Floating windmill

Abstract

The present invention provides a floating wind turbine comprising a floating body element and a wind turbine, characterized in that the floating wind turbine further comprises a tension leg, an anchor, a buoyant element, a swivel and a crossbar, the swivel being arranged on the buoyant element, and in operation the floating wind turbine is arranged such that the wind turbine is provided on an upper end of the floating body element extending above the sea level, the lower end or part of the floating body element is located in the sea, one end of the crossbar is connected to a lower part or end of the floating body element and the other end of the crossbar is connected to the buoyant element, the entire buoyant element is located in the sea, preferably with a safe draft depth below the water surface of a work vessel and / or a marine transport vessel, and the tension leg is arranged between the buoyant element and the anchor on the seabed. The floating wind turbine is configured such that the floating element with the wind turbine at its upper end can freely rotate around the buoyant element in response to external forces, and in a low force state where the forces due to ocean currents, wind and waves are weak, the floating element, the buoyant element and the tension leg are oriented substantially vertically and the crossbar is oriented substantially horizontally, and in a high force state where the forces due to ocean currents, wind and waves are strong, the shapes of the floating element, the crossbar, the buoyant element and the tension leg are stretched by the forces and assume a shape resembling a lying S-configuration, and the change in shape and dynamic behavior reduces extreme stress levels.

Description

Technical Field

[0001] The present invention relates to an anchor-fixed floating structure such as a floating windmill, also known as a floating wind turbine. More specifically, the present invention relates to a floating windmill that can reduce costs when the costs required for manufacturing, transportation, installation, and maintenance are levelized over an estimated lifespan of at least 20 to 30 years, compared to the electrical energy generated.

Background Art

[0002] If the cost of floating wind energy can be reduced, the transition to more environmentally friendly energy will be promoted. As a result, vast offshore areas can be utilized for the electrical energy generated by floating windmills. Floating energy islands and floating infrastructure hubs also promote the transition to more environmentally friendly energy.

[0003] Examples of the latest technologies related to floating windmills include Hywind, WindFloat, and Sway. However, cost is a factor limiting the use of floating wind power, and financial subsidies are still required to make the concept economically viable.

[0004] New windmills that lead to cost reduction are beneficial for the transition to more environmentally friendly energy. The object of the present invention is to provide such a new windmill. A new floating energy island or infrastructure hub also promotes the transition to more environmentally friendly energy. A further object of the present invention is to provide the floating energy island or infrastructure hub.

Summary of the Invention

[0005] The present invention provides a floating windmill comprising a floating element and a wind turbine. The floating windmill is further characterized by comprising a tension leg, an anchor, a buoyancy element, a swivel, and a crossbar. The swivel is arranged on the buoyancy element. During operation, the wind turbine of the floating windmill is provided at the upper end of the floating element that extends above the sea surface, the lower end or a part of the lower end of the floating element is located in the sea, one end of the crossbar is connected to the lower part or the end of the floating element, the other end of the crossbar is connected to the buoyancy element, the whole of the buoyancy element is preferably located in the sea while ensuring a safe draft depth below the water surface of a workboat and / or a marine transport ship, the tension leg is configured to be arranged between the buoyancy element and the anchor on the seabed, the floating element with the wind turbine at the upper end can freely rotate around the buoyancy element in response to external forces, in a low-force state where the forces by ocean currents, wind, and waves are weak, the floating element, the buoyancy element, and the tension leg are substantially oriented in the vertical direction, the crossbar is substantially oriented in the horizontal direction, in a high-force state where the forces by ocean currents, wind, and waves are strong, the shapes of the floating element, the crossbar, the buoyancy element, and the tension leg are stretched by the forces and become a shape like a horizontal S-shaped configuration, and due to the change in the shape and the dynamic behavior, an extreme stress level is reduced.

[0006] In a preferred embodiment, the floating element is a spar buoy.

[0007] In other preferred embodiments, the floating element is a square, triangular, polygonal, elliptical, or circular floating or semi-submersible structure having one, two, three, four, or more windmill towers.

[0008] Preferably, the underwater part of the floating element extends longer than the position where the crossbar is connected, so that it is possible to suppress or prevent the floating element from tilting in the leeward direction due to the wind load on the turbine blade. The efficiency is increased by maintaining the angle of the turbine blade surface substantially perpendicular to the wind direction.

[0009] The terms "vertical direction" of the floating body element and "the crossbar is substantially horizontal between the buoyancy element and the floating body element" have relative meanings and do not necessarily mean exactly vertical or exactly horizontal in the strict sense. When using a spar buoy as the floating body element and in a low-power state, it will be as described literally. In the case of other floating body elements, the terms have relative meanings, but the dynamic "extension" in the shape of a laterally S-shaped due to the force in the high-power state is retained as an essential feature. This also applies to embodiments where the floating body element retains a vertical orientation even in the high-power state because the orientation of the crossbar changes to open the angle with respect to the floating body element above the crossbar. When the floating body element is a triangular, polygonal, quadrilateral, rectangular, or other shaped floating structure and includes one, two, three, or more wind turbines, the vertical orientation of the floating body element literally applies only to the wind turbine tower.

[0010] The axial movement due to the above-mentioned extension combined with the lateral movement due to the direction change and position change suppresses the application of extreme stress to the structural element. The movement of these elements greatly alleviates the energy that may apply a high level of stress to the structural element. Since the dynamic flexibility acts on the force and strain, the acceleration of the element can also be reduced by this movement. Due to this effect, compared with a rigid and rigid structure, depending on several factors and general conditions, the extreme stress level can be reduced by at least 10%, 20%, 30%, or 50%.

[0011] Preferably, the floating wind turbine includes a releasable connection between the crossbar and the buoyancy element. Preferably, the floating wind turbine also includes a releasable connection between the crossbar and the floating body element. The releasable connection here means a connection that can be connected and separated / released at an offshore wind turbine installation site. The releasable connection preferably includes a conduit, i.e., a guide structure and / or a guideline, to facilitate connection and separation / release, regardless of the presence or absence of support by an ROV (remotely operated vehicle).

[0012] The floating wind turbine preferably does not include a gear rim within the wind power turbine / nacelle of the floating element. The swivel of the buoyancy element is sufficient if it can accommodate the rotation when freely swiveling according to an external force.

[0013] The present invention also provides a method for manufacturing, transporting, installing, and / or maintaining a floating wind turbine, including manufacturing, transporting, installing, and / or maintaining the components of the wind turbine.

[0014] The pre-manufacture of the elements or parts of the wind turbine is preferably carried out at the manufacturing site. The elements or their parts are transported to the pre-assembly site or the transportation site, from where they are transported to the installation site, and the parts of the elements and / or the final assembly of the elements are carried out.

[0015] In a preferred embodiment, the method includes transporting the floating element and the wind power turbine to the installation site of the wind turbine, and installing them by connecting the components to the buoyancy element pre-installed on the seabed anchor there. Preferably, a crossbar is connected to the floating element, and the installation includes connecting the crossbar to the buoyancy element. Alternatively, a crossbar is connected to the buoyancy element, and the installation includes connecting the floating element to the crossbar. Preferably, the buoyancy element and / or the ship used during operation are equipped with a buoyancy system that enables the buoyancy element to be raised and lowered between the water surface position and the underwater position, and to carry out the connection operation near or at the water surface position.

[0016] As will be described in more detail below, variable or non-rigid tension legs are preferred, although a combination of rigid tension legs and flexible tension legs may also be used. More specifically, the tension leg can be one or more wires such as three or four wires, or one or more rigid tension legs such as three or four rigid tension legs. However, a combination of rigid tension legs and flexible tension legs is preferred. In this case, the rigid tension legs, for example three rigid tension legs, extend from the anchor to the operating position of the buoyancy element at the maximum operating depth of the buoyancy element, at which position the rigid body element can be fixed to the buoyancy element for connection or separation. Here, it is preferable that a wire winch system is mounted on the buoyancy element so that the buoyancy element can be controlled to float to the water surface or lowered to the operating position. This facilitates the installation, connection, and separation of the crossbar. The rigid portion or lower portion of the tension leg preferably includes a truss structure to increase torsional rigidity and / or to maintain the relative position. The connection to the anchor may include a swivel to reduce or eliminate the torsional force on the anchor.

[0017] In a preferred embodiment, the method includes that only the anchor is pre-installed, and one or more remaining parts of the pre-manufactured structure are towed to the position of the pre-installed anchor, where the anchor is connected to the tension leg, and further other elements are connected to each other. To facilitate the operation, it is preferable to arrange a guideline equipped with a conduit and a transponder on the anchor.

[0018] In another preferred embodiment, the method includes replacing components at the wind turbine installation site by installing new components or removing damaged or parts requiring maintenance or repair, so that maintenance is performed in a single combined operation, preferably in a single voyage of one ship.

[0019] The advantages of the floating wind turbine of the present invention are as follows. Since there is no gear rim, the weight of the wind turbine / nacelle is reduced, and at least 3 to 5 times the weight of the corresponding floating structure in the sea can be saved. Only one anchor point is required, and the safe zone area can be reduced. Self-orientation can be achieved by free rotation (weather vane) according to external forces. The extreme tension can be reduced by the self-damping effect due to the shape change. The cable wiring is simplified, and a swivel is not required for the wind turbine / nacelle. Logistics is simplified by the manufacture of parts, the transportation of parts or pre-assembled structures in part, making manufacturing, transportation, and installation easier, and enabling work with fewer and / or smaller ships less frequently for larger structures. Maintenance is simplified by replacing / maintaining only the elements that require maintenance on-site, reducing the downtime of the windmill and the operation time of the ship. When including manufacturing, transportation, installation, and maintenance in the cost and leveling it over a lifespan of at least 20 or 30 years, the total cost reduction is, approximately, more than 30%, 40%, or 50% per MWh (megawatt-hour) generated.

[0020] In some embodiments, the floating windmill of the present invention is not only a floating windmill but also a floating energy island or a floating infrastructure hub including one, two, three, or more of the anchor systems described in claim 1. In embodiments with two or more defined anchor systems, the function of free rotation according to external forces is reduced or lost, but the reduction in the essential extreme stress level is retained.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Best Mode for Carrying Out the Invention

[0022] Referring to FIG. 1, an embodiment of the floating windmill 1 of the present invention including a floating element 2 and a wind turbine 3 is shown. The floating windmill further includes tension legs 4, an anchor 5, a buoyancy element 6, a swivel 7, and a crossbar 8, and the swivel is disposed within the buoyancy element.

[0023] The illustrated floating windmill includes a spar buoy as the floating element 2, and the wind turbine 3 is provided at the upper end of the floating element 2 which is higher than the sea surface. The lower end of the floating element is located in the sea and is connected to one end of the crossbar 8, and the opposite end of the crossbar is connected to the buoyancy element 6. The buoyancy element 6 is entirely located in the sea, the lower end is connected to the upper end or a part of the tension leg 4, and the lower end or a part of the tension leg is connected to the anchor 5.

[0024] The anchor is preferably a weight anchor or a suction anchor, or a combination of a weight anchor and a suction anchor. Other anchors such as pile anchors can also be used.

[0025] As indicated by the rotation symbol above the buoyancy element, the floating element 2 can freely swivel around the buoyancy element 6 according to an external force.

[0026] The illustrated operating state is a low-force state, that is, the forces due to ocean currents, wind, and waves are weak, and the components / elements are in an equilibrium state, that is, a state not deviating greatly from the arrangement when there are no ocean currents, wind, and waves. As defined, being in an equilibrium state or not deviating greatly from the arrangement means that the orientation with respect to a vertically or horizontally oriented element is less than 5°.

[0027] As will be understood by those skilled in the art, in the high force state, the deviation from the equilibrium state is greater than 5°, and the shape of the configuration of the elements becomes a laterally S-shaped configuration. This is illustrated by a rotation angle greater than 5° indicated by the dashed line between the tension leg and the buoyancy element. For clarity, only the deviation from the vertical direction due to a strong force on the buoyancy element is shown for such a deviation indicated by a dashed line. As will be understood by those skilled in the art, when the configuration of the elements is extended to have a laterally S-shaped configuration, the angular direction of the crossbar also, and in many embodiments the angular direction of the floating element, also changes.

[0028] As mentioned, FIG. 2 is a side view showing an embodiment of the floating windmill of the present invention, showing the low force state. The S-shaped configuration of the structure is clearly shown in the figure. FIG. 3 is a perspective view showing the embodiment of FIG. 2. The reference numbers are the same as in FIG. 1, but in FIG. 2, the water level line is indicated by reference number 9. FIGS. 2 and 3 are embodiments with a larger scale for depth than the embodiment shown in FIG. 1. For clarity of features, the figures are generally not to scale.

[0029] Preferably, the anchor, tension leg, and buoyancy element are pre-installed, the floating element with the crossbar is connected to the buoyancy element at the windmill installation site, and the cable is pre-installed from the swivel, placed on the crossbar, and drawn into the interior of the floating element, with or without using a connection located in a dry place within the floating element. The pre-assembly can also be carried out in another configuration, preferably including connecting at least two groups of pre-assembled components to one or both ends of the crossbar.

[0030] The tension leg can be a single flexible wire or multiple flexible wires, and preferably is combined with a buoyancy system within the buoyancy element or a buoyancy system connectable from the ship, such as pumps, pipes, and valves for adjusting the ballast level of the buoyancy element to move the buoyancy element to the water surface or near it or lower it to the operating position when connecting to the crossbar. The tension leg can also be or include some rigid elements, such as a rigid element for providing torsional rigidity or three elements in a triangular configuration. The rigid element may be provided with a conical portion and a guideline at the upper end to enable a controlled arrangement during the installation and recovery of the buoyancy element that combines ballast and winching. The buoyancy element preferably comprises a recoverable transponder with electrical and / or hydraulic connections for controlled ballast and a controlled winch, and the buoyancy element includes electrical or hydraulic winches and / or electrical or hydraulic pumps or hydraulic connections to the ship's ballast pump.

[0031] The buoyancy element preferably also comprises a releasable connection to the tension leg.

[0032] The floating body element preferably also comprises facilities for connecting to the buoyancy system and / or the ship's buoyancy system. The buoyancy system is a pump within the floating body element or the ship, and the pipes and valves necessary for adjusting the ballast level of the floating body element. By doing so, the installation, replacement, or maintenance of the wind turbine, nacelle, or their components can be simplified by sinking the floating body element more. The underwater position is preferably lowered to a level accessible to the nacelle by the crane of the ship used for installation.

[0033] As will be understood by those skilled in the art, the anchor can be a single anchor that is vertically below the buoyancy element when in the equilibrium position. However, embodiments are also contemplated where multiple anchors, such as suction anchors, are arranged in proximity to each other as substantially one unit below the buoyancy element, but are separated due to the soil conditions requiring sufficient strength, and are also included within the scope of the term "one anchor". One large weight anchor that can be weighted on-site to achieve sufficient weight / strength is a preferred embodiment in many shallow sea areas with relatively firm bottoms.

[0034] The present invention also provides an energy island or energy hub with or without a windmill, having a maximum stress level reduction structure, namely, one or more tension legs, anchors, buoyancy elements, preferably swivels, and crossbars. Here, when a swivel is present, the swivel is arranged within the buoyancy element, and the structure is arranged as a dynamic S-shaped structure that extends from an S-shape and becomes a horizontal S-shape in the high force state, as defined in claim 1.

[0035] The floating windmill or energy island of the present invention preferably includes a vertical axis windmill. This is because such windmills can be arranged closer to each other than horizontal axis windmills. The absence of a wind shadow also eliminates the need for free rotation in response to external forces and a gear rim, which is a further advantage of vertical axis windmills.

[0036] The floating windmill or energy island of the present invention preferably includes a frame with a number of windmills that self-align with respect to the wind direction, preferably on an energy island that does not self-rotate in response to external forces, or the frame itself self-rotates as a single floating windmill in response to external forces. The frame is preferably arranged on a triangular floater or semi-submersible floater fixed by an anchor according to the present invention.

[0037] The floating wind turbine or energy island of the present invention preferably comprises a water current turbine suspended from and / or anchored to the floating wind turbine, preferably configured to be recoverable for ease of installation and maintenance.

[0038] The floating wind turbine or energy island of the present invention preferably comprises a solar panel. The floating wind turbine or energy island of the present invention preferably comprises a battery.

[0039] The floating wind turbine or energy island of the present invention can preferably be provided with any combination of the energy generation structures described herein and / or connected to surrounding stand-alone devices, thereby enabling the floating wind turbine of the present invention to be expanded into an energy island and / or an energy hub.

Claims

A floating structure in the form of a floating wind turbine (1), energy island, energy hub and / or infrastructure hub, comprising a floating element, The floating structure further comprises Tension legs (4), an anchor (5), a buoyancy element (6), a swivel (7) and a crossbar (8), The swivel (7) is arranged on the buoyancy element (6), During operation of the floating structure, the upper part of the floating element extends above the sea surface, the lower part of the floating element is located in the sea, one end of the crossbar (8) is connected to the lower part of the floating element (2), the other end of the crossbar (8) is connected to the buoyancy element (6), the entire buoyancy element (6) is completely located in the sea at a safe draft depth below the water surface of a workboat, and the tension leg (4) is arranged between the buoyancy element (6) and the anchor (5) on the seabed, When there is only one anchor system, the floating element (2) can freely rotate around the buoyancy element (6) in response to an external force, In the absence of forces due to ocean currents, wind and waves, the tension leg is oriented in the vertical direction and the crossbar (8) is oriented in the horizontal direction, In a high-force state with strong forces due to ocean currents, wind and waves, the shapes of the floating element, the crossbar, the buoyancy element and the tension leg exhibit an extended shape extended by the forces, and the orientation of the element oriented in the vertical direction and the element oriented in the horizontal direction deviates by more than 5° from the equilibrium state, and the extreme stress level is reduced by the change in shape and dynamic behavior, Floating structure.

2. Further comprising a releasable connection between the crossbar and the buoyancy element, The floating structure according to claim 1.

3. Further comprising a releasable connection between the crossbar and the floating element, The floating structure according to claim 1 or 2.

4. When a nacelle and / or a wind turbine is provided, a gear rim is not provided at the upper end of the floating body element in the nacelle and / or the wind turbine. The floating structure according to claim 1.

5. Including transporting, installing, or maintaining the components of the floating structure. A method for transporting, installing, or maintaining the floating structure according to claim 1.

6. The floating structure is transported to the installation site and installed there by connecting the floating structure to the buoyancy element pre-installed on the seabed anchor. The buoyancy element is provided with a buoyancy system that allows the buoyancy element to move up and down between the water surface position and the underwater position and enables connection work to be performed near or at the water surface position. The method according to claim 5.

7. By replacing the components of the floating structure by installing new components or removing damaged or parts requiring maintenance or repair, maintenance is performed as a single combined operation during a single voyage of a single ship. The method according to claim 5.

8. The anchor, the tension leg, and the buoyancy element are pre-installed, the floating structure with the crossbar is connected to the buoyancy element on the floating structure, the cable is pre-installed from the swivel, arranged on the crossbar, and is drawn into the interior of the floating structure with or without using a connection part located in a dry place within the floating body element. The method according to claim 5 or 6.

9. Use of the floating structure according to claim 1 for reducing the extreme stress level of a floating structure in the form of a windmill, an energy island, an energy hub, and / or an infrastructure hub.

10. The floating structure according to claim 9, wherein the floating structure includes a water current turbine, a solar panel, and / or a battery.

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