Buoyant offshore renewable energy system mounting platform and a method of assembling and deploying buoyant offshore platforms

Abstract

A buoyant offshore renewable energy system mounting platform is provided for use in supporting a renewable energy system in a body of water. The platform (100) comprises: a support node (108); two distal nodes (110); and a first lateral brace and a second lateral brace (102, 104), each of the first and second lateral braces extending between the support node and a corresponding distal node to form a platform base; the platform further comprising a plurality of mooring lines (116), wherein a corresponding said mooring line is affixed to each of the support node and the two distal nodes and arranged to tether the support node and the two distal nodes to a bed of a body of water such that the support node and the two distal nodes are positioned in the body of water at an operating depth; wherein the support node is arranged to support a renewable energy converter (114) thereon, and wherein at the operating depth, the support node is arranged to support the renewable energy converter above a surface of the body of water. The described platform aims to provide a safer and more efficient mode of deploying a buoyant offshore platform to a partially submerged operating configuration.

Description

[0001] BUOYANT OFFSHORE REWEWABLE ENERGY SYSTEM MOUNTING PLATFORM AND A METHOD OF ASSEMBLING AND DEPLOYING BUOYANT OFFSHORE PLATFORMS

[0002] Field of the Disclosure

[0003] The present disclosure relates to a buoyant offshore platform for mounting a renewable energy device or system at an offshore marine location, and a method of assembling and deploying such buoyant offshore platforms.

[0004] Background to the Disclosure

[0005] Wave energy and offshore wind energy have both been identified as leading technology options to decarbonise the global energy system. The economic viability and practical feasibility of these renewable energy systems are heavily reliant on the ease and cost of installation and maintenance of these systems offshore. One solution to minimise the costs of these systems is to install the wave energy and wind energy systems offshore on floating or buoyant platforms.

[0006] Buoyant offshore platforms are beneficial in that the foundations required for a buoyant offshore platform are typically quicker and easy to install on the bed of the body of water, and the foundations can be more easily laid at greater depths. Furthermore, a complete buoyant offshore platform may be manufactured on or adjacent to land and can then be towed out to the desired location rather than assembled offshore piece-by-piece. However, problems exist with current state-of-the-art buoyant offshore platforms and with the methods and equipment used to install them offshore. Objects and aspects of the present disclosure seek to alleviate at least these problems with the prior art.

[0007] Summary of the Disclosure

[0008] The present disclosure is directed 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 number of outer vertices, wherein at least one of said vertices is used to support the renewable energy system thereon. The vertices of the platform are affixed to a bed of a body of water by way of mooring lines and submerged in the body of water to an operating depth. In most preferable embodiments, the outer vertex of the frame supporting the renewable energy system, when the platform is deployed to the operating depth, protrudes through the surface of the body of water such that, at the operating depth, the platform is arranged to support the renewable energy system above the surface of the body of water. As such, the renewable energy system is protected from the effects of sea water exposure, or from the effects of variable wave forces, on the system. The combined buoyancy of the platform, and the resultant tension in the mooring lines at the operating depth preferably confers a stability on the platform such that the renewable energy system is supported substantially stationary, thus optimising working efficiency of renewable energy capture and conversion by the system.

[0009] In order to maximise said stability, the platform frame is preferably made up of a skeletal structure of elongate structural braces connecting said vertices, thereby minimising the effect of dynamic wind and wave forces and currents acting on said platform. A lowermost level of said elongate braces connecting the vertices preferably forms a planar base of the platform.

[0010] In most preferable embodiments, the vertices of the platform are buoyant and therefore contribute to the platform buoyancy. In some preferable embodiments, the buoyancy of the vertices provides the majority of the platform buoyancy. Embodiments will be appreciated wherein one or more of the elongate braces are also, or instead, buoyant. Embodiments will also be appreciated wherein the elongate braces are substantially non-buoyant, for example such that a majority of the buoyancy of the platform is provided by the vertices.

[0011] Additionally, the tension conferred upon the mooring lines by way of the buoyancy of the platform vertices and / or the elongate braces, is preferably substantially uniform across all of said mooring lines. In order to aid said uniformity, the masses of the vertices and / or the elongate braces may be freely adjusted, whether by way of adding additional mass in the form of ballasts, or by way of pumping a fluid into, or out of, a cavity in said vertices and / or elongate braces. Such additions or adjustments may in some cases be in reaction to varying sea or wind states in order to maintain optimum stability.

[0012] Supporting a renewable energy system on a vertex of such a platform preferably improves accessibility when affixing or maintaining the renewable energy system as the renewable energy system is positioned at or close to a lateral extent of the structure. When assembling the renewable energy system to the structure at quayside, for example, the attachment point on the supporting vertex is preferably close to the quay edge reducing the outreach of the lifting operation required for assembly. When accessing the renewable energy system for maintenance when installed, for example, a vessel can approach the supporting vertex with less consideration for interference with the rest of the structure.

[0013] The asymmetrical nature of the platform vertices, with one said vertex intended for supporting a renewable energy system above a surface of a body of water, preferably also permits stackability of a plurality of such platforms, such that a larger multiple of said platforms can fit into a smaller area of space when being transported or stored. Because the platforms are large in size, and quantities of platforms needed to execute large energy projects is significant, transportation and / or storage can create a bottleneck in the project execution process. Platforms may need to be transported long distances from a manufacturing site to a project marshalling or installation site and therefore require loading onto a separate transportation vessel. Such vessels are typically large and expensive and maximising utilisation of deck space is economically advantageous. Similarly, manufacturing of platforms may require a continuous process whereas the installation of platforms will be limited to seasons of good weather, leading to a requirement to store platforms. Minimising the storage area needed preferably reduces the quantity and therefore cost of high value port or yard space needed to execute the project.

[0014] The present disclosure is further directed to a method of assembling and deploying such a buoyant offshore platform to a desired location in a body of water.

[0015] Therefore, in accordance with a first aspect of the present disclosure, there is provided a buoyant offshore renewable energy system mounting platform, the platform comprising: a support node; two distal nodes; and a first lateral brace and a second lateral brace, each of the first and second lateral braces extending between the support node and a corresponding distal node to form a platform base; the platform further comprising a plurality of mooring lines, wherein a corresponding said mooring line is affixed to each of the support node and the two distal nodes and arranged to tether the support node and the two distal nodes to a bed of a body of water such that the support node and the two distal nodes are positioned in the body of water at an operating depth; wherein the support node is arranged to support a renewable energy converter thereon.

[0016] It will be appreciated that the term “node” is used herein to refer to the vertices of the buoyant platform. The term “distal node” will be appreciated within the context of the present invention to mean a vertex of the platform which is not used to support the renewable energy system. In preferable embodiments, the support node and the two distal nodes are buoyant in the body of water. In most preferable embodiments, the buoyancy of the support node and the buoyancy of the two distal nodes provides a majority of the buoyancy of the platform. Providing a majority of the buoyancy of the platform will be understood within the context of the present invention to mean that of the net buoyancy forces exerted on the platform, the majority of said net buoyancy forces are contributed by the combined buoyancy of the support node and the two distal nodes. In some embodiments, the first and second lateral braces are buoyant in the body of water. Other embodiments will be appreciated wherein the first and second lateral braces are substantially non-buoyant in the body of water.

[0017] In preferable embodiments, at the operating depth, the support node is arranged to support the renewable energy converter above a surface of the body of water. In preferable embodiments, at the operating depth, the two distal nodes and the first and second lateral braces are submerged below a surface of the body of water.

[0018] In most preferable embodiments, the renewable energy system comprises a wind turbine. It will be appreciated that embodiments are intended wherein the renewable energy system may be any suitable system, and may include a wave energy capture and conversion device.

[0019] The renewable energy system is preferably supported on an uppermost surface of the support node which is preferably positioned in a plane such that when the platform is at the operating depth, said surface is positioned above the surface of the body of water. Said plane of the uppermost surface of the support node, in most preferable embodiments, is vertically above a plane occupied by an uppermost surface of the two distal nodes. In most preferable embodiments, the support node is taller than each of the two distal nodes, such that while a lower portion of the support node is connected to the two distal nodes by the first and second lateral braces to form a planar platform base, at the operating depth the two distal nodes are submerged while the support node protrudes through the surface of the body of water. In most preferable embodiments, the support node is arranged to support the renewable energy system above a surface of the body of water when the platform is positioned at the operating depth. As such, the support node is preferably arranged to protrude through the surface of the body of water when the platform is positioned at the operating depth, such that when the renewable energy system is supported on an uppermost surface of the support node, the renewable energy system is maintained at a height above the surface of the body of water. In preferable such embodiments, the two distal nodes remain below the surface of the body of water when the platform is at the operating depth. In preferable embodiments, each of the first and second lateral braces extend between points located on the support node and the corresponding distal node, said points positioned proximate a lowermost end of the support node, and optionally said distal node. The term “proximate a lowermost end of the support node” will be understood by the skilled addressee to mean more proximate the lowermost end than an uppermost end, which may be interpreted as an end distal to the end arranged to support the renewable energy system. In some preferable embodiments, the platform further comprises two diagonal braces, each of the two diagonal braces extending between a corresponding point located on the support node and a point on a corresponding distal node of the two distal nodes, the corresponding point on the support node located above a plane of the first and second lateral braces, and / or preferably proximate an uppermost end of the support node. The term “proximate an uppermost end of the support node” will be understood to mean more proximate the uppermost end than the lowermost end. The positioning of the diagonal braces in this manner preferably confers structural stability on the support node, which may in such embodiments be taller in height than the two distal nodes. The two diagonal braces thereby preferably stabilise the support node near the uppermost end thereof against angular moments acting thereon by way of wind forces or the mass of the renewable energy system. In some preferable embodiments, the two diagonal braces extend in a common diagonal plane intersecting a vertical plane of the support node and a horizontal plane of the first and second lateral braces.

[0020] In preferable embodiments, the first and second lateral braces extend in a common plane perpendicular to a longitudinal plane of the support node. In most preferable embodiments, the platform further comprises a third lateral brace, the third lateral brace extending between the two distal nodes to form a substantially triangular base of the platform, the support node forming one vertex of the triangular base. The third lateral brace preferably provides optimum structural stability to the base by resisting angular moments occurring against the first and second lateral braces. In some embodiments, the third lateral brace extends in the common plane of the first and second lateral braces. In preferable embodiments, the third lateral brace extends in a plane below or above the plane of the first and second braces. In such embodiments, multiple said platforms may be stacked togetherwith the first and second lateral braces of each additional platform extending either over or under the third lateral brace of the previous platform, or platforms, in the stack.

[0021] The first, second and third lateral braces are preferably substantially cylindrical. Cylindrical braces preferably provides minimal drag against wind and wave forces acting against the lateral braces, thereby preferably optimising stability of the platform in use. Embodiments will be appreciated wherein the first, second and third lateral braces are any suitable shape where said shape acts to reduce or minimise the drag against wind and wave forces acting against the lateral braces. Embodiments will be appreciated wherein the braces are buoyant and contribute to the overall buoyancy of the platform.

[0022] In some embodiments, a net buoyancy of each of the two distal nodes is preferably substantially equal to a net buoyancy of the support node and the renewable energy converter. The “net buoyancy” of each distal node may comprise the buoyancy of the corresponding distal node either alone or when combined with one or more additional ballasts. As such, the net buoyancy of the platform is preferably substantially equally distributed across the three vertices of the platform and therefore substantially equally distributed across the moorings to the benefit of stability when the platform is installed and positioned at the operating depth.

[0023] When the platform is in a floating configuration it can be appreciated that the mass of the renewable energy system or device positioned on the support node of the platform can lead to floating imbalance. Therefore, in some embodiments, each of the two distal nodes may support one or more additional ballasts, each additional ballast contributing a ballast mass to the mass of the corresponding distal node. This preferably allows the platform to be balanced when in the floating configuration, allowing the platform to be towed across the sea surface with a greater stability and therefore a greater tolerance to poor weather conditions. Each additional ballast may additionally affect the net buoyancy of the corresponding distal node.

[0024] The additional ballasts may in some embodiments be removable, such that the additional ballasts are arranged to influence the floating stability of the platform, but not the installed stability of the platform, for example when at the operating depth.

[0025] Embodiments will be appreciated wherein the support node mass and the distal node mass is the same. In some such embodiments, it may be beneficial for a sum of the ballast masses contributed by the additional ballasts to each distal node to preferably be substantially equal to the mass of the renewable energy converter, in order to aid balancing for improved stability of the platform. In such embodiments it may be appreciated that each of the support node and the two distal nodes preferably comprises the same buoyancy, and therefore that the mass of the renewable energy system on the support node is preferably matched on each of the two distal nodes by corresponding additional ballasts. In some embodiments, the two distal nodes and / or the additional ballasts each comprise a cavity, and a water pump arranged to selectively pump water into and out of the cavity such that the distal node mass and / or the additional ballast mass is freely adjustable. Such an adjustable mass of the distal nodes and / or the ballasts preferably further aids in balancing the platform for improved stability. Embodiments will also be appreciated wherein any of the support node, the first and second lateral braces and the third lateral braces preferably comprises a cavity and a water pump arranged to selectively pump water into and out of the cavity such that the support node mass is freely adjustable.

[0026] In preferable embodiments, at the operating depth, the support node comprises a support node net buoyancy (which may in some embodiments include or take into account the mass of the renewable energy system), and the two distal nodes each comprise a distal node net buoyancy (which may in some embodiments include or take into account the mass of any additional ballasts), the support node buoyancy and the distal node buoyancy being arranged to apply a support node tension and a distal node tension to the corresponding mooring lines connected thereto, wherein the support node tension and each distal node tension are substantially equal. Equal tension applied across all of the mooring lines preferably acts to improve stability of the platform against dynamic wave and wind forces acting thereon. Embodiments will be appreciated wherein the tension applied across each of the mooring lines is not required to be equal.

[0027] In most preferable embodiments, the support node comprises one or more landing features arranged to engage with corresponding connecting means of a marine vessel. The improved accessibility of the support node and any renewable energy system mounted thereon, afforded by the positioning of the support node at an outer vertex of the platform, may be supplemented in some embodiments by landing features arranged to aid connecting of a marine vessel to the platform. Such landing features may be any suitable landing features, and preferably complement a corresponding connecting mechanism of a marine vessel.

[0028] In some preferable embodiments, each of the mooring lines is affixed to the bed of the body of water at a corresponding anchor point, each said anchor point positioned vertically below the corresponding support node or distal node. Positioning of the anchor points in line with the support node and distal nodes in this manner preferably provides maximum stability to the platform in counteracting buoyancy forces from the buoyant support node and distal nodes.

[0029] In some preferable embodiments, the operating depth may be adjustable. The operating depth may be adjustable by retracting, extending or otherwise applying or releasing a tensioning force to each of the one or more mooring lines using any suitable means. Control of the operating depth in this manner may for example be in response to changing sea states, and may permit maintaining the support node protruding through the surface of the body of water such that the renewable energy system is maintained above the surface of the body of water in any sea state.

[0030] In accordance with a second aspect of the present disclosure, there is provided a method of assembling an offshore renewable energy system mounting platform, the method comprising assembly steps including: positioning a buoyant support node and two buoyant distal nodes of a platform frame at locations relative to one another; connecting each of a first lateral brace and a second lateral brace between the support node and a corresponding distal node in a common plane to form a triangular platform base.

[0031] The method further comprises deployment steps, the deployment steps including: transporting the platform base on the surface of a body of water to a deployment location; engaging the support node and each of the two distal nodes with a bed of the body of water by way of one more mooring lines; and lowering the platform base in the body of water to an operating depth at which the support node supports the renewable energy system above a surface of the body of water.

[0032] The method further comprises: affixing a renewable energy system atop the support node. It will be appreciated that the affixing of the renewable energy system atop the support node may be performed during the assembly steps, and prior to the transporting of the platform base to a deployment location. Other embodiments of the method will also be appreciated wherein the affixing of the renewable energy system atop the support node may be performed during the deployment steps, and after the transporting of the platform base to the deployment location, and preferably after the engaging of the support node and each of the two distal nodes with the bed of the body of water by way of the one or more mooring lines. For example, said affixing step may comprise, engaging the support node with a marine vessel carrying a renewable energy system; and affixing, using the marine vessel, the renewable energy system atop the support node.

[0033] It will be appreciated that the offshore renewable energy system mounting platform assembled and deployed in accordance with the second aspect may be a platform in accordance with the first aspect.

[0034] In some embodiments, said connecting preferably further comprises connecting a third said lateral brace between the two distal nodes.

[0035] In some embodiments, said connecting preferably further comprises connecting two diagonal braces between a corresponding point located on the support node and a point on a corresponding distal node of the two distal nodes, the corresponding point on the support node located proximate an upper end of the support node.

[0036] In some embodiments, the method preferably further comprises the step of affixing one or more additional ballasts atop each of the two distal nodes.

[0037] In some embodiments, said transporting is preceded by the step of: stacking a plurality of said platform bases. It will be appreciated that the stacked platform bases may be transported to the deployment location together as a complete stack, before destacking one or more platforms in-turn for transportation to a final deployment location. Thereby a single, or a minimal number of, marine vessels may be used to transport multiple platforms intended for deployment. Said transporting may include towing of the platform, or multiple stacked platforms by the at least one marine vessel along the surface of the body of water, or may instead include carrying of the platform, or multiple stacked platforms, atop the at least one marine vessel. As such, only a minimum number of resources are required for deployment of a complete set of platforms and corresponding renewable energy systems, such as wind turbines.

[0038] It will be appreciated that any features described herein as being suitable for incorporation into one or more aspects or embodiments of the present disclosure are intended to be generalizable across any and all aspects and embodiments of the present disclosure. Other aspects of the present disclosure can be understood by those skilled in the art in light of the description, the claims, and the drawings of the present disclosure. The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claims.

[0039] Detailed Description

[0040] Specific embodiments will now be described by way of example only, and with reference to the accompanying drawings, in which:

[0041] FIG. 1A provides a perspective view of a platform in accordance with the first aspect tethered to a bed of a body of water at an operating depth;

[0042] 'FIG. 1 B and FIG. 1C provide additional views of the platform of FIG. 1A; FIG. 2A to FIG. 2C depict steps in a procedure for assembling a platform as shown in FIG. 1A to FIG. 1C;

[0043] FIG. 3 shows a flowchart outlining example steps of a method of deploying a buoyant offshore renewable energy system mounting platform in accordance with the second aspect;

[0044] FIG. 4A and FIG. 4B provide views of another example embodiment of a platform in accordance with the first aspect, substantially the same as that shown in FIG. 1A to FIG. 1C, comprising the addition of ballasts on the two distal nodes;

[0045] FIG. 5A to FIG. 5C show steps in a stacking procedure wherein a plurality of an embodiment of a platform in accordance with the first aspect are sequentially stacked; and

[0046] FIG. 6A and FIG. 6B provide views of the example embodiment of a platform shown in FIG. 5A and FIG. 5B deployed to an operating depth and tethered to a bed of a body of water.

[0047] Referring to FIG. 1A, a perspective view of an example embodiment of a buoyant offshore platform 100 is shown in accordance with the first aspect, the platform 100 being suitable for supporting a renewable energy system mounted thereon. In the particular example described, the platform 100 comprises a base portion formed of a first, second and third identical, elongate, cylindrical lateral braces 102, 104, 106. The first and second lateral braces 102, 104 are connected to one another at adjacent ends thereof by way of a buoyant support node 108. The support node 108 in the embodiment shown comprises corresponding connectors located proximate a lower end thereof and arranged to engage the ends of the first and second lateral braces 102, 104. The first and second lateral braces 102, 104 are each further connected at ends thereof distal to the support node 108 to a buoyant distal node 110. Each distal node 110 comprises a corresponding connector located proximate a lower end thereof and arranged to engage the distal end of the first or second lateral brace 102, 104. Each end of the third lateral brace 106 is connected to a corresponding said distal end of the first and second lateral braces 102, 104 by way of the respective distal node 110, the distal node 110 further comprising aa connector located proximate a first end thereof and arranged to engage said end of the third lateral brace 106. The first, second and third lateral braces 102, 104, 106 thereby together form a planar triangular base of the buoyant platform 100, each of the support node 108 and the two distal nodes 110 extending perpendicularly to the planar base and forming one of the three vertices of the triangular platform base. The platform 100 further comprises two diagonal braces 112, each diagonal brace connected at a first end thereof to the support node 108 at a corresponding connector located proximate an upper end of the support node 108. Each of the two diagonal braces 112 is further connected at a second end thereof distal to the first end to a corresponding distal node 110, at a corresponding connector located proximate an upper end of the respective distal node 110. The affixing of the diagonal braces 112 in this manner, having one end connected proximate the upper end of the support node 108 permits the diagonal braces 112 to provide maximum structural support to the support node 108.

[0048] The upper end of each of the support node 108 and the two distal nodes 110 defines a support node height 108 and a distal node height 110 respectively. In the embodiment shown, the support node height is greater than the distal node height. An upper surface of the support node 108 comprises a connector arranged to engage a lowermost surface of a mast of a wind turbine 114, such that the wind turbine 114 is supported on the support node 108. Each of the support node 108 and the two distal nodes 110 are each additionally connected to a corresponding mooring line 116, each mooring line 116 arranged to tether the corresponding support node 108 or distal node 110 to a bed of a body of water, for example, and as shown in the present embodiment, by way of an anchor 118.

[0049] The first, second and third lateral braces 102, 104, 106, the support node 108, the two distal nodes 110 and the two diagonal braces 112 of the platform 100 are assembled quayside. Post-assembly, the support node 108 of the platform 100 can then be connected to a marine vessel for transporting the platform 100 in a body of water to a desired wind turbine deployment location. During transportation, the platform 100 floats on a surface of the body of water, by virtue of the buoyancy of the support node 108 and the two distal nodes 110. The positioning of the support node 108 at one vertex of the triangular base of the platform permits a simple engagement of the marine vessel thereto, and provides maximum ease of transport of the platform 100 across the surface of the body of water. Once at the desired location, a wind turbine 114 may be positioned atop the support node 108, with the location of the support node 108 at a vertex of the platform base providing ease of access for a relevant marine vessel and assembly personnel in erecting the turbine. Erecting the turbine 114 at the deployment location preferably improves ease of transport of the platform to the deployment location, but embodiments will be appreciated wherein the turbine 114 may be affixed to the support node 108 prior to transport to the deployment location. In embodiments wherein the wind turbine 114 is erected prior to transport of the platform 100, the location of the wind turbine 114 on the support node 108, with a marine vessel directing the support node 108 during transport, permits stable transport of the platform 100 in such embodiments. During ongoing maintenance and repair of the platform and the turbine, the positioning of the support node 108 at a vertex of the platform base aims to provide maximum ease of engagement of marine vessels with the platform, and access to the wind turbine 114.

[0050] In use, once transported to the desired location on the body of water, the mooring lines are engaged with the bed of the body of water, such as by way of anchors, and the platform is then partially submerged in the body of water to an operating depth, wherein at the operating depth the support node 108 protrudes through a surface of the body of water such that the uppermost surface of the support node 108 remains above the surface of the body of water. As such the wind turbine 114 and associated fixings involved in connecting the wind turbine 114 to the support node 108 are protected from weathering effects of continued water exposure while providing ease of access for deployment and maintenance of the wind turbine 114. Such submersion may take place either before or after affixing of the wind turbine 114 atop the support node 108. FIG. 1 B and FIG. 1C depicts the example platform 100 of FIG. 1A deployed at the operating depth.

[0051] When submerged at the operating depth, the buoyancy forces exerted by the buoyant support node 108 and the two buoyant distal nodes 110 causes a counteracting tension in the mooring lines 116 such that a stability is conferred upon the platform 100 at the operating depth shown. Such a stability preferably aids in maintaining the platform 100 in a substantially stationary lateral, rotational and vertical position when exposed to dynamic wave and wind forces acting thereon. Maintaining a stationary platform aims to maintain maximum operating efficiency of the wind turbine 114 such that optimal wind energy conversion may continue to take place when the platform 100 is exposed to various directional wind and wave forces. In the particular embodiment 100 shown, a tension applied to each of the mooring lines is substantially equal. Such an equal tension is provided by the net buoyancy of the platform being preferably substantially equally distributed across the three vertices of the platform and therefore substantially equally distributed across the mooring lines to the benefit of stability. The masses of each of the two distal nodes is substantially equal to a sum of the masses of the support node and the renewable energy converter. As such, the masses each of the two distal nodes in the embodiment shown acts to balance the summed masses of the support node and the renewable energy converter. Such balancing preferably aids stability of the platform when deployed to the operating depth. Embodiments will be appreciated wherein mass and buoyancy of the support node and the distal nodes may be adjustable and may be adjusted in order to provide an equal tension on each of the mooring lines. Referring to FIG. 2A to 2D, an assembly sequence 200 is shown comprises sequential steps in the assembly of a platform 100 substantially as shown in FIG. 1A to FIG. 1C, and the same numbering will be adhered to. In the assembly sequence 200 shown, the support node 108 and the two distal nodes 110 are positioned at an on-shore located relative to one another (as shown in FIG. 2A). First ends of each of the first and second lateral braces 102, 104 are then engaged with corresponding connectors located on the support node 108, and second ends of the first and second lateral braces 102, 104 are engaged with a corresponding connector on a respective distal node 110. Each end of the third lateral brace 106 is then engaged with a corresponding connector on each of the distal nodes 110 to form the planar triangular base of the platform 100 (as shown in FIG. 2B). An end of each of the two diagonal braces is then engaged with a corresponding connector on a respective distal node 110, with the other end thereof engaged with a corresponding connector of the support node 108 to form the tetrahedral platform frame (as shown in FIG. 2C). Whether at the on-shore location, or following transport of the platform frame shown in FIG. 2C to a desired deployment location in a body of water, the lowermost end of a wind turbine 114 mast is then affixed to the uppermost surface of the support node 108 such that the wind turbine 114 is supported thereon.

[0052] FIG. 3 depicts steps in an assembly and deployment procedure 300 in accordance with the second aspect, and comprises the steps of: positioning a buoyant support node and two buoyant distal nodes of a platform frame at locations relative to one another 302; connecting each of a first lateral brace and a second lateral brace between the support node and a corresponding distal node in a common plane to form a triangular platform base 304; transporting the platform base on the surface of a body of water to a deployment location 306; engaging the support node and each of the two distal nodes with a bed of the body of water by way of one more mooring lines 308; engaging the support node with a marine vessel carrying a renewable energy system 310; affixing, using the marine vessel, the renewable energy system atop the support node 312; lowering the platform base in the body of water to an operating depth at which the support node supports the renewable energy system above a surface of the body of water 314. In the particular embodiment shown, the affixing of the renewable energy system, which in the present embodiment is a wind turbine, atop the support node 312 is performed once the platform is at the desired deployment location, and after the engaging of the support node and each of the two distal nodes with the bed of the body of water by way of the one or more mooring lines 308. Embodiments will be appreciated wherein the renewable energy system, e.g. wind turbine, may be affixed atop the support node after the lowering of the platform to the operating depth. Embodiments will additionally be appreciated wherein the affixing of the renewable energy system, for example a wind turbine as in the presently described embodiments, atop the support node may instead performed at quayside and during the assembly steps.

[0053] As noted above in relation to the embodiment described in reference to FIG. 1A to 1C, embodiments may be appreciated wherein a mass of the support node and a mass of the two distal nodes may be of importance to the stability of the platform, particularly when considering the relative buoyancies of the support node when supporting the wind turbine, and the two distal nodes, and the effects of the respective masses thereon. This is particularly true when the platform 100 is in a floating configuration shown in FIG. 4B, prior to deployment to the operating depth, where it can be appreciated that the mass of the wind turbine 114 positioned on the support node 108 of the platform 100 can lead to a floating imbalance. Referring to FIG. 4A and FIG. 4B, an alternate embodiment of a platform 400 is shown, substantially the same as the embodiment of FIG. 1A to 1C (and corresponding numbering will be adhered to), but wherein the mass of the each of the distal nodes 110 is supplemented by an additional ballast 402. Each additional ballast contributes a corresponding mass to the mass of the respective distal node 110 such that an equal tension is applied across all of the respective mooring lines when the wind turbine is supported on the support node 108. In the particular embodiment shown, the additional ballast mass contributed to each distal node 110 by the corresponding additional ballast 402 is equal to the mass of the wind turbine 114, thereby eliminating the floating imbalance caused by the positioning of the wind turbine 114 on the support node 108. Embodimentswill be appreciated wherein more additional ballasts 402 may be added to alter the distal node mass, or wherein the mass of the distal nodes 110 themselves, or that of the ballasts 402, may be adjustable. Such adjustment may be permitted by a fluid pump arranged to pump a fluid (such as air or water) into and / or out of the distal nodes 110 and / or ballasts 402 in order to provide equal tension across all of the mooring lines. It will be appreciated that in some embodiments and applications, such equal tensioning of the mooring lines may not be of concern.

[0054] In the embodiments described in relation to FIG. 1A to FIG. 4B, the third lateral brace 106 is positioned in a common plane with that of the first and second lateral braces 102, 104. FIG. 5A to FIG. 5C show an alternate embodiment 500, substantially equivalent to the embodiment 100 of FIG. 1A and corresponding numbering will be adhered to, wherein the third lateral brace 506 is positioned in a plane below the plane of the first and second lateral braces 102, 104. As such, stacking of the platforms 500 is permitted in such embodiments as shown in the stacking sequence depicted in FIG. 5A to FIG. 5C. By stacking multiple platforms 500 in this manner, multiple platforms 500 can be transported to a desired deployment region as a single stack and by a single marine vessel, with simple connection thereto afforded by the positioning of the support node 108 at a vertex of the platform. Once transported to a desired deployment region, the platforms 500 may be sequentially de-stacked and individually deployed to the operating depth as shown in FIG. 6A and FIG. 6B, enabling the simple assembly and deployment of a plurality of such platforms with minimal effort and resources. While the embodiment shown 500 provides a third lateral brace 506 positioned below the plane of the first and second lateral braces 102, 104, alternate embodiments may be appreciated wherein the third lateral brace is positioned above the plane of the first and second lateral braces 102, 104 for stacking.

[0055] It will be appreciated that the above-described embodiments are given as examples only and that alternatives are also considered within the scope of the disclosure. For example, the renewable energy system described in the example embodiments is a wind turbine, but embodiments will be appreciated wherein the renewable energy system is any suitable renewable energy conversion and / or storage device or system.

[0056] While the buoyancy of the present embodiment 100 is described in relation to a buoyancy of each of the support node 108 and the two distal nodes 110, it will be appreciated that the first, second and third lateral braces 102, 104, 106 may each additionally comprise their own buoyancy. The sum of these respective buoyancies of the first, second and third lateral braces 102, 104, 106 in the present embodiment 100 is less than the sum of the respective buoyancies of the support node 108 and the two distal nodes 110, such that the support node 108 and the two distal nodes 110 provide the majority of the buoyancy of the platform 100. Embodiments will, however, be appreciated wherein the respective buoyancies of the support node 108, the two distal nodes 110 and the first, second and third lateral braces 102, 104, 106 may be any suitable combination of buoyancies, and embodiments will be further appreciated wherein the first, second and third lateral braces 102, 104, 106 may be substantially nonbuoyant. Such considerations may be determined for example based on the expected stability requirements for a particular deployment location or type of renewable energy system.

[0057] In the presently described embodiments, during transportation to a deployment location, the platform, or stacked platforms, are towed along the surface of the body of water by a marine vessel. Embodiments will be appreciated wherein the platform(s) may be carried to the deployment location by the marine vessel. The submerging of the platform may be performed in any suitable manner, such as by retracting or otherwise applying a tensioning force to each of the one or more mooring lines using any suitable means to draw the platform from a floating configuration to a partially submerged configuration. Once at the operating depth, each of the one or more mooring lines may be substituted for one or more fixed-length mooring lines, said fixed length defining the operating depth.

[0058] Other suitable features will be appreciated in line with the present disclosure without departing from the scope of the claims.

Claims

CLAIMS1. A buoyant offshore renewable energy system mounting platform, the platform comprising: a support node; two distal nodes; and a first lateral brace and a second lateral brace, each of the first and second lateral braces extending between the support node and a corresponding distal node to form a platform base; the platform further comprising a plurality of mooring lines, wherein a corresponding said mooring line is affixed to each of the support node and the two distal nodes and arranged to tether the support node and the two distal nodes to a bed of a body of water such that the support node and the two distal nodes are positioned in the body of water at an operating depth; wherein the support node is arranged to support a renewable energy converter thereon; and wherein at the operating depth, the support node is arranged to support the renewable energy converter above a surface of the body of water.

2. A buoyant offshore renewable energy system mounting platform as claimed in claim 1 , wherein: i. the support node and the two distal nodes are buoyant in the body of water; and / or ii. the first lateral brace and the second lateral brace are buoyant in the body of water.

3. A buoyant offshore renewable energy system mounting platform as claimed in claim 1 or claim 2, wherein at the operating depth, the two distal nodes and the first and second latera braces are submerged below a surface of the body of water.

4. A buoyant offshore renewable energy system mounting platform as claimed in claim 1 , claim 2 or claim 3, wherein the renewable energy system comprises a wind turbine.

5. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, wherein the support node is taller than each of the two distal nodes.

6. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, wherein each of the first and second lateral braces extend between points located on the support node and the distal node, said points positioned proximate a lower end of the support node and the distal node.

7. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, wherein the platform further comprises two diagonal braces, each of the two diagonal braces extending between a corresponding point located on the support node and a point on a corresponding distal node of the two distal nodes, the corresponding point on the support node located above a plane of the first and second lateral braces.

8. A buoyant offshore renewable energy system mounting platform as claimed in claim 7, wherein the two diagonal braces extend in a common diagonal plane intersecting a vertical plane of the support node and a horizontal plane of the lateral braces.

9. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, wherein the first and second lateral braces extend in a common plane perpendicular to a longitudinal plane of the support node.

10. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, further comprising a third lateral brace, the third lateral brace extending between the two distal nodes to form a substantially triangular base of the platform, the support node forming one vertex of the triangular base.

11. A buoyant offshore renewable energy system mounting platform as claimed in claim 10, wherein the third lateral brace extends in the common plane of the first and second lateral braces.

12. A buoyant offshore renewable energy system mounting platform as claimed in claim 10, wherein the third lateral brace extends in a plane below or above the plane of the first and second braces.

13. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, wherein the first, second and third lateral braces are substantially cylindrical.

14. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, wherein a net buoyancy of each of the two distal nodes is substantially equal to a net buoyancy of the support node and the renewable energy converter.

15. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, wherein each of the two distal nodes is arranged to support one or more additional ballasts, each additional ballast contributing a ballast mass to the mass of the corresponding distal node.

16. A buoyant offshore renewable energy system mounting platform as claimed in claim 16, wherein the one or more additional ballasts are removable.

17. A buoyant offshore renewable energy system mounting platform as claimed in claim 15 or claim 16, wherein the sum of the ballast masses contributed by the additional ballasts to each distal node is substantially equal to the mass of the renewable energy converter.

18. A buoyant offshore renewable energy system mounting platform as claimed in claim 15, claim 16 or claim 17, wherein: i. the two distal nodes and / or the additional ballasts each comprise a cavity, and a water pump arranged to selectively pump water into and out of the cavity such that the distal node mass and / or the additional ballast mass is freely adjustable; and / or ii. the support node comprises a cavity and a water pump arranged to selectively pump water into and out of the cavity such that the support node mass is freely adjustable.

19. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, wherein at the operating depth, the support node comprises a support node buoyancy and the two distal nodes each comprise a distal node buoyancy, the support node buoyancy and the distal node buoyancy being arranged to apply a support node tension and a distal node tension to the corresponding mooring lines connected thereto, wherein the support node tension and each distal node tension are substantially equal.

20. A buoyant offshore renewable energy system mounting platform as claimed in any one of the preceding claims, wherein the support node comprises one or more landing features arranged to engage with corresponding connecting means of a marine vessel.

21. A method of assembling and deploying an offshore renewable energy system mounting platform, the method comprising assembly steps including: positioning a buoyant support node and two buoyant distal nodes of a platform frame at locations relative to one another; and connecting each of a first lateral brace and a second lateral brace between the support node and a corresponding distal node in a common plane to form a triangular platform base; the method further comprising deployment steps including: transporting the platform base on the surface of a body of water to a deployment location; engaging the support node and each of the two distal nodes with a bed of the body of water by way of one more mooring lines; and lowering the platform base in the body of water to an operating depth at which the support node supports a renewable energy system above a surface of the body of water; wherein the assembly steps or the deployment steps further include: affixing the renewable energy system atop the support node.

22. A method as claimed in claim 21 , wherein said connecting further comprises connecting a third said lateral brace between the two distal nodes.

23. A method as claimed in claim 21 or claim 22. wherein said connecting further comprises connecting two diagonal braces between a corresponding point located on the support node and a point on a corresponding distal node of the two distal nodes, the corresponding point on the support node located proximate an upper end of the support node.

24. A method as claimed in claim 21 , claim 22 or claim 23, wherein the assembly steps or the deployment steps further includes the step of: affixing one or more additional ballasts atop each of the two distal nodes.

25. A method as claimed in any one of claims 21 to 24, wherein said transporting is preceded by the step of:stacking a plurality of said platform bases.

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