Patent Description:
In recent years, there has been increased emphasis on the need to exploit renewable energy so that it significantly contributes to global energy production. A combination of government targets, media representation of the issues associated with non-renewable energy sources, and ever increasing energy costs have all created a powerful driving force for the development of renewable energy systems.

Negative impacts of fossil fuels on the environment are well known, as are the problems and high costs associated with nuclear energy. Harnessing of the huge natural abundance of renewable energy on the other hand is constrained merely by our capability of capturing and supplying it at an economically viable price.

One potential renewable energy source is wave power - an abundant and consistent energy resource available in all of the world's large oceans and seas. Another is wind power, with wind speeds being higher and more consistent over oceans and seas compared to land.

For these reasons, offshore platforms providing means to mount renewable energy devices which harness wave and/or wind power are required.

Adequate buoyancy to support the heavy offshore platform, good stability of the platform and means to mount the renewable energy devices to the platform are required. Problems with known offshore platforms include a failure to successfully provide the above. Known offshore platforms have potential for further improvement.

<CIT> describes a pre-stressed concrete floating platform for supporting an offshore wind turbine and marine energy converter.

<CIT> describes a buoyant energy converting apparatus for converting energy obtained from renewable ocean energy sources to useful energy.

The present invention is directed to a buoyant platform arranged to support a renewable energy device which may be used for one or more of: renewable energy capture or harnessing, renewable energy processing, renewable energy storing, renewable energy data capture and/or data storing. In particular the present invention is directed to a buoyant platform having improved modularity, and improved stability when positioned in an in-use configuration within a body of water.

In accordance with an aspect of the present invention, there is provided a buoyant offshore renewable energy system mounting platform for positioning a renewable energy device in a body of water as claimed in claim <NUM>.

It will be understood that the at least one of said buoyancy members comprises a renewable energy device such that the renewable energy device is at least partially attached or affixed thereto, at least partially supported thereon, and/or at least partially accommodated therewithin. The present invention is therefore preferably arranged to combine a buoyancy of said one or more buoyancy members with a weight of a respective renewable energy device such that the respective forces are optimally counteracted with minimal remaining residual internal forces acting on the platform such that stability is maximised. Such preferable improved stability is intended to maximise safety and utility of the platform, which may include capturing, conversion and/or storing of renewable energy, such as wave, tidal and/or wind energy.

In some preferable embodiments, at least three of the at least three vertexes comprise at least one mooring member, which may preferably provide optimum stability to the platform in-use.

In some preferable embodiments, said renewable energy convertor comprises one selected from: a wave energy convertor system (WEC); a tidal energy convertor system; a wind energy convertor system. The WEC can in some embodiments comprise of any suitable type of WEC design, for example a point absorber, an oscillating wave surge absorber, or a submerged pressure differential absorber. In some preferable embodiments, said renewable energy harnessing apparatus comprises one selected from: a wave energy convertor; a tidal energy converter; a wind turbine. The tidal energy converter may comprise any suitable tidal energy converter and may, for example, comprise a tidal turbine having a horizontal axis turbine or a vertical axis turbine. The wind energy converter may be any suitable wind energy converter and may for example comprise a wind turbine. In some preferable embodiments, the renewable energy processing apparatus comprises a hydrogen electrolyser. Embodiments will be appreciated wherein any suitable renewable energy processing apparatus is provided which is arranged to generate a secondary resource from energy harnessed and/or stored. In embodiments that comprise hydrogen generation, electricity may be generated by any renewable energy harnessing and/or converting apparatuses which may be attached to, affixed to, support on, or housed within the invention, which can then be used to generate hydrogen, singly or in combination.

The renewable energy device is engaged with the buoyancy member by an engagement means, wherein the renewable energy device is removable from the buoyancy member by way of the engagement means. The engagement means may be any suitable engagement means providing secure attachment or affixing of the renewable energy device to the respective buoyancy member such that maximum stability is said attachment or affixing is provided. The engagement means preferably supports the modularity of the present invention such that a variety of desirable configurations of platforms with renewable energy devices may be achieved. In some embodiments, the buoyancy member may be engaged with the framework by an engagement means. In such embodiments, a similar modularity is provided, particularly wherein buoyancy members may be adapted to comprise a specific type of renewable energy device. A change in configuration to provide a platform having a different renewable energy device configuration may therefore involve a removal of a buoyancy member adapted to comprise a specific renewable energy device, and replacement with a buoyancy member adapted to comprise a different renewable energy device.

In some preferable embodiments, the platform may further comprise a conveying means extending therefrom, the conveying means arranged to convey one or more resources from the platform. The one or more resources, in some preferable embodiments, may for example comprise: electricity which may be generated by a renewable energy harnessing and/or converting apparatus of the platform and/or stored by a renewable energy storing apparatus of the platform; a secondary resource, such as hydrogen, which may be generated by a renewable energy processing apparatus of the platform. In embodiments wherein the resource comprises electricity, the conveying means is preferably a suitable cable, such as a power cable. In embodiments wherein the resource comprises hydrogen, the conveying means is preferably any suitable conveying means, such as a pipeline for example.

In some preferable embodiments, the renewable energy storage apparatus comprises one selected from: a battery bank comprising one or more batteries; a secondary resource storage apparatus, which may comprise a hydrogen storage apparatus. In specific embodiments comprising hydrogen generation, a hydrogen storage tank may be provided.

In some preferable embodiments, the framework may comprise a lower portion and an upper portion; the platform having an in-use configuration wherein the lower portion is positioned below the surface of said body of water and the upper portion is positioned above the surface of the body of water. In the in-use configuration, the upper portion may be arranged to remain positioned above the surface of the body of water. It will be understood that the upper portion may therefore comprise a device or housing optimised for dry conditions, and therefore preferably remains above the surface of the body of water in-use. The housing may, for example, be a room housing controlling, operation or maintenance equipment. The upper portion of the framework may, in some embodiments comprise renewable energy device such as a wind turbine.

In some embodiments, one or more of the buoyancy members may comprise a said upper portion wherein, in an in-use configuration of the platform, the upper portion is positioned above the surface of the body of water. In said in-use configuration, the upper portion may be arranged to remain positioned above the surface of the body of water. Such an upper portion of the buoyancy member may comprise a renewable energy device such as a wind turbine, or any other suitable renewable energy device described herein, and may be particularly suitable for a hydrogen electrolyser.

In some preferable embodiments, two or more of the buoyancy members each comprise a said renewable energy device. Each said renewable energy device may be arranged to comprise a common orientation on the respective buoyancy member. Such embodiments may be optimised for orienting the renewable energy device according to a wave direction; a wind direction; or a tide direction. Such a common orientation across renewable energy devices therefore preferably maximises renewable energy capture and/or harnessing. In such embodiments, the renewable energy device is preferably a wave energy capturing and/or converting apparatus or system; a tidal turbine; and/or a wind turbine. In some preferable embodiments, one or more of said renewable energy devices comprise an orientation, which may be the common orientation discussed, and wherein the orientation is preferably freely adjustable. Such adjustment of the orientation may, for example, be performed manually or automatically by way of a control mechanism, and may be performed according to a change in wave direction, wind direction and/or tide direction. In embodiments wherein the renewable energy devices comprise an adjustable orientation, the renewable energy devices may comprise an orienting mechanism, such as a yaw mechanism arranged to rotate the renewable energy device about an axis.

In preferable embodiments, each buoyancy member comprises two or more buoyancy units. The two or more buoyancy units of a buoyancy member are preferably each positioned on a different adjacent framework edge extending from the corresponding vertex of the buoyancy member; and/or preferably positioned on the framework approximately equidistant from the corresponding vertex of the respective buoyancy member. In preferable embodiments, the two or more buoyancy units of a buoyancy member are proximate one another, and/or proximate the corresponding vertex. The term "proximate one another" will be understood to mean more proximate relative to a proximity to other buoyancy members. The term "proximate the corresponding vertex" will be understood to mean more proximate relative to a proximity to other such vertexes. Such proximity to each other or the vertex, or equidistance about the vertex, preferably provides a combined centre of buoyancy of the respective buoyancy member, which is preferably positioned at or proximate the corresponding vertex.

In some preferable embodiments, the two or more buoyancy units of a respective buoyancy member have a combined buoyancy defining a centre of buoyancy of the respective buoyancy member. The two or more buoyancy units are preferably positioned relative to the corresponding vertex of said buoyancy member such that the centre of buoyancy of the buoyancy member defines a centre of buoyancy of the corresponding vertex. The combined weight and buoyancy forces acting at the vertex in such embodiments preferably confers optimal stability to the platform in use.

In some preferable embodiments, at least one mooring member of a vertex is attached to the platform at a mooring point, the mooring point being positioned proximate, or at, the centre of buoyancy of the corresponding buoyancy member.

In preferable embodiments, the centre of buoyancy of the buoyancy member is defined by a location on a first plane parallel to the framework, and a second plane perpendicular to the framework, wherein the mooring point is positioned proximate, or at, the location of the centre of buoyancy of the corresponding buoyancy member in at least one of: the first plane; the second plane. In some preferable embodiments, said at least one mooring member is arranged to apply a tensioning force on the respective mooring point, the tensioning force acting in a plane parallel to the second plane, and proximate to or coplanar with the second plane. The mooring point preferably provides the tensioning force in a plane parallel to a plane occupied by a buoyancy force acting upon the platform at the centre of buoyancy. The tensioning force applied at the mooring point by the mooring member of a vertex therefore preferably counteracts the buoyancy acting at the centre of buoyancy of the corresponding buoyancy member. The parallel and proximate, and preferably coplanar, nature of said counteracting forces preferably provides optimal stability to the platform in use.

In preferable embodiments, the at least three vertexes form outer extremities of the framework. Positioning said vertexes and the corresponding buoyancy members at the outer extremities of the platform preferably confers optimal stability on the platform in-use. The at least three vertexes are preferably positioned in a common plane parallel to a plane of the framework.

In preferable embodiments, the at least three vertexes are substantially equidistant from a central axis of the framework and substantially equispaced around the central axis of the framework.

The framework may, in some embodiments, further comprise at least three non-buoyant vertexes, and at least three buoyant vertexes, wherein the at least three non-buoyant vertexes are present at a frequency equal to a frequency of the at least three buoyant vertexes. The at least three non-buoyant vertexes are preferably evenly distributed about the framework, interspaced about the periphery of the framework by one or more of said buoyant vertexes. It will be appreciated that the buoyant vertexes comprise a buoyancy member as described herein having a positive buoyancy, and that the non-buoyant vertexes either do not have a buoyancy member having a positive buoyancy, or comprise a buoyancy member having a net non-positive buoyancy, such as a neutral buoyancy or negative buoyancy.

Preferably, the wave energy convertor (WEC) may comprise a power take off convertor with an orbiting absorber and lever arm. More preferably, the WEC comprises a cylindrical absorber with four lever arm Power Take Off (PTO) units arranged with two lever arm PTO units on top of each of two buoyancy units of a respective buoyancy member.

Embodiments will be appreciated wherein two or more buoyancy members may comprise or support the same renewable energy device between them.

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:.

With reference to <FIG>, there is illustrated an embodiment of the offshore platform <NUM> of the present claimed invention, in use, tethered to a bed <NUM> of a body of water. A portion of the platform <NUM> remains above a surface <NUM> of the body of water.

The platform <NUM> comprises a framework <NUM>. The framework comprises an upper portion <NUM>, which remains above the surface <NUM> of the body of water, and a lower portion <NUM> which remains below the surface <NUM> of the body of water. In alternative embodiments, all of the framework <NUM> remains below the surface <NUM> of the body of water in use.

The lower portion <NUM> of the framework <NUM> comprises a triangular base such that there are three distinct vertexes below the surface <NUM> of the body of water. Each vertex is equidistant from the central point of the triangle and each vertex is equispaced about the central point of the triangle, such that the base has the shape of an equilateral triangle. The framework <NUM> also comprises a central podium, which extends vertically upwards from the central point of the triangular base. The top section of this podium comprises the upper portion <NUM> of the framework <NUM>, which extends above the surface <NUM> of the body of water. The podium is aligned with the central axis of the framework and is symmetrical about the central axis of the framework.

The upper portion <NUM> of the framework <NUM> may be used as an access point for the platform <NUM>. Additionally, electrical, control and/or communication equipment may be housed on the upper portion <NUM>, such that the equipment is not required to be suitable for prolonged submersion in the body of water.

Each vertex of the framework <NUM> comprises a pair of mooring members <NUM>, <NUM> and a buoyancy member <NUM>. In other embodiments, it is envisaged that one or a plurality of mooring members <NUM>, <NUM> may be employed. The mooring members <NUM>, <NUM> may comprise a mooring line, rope, chain or other suitable mooring means.

The mooring members <NUM>, <NUM> tether the platform <NUM> to the bed <NUM> of the body of water or to other fixing means. In this way the mooring members <NUM>, <NUM> prevent unwanted overturning, drifting, sinking or rising of the platform <NUM>. The mooring members <NUM>, <NUM> extend from each vertex of the framework <NUM> to the bed <NUM> of the body of water. On each vertex, an inner mooring member <NUM> extends vertically downwards to the bed <NUM> of the body of water. The outer mooring member <NUM> extends away from the framework <NUM> to the bed <NUM> along a horizontal line parallel to the axis where the vertex meets the central axis of the framework <NUM>. Each pair of mooring members <NUM>, <NUM> on each vertex has a complimentary pair on each other vertex. As such, the contact points these outer mooring members <NUM> make with the bed <NUM> form an equilateral triangle and all vertexes are in the same horizontal plane, parallel to the surface <NUM> of the body of water.

Additionally, the mooring members <NUM>, <NUM> may comprise anchoring means that are fixed or removably retained in the bed <NUM> of the body of water. In this way the anchoring means assist in the mooring of the platform <NUM> to the bed <NUM>.

Each buoyancy member <NUM> comprises two buoyancy tanks <NUM>, such that there are six tanks <NUM> in total. Each tank <NUM> is filled with a gas, such as air or nitrogen, such that the tank <NUM> is less dense than water. The buoyancy tanks <NUM> provide a buoyant force upwards towards the surface <NUM> of the body of water. In some embodiments, it is possible to monitor and control the buoyant force provided by the buoyancy members <NUM>, for example by removing or adding gas or fluid into the buoyancy tanks <NUM>. It is appreciated that alternative buoyancy means may be employed which provide this buoyant force.

In use, tension is held in the mooring members <NUM>, <NUM> due to the buoyant forces acting on the platform <NUM>. The downwards gravitational pull of the platform <NUM> is exceeded by the upwards buoyant force of the platform <NUM>. The buoyancy member's <NUM> provide the predominant upwards buoyant force to the platform <NUM>.

The body of water, and other internal and external sources, will subject the platform <NUM> to numerous forces and moments, in use. It is desirable for the platform <NUM> to remain stable in use so that, for example, toppling of the platform <NUM> does not occur. Tension in the mooring members <NUM>, <NUM> allows the three vertexes of the framework <NUM> to return to a horizontal plane, parallel to the surface <NUM> of the body of water after the platform <NUM> is subjected to forces and moments. In this way, the mooring members <NUM>, <NUM> assist in stability of the platform <NUM>.

In the embodiment illustrated, each buoyancy tank <NUM> is identical. Both buoyancy tanks <NUM> sit proximate to each other on the vertex of the framework <NUM>. Each buoyancy tank <NUM> sits on either side of the vertex, symmetrically about the axis where the vertex meets the centre of the triangular base. Each pair of tanks <NUM> are braced to the framework <NUM> in a way such that relative motion of each tank <NUM> to the other is minimised. In this way, the structural behaviour of the two tanks <NUM> is similar to that of a single, larger tank, and the behaviour of the pair of tanks <NUM> can be effectively modelled as that of a single unit. The tanks <NUM> have a combined centre of buoyancy.

The tanks <NUM> are cylindrical and the longitudinal axis of each tank <NUM> is vertically upwards. In this way, the tanks <NUM> are less prone to toppling and rotating when subject to internal and external forces and moments given the shorter moment arm (lateral axis) of the tanks <NUM>. It should be understood that other tank <NUM> geometries and shapes are envisaged.

The presence of more than one tank <NUM> provides the advantage that if damage or failure occurs in one tank <NUM>, such as loss of buoyancy, at least one additional tank <NUM> remains on the vertex. This ensures the buoyancy of the overall platform <NUM> is not entirely compromised when failure of a tank <NUM> occurs. By ensuring each vertex has at least one additional buoyancy tank <NUM>, the platform <NUM> is less prone to overturn or sink upon failure of a buoyancy tank <NUM>, as a buoyant force is still being provided at every vertex. This reduces the likelihood of damage to or loss of function of the platform <NUM>. Repair or replacement of the compromised tank <NUM> can then be undertaken to rebalance the platform <NUM>.

Each buoyancy member <NUM> comprises a wave energy convertor system (WEC) <NUM>. The WEC <NUM> may comprise a point absorber, an oscillating wave surge absorber, a submerged pressure differential absorber or another form of WEC technology.

The WEC <NUM> is connected to both buoyancy tanks <NUM>. The WEC <NUM> is mounted above the buoyancy tanks <NUM>, such that, in use, the WEC <NUM> sits between the buoyancy tanks <NUM> and the surface <NUM> of the body of water. In this way the WEC <NUM> does not interfere with the mooring members <NUM>, <NUM>. The WEC <NUM> is mounted centrally above the tanks <NUM>, such that the longitudinal axis of the WEC <NUM> is parallel to the axis between the centre of each tank <NUM>.

Any reasonable means for connecting the WEC <NUM> onto or proximal to one or both of the tanks <NUM> is envisaged, such as permanent or removable connection, rigid or deformable levers, lines or chains, or direct mounting on the tanks <NUM>. Additionally, a connection between the WEC <NUM> and the framework <NUM> is envisaged. Components associated with converting energy from the WEC <NUM> may be mounted on or within the tanks <NUM> or on the framework <NUM>.

Each WEC <NUM> is identical. In alternative embodiments, the WECs <NUM> may be non-identical. The WEC <NUM> is cylindrical with a longitudinal axis parallel to the surface <NUM> of the body of water. Each WEC <NUM> may rotate fully or partially about the longitudinal axis of the WEC <NUM>. The WEC <NUM> is orientated such that its longitudinal axis is horizontal and parallel to the surface <NUM> of the body of water. In this way, the WEC <NUM> is aligned with the direction of current or flow of the water in the body of water. The angle the longitudinal axis of the WEC <NUM> makes with the surface <NUM> of the body of water and/or the angle the longitudinal axis of the WEC <NUM> makes with the framework <NUM> may be altered, such that the orientation of the WEC <NUM> is optimal for wave energy conversion purposes.

Each WEC <NUM> is orientated identically on each vertex. Alternatively, the orientation of each WEC <NUM> relative to each other WEC <NUM> is different, such that the capturing of wave energy is improved in each application.

Consideration may be taken to reduce the platform <NUM> weight such as to reduce the gravitational pull of the platform <NUM> towards the bed <NUM> of the body of water is preferential.

Turning now to <FIG> and <FIG> of the platform of the present invention, in the following description similar numerals will be used for similar parts of each embodiment of the present invention.

<FIG> depicts an embodiment of the present invention, wherein the platform <NUM> further comprises a turbine <NUM>. The turbine <NUM> is mounted on the upper portion <NUM> of the framework <NUM>, such that the turbine <NUM> remains above the surface <NUM> of the body of water, in use. The turbine <NUM> is mounted vertically upwards, perpendicular to the surface <NUM> of the body of water.

The buoyant force provided by the buoyancy members <NUM> is such that the considerable weight of the turbine <NUM> is supported. In this embodiment, reducing the platform <NUM> weight to reduce the gravitational pull of the platform <NUM> towards the bed <NUM> of the body of water is preferential.

In this embodiment, multiple forms of renewable energy convertors are present on the platform <NUM>: a turbine <NUM> and WECs <NUM>.

<FIG> depicts an embodiment of the present invention, wherein each buoyancy member <NUM> of the platform <NUM> comprises a tidal energy convertor (TEC) <NUM>, for example a tidal turbine. Each TEC <NUM> may have an orientation that is fixed relative to the framework <NUM>. Alternatively, each TEC <NUM> is able to yaw to face the direction of the current.

<FIG> depict the present claimed invention, with no renewable energy convertors shown. The buoyancy tanks <NUM> are spaced apart and symmetrically on the vertex about the axis where the vertex meets the central axis of the framework <NUM>.

C indicates the combined centre of buoyancy of the buoyancy tanks <NUM>. The centre of buoyancy point C is the effective point at which the buoyant force B from the tanks <NUM> act. The mooring members <NUM>, <NUM> are attached to the framework <NUM> at a mooring point M. The mooring point M is the point at which the tension forces T from the mooring members <NUM>, <NUM> act on the framework <NUM>. The buoyant force B acts vertically upwards. The tension forces T act through the mooring members <NUM>, <NUM>.

The mooring point M and the centre of buoyancy C of the buoyancy tanks <NUM> are the same. In this way, the mooring point M and the centre of buoyancy C are in the same horizontal and vertical planes.

As the buoyant force B and tension forces T act at the same point (the centre of buoyancy C and the mooring point M), no moment from the buoyant force B and tension forces T acts on the platform <NUM>. Such moments are disadvantageous as they can cause high structural loads and hinder platform stability. It is appreciated that a moment will result due to each individual buoyant force from each tank <NUM>, however, each tanks <NUM> proximate position to the other of the pair of tanks <NUM> on the framework <NUM> reduces this moment.

In a further embodiment of the present invention, the platform comprises two vertexes, such that the vertexes are in a line parallel to the surface of the body of water. In this way, the buoyancy members are horizontally spaced apart from each other.

Referring to <FIG>, a further example embodiment of a platform <NUM> in accordance with the present invention is shown, similar top the embodiment of <FIG>. In <FIG>, the platform <NUM> comprises a wind turbine <NUM>. The turbine <NUM> is mounted on the upper portion of the framework <NUM>, such that the turbine <NUM> remains above the surface <NUM> of the body of water, in use. The turbine <NUM> is mounted vertically upwards, perpendicular to the surface <NUM> of the body of water.

The buoyant force provided by the buoyancy members <NUM> is such that the considerable weight of the turbine <NUM> is supported. In this embodiment, reducing the platform <NUM> weight to reduce the gravitational pull of the platform <NUM> towards the bed <NUM> of the body of water is preferential, hence the skeletal frame structure. The upper portion of the platform <NUM> is supported partially by diagonally extending frame members <NUM> linking the upper portion to each of three vertexes of the frame work <NUM>, thereby partially distributing the weight of the turbine <NUM> to the vertexes, at which the buoyancy tanks <NUM> exert a counteracting buoyancy force. As with previous embodiments, each vertex is tethered to the bed <NUM> by a set of mooring lines <NUM> and anchors <NUM>. The mooring lines <NUM> exert a tensioning force to the mooring point at which the mooring lines are connected to the vertex, providing a counteracting force to the combined centre of buoyancy of the buoyancy tanks <NUM>, the tensioning force and at least part of the weight of the turbine <NUM> in the embodiment shown being applied coplanar with the buoyancy force thereby minimising residual internal forces acting on the platform <NUM>.

In this embodiment, the buoyancy tanks each comprise an renewable energy storage unit (not shown) housed therein.

The embodiments of <FIG> and <FIG> are substantially equal to the embodiment described for <FIG>. The embodiment <NUM> of <FIG> replaces the energy storage units for a hydrogen electrolyser <NUM> and a hydrogen storage tank <NUM> arranged to receive and store the hydrogen from the electrolyser <NUM> by way of pipes concealed within the skeletal framework of the platform. The electrolyser, in the embodiment shown, is powered by electrical energy provided by the wind turbine. In the embodiment shown, the storage tank <NUM> can be routinely collected and replaced, or the hydrogen therein detanked into a mobile gas transportation vessel. Embodiments will be appreciated wherein the platform comprises a gas pipe leaving the platform and arranged to convey the gas from the storage tank <NUM>. The embodiment <NUM> of <FIG> replaces the energy storage units of <FIG> for data storage units <NUM> arranged to receive usage data from data collectors located on the platform (not shown). The data collectors may, for example, collect data about the functioning of the wind turbine and/or the sea conditions, which may be used to inform a modification made, for example to the height of the platform in the body of water.

The embodiment <NUM> of <FIG> and <FIG> comprises a platform having six buoyant vertexes forming a hexagonal platform. A buoyancy tank of each other vertex supports a raised upper portion thereon comprising a wind turbine arranged to remain above the surface of the body of water. The remaining buoyancy tanks at each remaining vertex supports a WEC as described previously. In the embodiment <NUM> shown, two pairs of opposing vertexes of the six vertexes comprise mooring lines extending therefrom anchoring the platform to the bed of the body of water. In the embodiment shown, the equal dispersal of a large amount of weight from the wind turbines and WECs is sufficient in order to counteract the buoyancy of the corresponding buoyancy tanks with only set of mooring lines. Embodiments will be appreciated wherein the platform comprises three sets of mooring lines positioned at three of the six vertexes and evenly spaced about the platform. Other embodiments will be appreciated wherein each of the vertexes comprises its own set of one or more mooring lines. The use of a larger number of below and above water platforms may allow for a greater number and/or a larger size of renewable energy devices (or processors or storage) to be housed by the platform, increasing its energy output.

The wind turbine towers of the embodiment <NUM> may be of different heights to mitigate against the turbines shadowing each other in certain wind directions, improving energy yield from the platform.

Claim 1:
A buoyant offshore renewable energy system mounting platform (<NUM>) for positioning a renewable energy device (<NUM>) in a body of water, said body of water comprising a surface (<NUM>) and a bed (<NUM>), said platform (<NUM>) comprising:
a framework (<NUM>) comprising at least three vertexes;
at least two of said at least three vertexes having at least one mooring member (<NUM>, <NUM>) for positioning said platform (<NUM>) relative to said surface (<NUM>) and bed (<NUM>) of said body of water; and
each of said at least three vertexes having a buoyancy member (<NUM>) ; wherein at least one of said buoyancy members houses a renewable energy device (<NUM>) at least partially accommodated therewithin, the renewable energy device (<NUM>) selected from the group of: a renewable energy convertor; a renewable energy harnessing apparatus; a renewable energy processing apparatus; a renewable energy storing apparatus; a renewable energy data capture apparatus; a data storing apparatus;
characterised in that the renewable energy device (<NUM>) is engaged with the corresponding at least one buoyancy member (<NUM>) by an engagement means, the renewable energy device (<NUM>) being removable from the buoyancy member (<NUM>) by way of the engagement means; and
wherein the engagement means is configured such that, following said removal, a different renewable energy device (<NUM>) selected from the group is arranged to be engaged with the corresponding at least one buoyancy member (<NUM>) by the engagement means.