NL2026381B1

NL2026381B1 - Support comprising a buoyant member, and a stabilizer configured to stabilize the support in a submerged state, such as in deep water, assembly comprising the support and a superstructure, preferably comprising a wave energy extractor, and method of supporting a superstructure on a support

Info

Publication number: NL2026381B1
Application number: NL2026381A
Authority: NL
Inventors: Jacobus Gerhardus Bartels Michail; Nicolaas Rudolf Keegstra Peter; Kristinsson Jón
Original assignee: Kristinsson Reitsema B V
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2022-04-29
Also published as: WO2022045894A1

Abstract

1 5 ABSTRACT The invention relates to a support, comprising a buoyant member and a stabilizer comprising one or more than one elongate member conﬁgured to connect the buoyant member to 5 an anchoring, wherein the one or more than one elongate member is length-adjustable and thereby conﬁgured to stabilize the support in a submerged state. The invention further relates to an assembly, comprising the support, said support supporting a superstructure that is conﬁgured to extend above a water surface of a water body. In an embodiment, the assembly comprises a wave energy extractor. 10 The invention further relates to a method of supporting a superstructure on a support.

Description

SUPPORT COMPRISING A BUOYANT MEMBER, AND A STABILIZER CONFIGURED TO STABILIZE THE SUPPORT IN A SUBMERGED STATE, SUCH AS IN DEEP WATER, ASSEMBLY COMPRISING THE SUPPORT AND A SUPERSTRUCTURE, PREFERABLY COMPRISING A WAVE ENERGY EXTRACTOR, AND METHOD OF SUPPORTING A

SUPERSTRUCTURE ON A SUPPORT The invention relates to a support, comprising a buoyant member. Water bodies may be applied for a wide variety of applications. In a first aspect, the exposure of water bodies, such as the sea, to wind and/or the gravitational pull of the sun and moon on the earth, will cause the formation of waves in the water body. These waves hold a substantial amount of wave energy, which may be converted into other types of energy, such as with a device as described in Dutch patent 2012880, which comprises a device for extracting energy from waves, and may therefore also be referred to as a wave energy extractor. However, the operation of currently known wave energy extractors is suboptimal, for instance since they are prone to wear as a consequence of prolonged contact with water from the water body. In a second aspect, with the population of the planet Earth growing over time, the building density is increasing steadily. Since water covers approximately 71% of the surface of the planet Earth, it is an attractive perspective to be able to also build structures at sea. When building at sea, it is either possible to build a fixed structure, such as a wind turbine, which is built onto a foundation on the bottom of the water body. However, the construction of such a structure is relatively expensive, both in terms of the construction thereof as well as maintenance. Alternatively, use can be made of a support comprising a buoyant member. However, these supports provide a suboptimal stability in order to put up heavy structures, such as a wind turbine, to such a buoyant member. It is an object of the invention to reduce or even obviate the above-mentioned disadvantages. In particular, it is an object of the invention to provide a support which is more appropriate in terms of its ability to support structures, such as heavy structures, and in particular structures used for extracting wave energy such that these are operable with a reduced amount of wear. This object is achieved with a support, comprising: - a buoyant member, and - a stabilizer comprising one or more than one elongate member configured to connect the buovant member to an anchoring wherein the one or more than one elongate member is length-adjustable and thereby configured to stabilize the support in a submerged state. Said stabilizer comprises one or more than one elongate member which is adjustable in length. When connected to the anchoring, the stabilizer allows the buoyant member to be stabilized in a position in which it is concealed beneath the water level of a water body, in particular open sea and/or deep water, in order to provide a solid base for mounting other structures on the support, as will be elucidated in the following. In this configuration, the elongate member counteracts the buoyancy of the buovant member. The provision of more than one elongate member increases the stability of the buoyant member in the water body. As an example, the support may be provided with a plurality of elongate members (such as two or three), arranged side-by-side and/or following a path towards a lower edge or vertex of the buoyant member. In its mounted state, i.e. the state in which the support is stabilized in the water body. the elongate members which are arranged side- by-side, separate from each other, preferably to extend in a crosswise configuration. If the support comprises more than one elongate member, each elongate member is preferably of the same type and/or material.

In this respect, the term “anchoring” may refer to a single anchor, but generally refers to the totality of anchors stabilizing the support in the water body.

Typically, the buoyant member is rectangular and has a length and/or width of at least 100 meters and/or a depth of at least 20 meters. With such dimensions, the buovant member has a size which makes it suitable to support a wide variety of structures, and in particular a superstructure with a wave energy extractor as will be described in the following. However, the buovant member is not restricted to this size and/or shape.

In an embodiment of the support according to the invention, the one or more than one elongate member comprises at least two elongate members that are length-adjustable independently from each other.

As mentioned, it may be preferred to provide the support with a plurality of elongate members. Preferably at least some of these elongate members are adjustable in length independently from each other. This makes it possible to more flexibly determine the position of the buovant member with respect to the anchoring. Furthermore, it may further increase the stability obtained with the stabilizer.

In an embodiment of the support according to the invention, the support comprises one or more than one winch configured to adjust the length of at least one elongate member and set at least one of a depth and an orientation of the support.

Preferably, the adjustment of the length of the one or more elongate member of the support is achieved with at least one winch which is arranged on the support, which may or may not include any other structure connected to the support. The elongate member may be wound onto a reel of the winch, and thereby shortened in length efficiently.

The winch makes it possible to set the depth and/or an orientation of the support, such as in particular the orientation with respect to the horizontal. When the support is provided with at least two elongate members which are shortened in length in the depth direction to the same extent, the depth of the support is changed, whereas, when the at least two elongate members are shortened in length in the depth direction to a substantially different extent, the orientation is changed.

When the support comprises more than one elongate member, such as two or three elongate members which are arranged side-by-side. the winches of these elongate members are preferably also arranged side-by-side, in order to make the construction of the support less complex.

In an embodiment of the support according to the invention, the one or more than one elongate member comprises one or more than one flexible member, in particular a cable.

In contrast to the use of an elongate member which is relatively rigid, such as for instance a metal chain, it is preferred if at least one of the elongate members is flexible. such that it is possible to wind the elongate member more compactly for adjusting its length. In particular, the flexible member may be a cable since these cables take up a relatively small volume and thereby reduce energy consumption when adjusting the length of the elongate member. Steel cables are preferred for their relatively large load-bearing capacity, in absolute terms and/or per amount of volume.

In an embodiment of the support according to the invention, the support comprises one or more than one cable guide, such as a pulley, configured to guide the cable via at least two anchors of the anchoring.

Cable guides, such as pulleys, allow the cable to be directed in a required direction, e.g.

towards the anchormg or towards a section of the support. For example, the bottom vertices of the buoyant member may be provided with one or more cable guides for guiding the cable towards the anchoring, such as 1n the above-mentioned referred diagonal orientation.

In an embodiment of the support according to the invention, the buoyant member is a truss frame.

A truss frame, which is typically made up out of hollow tube sections extending in horizontal, vertical and preferably also diagonal directions, and connectors, connecting said tube sections, is a relatively open structure. In this way, the construction of the buoyant member is relatively strong while still allowing water to flow through the buovant member, which is advantageous for its increased ability to withstand waves. The design (such as diameter and wall thickness) of the hollow tube sections and the connectors is selected for obtaining buoyancy as required for serving as a support.

The invention further relates to an assembly, comprising a support according to the invention, said support supporting a superstructure that is configured to extend above a water surface of a water body.

The degree of stability attainable with the support according to the invention allows the support to be used for stably supporting other structures, such as for instance a superstructure,

which is configured to extend above a water surface of a water body, such as open sea, for obtaining an off-shore water energy extraction platform. In between the support and the superstructure, the assembly may comprise a mid-section, which may or may not extend above the water surface dependent on the conditions, such as the wave amplitude around the assembly.

Preferably, said mid-section has a relatively open structure in order to reduce the impact of waves on the support, in order to increase the stability of the support, and may for instance also comprise a truss frame.

When the support comprises one or more winch, it may be preferred to arrange this one or more winch on the superstructure, since it is reduces the amount of contact of the winch with the water body and thereby wear.

The superstructure, or part of the superstructure, may also be a truss frame.

In an embodiment of the assembly according to the invention, the assembly further comprises a wave energy extractor.

As mentioned, the support according to the invention is advantageously used for accommodating a wave energy extractor, for extracting wave energy. The provision of the wave energy extractor as part of the assembly according to the current invention allows the part of the wave energy extractor which is in contact with the water body to be minimized. In particular, it is preferred if the only part of the wave extractor which comes into direct contact with the water body is the part which is responsible for catching the wave energy, whereas other parts (such as energy converters) are located above the water level of the water body. This is expected to reduce the amount of wear to the wave energy extractor, thereby increasing its lifespan.

In an embodiment of the assembly according to the invention, the wave energy extractor comprises one or more than one blade, configured to be moveable relative to the superstructure and/or the support by waves and/or a flow in the water body.

Such a blade will move with respect to the superstructure, the support or both as the waves and/or a flow in the water body hit the blade, and thereby depart from a starting position. In the wave energy extractor, the energy collected with this movement and/or the energy collected when the blade is retumed towards its starting position may be used for driving other useful applications.

Preferably. when hit by the water body, in particular waves, the blade moves in a direction with a substantial horizontal component, to thereby extract energy from the movement of the water body in the horizontal direction.

In an embodiment of the assembly according to the invention, the one blade or more than one blade is pivotably or rotatably connected to the superstructure above the water level.

For instance, one or more than blade may have a top edge, pivotably connected to the superstructure at a location above the water surface of the water body, and projecting downwardly to a bottom edge, which bottom edge is, at least in a substantially downwardly directed orientation of the blade, and maybe even over its entire range of motion, beneath the water surface in the submerged state of the support.

Such a blade is then mounted in a basic vertical or at least substantially vertical position. From this basic position, any movement in the horizontal direction, such as wave surge excitation, 5 will force the blade to a maximum displacement or deflection, also referred to as ‘slamming’. However, the assembly preferably comprises a spring, such as a torsion spring, which is able to limit the horizontal displacement, to prevent the phenomenon of slamming. The spring serves as a buffer, preventing other parts of the assembly, such as an energy convertor, which is typically coupled to the blade, to function as such a buffer, thereby reducing the chance of damage to the assembly. The energy stored in the spring will force the blade back to its neutral position, and the process repeats itself with the then reversed wave surge excitation forces.

Preferably, this blade has positive buoyancy. In such a case, the aforementioned surge excitation forces may be amplified by the torque of the buoyancy forces, thereby increasing the amount of extracted energy relative to a blade without buoyancy.

In order to achieve positive buoyancy, such a blade may be provided with a hollow chamber, protruding outwardly from the blade plane, preferably in both directions. The hollow chambers in total may have a buovancy for keeping the superstructure afloat.

In this case, the blade is preferably mirror symmetrical. The hollow chamber is preferably spaced apart from the top and/or bottom edge in order to position the chamber in the operational area where extra torque is preferred. The blade with the hollow chamber is preferably streamlined in at least one of the length and width direction in order to reduce the amount of interference caused by the presence of the chamber when encountering waves oriented along the length direction of the blades. The chamber may be provided with ballasting means in order to ballast the chamber and thereby change its buoyancy. One blade, typically has a size of at least 15 meters in length (from its top edge to its bottom edge), at least 10 meters in width and 3 meters in depth (near the middle of the hollow chamber in the blade).

However, other designs of the energy extractor are also possible. For instance, the energy extractor may additionally and/or alternatively comprise a rotatable substantially horizontally oriented disc, with at least one and preferably a plurality of downwardly directed blades connected to the bottom of the disc, for driving the disc around its substantially vertical axis when the blades are impacted by waves.

Providing the connection of the one or more than one blade above the water level is preferred. since prolonged contact with the water body is thereby reduced. It is expected that this will reduce the onset of wear to the wave energy extraction device.

Preferably, one, more than one or each blade is provided with one or more than one bearing in order to reduce the amount of friction between the blade and the superstructure.

In order to accommodate the blades, the buoyant member preferably comprises an opening in the buoyant member suitably sized for allowing the blades to rotate and/or pivot. Such a opening typically: has a much larger size than the openings provided by the sole fact that the buovant member may be a truss frame.

In an embodiment of the assembly according to the invention, an orientation of the one blade or more than one blade is adjustable, said assembly further comprising: - a detector configured to detect at least one characteristic of the movement of a water body, such as the wave direction and/or wave amplitude, and - a controller configured to set the orientation of the blades in dependency of the at least one characteristic.

As a consequence of weather, the direction and amplitude of waves in a water body constantly may change over time. Preferably, the assembly according to the invention is configured to adjust the orientation of the blades in dependency of changing characteristics. Such a change may comprise the step of adjusting the blade orientation with respect to the wave direction, i.e. a substantially vertical axis, to catch the maximum amount of waves, however may also comprise the step of orienting the blade such that it is protected from the impact from waves with a wave characteristic, such as wave amplitude, above a certain threshold value.

In order to arrive at an assembly which is able to carry out these tasks autonomously, the assembly preferably comprises a detector configured to detect at least one characteristic of the movement of the water body, and a controller configured to set the orientation of the blades in dependency of this characteristic.

Preferably, the step of setting the orientation comprises the step of rotating rotate the at least one blade and the support with respect to each other around a substantially vertical axis. For this purpose, the superstructure may comprise a sub-frame, provided with the at least one blade, provided with a ring-shaped circumferential rail, and a circumferential frame, surrounding the sub- frame, provided with a plurality of guides, provided with the rotating means for rotating the sub- frame by its rail with respect to the guides around a substantially vertical axis. The step of rotating may be carried out by a rotator, comprising a plurality of wheels, arranged in at least some of the guides, preferably distributed along the circumference of the rail for locking the rail in the guides.

In addition to this or as an alternative, the change of the orientation of the one blade or more than one blade with respect to the wave direction, may also be achieved with the adjustment of the elongate member. such as with the winch.

In an embodiment of the assembly according to the invention, the superstructure is moveable relative to the support, wherein the wave energy extractor is configured to extract energy from the relative movement between the superstructure and the support.

It is preferred to support the superstructure on the support such that it is moveable relative to the support, since this allows the wave energy extractor to extract energy from this relative movement. Typically, this is realized by providing a generator, which extracts energy from said relative movement.

Preferably, when lifted or heaved bv the water body, in particular by swell, the superstructure and the support move in a direction with a substantial vertical component, to thereby extract energy from the movement of the water body in the vertical direction.

In an embodiment of the assembly according to the invention, the assembly comprises a guider, preferably a substantially upright guide, configured to guide the superstructure up and down relative to the support.

The provision of a guider, such as a substantially upright guide, such as a one or a plurality of tubes m the support, configured for receiving one or a plurality of tubes directed towards the support, restricts the degrees of freedom of the superstructure with respect to the support such that its movability 1s restricted to a substantially up and down directed movement. As a consequence, the movement of the superstructure with respect to the support will allow extraction of most of the vertical energy, while keeping the influence on the extraction of energy from the horizontal movement of the water body by the blades, where applicable, as low as possible.

As is clear from the foregoing, the guider is not restricted to a substantially upright guide and may for instance also comprise a structure such as an articulating arm or preferably more than one articulated arm, connecting the superstructure to the support.

In an embodiment of the assembly according to the invention, the wave energy extractor comprises at least one of an energy converter and an energy storage.

Preferably, the energy extracted with the wave energy extractor comprises a useful application such as an energy converter, for converting energy into other forms of energy and/or an energy storage, which is configured to store the energy for later use. The energy extractor may for instance comprise a plurality of energy converters of a same and/or different type, which may in each case be arranged in series.

In an embodiment of the assembly according to the invention, the energy converter comprises at least one of: - a dynamo; - a hydraulic motor; - an accumulator, such as a hydraulic accumulator, and - a hydrogen plant.

These are examples of energy converters which are suitable to convert the energy extracted with the wave extractor into other forms of energy. The dynamo may be a dynamo which is of a type similar or equal to the types normally applied in wind turbines, and is in such an application driven by wind turbine blades, but which is in this case be driven by the movement of the blade and/or the relative movement between the superstructure and the support.

As mentioned, the energy converters may be arranged in series. For example the devices for extracting energy from the horizontal and/or vertical movement of the water body may comprise at least one hydraulic motor, used for driving said dynamo, which 1s used for driving a hydrogen plant.

In an embodiment of the assembly according to the invention, the assembly comprises one or more than one wind turbine.

In addition to and/or as an alternative to the aforementioned components of the superstructure, the superstructure may also be provided with one or more than one wind turbine provided with wind turbine blades configured for extracting energy from wind. When the assembly comprises more than one wind turbine, these are arranged such that the blades will not be able to strike each other. To achieve this, it may be preferred to mount the wind turbines at or near the corners of the support.

In order to fix the wind turbines to the support, the base of the turbine is fixed to the support and, additionally, the assembly may be provided with one or more links, providing a further connection of the base of the turbine to the support, in order to increase the stability of the assembly. The assembly is preferably configured such that the wind turbine drives an energy converter of the wave energy extractor.

In an embodiment of the assembly according to the invention, the assembly further comprises an anchoring, such as a suction pile, connectable to the elongate member, for anchoring the buoyant member at the bottom of the water body, in particular offshore.

While the assembly may be connected to an external anchoring (either an anchoring adapted for functioning as such, such as a suction pile and/or a block of concrete, or objects which are accidentally able to serve a role as an anchoring, such as a shipwreck), the assembly may alternatively and/or additionally comprise an anchoring as a part of the assembly.

The invention further relates to a method of supporting a superstructure on a support, comprising the steps of: - providing a support comprising a buoyant member in a water body; - connecting the buoyant member with one or more than one elongate member to an anchoring at or near a bottom of the water body; - adjusting a length of the one or more than one elongate member to thereby support and stabilize the support in a submerged state below a water level of the water body, and - arranging a superstructure on the support.

In an embodiment of the method according to the invention, the method comprises the step of applying an assembly according to the invention.

The invention will be further elucidated with reference to figures, wherein: Figure 1 is a perspective view of a first embodiment of an assembly according to the invention; Figure 2 is a front view of the first embodiment of the assembly; Figure 3 is a left side view of the first embodiment of the assembly; Figure 4 1s a top view of the first embodiment of the assembly according; Figure 5 is a top view of the first embodiment of the assembly, without the superstructure; Figure 6 is a detailed perspective view of the first embodiment of the assembly; Figure 7 is a detailed perspective view of the first embodiment of the assembly; Figure 8 is a perspective view of a second embodiment of an assembly according to the invention; Figure 9 is a detail showing the winch of the second embodiment, and Figure 10 shows a schematic view of a blade according to the invention. Figures 1 to 7 show an assembly 1 comprising a buovant member 2, deploved in a water body below water level W (see Figures 2 and 3). The buovant member 2 is anchored to the bottom 3 of the water body by elongate flexible cables 4, which connect the buoyant member 2 to an anchoring, here embodied as suction piles 5. One end of the cables 4 is connected to winches 6 (see Figures 2 and 3), and follows a path via cable guides 7 towards suction piles 3, to which the other end of the cable 4 is connected. The length of the cables 4 is adjusted with the winches 6.

The buoyant member 2 is a truss frame, i.e. a frame which is made up out of horizontal tube sections 10, vertical tube sections 11 and diagonal tube sections 12, as well as connectors 13, connecting said tube sections 10, 11, 12. Since these tube sections 10, 11, 12 and connectors 13 are hollow, the truss frame has a buoyancy.

The buoyant member 2 serves as a support for supporting a superstructure 30 (see Figures 2 and 3). The superstructure comprises a sub-frame 31, provided with a ring-shaped circumferential rail 32, and a circumferential frame 33, surrounding the sub-frame 31, provided with a plurality of circumferentially arranged guides 34 (see Figures 6 and 7), provided with means for rotating the sub-frame 31 by its rail 32 with respect to the guides 34 around a substantially vertical axis (indicated with arrows 35 in Figure 4) for adjusting the orientation of the sub-frame 31 with respect to the circumferential frame 33 for a purpose to be discussed in the following.

The sub-frame 31 comprises two perpendicular beams 36, 37, for accommodating an energy extractor comprising a plurality of blades 40 (see Figures 2, 3 and 5). which are mounted to the superstructure with a top edge 41, and which, in the shown neutral position, project down to a bottom edge 42, and which is provided with a hollow chamber 43 spaced apart from the top 41 edge and bottom edge 42. such that it is mirror symmetrical (see Figure 3). The blades 40 are mounted such that they are able to pivot out of the neutral position according to a range R (see

Figure 3), in order to extract energy from waves in the water body, especially the horizontal component of the waves. The blades 40 are mounted at a level such that the top edge 41 is not or not likely to come in direct contact with the water from the water body in which the assembly 1 is mounted.

As a consequence of weather, it may be preferred to change the orientation of the blades 40, for instance for protecting the blades 40 against damage, or for orienting the blades 40 in order to catch a maximum amount of wave energy. The above-mentioned mechanism for rotating the sub-frame 31 with respect to the circumferential frame 33 serves this purpose, since the blades 40 are mounted to the sub-frame 31.

The superstructure 30 is supported by the buoyant member 2, however is, as is the case in the present embodiment, not fixed to the buoyant member 2. Instead. the superstructure 30 is moveable with respect to the buoyant member 2 in an up-and-down direction, to which movement these components are restricted in relation to each other by guides 47 provided as part of the buoyant member 2. The energy extractor also comprises a device (not shown) for extracting energy from this movement, i.e. especially the vertical component of the waves in the water body.

The superstructure 30 furthermore comprises a number of platforms 44, such as helipads. In this embodiment, the assembly is provided with wind turbines 100, 110, tied to the superstructure 30 with tie frames 101, 111. The blades 102. 112 of the respective wind turbines 100, 110 are designed and arranged on the assembly such that they will not strike each other or other parts of the assembly 1 during normal operation, i.e. when catching wind.

The assembly 1 is provided with a dynamo 50 configured for converting the energy extracted from the up-and-down movement of the sub-frame 31 with respect to the circumferential frame 33 and/or the movement of the blades 40 and the energy collected by the rotation of the blades 102, 112 of the turbines 100, 110 into other forms of energy, which may for instance be used for driving a hydrogen plant (not shown), mounted on the buoyant member 2.

Another embodiment of an assembly 1000 according to the invention is shown in Figure 8. The second embodiment does not comprise wind turbines 100, 110, but instead comprises four instead of two platforms 1044. Otherwise, the second embodiment 1000 is equal to the first embodiment 1. A detail of the winch 1006 is shown in Figure 9.

A blade 40 according to the invention is shown in Figure 10. The blade 40 is mounted in a bearing 60 provided with a torsion spring, spaced apart from top edge 41. The energy extracted with the blade 40 is used for pivoting a framework 61 around an axis 62, thereby driving hydraulic cylinder 63, configured for driving dynamo 50.

It is noted that the invention is not limited to the shown embodiments but also extends to variant within the scope of the appended claims.

Furthermore, in the foregoing, the support is described as a support for a superstructure, which may be provided with a wave energy extractor, the support may. with or without a superstructure, also be used for other purposes. such as, but not limited to serving as a support of at least one of a quay, a helipad, a garden, a fish farming basin, a device for extraction of fossil fuels from the sea bed and an agglomeration of buildings, such as a city, town or village, an airport, an event area, a harbor, or a breakwater.

Claims

Conclusions l. Support comprising: - a buoyancy element, and - a stabilizer comprising one or more elongate element configured for connecting the flotation element to an anchorage wherein the one or more elongate element is adjustable in length and thereby configured to stabilize of the support m in a submerged state.

The support of claim 1, wherein the one or more elongate element comprises at least two elongate elements that are independently adjustable in length.

The support of claim 2, wherein the support comprises one or more winch configured to adjust the length of at least one elongate member and adjust at least one of a depth and an orientation of the support.

Support according to any one of the preceding claims, wherein the one or more elongate element comprises one or more than one flexible element, in particular a cable.

The support of claim 4, comprising one or more cable guides, such as a pulley, configured to guide the cable through at least two anchors of the anchorage.

Support according to any one of the preceding claims, wherein the floating element is a truss frame.

An assembly comprising a support according to at least one of the preceding claims, which support supports a superstructure configured to extend above a water surface of a water body.

The assembly of claim 7, further comprising a wave energy extractor.

An assembly according to claim 8, wherein the wave energy extractor comprises one or more blades configured to be movable relative to the superstructure and/or the support by waves and/or a current in the body of water.

The assembly of claim 9, wherein the one blade or more than one blade is pivotally or rotatably attached to the superstructure above the water level.

An assembly according to claim 10, wherein an orientation of the one leaf or more than one leaf is adjustable, the assembly further comprising: - a detector configured to detect at least one characteristic of the movement of a body of water, such as the wave direction and/or the wave amplitude, and a controller configured to adjust the orientation of the blades depending on the at least one characteristic.

An assembly according to any one of claims 8 to 11, wherein the superstructure is movable relative to the support, and wherein the wave energy extractor is configured to extract energy from the relative movement between the superstructure and the support.

An assembly according to claim 12, comprising a guide, preferably a substantially upright guide, configured to guide the superstructure up and down relative to the support.

An assembly according to any one of claims 8 to 13, wherein the wave energy extractor comprises at least one of an energy converter and an energy store.

An assembly according to claim 14, wherein the energy conversions comprise at least one of: - a dynamo; - a hydraulic motor; - an accumulator, such as a hydraulic accumulator, and - a hydrogen plant.

An assembly according to any one of claims 7 to 15, wherein the superstructure comprises one or more wind turbines.

An assembly according to any one of claims 7 to 16, and an anchorage, such as a suction anchor, connectable to the elongate element, for anchoring the floating element to the bottom of the body of water, in particular in the open sea.

18. Method of supporting a superstructure on a support. comprising the steps of: - providing a support comprising a floating element in a body of water; - connecting the floating element to one or more elongate element with an anchorage on or near the bottom of the water body; - adjusting the length of the one or more elongate element to thereby support and stabilize the support in a submerged state below a water level of the water body, and - mounting a superstructure on the support.

A method according to claim 18, comprising the step of applying an assembly according to any one of claims 7 to 17.