] Hereinafter, embodiments of the floating offshore wind turbine system of the present invention will be described using drawings. [Example 1]

[0011] Figure 1 is a bird's-eye view of the floating offshore wind turbine system 100 according to Embodiment 1 of the present invention. The floating offshore wind turbine system illustrated here is a marine power generation system installed in a deep sea area with a water depth of about 50 to 100 m, which converts offshore wind energy into electricity and transmits it to a land system, and includes a floating offshore wind turbine 1, a main float 2, a mooring body 3, a marine cable 4, and a submarine cable 5. The details are described below in sequence.

[0012] The floating offshore wind turbine 1 includes: blades 11 that withstand the wind at sea; a hub 12 that fixes the blades 11; a compartment 13 that houses a generator that converts the rotational energy of the hub 12 into electricity; a tower 14 that supports the compartment 13; a secondary floating body 15 that serves as a base for supporting the tower 14; and a connecting part 16 whose shape can fit into the connecting part 61 of the transport vessel 6.

[0013] The main float 2 is a float with a space for inserting into the secondary float 15 of the floating offshore windmill 1, and is moored to the seabed by anchor chains or other mooring bodies 3 while floating on the sea surface SL. Figure 1 shows an example of a barge-type structure formed by connecting the main float 2 and the secondary float 15 with a connecting part J. Specifically, the connecting part J is a bolted or welded part used to securely connect the main float 2 and the secondary float 15, which can be removed as needed during maintenance of the floating offshore windmill 1. The secondary float 15 is moored indirectly to the seabed via the connecting part J, rather than directly to the seabed.

[0014] The marine cable 4 is the power line for generating electricity from the generator in the relay compartment 13, and the submarine cable 5 is the power line for transmitting electricity generated by the marine cable 4 to the land system.

[0015] In the floating offshore wind turbine system 100 of this embodiment, the manufacturing cost of the floating offshore wind turbine 1 is reduced by miniaturizing the auxiliary float 15. In this case, since the buoyancy of the auxiliary float 15 alone cannot stably transport the floating offshore wind turbine 1 before or after connection with the main float 2, in this embodiment, buoyancy that compensates for the insufficient buoyancy of the auxiliary float 15 is supplied from the transport vessel 6 to the floating offshore wind turbine 1 via the joints 61 and 16. Therefore, the transport vessel 6 can transport the floating offshore wind turbine 1 at sea in a stable state.

[0016] Figure 2 is a side view showing the floating offshore wind turbine 1 before it is connected to the main buoy 2, or after it is disconnected from the main buoy 2, transported by the transport vessel 6. As shown in the figure, since the connecting part 61 of the transport vessel 6 and the connecting part 16 of the floating offshore wind turbine 1 are engaged, the forward or backward movement of the transport vessel 6 can be linked with the movement of the floating offshore wind turbine 1.

[0017] Furthermore, as shown in the figure, the downward force acting on the floating offshore windmill 1 includes the combined force of the gravity acting on the blades 11, hub 12, and compartment 13, namely gravity F1; the gravity acting on the tower 14; and the gravity acting on the auxiliary float 15. Furthermore, the upward force acting on the floating offshore windmill 1 includes the buoyancy F4 acting on the auxiliary float 15 and the buoyancy F5 transmitted from the joint 61 of the transport vessel 6 via the joint 16.

[0018] Here, as shown in Figure 2, to transport the floating offshore windmill 1 under stable conditions, the relationship F1+F2+F3=F4+F5 needs to be satisfied. Furthermore, by placing the center of gravity G of the floating offshore windmill 1 further below the point of application of buoyancy F5 (the contact position between the upper end of the joint 61 and the lower surface of the joint 16), the stability during transport can be further improved. To lower the position of the center of gravity G, for example, the mass of the auxiliary float 15 can be designed to be larger.

[0019] Figure 3 illustrates the sequence in which the joint 16 of the floating offshore windmill 1 and the joint 61 of the transport vessel 6 are fitted together. Here, the joint 16 of the floating offshore windmill 1 is designed with a generally L-shaped cross-section extending downward from the front end of the horizontal portion fixed to the auxiliary float 15 and extending vertically therefrom. The joint 61 of the transport vessel 6 is designed with a generally L-shaped cross-section extending upward from the front end of the horizontal portion fixed to the main body of the transport vessel and extending vertically therefrom. The vertical portion of the joint 61 is longer than the vertical portion of the joint 16. However, as long as the two can be fitted together, the shapes of the joints 16 and 61 are not limited to those illustrated here.

[0020] Figure 3(a) is a schematic diagram illustrating the relative relationship of joints 16 and 61 when ballast water is injected into the transport vessel 6, causing the waterline of the transport vessel 6 to rise. In this state, since the upper end of joint 61 is lower than the lower end of joint 16, joint 61 can be positioned below joint 16 by moving the transport vessel 6.

[0021] On the other hand, Figure 3(b) is a schematic diagram illustrating the relative relationship of joints 16 and 61 when the waterline of the transport vessel 6 is lowered due to the discharge of ballast water from the transport vessel 6. In this state, since the upper end of joint 61 is pressed against the lower surface of the horizontal portion of joint 16, a portion of the buoyancy of the transport vessel 6 (buoyancy F5) is transmitted to the auxiliary float 15 of the floating offshore windmill 1 via joints 61 and 16, thus compensating for the insufficient buoyancy of the auxiliary float 15. Therefore, by moving the transport vessel 6 in the state shown in Figure 3(b), the floating offshore windmill 1 can be moved in the desired direction while maintaining a stable draft.

[0022] In addition, as described above, the waterline of the transport vessel 6 is raised or lowered by injecting and discharging ballast water, which changes the relative position of the joints 61 and 16. However, the waterline of the auxiliary float 15 and the main float 2 can also be raised or lowered by injecting and discharging ballast water, which changes the relative position of the joints 61 and 16.

[0023] <Variations of Example 1> The above shows an example of connecting the main float 2 and the auxiliary float 15 to form a barge-type float, but other types of floats can also be formed depending on the situation. For example, as shown in the bird's-eye view of FIG4, a tension leg platform (TLP) type float can be formed to replace the mooring body 3 and use the tension mooring body 31; a semi-submersible float can be formed as shown in the bird's-eye view of FIG5; and a single-column type float can be formed as shown in the bird's-eye view of FIG6.

[0024] As described above, this embodiment is configured such that a main float anchored on the seabed and a secondary float for fixing the windmill constitute the float of the floating offshore windmill system. The two floats are connected in a detachable manner, and the secondary float has a joint that engages with the transport vessel. In this way, the buoyancy from the transport vessel can compensate for the insufficient buoyancy of the floating offshore windmill when the autonomous float is separated. Therefore, even when using a miniaturized and economical secondary float, the floating offshore windmill can be transported stably.

[0025] [Example 2] Next, the floating offshore windmill system 100 of Example 2, which constitutes a single-column or semi-submersible floating body, will be described using FIG7. Furthermore, the commonalities with Example 1 will be omitted from the description.

[0026] In Figure 2 of Embodiment 1, when the joint 16 of the floating offshore wind turbine 1 and the joint 61 of the transport vessel 6 are engaged, a portion of the buoyancy of the transport vessel 6 (buoyancy F5) is transferred to the floating offshore wind turbine 1. In this case, since the horizontal distance from the center of gravity G of the floating offshore wind turbine 1 to the point of application of buoyancy F5 becomes longer, the torque around the center of gravity G caused by buoyancy F5 becomes larger, which may impair the stability of the floating offshore wind turbine 1 during transport.

[0027] Therefore, in this embodiment, as shown in the side view of FIG7, a configuration is provided to transfer a portion of the buoyancy of the transport vessel 6 (buoyancy F5) to the floating offshore windmill 1, and a support portion 62 is provided on the transport vessel 6 extending from the rear end of the joint 61 to the distance (more preferably, extending directly above the center of gravity G). When this configuration is adopted, since the horizontal distance between the point of application of buoyancy F5 and the center of gravity G is shorter than that in FIG2 of Embodiment 1, the torque around the center of gravity G caused by buoyancy F5 is smaller, which can further improve the stability of the floating offshore windmill 1 during transport. The stability during transport can also be improved by increasing the mass of the auxiliary float 15 to lower the center of gravity G, but by providing the support portion 62, the mass of the auxiliary float 15 can be reduced.

[0028] Furthermore, in the configuration of this embodiment, the joint 16 of the floating offshore wind turbine 1 and the joint 61 of the transport vessel 6 transmit buoyancy F5 only during the period before the auxiliary floating body 15 is supported by the support part 62 of the transport vessel 6, or only bear the transmission of horizontal force (such as the traction force of the floating offshore wind turbine 1). [Simplified Explanation of the Diagram]

[0009] Figure 1 is a bird's-eye view of the floating offshore wind turbine system of Embodiment 1 (barge type). Figure 2 is a side view of the floating offshore wind turbine and the transport vessel in the engagement state of Embodiment 1. Figures 3(a) and (b) are diagrams illustrating the sequence in which the joints of the floating offshore wind turbine and the transport vessel are engaged with each other. Figure 4 is a bird's-eye view of the tension leg platform type floating offshore wind turbine system. Figure 5 is a bird's-eye view of the semi-submersible type floating offshore wind turbine system. Figure 6 is a bird's-eye view of the single-column type floating offshore wind turbine system. Figure 7 is a side view of the floating offshore wind turbine and the transport vessel in the engagement state of Embodiment 2.

Claims

1. A floating offshore wind turbine system, characterized in that it comprises a floating offshore wind turbine, a main float, and a mooring body; and the floating offshore wind turbine comprises: blades for receiving wind; a hub for fixing the blades; a compartment for housing a generator that converts the rotational energy of the hub into electricity; a tower for supporting the compartment; and a secondary float for supporting the tower. The main float is anchored on the seabed by the mooring body and has an insertion space for the auxiliary float to be inserted. The main float is generally L-shaped in cross-section, extending vertically upward from the front end of the horizontal part fixed to the main body of the transport vessel. The aforementioned sub-buoy joint has an approximately L-shaped cross-sectional shape, extending downwards from the front end of the horizontal part fixed to the sub-buoy to form a vertical part.

2. The floating offshore wind turbine system of claim 1, wherein the center of gravity of the floating offshore wind turbine is located below the contact position between the transport vessel joint and the auxiliary floating body joint.

3. The floating offshore wind turbine system of claim 1, wherein the auxiliary floating body is connected to the connecting part of the main floating body in a detachable manner.

4. The floating offshore wind turbine system as described in claim 3, wherein the main float and the auxiliary float are connected to form any one of the following: barge-type float, tension leg platform-type float, semi-submersible float, and monopole-type float.

5. A method for transporting a floating offshore wind turbine, characterized in that it is a method for transporting a floating offshore wind turbine of the floating offshore wind turbine system as claimed in claim 3, and the method comprises: an engagement step, which engages the aforementioned transport vessel joint with the aforementioned sub-float joint; and a transport step, in which the floating offshore wind turbine is transported while being supported by the transport vessel.

6. The method for transporting a floating offshore wind turbine as claimed in claim 5, wherein, in the above-mentioned transport steps, a portion of the buoyancy of the transport vessel is transferred to the floating offshore wind turbine via the transport vessel joint and the auxiliary floating body joint.

7. The method for transporting a floating offshore wind turbine as claimed in claim 5, wherein, during the transport step, a portion of the buoyancy of the transport vessel is transferred to the floating offshore wind turbine via a support extending from the rear end of the transport vessel joint to a distance.

8. A floating offshore wind turbine, characterized in that it is insertable into a main float of a floating offshore wind turbine system; and has: blades that withstand wind; a hub that fixes the blades; a compartment that houses a generator that converts the rotational energy of the hub into electricity; a tower that supports the compartment; a secondary float that supports the tower; and a secondary float coupling that can be fitted with a transport vessel coupling; wherein the transport vessel coupling has a generally L-shaped cross-sectional shape extending upward from the front end of a horizontal portion fixed to the transport vessel body; wherein the secondary float coupling has a generally L-shaped cross-sectional shape extending downward from the front end of a horizontal portion fixed to the secondary float; and, when the transport vessel is transporting goods, it imparts a portion of the buoyancy of the transport vessel.

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