Spar-type floating structure and method for assembling offshore wind power generation facilities

Abstract

To solve a problem in prior art, that is, to provide a spar type floating body capable of suppressing rolling and pitching when utilized as well as at assembly and an assembly method for an ocean wind power generation facility using the same.SOLUTION: The spar type floating body of an ocean wind power generation facility in which a wind mill power unit is installed on ocean includes a hollow pillar state body, a cell for storing weight material, and ejection means. In addition, the cell is provided inside the pillar state body and the ejection means is means to eject the weight material stored in the cell. Then, the weight material is ejected from the cell by operating the ejection means.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an offshore wind power generation facility, and more specifically, to a spar-type floating body capable of suppressing the sway of an offshore wind power generation facility not only during operation but also during the construction stage of completing the facility, and a method for assembling an offshore wind power generation facility using the same.

Background Art

[0002] In Japan, although the electricity consumption once decreased due to the impact of the global financial crisis in 2008, it has continuously increased since 1973 when there was an oil shock, and it has expanded to 2.6 times between 1973 and 2007. The background includes the spread of so-called household appliances such as air conditioners and electric carpets due to the improvement of living standards, or the spread of OA (Office Automation) equipment and communication equipment due to the increase in office buildings.

[0003] Hitherto, a huge amount of electricity demand has been mainly supported by power generation using so-called fossil fuels such as oil and coal. However, in recent years, the depletion problem of fossil fuels and environmental problems associated with global warming have been attracting attention, and accordingly, the power generation method has gradually changed. As a result, around 1973 as described above, power generation by oil and coal accounted for about 90% of the whole, whereas the proportion decreased to 66% in 2010. Instead, nuclear power generation, which accounts for just over 10% of the whole (in 2010), has increased. Nuclear power generation has contributed significantly to the electricity demand in Japan because it has a remarkable effect of reducing greenhouse gas emissions compared with conventional power generation methods and can provide electricity at low cost.

[0004] Furthermore, renewable energy power generation methods are being adopted because they can reduce greenhouse gas emissions. These renewable energy sources include solar, wind, geothermal, small-scale hydropower, and woody biomass, which are literally renewable energy sources that can be produced domestically and reduce greenhouse gas emissions, making them promising low-carbon energy sources.

[0005] Among renewable energy sources, wind power generation, in particular, is characterized by its high efficiency in converting electrical energy. Generally, the conversion efficiency of solar power generation is said to be about 20%, wood biomass power generation about 20%, and geothermal power generation 10-20%, while wind power generation is said to be 20-40%, meaning it can convert energy into electricity more efficiently than other power generation methods. In addition, unlike solar power generation, wind power generation can generate electricity day and night, which is another characteristic of wind power generation. Due to these characteristics, wind power generation is already widely used as a major power generation method in Europe, and in Japan, as part of its "energy mix" initiative, it aims to account for 1.7% of the power generation mix by 2030.

[0006] Wind power generation is broadly classified into onshore wind power generation and offshore wind power generation depending on the installation location. Onshore wind power generation has the advantage of being easier to install and therefore less expensive than offshore wind power generation. Offshore wind power generation, on the other hand, does not have the noise problems associated with onshore wind power generation, and the risk of damage from toppling etc. is avoided, and above all, it has the advantage of being able to obtain a large amount of wind power stably compared to onshore. Japan, which has the world's sixth-largest exclusive economic zone, is a suitable location for offshore wind power generation and is considered to have the potential to become a promising source of renewable energy in the future.

[0007] Furthermore, different types of offshore wind power generation are adopted depending on the installation location. Fixed-bottom offshore wind power generation is suitable for sea areas shallower than 50m, while floating offshore wind power generation is suitable for sea areas deeper than 50m. Floating offshore wind power generation utilizes a floating structure that floats on seawater. The power generation mechanism is installed on the floating structure, which is connected by mooring lines, and this mechanism generates electricity. Examples of floating structure types include barge type, semi-submersible type, spar type, and tension-leg platform (TLP). Of these, the spar type offshore wind power generation facility is considered advantageous in terms of floating structure manufacturing costs because the structure of its floating structure (hereinafter referred to as "spar type floating structure") is not very complex, which reduces the effort required for manufacturing. Also, because the spar type floating structure is lightweight, the material costs can be reduced.

[0008] Figure 8 is a schematic side view of a spar-type offshore wind power plant. As shown in this figure, a spar-type offshore wind power plant consists of a spar-type floating body that floats in the sea, and a tower, rotor, nacelle, etc. (hereinafter collectively referred to as the "wind turbine section") installed on top of it. The tower is a structure that supports the rotor and nacelle, and the spar-type floating body functions as the base of the tower. The rotor, consisting of blades and a hub, converts wind into power, and the nacelle, which includes a gearbox, generator, transformer, etc., converts the power into electricity, which is then transmitted to land via power cables (dynamic cables and submarine cables). The spar-type floating body is generally moored by the weight of mooring cables arranged in a catenary shape.

[0009] The main body of the spar-type floating structure is a so-called elongated body in which the axial dimension (hereinafter referred to as the "column axis") is predominantly larger than the cross-sectional dimension, and it has a hollow, tubular shape inside. As shown in Figure 8, when the spar-type floating structure is in operation, its column axis direction is approximately vertical (including vertical) (hereinafter referred to as the "upright state"). Because a spar-type floating structure in this upright state is prone to swaying such as vertical and horizontal motion, various technologies have been proposed to suppress such swaying. For example, Patent Document 1 proposes a technology to suppress swaying by using annular members that function as "lifebuoys," that is, by connecting annular members arranged to surround the floating structure with ropes or the like. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2013-141857 [Overview of the project] [Problems that the invention aims to solve]

[0011] Typically, spar-type floating structures are manufactured on land, such as in dry docks, and must be transported by sea to the operational site (wind farm: WF). During this transport, as shown in Figure 9(a), the spar-type floating structures are transported with their axis of rotation approximately horizontal. Therefore, to make them operational, they must be rotated from the approximately horizontal position to an upright position (hereinafter referred to as "erecting"), as shown in Figure 9(b). Since wind farms are expected to experience considerable wind force, they are not suitable locations for erecting spar-type floating structures; instead, they are erected in a pre-selected calm area of ​​the sea. Furthermore, the wind turbine components (tower, rotor, nacelle, etc.) are manufactured separately from the spar-type floating structures, transported to a calm area, and installed on the erected spar-type floating structures using crane vessels, as shown in Figure 9(c). Finally, the largely completed offshore wind power generation facility is transported to the wind farm in an operational state (i.e., with the spar-type floating structures in an upright position).

[0012] Since spar-type offshore wind power facilities are assembled according to the procedure described above, before the completed structure with the wind turbine attached, as shown in Figure 10(a), a spar-type floating structure without the wind turbine attached is temporarily placed on the sea, as shown in Figure 10(b). In other words, the wind turbine is installed on the spar-type floating structure in the state shown in Figure 10(b). For convenience, the spar-type floating structure in the state shown in Figure 10(b) will be referred to here as the "spar-type floating structure during assembly."

[0013] As described above, since spar-type floating bodies in an upright position are prone to swaying, various technologies have been employed to suppress this swaying. However, conventional technologies all suppress the swaying of spar-type floating bodies during operation, that is, technologies to suppress the swaying of spar-type floating bodies with the wind turbine attached, and did not suppress the swaying of spar-type floating bodies during assembly (Figure 10(b)). In operation, the spar-type floating body has a wind turbine attached to the top, so its center of gravity is higher than that of the spar-type floating body during assembly, and its natural period of swaying is longer. On the other hand, the spar-type floating body during assembly does not have a wind turbine, so its center of gravity is lower and its natural period is shorter. Figure 11(a) is a graph showing the wave spectrum under normal sea conditions and during storms, and Figure 11(b) is a graph showing the frequency response function (RAO: Response Amplitude Operator) representing the swaying characteristics of the spar-type floating body during assembly (when the wind turbine is installed) and during operation when conventional technology is used. The wave spectrum, when an irregular wave is described as a superposition of countless sine waves, shows the amount of energy of the sine waves at each frequency. As shown in this figure, the motion characteristics of a spar-type floating structure during operation have a long natural period, so the response peak is at a long-period position, and it does not interfere much with the wave spectrum of normal sea conditions and storms, so the motion is suppressed. In contrast, the motion characteristics of a spar-type floating structure during assembly have a short natural period, so the response peak is at a short-period position, and it interferes greatly with the wave spectrum of normal sea conditions, so it is prone to motion, that is, it is prone to motion synchronized with the waves.

[0014] To install the wind turbine section on a spar-type floating structure, it is naturally necessary to avoid storms and choose normal sea conditions. However, as shown in Figure 11, the spar-type floating structure is prone to swaying even under normal sea conditions during assembly. Therefore, the wind turbine section installation work needs to be carried out under normal sea conditions, but in a calmer state. As a result, the operational rate of the installation work is significantly limited by ocean conditions, meaning that the swaying of the spar-type floating structure during assembly drives up construction costs.

[0015] The objective of the present invention is to solve the problems of the prior art, namely, to provide a spar-type floating body that can suppress oscillations not only during operation but also during assembly, and a method for assembling an offshore wind power generation facility using the same. [Means for solving the problem]

[0016] The present invention focuses on the fact that a compartment for housing weight material (ballast, etc.) is provided within a hollow columnar body, and that the weight material is housed in the compartment during assembly but discharged from the compartment during operation. This invention is based on an unprecedented idea.

[0017] The spar-type floating body of the present invention is a spar-type floating body for an offshore wind power generation facility in which a wind turbine is installed offshore, and comprises a hollow columnar body, a compartment for housing weight material, and a discharge means. The compartment is provided inside the columnar body, and the discharge means is used to discharge the weight material housed in the compartment by operating the discharge means. The weight material is then discharged from the compartment by operating the discharge means.

[0018] The spar-type floating body of the present invention may also be composed of two or more horizontally divided compartments, the compartments of which are arranged along the inner circumferential surface of the columnar body. In this case, the discharge means can discharge the weight material independently from each horizontally divided compartment.

[0019] The spar-type floating body of the present invention may also be composed of two or more vertically divided compartments, the compartments of which are arranged along the axial direction of the columnar body. In this case, the discharge means can discharge the weight material independently from each vertically divided compartment.

[0020] In the spar-type floating body of the present invention, the columnar main body is in a substantially upright position (including upright), and when the wind turbine section is installed, the partition chamber may be provided at the planned waterline position within the columnar main body.

[0021] The offshore wind power generation facility assembly method of the present invention is a method for assembling an offshore wind power generation facility by installing a wind turbine section on a spar-type floating body of the present invention offshore, and comprises a main body erection step, a weight insertion step, a wind turbine section installation step, and a weight removal step. Of these, in the main body erection step, a bottom weight is inserted into the bottom of the columnar main body to make the columnar main body in a nearly upright position (including upright), and in the weight insertion step, weight is inserted into the interior of the compartment. In the wind turbine section installation step, the wind turbine section is installed on the spar-type floating body which has been made nearly upright (including upright) offshore, and in the weight removal step, the weight is removed from the compartment by operating a removal means.

[0022] The offshore wind power generation facility assembly method of the present invention may further include a posture adjustment step. In this case, it is preferable to use a spar-type floating body composed of two or more horizontally divided compartments. In this posture adjustment step, when the columnar body is tilted after the weight insertion step, additional weight is inserted into a predetermined divided compartment (or the weight is removed from a predetermined divided compartment) to bring the columnar body into a nearly upright position (including upright). [Effects of the Invention]

[0023] The spar-type floating structure and the offshore wind power generation facility assembly method of the present invention have the following advantages. (1) The spar-type floating body's movement is suppressed not only during operation but also during assembly (when installing the wind turbine section). As a result, the operational efficiency of the installation work is improved compared to conventional technology, which means that construction costs can be reduced. (2) By providing the compartment at the planned draft position in the columnar main body, this compartment can be used as a structure for restoring resilience during damage, and can also be expected to be a stiffening material against external forces that are likely to occur near the waterline. (3) By configuring the compartment with two or more horizontally divided compartments, when the columnar main body tilts, it can be corrected to a substantially upright (including upright) posture.

Brief Description of the Drawings

[0024] [Figure 1] Side view schematically showing the spar-type floating body of the present invention. [Figure 2] (a) is a perspective view schematically showing the spar-type floating body of the present invention, and (b) is a cross-sectional view taken along a vertical plane schematically showing the spar-type floating body of the present invention. [Figure 3] (a) is a graph showing "wave spectra during normal sea conditions and storm conditions", and (b) is a graph showing "frequency response functions representing the sway characteristics of the spar-type floating body during assembly (when installing the wind turbine section) and operation when the spar-type floating body of the present invention is adopted". [Figure 4] (a) is a perspective view schematically showing a spar-type floating body not equipped with a lifting means, and (b) is a cross-sectional view taken along a vertical plane schematically showing a spar-type floating body not equipped with a lifting means. [Figure 5] [[ID=2)2]](a) is a plan view schematically showing a compartment composed of eight horizontally divided compartments, and (b) is a side view schematically showing a compartment composed of three vertically divided compartments. [Figure 6] Flow chart showing the main steps of the method for assembling an offshore wind power facility of the present invention. [Figure 7] Step diagram showing the main steps of the method for assembling an offshore wind power facility of the present invention. [Figure 8] Side view schematically showing a spar-type offshore wind power facility. [Figure 9] Step diagram schematically showing the situation of assembling a spar-type offshore wind power facility at sea. [Figure 10](a) is a schematic side view showing a spar-type floating structure with the wind turbine attached, and (b) is a schematic side view showing a spar-type floating structure before the wind turbine is attached. [Figure 11] (a) is a graph showing the wave spectrum under normal sea conditions and during storms, and (b) is a graph showing the frequency response function representing the motion characteristics of the spar-type floating body during assembly (when the wind turbine section is installed) and operation when conventional technology is used. [Modes for carrying out the invention]

[0025] An example of an embodiment of the spar-type floating body and the offshore wind power generation facility assembly method of the present invention will be described with reference to the drawings.

[0026] 1. Spar-type floating body First, the spar-type floating body of the present invention will be described. The offshore wind power generation facility assembly method of the present invention is a method for assembling an offshore wind power generation facility that includes the spar-type floating body of the present invention. Therefore, the spar-type floating body of the present invention will be described first, and then the offshore wind power generation facility assembly method of the present invention will be described in detail.

[0027] Figure 1 is a schematic side view of the spar-type floating body 100 of the present invention. As shown in this figure, the spar-type floating body 100 of the present invention is composed of a columnar body 110, a partition 120, and a discharge means 130, and can also be composed of a discharge pipe and the like, which will be described later. When the wind turbine section (tower, rotor, nacelle, etc.) is installed on the upright spar-type floating body 100, a spar-type offshore wind power generation facility is completed. The main elements constituting the columnar floating body 100 will be described below.

[0028] (Columnar body) As shown in Figure 1, the column body 110 is a long body in which its axial dimension is significantly larger than its cross-sectional dimension, and its interior is hollow. The column body 110 is a so-called bottomed open pipe with one end (the lower end in the figure) closed and the other end (the upper end in the figure) open. It can be cylindrical with a circular cross-section or prismatic with a polygonal cross-section. Furthermore, as shown in Figure 1, a reduced diameter section can be formed at the top of the column body 110. This reduced diameter section is the part to which the tower is connected, and is a kind of adjustment section for changing from the large diameter of the column body 110 to the small diameter of the tower. In this figure, only one reduced diameter section is formed, but it is not limited to this and reduced diameter sections can be formed in two or more locations.

[0029] (Separate room) As shown in Figure 2, the compartment 120 is located inside the columnar main body 110 and is positioned above the upright spar-type floating body 100 as shown in Figure 1. It is a box-shaped structure with a space formed inside that can accommodate "weight material". Here, "weight material" refers to various heavy objects, including ballast such as seawater and crushed stone, as well as solid weights (so-called counterweights). For convenience, in order to distinguish it from the weight material placed at the bottom when the spar-type floating body 100 is erected, the weight material housed in the compartment 120 will be specifically referred to as "compartment weight material BLr," and the weight material placed at the bottom will be specifically referred to as "bottom weight material BLb."

[0030] In the case of the conventional technology, a spar-type floating body without a wind turbine section at the top (i.e., during assembly) has a low center of gravity and is prone to oscillation in sync with waves, making it susceptible to motion. On the other hand, in the case of the present invention, a compartment 120 is provided at the top of the upright spar-type floating body 100, and a compartment weight BLr can be housed in this compartment 120. As a result, the center of gravity can be placed at a higher position compared to the conventional technology, making it less prone to oscillation in sync with waves, and thus suppressing motion. Figure 3(a) is a graph showing the wave spectrum under normal sea conditions and during storms, and Figure 3(b) is a graph showing the RAO of the spar-type floating body during assembly and operation when the spar-type floating body of the present invention is adopted. As shown in these figures, the motion characteristics of the spar-type floating body during assembly do not interfere with the wave spectrum under normal sea conditions (Figure 11) compared to the conventional technology, indicating that motion is suppressed.

[0031] The partition chamber 120 is described as being located above the upright spar-type floating body 100, but it is preferable to place it around the "planned waterline position." Here, the "planned waterline position" is the position (height) at which the spar-type floating body 100 intersects the sea surface when the spar-type offshore wind power generation facility is completed (i.e., when it is operational). This planned waterline position is also called the splash zone, and it is a part where the fatigue of the members due to external forces such as waves is severe. Therefore, by installing the partition chamber 120 at the planned waterline position and increasing the rigidity (second moment of area, etc.) of that part, the fatigue of the members is mitigated. Furthermore, if the structure can be positioned to include the planned waterline, the length of the chamber 120 protruding into the air (i.e., the length from the planned waterline to the upper end of the chamber 120) and the length of the chamber 120 submerged in the sea (i.e., the length from the planned waterline to the lower end of the chamber 120) can be designed to the desired values.

[0032] Furthermore, by installing the compartment 120 at the planned waterline, the requirement for stability in the event of damage can also be met. Since seawater enters the interior when part of the floating body is damaged, conventionally, fenders were considered to be wrapped around the area around the planned waterline where damage is likely to occur due to collisions with other vessels, etc. As will be described later, during operation, the compartment weight BLr is already discharged from the compartment 120. Therefore, if the compartment 120 is installed at the planned waterline, even if part of the spar-type floating body 100 is damaged, the seawater will only enter the compartment 120, and as a result, it is possible to prevent a large amount of seawater from entering the interior of the spar-type floating body 100. In this case, to prevent seawater that has entered the compartment 120 from leaking into the interior of the spar-type floating body 100, the compartment 120 should be a sealed (especially watertight) structure with a top plate. Furthermore, the installation range of the compartment 120 (especially the vertical range) should preferably be positioned to include the area up to 5m above and 3m below the planned draft, taking into consideration the extent of damage. Also, if the compartment 120 is installed at the planned draft, it is not necessarily required to install fenders, but of course, fenders can be installed.

[0033] The spar-type floating body 100 of the present invention can be equipped with a lifting means for introducing a partition weight BLr into the partition chamber 120, as shown in Figure 2. This lifting means 150 is positioned slightly above the partition chamber 120 and can lift and lower the partition weight BLr. For example, the lifting means 150 shown in Figure 2 is composed of a ceiling beam 151, a hook 152, and a towing device such as a winch. As a result, when the winch winds up the wire rope, the partition weight BLr is lifted up together with the hook 152, and when the winch unwinds the wire rope, the partition weight BLr is lowered down together with the hook 152. Also, when the hook 152 moves horizontally along the ceiling beam 151, the partition weight BLr moves horizontally in the same way. The partition weight BLr moved using the lifting means 150 can be a solid counterweight, bagged crushed stone, or seawater contained in a container.

[0034] In addition to the lifting means 150, a temporary storage deck 160 can also be installed. This temporary storage deck 160 is positioned slightly above the partition chamber 120 and slightly below the lifting means 150 (i.e., between the partition chamber 120 and the lifting means 150), and serves as a storage shelf for the partition chamber weight material BLr. In this case, the lifting means 150 can lift the partition chamber weight material BLr placed on the temporary storage deck 160, move it horizontally to above the partition chamber 120, and then lower the partition chamber weight material BLr into the partition chamber 120. After the wind turbine section is installed on top of the spar-type floating body 100, the lifting means 150 lifts the partition chamber weight material BLr housed in the partition chamber 120 and lowers it to the bottom of the spar-type floating body 100 (in some cases, the partition chamber weight material BLr can also be discharged using the discharge means 130 described later). The lifting mechanism 150 can be configured to be remotely operated, or it can be operated on-site (i.e., at the installation location of the lifting mechanism 150). However, if it is configured to be remotely operated, it is desirable to also install a video camera or similar device to check the situation on-site. In addition, the lifting mechanism 150 can directly lift the bulkhead material BLr for the compartment from, for example, on a ship, without providing a temporary deck 160.

[0035] The spar-type floating body 100 of the present invention is not limited to those equipped with a lifting means 150 and a temporary deck 160, but can also be made without a lifting means 150 and a temporary deck 160, as shown in Figure 4. Figure 4 is a schematic diagram of a spar-type floating body 100 without a lifting means 150, etc., where (a) is a perspective view thereof and (b) is a cross-sectional view thereof. In this case, fluid ballast or granular ballast is suitable as the partition weight BLr, and the partition 120 in this case can be made open to facilitate the insertion of the partition weight BLr, or it can be made into a structure with a top plate so that the contained partition weight BLr is sealed (especially watertight). When the partition 120 is equipped with a top plate, it is preferable to install an injection pipe for injecting the partition weight BLr into the top plate, or to make the top plate into an openable and closable structure.

[0036] (Discharge means) When the wind turbine section is installed on top of the spar-type floating body 100 (i.e., when in operation), its center of gravity is positioned sufficiently high, allowing the compartmental weight material BLr to be discharged from the compartmental chamber 120. The discharge means 130 is a means for discharging the compartmental weight material BLr contained in the compartmental chamber 120. However, the discharge means 130 can be operated by an operator at a remote location, such as on land, on a ship, at another location inside the spar-type floating body 100, or on a working platform located outside the spar-type floating body 100; in other words, it is remotely controllable. In the example shown in Figure 4, a valve that can be opened and closed remotely is used as the discharge means 130, and the discharge means 130 is attached to a discharge pipe 140 that communicates with the compartmental chamber 120. In this case, if the partition weight BLr is a fluid or granular ballast, when the operator remotely opens the discharge means 130, the partition weight BLr contained in the partition 120 is discharged through the discharge pipe 140, and if the spar-type floating body 100 is in an upright position, the partition weight BLr falls towards the bottom.

[0037] (Divided rooms) The partition chamber 120 has been described as a box-shaped structure with a space formed inside the columnar body 110, but it can be formed from one box-shaped structure or from multiple box-shaped structures. In other words, the partition chamber 120 can be composed of multiple divided sections (hereinafter referred to as "divided partition chambers"). For example, as shown in Figure 5(a), it can be composed of multiple divided partition chambers (hereinafter specifically referred to as "horizontal divided partition chambers 120H") arranged along the inner circumferential surface of the columnar body 110. This figure illustrates a partition chamber 120 composed of eight horizontal divided partition chambers 120H, but of course, it is not limited to eight; the partition chamber 120 can be composed of two or more horizontal divided partition chambers 120H. In this case, it is advisable to install a discharge means 130, such as the one shown in Figure 4, in each horizontal divided partition chamber 120H. This allows for the storage of partition chamber weight material BLr in each horizontal divided partition chamber 120H, and also allows for the independent discharge of partition chamber weight material BLr from each horizontal divided partition chamber 120H.

[0038] As previously described, the spar-type floating body 100 is transported with its column axis direction approximately horizontal, and is erected from the approximately horizontal position to an upright position in order to make it operational. When erecting the spar-type floating body 100, bottom weight material BLb is placed at the bottom of the spar-type floating body 100. In particular, when crushed stone is used as the bottom weight material BLb, the upper surface of the bottom weight material BLb accumulated at the bottom may be sloped (i.e., not horizontal), and as a result, the spar-type floating body 100 may also be sloped (i.e., not vertical). In this case, the posture of the spar-type floating body 100 can be adjusted relatively easily by using multiple horizontally divided compartments 120H.

[0039] Specifically, after the spar-type floating body 100 is erected, the chamber weights BLr are placed into each of the horizontally divided chambers 120H. However, when the spar-type floating body 100 is tilted, a suitable horizontally divided chamber 120H is selected, and more chamber weights BLr are placed into that chamber 120H than in the others, adjusting the spar-type floating body 100 to be approximately vertical (including vertical). Alternatively, a suitable horizontally divided chamber 120H can be selected, and the chamber weights BLr from that chamber 120H can be discharged to adjust the posture of the spar-type floating body 100. Furthermore, a pumping device such as a submersible pump can be installed to move the chamber weights BLr contained in a predetermined horizontally divided chamber 120H to other horizontally divided chambers 120H, thereby adjusting the posture of the spar-type floating body 100.

[0040] The partition chamber 120 can also be composed of multiple divided partition chambers (hereinafter referred to as "vertical divided partition chambers 120V") arranged along the axial direction of the columnar body 110, as shown in Figure 5(b). This figure illustrates a partition chamber 120 composed of three vertical divided partition chambers 120V, but of course, the partition chamber 120 can be composed of two or more vertical divided partition chambers 120V, not just three. Furthermore, each vertical divided partition chamber 120V can be further composed of multiple horizontal divided partition chambers 120H. When the partition chamber 120 is composed of multiple vertical divided partition chambers 120V, it is preferable to install a discharge means 130, such as shown in Figure 4, in each vertical divided partition chamber 120V, and to configure the partition chamber weight material BLr discharged from the upper vertical divided partition chamber 120V to flow into the vertical divided partition chamber 120V directly below (the adjacent lower vertical divided partition chamber). This allows for the storage of partition weights BLr for each vertically divided partition 120V, and also allows for the independent discharge of partition weights BLr for each vertically divided partition 120V.

[0041] (Mobile partition) As previously mentioned, it is desirable to position the compartment 120 around the planned waterline within the spar-type floating body 100. However, even when the body is in an upright position and the wind turbine section is installed, it is possible that the compartment 120 may not be positioned around the planned waterline as planned. Therefore, it is preferable to configure the compartment 120 to slide up and down. Rails or guide grooves are provided on the inner circumference of the columnar body 110, and the compartment 120 is slid up and down along these rails, etc. In this case as well, similar to the discharge means 130, it is desirable that the compartment 120 be slid up and down by an operator located at a distance, such as on land, on a ship, or at another location inside the spar-type floating body 100 or on a working platform located outside the spar-type floating body 100.

[0042] 2. Assembly Method for Offshore Wind Power Generation Facilities Next, the method for assembling the offshore wind power generation facility of the present invention will be explained in detail with reference to the diagrams. The method for assembling the offshore wind power generation facility of the present invention is a method for assembling an offshore wind power generation facility including the spar-type floating body 100 described above. Therefore, explanations that overlap with those described for the spar-type floating body 100 will be avoided, and only the contents specific to the method for assembling the offshore wind power generation facility of the present invention will be explained. In other words, contents not described here are the same as those described in "1. Spar-type floating body".

[0043] Figure 6 is a flowchart showing the main steps of the offshore wind power generation facility assembly method of the present invention, and Figure 7 is a step diagram showing the main steps of the offshore wind power generation facility assembly method of the present invention. When assembling a wind power generation facility including a spar-type floating body 100 offshore, first the spar-type floating body 100 is transported by sea in a state where the column axis direction is approximately horizontal, as shown in Figure 7(a) (Step 201 in Figure 6). In order to ensure a certain draft during transport, it is advisable to place some bottom weights BLb at the bottom of the spar-type floating body 100. In addition, depending on the situation, some compartment weights BLr may be contained in the compartment 120 during transport, or the compartment weights BLr may not be contained.

[0044] Once the spar-type floating body 100 is transported to the selected calm area, bottom weight material BLb is added to the bottom of the spar-type floating body 100 (Step 202 in Figure 6), and the spar-type floating body 100 is raised to an upright position as shown in Figure 7(b) (Step 203 in Figure 6). Once the spar-type floating body 100 is upright, compartment weight material BLr is added to the compartment 120 as shown in Figure 7(c), raising the center of gravity of the spar-type floating body 100 (Step 204 in Figure 6). At this time, if the spar-type floating body 100 is tilted as shown in Figure 7(d), further compartment weight material BLr is added to the predetermined horizontal division compartment 120H, or the compartment weight material BLr in the predetermined horizontal division compartment 120H is removed, thereby adjusting the spar-type floating body 100 to be approximately vertical (Step 205 in Figure 6).

[0045] Once the spar-type floating body 100 is in an upright position and the compartmental weight material BLr is placed into the compartmental chamber 120, the wind turbine section (tower, rotor, nacelle, etc.), which has been transported separately by sea, is installed on top of the spar-type floating body 100 by a crane ship, as shown in Figure 7(e) (Step 206 in Figure 6). Then, as shown in Figure 7(f), the compartmental weight material BLr contained in the compartmental chamber 120 is discharged and dropped to the bottom of the spar-type floating body 100 (Step 207 in Figure 6). [Industrial applicability]

[0046] The spar-type floating structure and offshore wind power generation facility assembly method of the present invention can be particularly suitably used for spar-type offshore wind power generation facilities in sea areas with a depth of 50m or more. Since the present invention allows for the installation of spar-type offshore wind power generation facilities at low cost and safely, it can be expected to create a more positive incentive for offshore wind power generation. Furthermore, considering that it can stably supply energy while suppressing greenhouse gas emissions, the present invention is not only industrially applicable but can also be expected to make a significant contribution to society. [Explanation of Symbols]

[0047] 100 Spar-type floating body of the present invention 110 Columnar body (of a spar-type floating structure) 120 (Spar-type floating) compartment 120H (Constitutes a partition) Horizontal partition 120V (Vertical partitioned partition) 130 Discharge means (for spar-type floats) 140 (Discharge pipe of spar-type floating structure) 150 (Lifting means for spar-type floating bodies) 151 Ceiling beam (of lifting means) 152 (Hook of lifting device) 160 (Spur-type floating) temporary deck BLr weight material for compartment BLb bottom weight material

Claims

1. A spar-type floating structure for offshore wind power generation facilities, in which the wind turbine section is installed offshore. A hollow columnar body, A compartment is provided inside the columnar body to house the weight material, The system includes a discharge means for discharging the weight material housed in the partitioned chamber, The partition is composed of two or more horizontally divided partitions arranged along the inner circumferential surface of the columnar main body. The discharge means discharges the weight material independently from each of the horizontally divided compartments. A spar-type floating body characterized by the following features.

2. The partition is composed of two or more vertically divided partitions arranged along the axial direction of the columnar main body. The discharge means discharges the weight material independently from each of the vertically divided compartments. The spar-type floating body according to feature 1.

3. When the columnar body is in an upright or nearly upright position, and the wind turbine section is installed, the compartment is positioned at the planned waterline, which is the point where the columnar body intersects with the sea surface. The spar-type floating body according to feature 1.

4. A method for assembling an offshore wind power generation facility by installing a wind turbine section on a spar-type floating structure at sea, The aforementioned spar-type floating body comprises a hollow columnar body, a compartment provided inside the columnar body, and a discharge means. The partition is composed of two or more horizontally divided partitions arranged along the inner circumferential surface of the columnar main body. The discharge means discharges the weight material contained in the partitioned chambers independently for each of the horizontally divided partitioned chambers. A body erection step is performed by inserting a base weight into the bottom of the columnar body and raising the columnar body to an upright or nearly upright position, A weight material insertion step in which the weight material is placed inside the partitioned chamber, A posture adjustment step is performed to adjust the columnar body to an upright or nearly upright position by adding more weight to a predetermined horizontal division chamber or removing the weight from a predetermined horizontal division chamber when the columnar body is tilted after the weight material insertion step, A wind turbine installation process involves installing the wind turbine section on the spar-type floating body at sea, The system includes a weight material discharge step of discharging the weight material from the partition by operating the discharge means, A method for assembling an offshore wind power generation facility, characterized by the following features.

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