Buoyant offshore renewable energy system platform
The buoyant platform with angled mooring lines and outrigger members stabilizes against wind and wave forces, improving operational efficiency and maintenance accessibility, addressing installation and stability challenges of current platforms.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MARINE POWER SYST
- Filing Date
- 2024-05-29
- Publication Date
- 2026-06-23
AI Technical Summary
Current buoyant offshore platforms for renewable energy systems face challenges in ease of installation, stability against dynamic wind and wave forces, and maintenance accessibility, with complex structures increasing the risk of damage and collision during deployment and maintenance.
A buoyant platform design featuring a single elongated or bottle-shaped structural element with mooring lines that engage the seabed at various angles and include outrigger members to stabilize the platform against wind and wave forces, minimizing surface area for resistance and maximizing vessel access, while using impact-absorbing surfaces to prevent collisions.
The design enhances stability and reduces platform movement, ensuring optimal operational efficiency and ease of maintenance by minimizing collisions and damage, while allowing for easy deployment and replacement.
Smart Images
Figure 2026520383000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a floating offshore platform for supporting offshore renewable energy systems such as wind turbines.
Background Art
[0002] Offshore wind energy and wave energy are both recognized as major technological options for decarbonizing the world's energy systems. The economic viability and practical feasibility of these renewable energy systems largely depend on the ease and cost of installation and maintenance of these systems offshore. One solution to minimize the cost of these systems is to install wave energy systems and wind energy systems offshore on floating or buoyant platforms.
[0003] The advantage of a buoyant offshore platform is that the foundations required for a buoyant offshore platform are typically installed on the seabed of a water area more quickly and easily, and these foundations can be laid more easily at greater depths. Furthermore, the completed buoyant offshore platform can be manufactured on land or near land rather than assembled piece by piece offshore, and then towed to the desired location. However, there are problems with current state-of-the-art buoyant offshore platforms and with the methods and equipment used to assemble and install the platforms offshore. Therefore, it is desirable to provide an offshore renewable energy system-mounted platform that overcomes these problems of the state-of-the-art technology.
Summary of the Invention
[0004] This disclosure relates to a buoyant platform intended for supporting a renewable energy system, preferably a wind turbine, in a body of water. In particular, the platform comprises a single buoyant structural element configured to be partially submerged in the body of water to an operating depth by any suitable means. The first end of the structural element comprises a surface configured to support a renewable energy system, preferably a wind turbine, above the surface of the body of water when the structural element is partially submerged to an operating depth. To maintain the structural element at the operating depth, the platform further comprises one or more first mooring lines for mooring the bottom end of the structural element to the seabed of the body of water. A plurality of further angled mooring lines are configured to moor one or more sides of the structural element to the seabed.
[0005] Preferably, one or more first mooring lines may be configured to engage with the seabed of the water body at a position vertically below the bottom end such that the first mooring lines are substantially coaxial with the spar at the operating depth, and / or one or more first mooring lines may include at least two (preferably three) first mooring lines configured to engage with the seabed of the water body such that at least two first mooring lines are oriented obliquely to the structural elements at the operating depth.
[0006] Preferably, the structural element is a buoyant, elongated spar, or the structural element is a buoyant spar having a first cylindrical section having a first predetermined diameter and a second cylindrical section having a second predetermined diameter, wherein the second predetermined diameter is smaller than the first predetermined diameter, and the tapered section between the first cylindrical section and the second cylindrical section forms a single structural element, which may be called a bottle-shaped structural element.
[0007] Preferably, the attachment points of the further angled mooring lines on the structural elements are located at a distance from one or more attachment points of the first mooring lines. At the operating depth, the buoyancy of the structural elements imparts tension to one or more of the first mooring lines and the further angled mooring lines. The buoyancy of the structural elements is also configured to support the mass of the renewable energy system supported on it. Therefore, the net buoyancy of the structural elements while supporting the renewable energy system in the water is positive so that tension is applied to the mooring lines. The combination of the tension of the mooring lines and the vertical and / or angled lines having fixed points located at a distance from each other on the structural elements, as well as positioning the anchor points of the mooring lines on the bottom of the water, preferably provides the structural elements with robustness against dynamic wind and wave forces acting on the platform in use. Therefore, the structural elements are constrained against vertical (heave), lateral (surge), and tilting motions, and thus can remain substantially stationary under various wind and wave conditions. This stationary property is useful for maintaining optimal operational efficiency of renewable energy capture and conversion by renewable energy systems supported on the structural elements, and also allows for easier access to the structural elements for maintenance of the renewable energy systems.
[0008] Using a single elongated or single bottle-shaped structural element to support a renewable energy system above the surface of a body of water in this manner maximizes ease of manufacture and deployment while minimizing resource consumption for the production of the renewable energy system platform. The properties of the elongated or bottle-shaped structural element provide the minimum surface area acting against wave and wind forces, thereby minimizing resistance to wave and wind forces and the currents acting on them, and thus minimizing the movement of the platform in the body of water under various weather and sea conditions. Supporting a renewable energy system on a single structural element preferably further maximizes the ease of access to the platform and the renewable energy system by vessels for deployment and maintenance, while minimizing the risk of damage to the platform or the renewable energy system by eliminating the need to cross complex structures. Using a single elongated or single bottle-shaped structural element for the platform further means that, in the event of damage, the platform can be easily and with minimal resources replaced.
[0009] In the most preferred embodiment, the upper end of a buoyant single structural element protrudes from the surface of the water body so that, when supporting the renewable energy system at the operating depth, the platform is positioned to keep the renewable energy system above the surface of the water body at the operating depth. Thus, the renewable energy system is protected from the effects of exposure to seawater or the effects of fluctuating wave forces.
[0010] In some preferred embodiments, additional mooring line anchoring points on structural elements may be positioned close to the upper end of the structural member for maximum platform stability in use. In some embodiments, this positioning may be inadequate and could pose a risk of collision between the vessel and the mooring line during deployment or maintenance. In such embodiments, additional mooring line anchoring points on structural elements may be further protected from collision by guard members having impact-absorbing surfaces positioned above the anchoring points. The impact-absorbing surfaces may be positioned at a distance from the body of the structural element to minimize the risk of collision with the vessel's structural element. The risk of collision with the mooring line can be minimized, or even further minimized, by positioning the anchoring points so that they are below the surface of the water when the platform is at operating depth. Positioning the anchoring points lower is preferable as it reduces the required distance between the vessel and the platform during maintenance, allowing the vessel to approach the platform more closely while reducing the risk of collision with the mooring line. Positioning the anchoring points lower on the body of the structural element in this way may, in some embodiments, impair the stability of the structural member in various weather and sea conditions. In such embodiments, outrigging can be used to support mooring anchor points away from the body of the structural element, which preferably provides a higher mooring anchor equivalent on the structural element, thereby preferably overcoming the loss of stability that may be associated with lowering the mooring anchor points relative to the structural element.
[0011] In some embodiments, a single outrigging can be used to provide a common mooring anchor point for each of the additional mooring lines. Such embodiments would maximize the surface area of the structural element that would otherwise lack anchoring, thereby maximizing vessel access to the structural element and the renewable energy system supported thereon. Such embodiments may be suitable for installations where the platform is expected to face wind and / or waves primarily from only one direction. In other embodiments, multiple outrigging members can be used, for example, one outrigging member for each additional mooring line. In such embodiments, the outrigging members are preferably spaced around the periphery surface area of the structural element to provide a vessel access portion of the structural element, which is free from mooring anchor points or outrigging, and therefore minimizes the risk of collision with vessels during deployment and ongoing maintenance.
[0012] In some embodiments, one or more of the further mooring lines preferably include a protective member, which extends a predetermined distance along the further mooring line from a first end of the further mooring line. In some embodiments, the protective member may be either an outer layer surrounding the further mooring line or a substantially solid member to which the further mooring line is attached.
[0013] Accordingly, according to one aspect of the present disclosure, a buoyant offshore renewable energy system platform comprising: a buoyant spar having an upper end and a lower end, configured to support a renewable energy system thereon; and a plurality of mooring lines configured to moor the spar to the seabed of a body of water such that the spar is positioned in the body of water at an operating depth, wherein the plurality of mooring lines are attached to the bottom end of the spar, the bottom end being distal to the upper end, and configured to engage with the seabed of the body of water. A platform comprising a plurality of mooring lines, each comprising: a mooring line and at least three further mooring lines, each having a first end that communicates with the spar between the upper and bottom ends of the spar, and a second end that engages with the seabed of the water body, so that the further mooring lines are oriented obliquely with respect to the spar at the operating depth, wherein at the operating depth, the first end of the spar is positioned above the surface of the water body and the second end is positioned below the surface of the water body.
[0014] In some embodiments, one or more first mooring lines may be configured to engage with the seabed of the body at a position vertically below the bottom end such that the first mooring lines are substantially coaxial with the spar at the operating depth. In some embodiments, one or more first mooring lines may include at least two (preferably three) first mooring lines configured to engage with the seabed of the body such that at least two first mooring lines are oriented obliquely to the spar at the operating depth.
[0015] In some embodiments, the spar may be a buoyant, elongated spar. In some embodiments, the spar may be a buoyant spar having a first cylindrical section having a first predetermined diameter, a second cylindrical section having a second predetermined diameter, and a tapered section between the first and second cylindrical sections, wherein the second predetermined diameter is smaller than the first predetermined diameter.
[0016] In a preferred embodiment, a non-zero vertical gap is defined between the mooring point of the first mooring line on the spar and each of the mooring points of the further mooring lines. Preferably, the mooring points of the further oblique mooring lines are positioned at a vertical distance from the mooring points of the first (coaxial) mooring line to restrain the spar with its oblique degrees of freedom. If the mooring points of the further oblique mooring lines are not positioned at a vertical distance from the mooring points of the first (coaxial) mooring line, the spar may be unstable in the oblique state (the spar may be able to rotate around the mooring points). Preferably, the larger the vertical gap, the more stable the spar will be with respect to a given buoyancy.
[0017] In some preferred embodiments, additional mooring lines are attached to the spar at each of the following locations, such that at the operating depth, each of the respective locations is either above the surface of the water body or below the surface of the water body.
[0018] In some embodiments, the spar preferably further comprises a guard member, the guard member having an impact-absorbing surface positioned at the guard member position along the side wall of the spar between the upper and lower ends. In some preferred embodiments, the impact-absorbing surface is supported at a non-zero distance from the side wall of the spar. In some embodiments, the guard member preferably extends at least partially around the spar at the guard member position. In some embodiments, the guard member is preferably substantially toroidal or segmented toroidal in shape.
[0019] In some preferred embodiments, the guard member is positioned at or above each of these positions. Thus, the guard member can act to prevent collision with the ship's mooring rope anchoring points.
[0020] In some preferred embodiments, the platform further comprises outrigger members mounted along the side wall of a spar between an upper and lower end, projecting outward from there, the outrigger members having mooring rope attachment points located on the distal portion of the spar of the outrigger members, and at least one first end of a further mooring rope being attached to the mooring rope attachment point.
[0021] In some preferred embodiments, the first end of each of the additional mooring lines is preferably attached to a mooring line anchoring point. In such embodiments, each of the additional mooring lines shares a common anchoring point on the spar by a single outrigger member.
[0022] In some preferred embodiments, the platform comprises corresponding outrigger members for each of the further mooring lines, with the first end of each of the further mooring lines being attached to the mooring line anchoring point of the corresponding outrigger member. In such embodiments, each of the further mooring lines is attached to the spar at a common anchoring point by the corresponding outrigger member.
[0023] The outrigger member is preferably configured to support the mooring anchor point at a non-zero distance from the spar. In some preferred embodiments, the outrigger member comprises a lateral brace extending substantially perpendicular to the spar between a first point along the side wall of the spar and the mooring anchor point, and an oblique brace extending between a second point along the side wall of the spar and the mooring anchor point, the second point being higher than the first point. The oblique support provided to the mooring anchor point by the oblique brace of the outrigger member is attached to the side wall of the spar at a point where its end is higher than the end of the lateral brace, preferably equal to a higher mooring anchor point of the corresponding mooring line. This provides greater stability that may be provided by a higher mooring anchor point, while minimizing the risk of collision between the mooring line and the vessel by positioning the actual mooring anchor point lower relative to the spar, preferably below the surface of the water, when the spar is positioned at the operating depth.
[0024] At the operating depth, the additional mooring lines are preferably oriented obliquely to the spar along their corresponding axes, and these corresponding axes do not intersect.
[0025] In embodiments equipped with outrigger members, at the operating depth, the mooring anchor point is positioned below the surface of the water. Therefore, the outrigger members preferably allow for lower positioning of the mooring anchor point relative to the spar, while maintaining the stability of the spar's top when supporting a renewable energy system or device on it.
[0026] Each second end of each additional mooring cable is preferably moored to a corresponding anchor point on the bottom of the body of water, and each such anchor point is spaced apart to form the vertices of a triangle on the bottom of the body of water. In some preferred embodiments, the triangle is an equilateral triangle. The spar can be positioned substantially at the center of the triangle. The regular spacing of the anchor points relative to the spar in such preferred embodiments can be intended to provide the same support against wind and wave forces in all directions, and may be multi-directional or have adjustable directions to account for changing wind directions, which can be preferred for platforms intended to support renewable energy devices such as wind turbines. In some preferred embodiments, the triangle is an isosceles triangle. The offset positioning of the vertex of the isosceles triangle relative to the vertices of the base of the isosceles triangle can be beneficial in providing more support in a single direction, and thus can be preferred for renewable energy devices such as wind turbines that are intended to account for wind impinging on the turbine mainly in a single direction.
[0027] Any suitable number of additional mooring cables greater than three may be used, and regardless of the number, it will be understood that the mooring cable attachment points of the additional mooring cables are preferably arranged angularly equidistantly around the spar.
[0028] In a preferred embodiment, the spar includes a ship access portion, which is a portion of the spar's side wall that is not accompanied by outrigger members or mooring anchor points. The ship access portion is, for example, a surface area of the spar that is not accompanied by outrigger members or mooring anchor points, thereby minimizing obstruction to access by vessels intended for the deployment or maintenance of a platform or a renewable energy system or device mounted thereon. In some embodiments, the ship access portion may extend along the length of the spar's side wall. In such embodiments, the ship access portion may have a constant width along the entire length of the spar. In some embodiments, the ship access portion may be a portion of the spar's side wall defined between two such mooring anchor points or outrigger members. In some embodiments, the two such mooring anchor points or outrigger members are at least 120 at the center of the spar o An angle of at least 120° at the center of the spar is understood to mean that when two lines intersecting at the center of the spar are drawn from the respective positions of two mooring line anchoring points or outrigger members on the outer surface of the spar, they form an angle of at least 120° between them. The ship access portion may extend, for example, to the peripheral edge of the spar or at least about 33% around its periphery.
[0029] In some embodiments, the platform further comprises a passageway at least partially positioned within the vessel access portion that extends from or communicates with the spar, the passageway being configured to remain above the surface of the body of water when the platform is at the operating depth. This passageway preferably enables maintenance personnel to disembark from the vessel onto the platform for the purpose of maintaining the platform or the renewable energy system. The passageway preferably allows for vessel clearance, which is the distance from the spar where the vessel can be located from which the maintenance personnel can step onto the passageway. The vessel clearance distance can be any suitable distance, preferably at least 10 meters. In some embodiments, the vessel may preferably be positioned laterally with respect to the platform during maintenance. The passageway may, in some embodiments, be configured to engage a separate vessel passage extending from the vessel to maximize vessel clearance during maintenance.
[0030] At the operating depth, the buoyancy of the spar is preferably configured to apply tension to the first mooring line and additional mooring lines. The buoyancy is further configured to support the mass of the renewable energy system such that the renewable energy system is maintained above the bottom of the body of water. Thus, the net buoyancy of the spar while supporting the renewable energy system thereon is preferably positive such that tension is applied to the mooring lines.
[0031] In the most preferred embodiments, the spar is substantially cylindrical. In some embodiments, the cylinder may be tapered near the upper end such that the diameter of the upper end is smaller than the diameter of the lower end. In such embodiments, the cylindrical body of the spar may comprise a first portion extending from the lower end of the spar along the spar to an intermediate point proximate to the upper end of the spar, the first portion having a constant diameter, and a second portion extending between the intermediate point and the upper end of the spar, the diameter of the second portion at the upper end of the spar being smaller than the diameter of the second portion at the intermediate point.
[0032] A platform according to any one of the preceding claims, wherein the renewable energy system is a wind turbine. Embodiments will be understood in which the renewable energy system is any suitable renewable energy system or device intended to capture a form of renewable energy, such as wind or wave energy, and convert or store it into usable energy.
[0033] In embodiments of renewable energy systems that include a wind turbine, the upper end of the spar is configured to support the wind turbine such that the wind turbine mast is substantially coaxial with the spar.
[0034] The renewable energy system is preferably supported on the uppermost surface of the elongated spar, which is positioned in a plane such that it remains above the surface of the water when the platform is at operating depth.
[0035] In some preferred embodiments, the spar comprises one or more landing features configured to engage with corresponding connecting means of the vessel. Accessibility of the spar and any renewable energy systems attached to the spar may be provided by vessel access portions in some embodiments and may be complemented in some embodiments by landing features configured to assist in connecting the vessel to a platform. Such landing features may be any suitable landing features and preferably complement the corresponding connecting mechanism of the vessel.
[0036] In some preferred embodiments, the operating depth may be adjustable. The operating depth may be adjustable by using any suitable means to pull in, extend, or otherwise apply or release tension to each of one or more mooring lines. Control of the operating depth in this manner may be, for example, in response to changing sea conditions and may allow the upper end of the spar projecting over the surface of the water body to be maintained so that the renewable energy system is kept above the surface of the water body in any sea conditions.
[0037] In some embodiments, one or more of the additional mooring lines preferably include a protective member, which extends a predetermined distance along the additional mooring line from a first end of the additional mooring line. In some embodiments, the protective member is preferably either an outer layer surrounding the additional mooring lines or a substantially solid member to which each additional mooring line is attached. The protective member may be added to one or more of the additional mooring lines between the platform and one or more of the additional mooring lines at a predetermined distance from the platform, where the predetermined distance is based on a calculated depth below the mean draft of the water. The protective member may be an armored outer layer applied to the additional mooring lines or a solid section to which the additional mooring lines are attached. Thus, the protective member may act to prevent damage to the additional mooring lines, for example, from collision with floating marine debris or accidental contact with a vessel.
[0038] It will be understood that any feature described herein as suitable for incorporation into one or more aspects or embodiments of the Disclosure is intended to be generalizable across all aspects and embodiments of the Disclosure. Other aspects of the Disclosure may be understood by those skilled in the art based on the description, claims, and drawings of the Disclosure. The above general description and the following “Modes for Carrying Out the Invention” are illustrative and descriptive and do not limit the claims. [Modes for carrying out the invention]
[0039] Here, specific embodiments are described by reference to the accompanying drawings, merely as examples. [Brief explanation of the drawing]
[0040] [Figure 1A] A perspective view is provided of an exemplary embodiment of a platform, in one aspect, moored to the seabed of a body of water at an operating depth. [Figure 1B] An alternative side view of the platform shown in Figure 1A is provided. [Figure 1C] An alternative side view of the platform shown in Figure 1A is provided. [Figure 1D] A plan view of the platform is provided in Figure 1A. [Figure 2A] A perspective view is provided of an exemplary alternative embodiment of a platform, in one aspect, moored to the seabed of a body of water at an operating depth. [Figure 2B] An alternative side view of the platform shown in Figure 2A is provided. [Figure 2C] An alternative side view of the platform shown in Figure 2A is provided. [Figure 2D] A plan view of the platform is provided in Figure 2A. [Figure 3A] A perspective view of a further exemplary alternative embodiment of the platform, in one aspect, is provided, moored to the seabed of a body of water at an operating depth. [Figure 3B] An alternative side view of the platform shown in Figure 3A is provided. [Figure 3C] An alternative side view of the platform shown in Figure 3A is provided. [Figure 3D] A plan view of the platform is provided in Figure 3A. [Figure 4A] A perspective view of a further exemplary alternative embodiment of the platform, in one aspect, is provided, moored to the seabed of a body of water at an operating depth. [Figure 4B] An alternative side view of the platform shown in Figure 4A is provided. [Figure 4C] An alternative side view of the platform shown in Figure 4A is provided. [Figure 4D]A plan view of the platform is provided in Figure 4A. [Figure 5A] A perspective view of a further exemplary alternative embodiment of the platform, in one aspect, is provided, moored to the seabed of a body of water at an operating depth. [Figure 5B] An alternative side view of the platform shown in Figure 5A is provided. [Figure 5C] An alternative side view of the platform shown in Figure 5A is provided. [Figure 5D] A plan view of the platform is provided in Figure 5A. [Figure 6A] A perspective view is provided of an exemplary embodiment of a platform, in one aspect, moored to the seabed of a body of water at an operating depth. [Figure 6B] An alternative side view of the platform shown in Figure 6A is provided. [Figure 7] The present invention provides arrangement configurations of structural elements according to one or more embodiments. [Figure 8] A perspective view is provided of an exemplary embodiment of a platform having protective members on mooring ropes.
[0041] Referring to Figure 1A, a perspective view of an exemplary embodiment of a buoyant offshore platform 100 according to one aspect is shown, the platform 100 being suitable for supporting a renewable energy system 124 mounted thereon. In the particular example described, the platform 100 comprises an elongated structural spar 102, which is buoyant in a body of water 104. A first mooring line 108 extends from the lower end 106 of the spar 102, attached to a corresponding anchor point 110 at its distal end, thereby mooring the spar 102 to the seabed 112 of the body of water 104. The length of the first mooring line 108 is such that the buoyant spar 102 is positioned partially submerged in the body of water 104 at an operating depth where the upper end 118 of the spar 102 is maintained above the surface 122 of the body of water 104, as can be seen more clearly in the side views of Figures 1B and 1C.
[0042] In the illustrated embodiment 100, the mast 126 of the wind turbine 124 is supported on and extends from the flat upper surface 118 of the spar 102, and the mast 126 extends substantially coaxially with the spar 102. Above the mast 126 is supported the wind turbine nacelle 128, which houses an energy capture machine driven by the rotation of a rotor having a plurality of wind turbine rotor blades 130.
[0043] The first mooring line 108 acts to stabilize the spar 102 against vertical motion that may otherwise result from the action of wave forces on the spar 102, but the action of wind forces on the wind turbine 124 causes an angular moment with respect to the mast 126 which would normally cause pitch and / or roll of the spar 102 within the water body 104. Such movement of the spar 102 within the water body 104 while the wind turbine 124 is operating may act to limit the operational efficiency of wind energy capture and conversion by the wind turbine 124. The platform 100 of the present invention comprises a plurality of further mooring lines 114 attached to mooring line fixing points 116 near the upper end 118 of the spar 102 and extending toward corresponding further anchor points 120 at an oblique / diagonal angle with respect to the spar 102. The oblique positioning of the additional mooring rope 114, which has a fixed point 116 positioned near the upper end 118 of the spar 102, stabilizes the spar 102 against any pitch and / or roll motion that may be caused by wind and / or wave forces acting on the spar 102 or wind forces acting on the wind turbine 124. Thus, the spar 102, and by extension the wind turbine 124, are held substantially stationary within the water body 104 so as to maintain the optimal operating efficiency of the wind turbine 124.
[0044] The corresponding additional anchor points 120 are positioned on the seabed 112 of the water body 104 such that they form the vertices of a triangle. In the particular embodiment shown, the platform 100 forms part of a larger farm of an offshore floating wind turbine intended to capture wind energy from winds that are mostly unidirectional. Thus, the nacelle 128 of the illustrated exemplary wind turbine 124 is fixed in direction, and the rotor blades 140 are positioned in a plane perpendicular to the primary wind capture direction. To provide sufficient stability for the spar 102 and turbine 124 against wind forces acting primarily in a single capture direction, one of the additional anchor points 120 is positioned in a plane immediately behind the nacelle 128 and substantially coplanar with its rotor. In the illustrated embodiment, the anchor point 110 of the first mooring rope 108 is positioned off-center within the triangle formed by the additional anchor points 120, and as a result, the anchor point is positioned further away from this rearward additional anchor point 120 than the other two laterally positioned additional anchor points 120. An embodiment will be understood in which the first mooring rope anchor point 110 is positioned in the center of a triangle formed by further anchor points 120 of the further mooring rope 114, thereby providing substantially equal stability in all directions.
[0045] Referring to Figure 6A, a perspective view of an alternative exemplary embodiment of mooring lines for a buoyant offshore platform 100 in one aspect is shown. Similar to Figure 1A, the platform 100 is suitable for supporting a renewable energy system 124 mounted thereon. In the particular example described, the platform 100 includes an elongated structural spar 102, which is buoyant in a body of water 104. However, in Figure 6A, three first mooring lines 108 extend from the lower end 106 of the spar 102, each attached to a corresponding anchor point 120 which is shared with a corresponding further mooring line 114. Each of the three first mooring lines extends toward its respective further anchor point 120 at an oblique / diagonal angle with respect to the spar 102. The lengths of the three first mooring lines 108 are such that the buoyant spar 102 is positioned partially submerged in the water body 104 at an operating depth where the upper end 118 of the spar 102 is maintained above the surface 122 of the water body 104, as clearly shown by the side view in Figure 6B. The three first mooring lines 108 act to stabilize the spar against any vertical motion that may otherwise occur as a result of, for example, the action of wave forces on the spar 102, and the action of wind forces on the wind turbine 124 causes an angular moment on the mast 126 that would normally cause pitch and / or roll of the spar 102 within the water body 104. The anchor point 120 is located on the seabed 112 of the water body 104 in the same manner as described in relation to Figures 1A and 1C. As can be understood, any number of first mooring lines may be present, and the arrangement of three first mooring lines shown in Figures 6A and 6B is merely an example. It will also be understood that the arrangement of the first mooring lines described in relation to Figures 1A to 1C may be combined with the arrangement of multiple first mooring lines described in relation to Figures 6A and 6B.
[0046] In exemplary embodiments, the spar is an elongated spar, and the elongated shape of the spar 102 essentially directs its minimum dimension (width) toward the reaction wave force, minimizing the resulting drag and its effect on the movement of the spar 102 in motion. The body of the spar 102 in the illustrated exemplary embodiment is substantially cylindrical, and therefore its curved surface provides a hydrodynamic surface that minimizes the drag against the force of the incident wave. The body of the spar 102 in the illustrated example includes a lower portion 132 extending from the lower end 106 of the spar toward a point along the spar adjacent to the upper end 118, the lower point 132 having a constant diameter along its length. The body of the spar 102 further includes an upper portion 134 extending from the portion adjacent to the lower portion 132 of the spar 102 toward the upper end 118, the upper portion 134 having a variable diameter along its length, the diameter of the portion adjacent to the lower portion 134 being greater than the diameter forming the upper end 118 of the spar 102. The larger volume of the lower portion 132 in the illustrated embodiment provides an appropriate internal volume to provide the necessary buoyancy for the spar 102. Embodiments in which any elongated shape of the spar is provided will be understood.
[0047] Referring to Figure 7, an alternative shape of spar 701 called a bottle-shaped spar is shown. The body of the bottle-shaped spar 701 in the illustrated example comprises a first cylindrical section 702 (e.g., lower section) having a first predetermined diameter, the first predetermined diameter being substantially constant along the length of the first cylindrical section 702. The body of the bottle-shaped spar further comprises a second cylindrical section 703 (e.g., upper section) having a second predetermined diameter, the second predetermined diameter being substantially constant along the length of the second cylindrical section 703, and the second predetermined diameter being smaller than the first predetermined diameter. The body of the bottle-shaped spar 701 in the example shown in Figure 7 further comprises a tapered section 704 (e.g., intermediate section) located between the first cylindrical section 702 and the second cylindrical section 703, joining them together. Therefore, in this example, the lower end 705 of the tapered section 704 has a diameter of the first predetermined diameter of the first cylindrical section 702, and the upper end 706 of the tapered section 704 has a diameter of the second predetermined diameter of the second cylindrical section 703. The diameter of the tapered section decreases along the length of the tapered section 704 from the first predetermined diameter to the second predetermined diameter. However, as can be understood, the bottle-shaped spar may have a flat section instead of a tapered section between the first cylindrical section 702 and the second cylindrical section 703. Similar to elongated spars, the bottle-shaped spar 701 essentially orients its minimum dimension (width) to the reaction wave force, minimizing the resulting drag and its effect on the movement of the spar 701 in motion. The body of the spar 701 in the illustrated exemplary embodiment is substantially cylindrical, and therefore its curved surface also provides a hydrodynamic surface that minimizes the drag to the incident wave force.
[0048] In the embodiments shown in Figures 1A-1D, 6A, and 6B, the fixing points 116 of the additional mooring ropes 114 are located on a common plane along the length of the spar 102, at points near the upper end 118 of the spar 102. As shown in the plan view of the platform 100 drawn in Figure 1D (wind turbine 124 omitted for simplicity), the fixing points 116 are located at corresponding positions around the circumference of the spar 102, and therefore the angle A defined by the arc between each adjacent pair of mooring rope fixing points 116 at the center of the spar 102 is the same. In the illustrated example, angle A is 120 o Therefore, in the illustrated embodiment, the distance along the perimeter of the spar between each pair of mooring anchor points 116 is the same. Thus, the spar in the illustrated example is equally accessible to the vessel 136 between any two mooring anchor points 116. The elongated nature of the spar 102, on which the wind turbine 124 is supported, maximizes this accessibility for the vessel 136, thereby improving the ease and safety of deployment of the platform 100 to a desired deployment area within the farm waters 104, and the ongoing maintenance of the platform 100 and the wind turbine 124. The sparse arrangement of the mooring anchor points 116 around the spar 102 in the illustrated example, and the resulting space between the mooring anchor points 116, therefore provides a vessel access portion of the spar 102 and a means for the vessel 136 to approach the spar, minimizing the risk of collision between the hull of the vessel 136 and the mooring anchor points 114 or anchor points 116.
[0049] However, in some cases, the approach of the vessel 136 may excessively increase the risk of collision with the spar 102 body, the mooring line 114, or the corresponding anchor point 116.
[0050] Figures 2A to 2D show an exemplary alternative embodiment 200 of the platform according to the present invention, which includes a bumper feature 238 intended to protect the spar body and / or mooring lines and anchoring points from collision with approaching vessels. The exemplary embodiment 200 is substantially the same as embodiment 100 in Figures 1A to 1D, and therefore, for ease of understanding, the same numbering scheme is used for the corresponding feature parts. For example, spar 202 is substantially the same as spar 102, and so on. As can be understood, the bumper feature can be equally applied to the bottle-shaped spar shown in Figure 7, and to the mooring device shown in Figures 6A and 6B.
[0051] Unlike the embodiments 100 shown in Figures 1A to 1D, the alternative embodiment 200 further comprises a guard member 238 formed from a substantially toroidal body 238 extending around the periphery of the spar 202, and separated from the periphery of the spar 202 by a plurality of cylindrical brackets 240 extending between the guard member 238 and the outer surface of the spar 202. The guard member 238 includes an outer impact-absorbing surface 239 intended to engage with the hull of an approaching vessel 236 before the hull of the vessel 236 can reach the spar 202 body, so that the spar 202 body is protected from impact. In the illustrated exemplary embodiment 200, the guard member 238 extends around the circumference of the spar 202 along its length, at a point closer to its upper end 218 than to its lower end 206. In exemplary embodiment 200, when the spar 202 is deployed to the operating depth shown in Figures 2B and 2C, the guard member 238 is positioned along the body of the spar 202 so that the guard member 238 is located below the surface 222 of the water body 204. Also in illustrated embodiment 200, the mooring anchor points 216 are positioned at substantially the same distance from each other as in embodiment 100 shown in Figures 1A to 1D, whereas in alternative embodiment 200, the mooring anchor points 216 are positioned directly below the guard member 238 so that at the operating depth, the mooring anchor points 216 are also positioned below the surface 222 of the water body 204. As illustrated, positioning the mooring anchor points 216 below the guard member 238 acts to further protect the mooring rope 214 and the corresponding anchor points 216 from collision and / or entanglement with the vessel 236 or associated rigging. As can be understood, the features of the guard member can be equally applied to the bottle-shaped spar shown in Figure 7, and to the mooring device shown in Figures 6A and 6B.
[0052] However, in some cases, lowering the mooring anchor point 216 along the body of the spar 202 may act to reduce the stability of the upper end 220 of the spar against angular moments acting on the upper end 218 of the spar 202 due to waves and wind forces. Figures 3A to 3D show a further alternative exemplary embodiment 300 of the platform according to the present invention, which includes outrigger members intended to define a corresponding effective mooring anchor point for each actual mooring anchor point, and each effective mooring anchor point is positioned above on the spar body relative to its respective actual mooring anchor point, thereby benefiting from a higher arrangement of mooring anchor points while potentially avoiding the risk of damage or entanglement that may occur in embodiments such as those in Figures 1A to 1D.
[0053] Exemplary embodiment 300 is substantially the same as embodiment 100 in Figures 1A to 1D, and therefore, for ease of understanding, the same numbering scheme is used for corresponding feature parts. For example, spar 302 is substantially the same as spar 102, and so on.
[0054] Unlike the embodiments 100 in Figures 1A to 1D, a further alternative embodiment 300 includes an outrigger member for each additional mooring rope 314, comprising an elongated cylindrical lateral brace 342 extending outward from a first point 344 on the spar 302 body to a distal body 346 supporting a mooring rope fixing point 348. Thus, the mooring rope fixing point 348 is laterally distanced from point 344 along the spar 302 body by the lateral brace 342 and the distal body 346. One of the additional mooring ropes 314 of the platform 300 is attached in communication with the spar 302 body at the corresponding mooring rope fixing point 348. The distal body 346 is further supported at a position away from the spar 302 body by an oblique brace 350 extending from the distal body 346 to a second point 352 along the spar 302 body, the second point 352 being located higher on the spar 302 body than the first point 344 of the lateral brace 342. Thus, the oblique brace 350 provides oblique support to the distal body 346, and by extension to the mooring rope fixing point 348, while also providing a higher effective mooring rope fixing point 352. As shown in the side views in Figures 3B and 3C, the effective mooring rope fixing point 352 provided by the engagement point between the oblique brace 350 and the spar 302 body is higher than the actual mooring rope fixing point 348, which is located on the distal body 346 and has engagement with the spar 302 body at the first point 344 by the lateral brace 342. In the particular embodiment shown, the second point 352 is located above the surface 322 of the water body 304 when the platform 300 is positioned at the operating depth, and the mooring rope 314 is attached to the distal body 346 below the surface 322 of the water body 304.
[0055] As shown in Figure 3D, the distance between the mooring rope fixing point 348 and the spar 302 body reduces the possibility of engagement and entanglement with an approaching vessel 336.
[0056] However, in some cases, positioning the outrigger members can improve the stability of the upper end of the spar, but it can also increase the risk of collision between the vessel and the outrigger members. Figures 4A–4D show a further alternative exemplary embodiment 400 of the platform according to the present invention, which includes outrigger members positioned to provide a larger vessel-access portion of the spar, intended to reduce the risk of undesirable engagement by a vessel with the spar body or outrigger members during approach, for example, during deployment or maintenance. The exemplary embodiment 400 is substantially the same as embodiment 100 in Figures 1A–1D, and therefore, for ease of understanding, the same numbering scheme is used for corresponding feature parts. For example, spar 402 is substantially the same as spar 102, and so on.
[0057] Embodiments 4A to 4D, like Embodiments 3A to 3D, include outrigger members for each further mooring rope 414. However, in Embodiments 4A to 4D, the two outrigger members extend in opposite directions from the main body of the spar 402 and in the same plane, and are ranged from the center of the spar 402 by an arc defined between them. o An angle A' is defined. The third outrigger member of the illustrated embodiment 400 extends in a plane perpendicular to the plane of the two coplanar outrigger members. Thus, positioning the two coplanar outrigger members provides a larger vessel access area, as shown in Figure 4D, thereby minimizing the risk of undesirable collisions between the vessel 436 and the outrigger members.
[0058] In the illustrated exemplary embodiment 400, the corresponding further anchor points 420 of the further mooring lines 414 are positioned such that each further mooring line 414 extends along its respective axis, and the axes do not intersect. Embodiments in which the axes intersect will be understood.
[0059] In some cases, providing access to larger or more vessels may be beneficial. Simplifying the outrigger structure may also be required to improve ease of assembly. In such embodiments, it may be beneficial to have a single outrigger member supporting a mooring point for each of the additional mooring lines. Positioning a single outrigger member in this way may reduce the stability of the spar against angular moments acting on it in one or more directions, and this stability is reduced in those directions compared to embodiments with multiple outrigger members, such as those shown in Figures 3A–4D. However, the increased simplicity and / or ease of vessel access in a particular direction may be suitable for project sites with primarily unidirectional wind and / or waves, and therefore such a solution may be preferable. An example of such a solution is shown in Figures 5A–5D, which illustrate a further alternative exemplary embodiment 500 of the platform according to the present invention, comprising a single outrigger member providing a mooring point for each of the additional mooring lines. Exemplary embodiment 500 is substantially the same as embodiment 100 in Figures 1A to 1D, and therefore, for ease of understanding, the same numbering scheme is used for corresponding feature parts. For example, spar 502 is substantially the same as spar 102, and so on.
[0060] Embodiment 500 provides an outrigger member for effectively raising the height of the mooring rope anchor points on the spar 502 body relative to the actual mooring rope anchor points 548, but unlike embodiments 300 and 400 in Figures 3A to 4D, the platform 500 comprises only a single outrigger member providing mooring rope anchor points 548 for each of the additional mooring ropes 514. The outrigger member in the illustrated embodiment 500 comprises two coplanar lateral braces 542 extending outward from corresponding points 544 on the spar 502 body to support the distal body 546. The mooring rope anchor points 548 are located in a common plane on the distal body 546, at respective positions around the outer surface of the distal body 548, and thereby approximately 120 degrees from the center of the distal body by an arc defined between the two said mooring rope anchor points 548. o The angle is determined. Thus, each of the mooring ropes 514 is in communication with the spar 502 by a single outrigger member. As can be understood, the features of the outrigger members can be equally applied to the bottle-shaped spar shown in Figure 7 and to the mooring configurations shown in Figures 6A and 6B.
[0061] Referring to Figure 8, one or more of the additional mooring lines may further comprise a protective member 801, which extends a predetermined distance along the additional mooring line 114 from its first end. In some embodiments, the protective member 801 is preferably either an outer layer surrounding the additional mooring line or a substantially solid member to which each additional mooring line is attached. The protective member 801 may be added to one or more of the additional mooring lines 114 between the platform and a predetermined distance therefrom, the predetermined distance may be based on a calculated depth below the mean draft of the water. The protective member 801 may be an armored outer layer applied to the additional mooring line 114 or a solid section to which the additional mooring line 114 is attached. Thus, the protective member 801 can act to prevent damage to the additional mooring lines 114, for example, from collision with floating marine debris or accidental contact with a vessel.
[0062] The embodiments described above are given only as examples, and it will be understood that alternative forms may also be considered within the scope of this disclosure. For example, while the renewable energy system described in the exemplary embodiments is a wind turbine, embodiments in which the renewable energy system is any suitable renewable energy conversion and / or storage device or system will be understood. In the embodiments described above, features described in relation to one embodiment or example may be combined in any way with features of different embodiments.
Claims
1. A buoyant offshore renewable energy system platform, A buoyant spar having an upper end and a lower end, configured to support a renewable energy system on it, The system comprises a plurality of mooring lines configured to anchor the spar to the seabed of a body of water so that the spar is positioned within the body of water at the operating depth, The aforementioned multiple mooring ropes are, One or more first mooring lines are attached to the bottom end of the spar, the bottom end being distal to the upper end, and configured to engage with the seabed of the water body. The system comprises at least three further mooring lines, each of which has a first end communicating with the spar between the upper and bottom ends, and each further mooring line has a second end that engages with the seabed of the body of water such that the further mooring lines are oriented obliquely to the spar at the operating depth. A platform in which, at the aforementioned operating depth, the first end of the spar is positioned above the surface of the water body and the second end is positioned below the surface of the water body.
2. In the platform described in claim 1, A platform in which one or more first mooring lines are configured to engage with the seabed of the water body at a position vertically below the bottom end, such that the first mooring lines are substantially coaxial with the spar at the operating depth.
3. In the platform according to claim 1 or 2, The platform includes one or more first mooring lines, each comprising at least two first mooring lines configured to engage with the seabed of the body of water such that at least two of the first mooring lines are oriented obliquely to the spar at the operating depth.
4. In the platform described in any one of claims 1 to 3, The aforementioned spar is a buoyant, elongated spar, which is a platform.
5. In the platform described in any one of claims 1 to 3, The aforementioned spar is a buoyant spar, A first cylindrical section having a first predetermined diameter, A second cylindrical section having a second predetermined diameter, wherein the second predetermined diameter is smaller than the first predetermined diameter, The tapered section between the first cylindrical section and the second cylindrical section A platform that has
6. In the platform described in any one of claims 1 to 5, A platform in which a non-zero vertical spacing is defined between each of the mooring point of the one or more first mooring lines on the spar and each of the mooring point of the further mooring lines.
7. In the platform described in any one of claims 1 to 6, At the aforementioned operating depth, the buoyancy of the spar is configured to apply tension to the one or more first mooring lines and any further mooring lines. The buoyancy of the spar is further configured to support the mass of the renewable energy system so that the renewable energy system is maintained above the seabed of the body of water, on the platform.
8. In the platform described in any one of claims 1 to 7, Further mooring lines are attached to the spar at each position, At the aforementioned operating depth, Each of the aforementioned locations is above the surface of the water body, or A platform in which each of the aforementioned locations is below the surface of the water body.
9. In the platform described in claim 8, The spar further comprises a guard member, The guard member is a platform having an impact-absorbing surface positioned at a location on the guard member that is arranged along the side wall of the spar between the upper end and the lower end.
10. In the platform described in claim 9, i. The impact-absorbing surface is supported at a non-zero distance from the side wall of the spar. ii. The guard member extends at least partially around the spar at the position of the guard member. iii. The guard member is substantially toroidal or segmented toroidal in shape. iv. The position of the guard member is located at or above each of the above positions. A platform that is one or more of the following.
11. In the platform according to any one of claims 1 to 10, The aforementioned platform further, The outrigger member is attached to a position along the side wall of the spar between the upper end and the lower end, and the outrigger member protrudes outward from that position, The outrigger member is provided with a mooring rope fixing point located on the portion of the outrigger member distal to the spar, A platform to which at least one first end of a further mooring rope is attached to the mooring rope fixing point.
12. In the platform according to claim 11, Each of the first ends of the further mooring ropes is attached to the mooring rope fixing point. The platform is equipped with corresponding outrigger members for each of the further mooring lines, A platform in which the first end of each of the additional mooring lines is attached to the mooring line fixing point of the corresponding outrigger member.
13. In the platform according to claim 11 or 12, A platform wherein the outrigger member is configured to support the mooring rope fixing point at a non-zero distance from the spar.
14. In the platform according to any one of claims 11 to 13, The outrigger member is A lateral brace extending substantially perpendicular to the spar is provided between a first point along the side wall of the spar and the mooring rope fixing point. The spar comprises an oblique brace extending between a second point along the side wall of the spar and the mooring rope fixing point, The second point is a platform that is higher than the first point.
15. In the platform according to any one of claims 11 to 14, At the aforementioned operating depth, further mooring lines are directed diagonally to the spar along their corresponding axes, and the corresponding axes do not intersect the platform.
16. In the platform according to any one of claims 11 to 15, A platform in which, at the aforementioned operating depth, the mooring rope fixing point is positioned below the surface of the water body.
17. In the platform according to any one of claims 11 to 16, Each of the second ends of the further mooring lines is moored to the corresponding anchor point on the seabed of the body of water. Platforms, each anchor point positioned at intervals on the bottom of the body of water to form the vertices of a triangle.
18. In the platform according to any one of claims 11 to 17, The aforementioned spar includes a ship access portion, The aforementioned ship access portion is a platform, which is the portion of the side wall of the spar defined between two mooring rope fixing points or outrigger members.
19. In the platform according to any one of claims 1 to 4 and 6 to 18, The aforementioned spar is substantially cylindrical, forming a platform.
20. In the platform according to claim 19, A platform in which the cylinder is tapered near the upper end such that the diameter of the upper end is smaller than the diameter of the lower end.
21. In the platform according to any one of claims 1 to 20, The aforementioned renewable energy system is a wind turbine, and the platform is configured accordingly.
22. In the platform according to claim 21, A platform wherein the upper end of the spar is configured to support the wind turbine such that the mast of the wind turbine is substantially coaxial with the spar.
23. In the platform according to any one of claims 1 to 22, One or more of the further mooring lines include a protective member, The protective member is a platform that extends from the first end of a further mooring rope along the further mooring rope for a predetermined distance.
24. In the platform according to claim 23, The protective member is An outer layer surrounding further mooring lines, or A substantially solid member to which further mooring ropes can be attached. A platform that is one of the following.