WO2022106831A1

WO2022106831A1 - Safe power generating apparatus

Info

Publication number: WO2022106831A1
Application number: PCT/GB2021/052996
Authority: WO
Inventors: William Annal; Andrew Harrison; Calum MILLER
Original assignee: Orbital Marine Power Limited
Priority date: 2020-11-20
Filing date: 2021-11-18
Publication date: 2022-05-27
Also published as: GB202018292D0

Abstract

Disclosed herein is a power generating apparatus for extracting energy from flowing water. The power generating apparatus comprises a buoyancy vessel, a platform integral with or coupled to the buoyancy vessel and a turbine assembly comprising a turbine rotor mounted to a nacelle, and a support structure. The platform extends along at least half of the length of the buoyancy vessel. The turbine assembly is pivotally moveable between a first position and a second position. When the power generating apparatus is floating on a body of water, in the first position the nacelle is configured to be fully submerged below the water surface, and in the second position at least a part of the nacelle is configured to project above the water surface.

Description

SAFE POWER GENERATING APPARATUS

Field of the Invention

The invention relates to the field of power generating apparatus, for extracting energy from flowing water, and in particular to a floating generating apparatus for use for example in the marine or river environment.

Background to the Invention

In recent years there has been a move towards energy generation from renewable energy sources, including the use of movable apparatus such as turbines to harvest energy from fluid movement, such as wind, tidal and wave power.

Energy generation from flowing water benefits from being capable of generating a relatively predictable energy supply, whether from a tidal stream or a river. A great number of powered generating apparatus for generating electricity from flowing water have been proposed; including apparatus fixed to the seabed, for example as described in US2015260148 (Aquantis, Inc), and floating apparatus, for example as described in WO 2015/090414 (Bluewater Energy Services).

Floating generators provide both a visible above-water warning that the generator is present, and are generally better able to utilise the faster streams that occur near the water surface (particular tidal streams) and accommodated changes in water level (particularly tidal changes). In addition, floating generators have lower operation and maintenance costs than power generating apparatuses that are fully submerged underwater.

Generating apparatus of this type may be large scale, particularly for tidal and marine applications, and so may be costly to manufacture and deploy. Some of these problems were addressed by the generating apparatus described by the applicant in EP1831544. The generating apparatus described in EP1831544 has turbine nacelles capable of being stowed close to the main buoyancy vessel, which reduces both the draft and the hydrodynamic drag of the generator. However, in some circumstances it may be desirable to still further reduce drag and/or draft.

Aggressive subsurface conditions also provide significant challenges in the use of such generating apparatus, and there is generally a trade-off between the costs of accessing normally submerged components for maintenance, and the engineering costs of apparatus engineered for very long service intervals. Some of these problems were addressed by the generating apparatus described in EP3559440. The apparatus disclosed in EP3559440 has a turbine assembly coupled to a buoyancy vessel, the turbine assembly comprising a turbine rotor mounted to a nacelle, and a support structure. The turbine assembly is pivotally moveable between a first position (fully submerged below the water surface when the power generating apparatus is floating on a body of water) and a second position (with at least a part of the nacelle projecting above the water surface). Movement of the turbine assembly to the second position may be desirable to reduce the draft or the drag of the power generating apparatus, for example when the power generating apparatus is being relocated, or to prevent damage during storms. Furthermore, movement of the turbine assembly to the second position allows access into the nacelle while the power generating apparatus remains in the water, thus further minimising operation and maintenance costs.

However, in some circumstances it may be desirable to reduce the visual impact of floating power generation apparatuses, as well as to improve the safety features of the apparatuses for passengers or operators who board the power generating apparatus, for example for maintenance. Furthermore, it is still desirable to further improve the roll stability of existing power generation apparatuses.

There remains a need for generating apparatus for extracting energy from flowing water which address or mitigates one or more of these issues.

Summary of the Invention

Described herein is a power generating apparatus for extracting energy from flowing water, comprising: a buoyancy vessel; a platform integral with or coupled to the buoyancy vessel. The platform may extend along at least half of the length of the buoyancy vessel. The apparatus may comprise a turbine assembly comprising a turbine rotor mounted to a nacelle, and a support structure.

The support structure of the turbine assembly may be movably coupled to the buoyancy vessel at one or more upper connection point or points and at one or more or more lower connection point or points. The lower connection point or points may be vertically separated from the upper connection point or points by a distance of from about 50% to about 100% of a height of the buoyancy vessel.

The turbine assembly may be pivotally moveable between a first position and a second position. When the power generating apparatus is floating on a body of water, in the first position the nacelle may be configured to be fully submerged below the water surface; and in the second position at least a part of the nacelle may be configured to project above the water surface.

In the first position, the nacelle is submerged and the turbine rotor is capable of being driven by movement of water flowing past the power generating apparatus (for example a tidal stream or the flow of a river). Movement of the turbine assembly to the second position may be desirable to reduce the draft and, in some instances, also the drag of the power generating apparatus, for example when the power generating apparatus is being relocated.

In the second position, at least a portion of the nacelle projects above the water surface, so as to provide access thereto for maintenance or repair. This may avoid the need for large and expensive barges/cranes, e.g. to raise the entire power generating apparatus from the water and so facilitate more frequent, rapid and cheaper maintenance than would otherwise be possible.

Increased ease of access to the nacelle or support structure may in turn facilitate the use of equipment having a shorter services interval, or may enable certain apparatus to be viably located in the turbine assembly (such as fluid filters, lubricating or cooling fluid reservoirs or circuits, or electricity generating equipment). The power generating apparatus of the present invention may therefore avoid some of the design compromises that have previously been required.

The at least a portion of the nacelle projecting above the water surface in the second position may be provided with an access hatch, providing access to apparatus housed therein.

The power generating apparatus may comprise a single buoyancy vessel (or hull) (as compared, for example to two or more interconnected buoyancy vessels (or hulls)).

The buoyancy vessel may have any suitable configuration. However, in some embodiments, the buoyancy vessel is elongate and may be generally cylindrical, so as to provide limit hydrodynamic drag and wave loading. In embodiments in which the buoyancy vessel is elongate, the buoyancy vessel may have a longitudinal axis disposed substantially parallel to the water surface (when the power generating apparatus is floating on a body of water).

A generally cylindrical (in cross section) buoyancy is inherently extremely strong and may be of particular benefit in adverse weather conditions, such as may be encountered in the marine environment.

The buoyancy vessel may itself be provided with a ballasting system (comprising ballast tanks, desirably front and rear), by which the trim of the power generating apparatus may be adjusted, in some embodiments automatically. The ballasting system may be used to compensate for the varying forces applied by a river or tidal flow impinging on the turbine rotor or other parts of the turbine assembly.

The or each turbine assembly may be coupled to a bow or stern section of the buoyancy vessel (it being understood that in some embodiments, the terms bow and stern are arbitrary).

The buoyancy vessel may comprise a keel.

The power generating apparatus may comprise two, or more than two, turbine assemblies. The turbine rotor of two such turbine assemblies may be counter-rotating.

The turbine rotor may comprise any suitable number of blades. The turbine rotor may comprise 2 blades, or 3 blades, or 4 blades, or 5 blades, or 6 blades. In preferred embodiments, the turbine rotor may comprise two blades. Providing a turbine assembly with two blades minimises the draft while the power generating apparatus is being towed between locations. Turbine rotors with two blades can be parked or locked in a horizontal position substantially parallel to the water surface when the power generating apparatus is in the second position. In this arrangement the rotor blades may remain above the water or minimally disturb the water, thus minimising draft. In contrast, power generating apparatus with more than two blades have at least one blade below the water surface (e.g. pointing at least partially towards the sea or river bed) at any one time, thus increasing draft during towing when the power generating apparatus is in the second position.

The power generating apparatus may comprise two or more turbine assemblies symmetrically disposed in relation to the buoyancy vessel. The power generating apparatus may be configured such that the turbine assemblies are symmetrically disposed at all times (i.e. in the first position, the second position and during movement therebetween). That is to say, the symmetrically disposed turbine assemblies may be symmetrically and pivotally moveable between their first a second positions.

In some embodiments, the power generating apparatus comprises two turbine assemblies, extending symmetrically in relation to a longitudinal axis of the buoyancy vessel.

Such symmetrically disposed turbine assemblies may, in normal use, be tethered together in the first position, for example by a cable extending between the turbine assemblies. The cable may form part of a powered mechanism, for mechanically assisting and/or damping motion between the first and second positions.

The turbine assembly may be biased to the first position. The turbine assembly may be biased to the second position.

It is to be understood that the power generating apparatus as a whole is buoyant and, in use floats on a body of water.

The power generating apparatus may comprise a powered mechanism, for moving the/each turbine assembly from the first to the second positions and/or from the second to the first position.

Movement between the first and second positions may at least in part be mechanically assisted, by the powered mechanism, e.g. a mechanism comprising a hydraulic ram and associated linkage mechanism or the like. Movement of the turbine assembly may be initiated by a powered mechanism. A powered mechanism may assist in lifting the nacelle, or a greater part of the nacelle, above the water surface.

In normal use, the powered mechanism may be the primary means of moving between the first and second positions. In some embodiments, buoyancy (e.g. by means of buoyant volumes such as tanks within the turbine assembly or assemblies) may provide additional assistance. The turbine assemblies may for example be configured for variable buoyancy to be used as a back-up to the powered mechanism, or vice versa.

The powered mechanism may be hydraulically powered. A hydraulic mechanism may comprise a hydraulic ram (i.e. a hydraulically controllable piston).

A hydraulic ram may be operatively coupled between the buoyancy vessel and a said turbine assembly (most typically a support structure thereof).

A hydraulic ram may be operatively connected between one or other of the turbine assembly and a mechanical linkage arrangement, wherein the mechanical linkage arrangement is coupled at a first end to the turbine assembly and at a second end to the buoyancy vessel, the distance between the first and second end of the mechanical linkage arrangement being variable by operation of the hydraulic ram.

The hydraulic ram may be pivotally connected to the buoyancy vessel, turbine assembly and mechanical linkage arrangement, as the case may be. A hydraulic ram is typically coupled at two points and each may be pivotal connections.

The buoyancy vessel and/or the turbine assembly (or support structure thereof) may comprise a fly brace, for connection to the mechanical linkage arrangement; to thereby increase leverage.

The mechanical linkage arrangement may comprise two or more pivotally interconnected linkages extending from the first to the second end. In some embodiments, when the turbine assembly is in the first position, the linkages are generally aligned between the first and second ends.

The hydraulic ram may have an axis (along which it deploys in use) that crosses a line described between the first and second ends of the mechanical linkage arrangement; at least when the respective turbine assembly is close to the first position, and optionally throughout the range of motion of the turbine assembly.

The hydraulic ram may have an axis extending generally perpendicular to the said line at least when the respective turbine assembly is close to the first position, and optionally throughout the range of motion of the turbine assembly.

It will be understood that as the turbine assembly or assemblies pivot between the first and second positions, the first and second ends of the mechanical linkage arrangement describe an arc in relation to one another. The powered mechanism may be configured such that the orientation of the axis of the hydraulic ram changes throughout the range of motion of the associated turbine assembly. The angle at which it crosses the line between the first and second ends may remain generally constant (e.g. perpendicular).

When the power generating apparatus is floating on a body of water and generating power from water currents, forces are transmitted to the buoyancy vessel from the turbine assemblies due to motion of the rotors (e.g. changes in rotor speed or forces applied thereto) and forces which act upon the turbine assembly/assemblies (e.g. caused by waves, changes in tidal force/di recti on and the like). Where the hydraulic ram deploys along an axis that crosses said arc, it is isolated to some degree from such dynamic forces.

This may be of particular benefit when the turbine assembly is at or near the first position, where the leverage applied between the ends of the mechanical linkage arrangement and the hydraulic ram is at a maximum (e.g. when two or more mechanical linkages are aligned). In this way, the hydraulic ram is better able to retain the turbine assembly in the first position, to resist dynamic forces that arise when the power generating apparatus is generating power from water currents.

The mechanical linkage arrangement (and any associated pivotal connections) may be configured to remain above the waterline in the second position, in normal use. At least part of the mechanical linkage arrangement (and any associated pivotal connections) may be configured to remain below the waterline in the second position, in normal use.

Each turbine assembly may be associated with a hydraulic ram (or more than one hydraulic ram) and, as the case may be, a corresponding mechanical linkage arrangement or arrangements.

A powered mechanism may be used to provide hydraulic resistance to said movement, in one direction, and mechanical assistance in the other direction.

A powered mechanism may be used to control or limit the rate of motion in one or both directions, along at least a part of the range of motion between the first and second positions. For example, where the/each turbine assembly is negatively buoyant, the powered mechanism (e.g. comprising a hydraulic ram as disclosed herein) may control or limit the rate of motion of the/each turbine assembly from the second to the first position.

This methodology may be of particular benefit to the overall stability of the power generating apparatus during movement between the first and second positions, particularly when the turbine assembly is closer to the second position (and thus has the greatest effect on changes in overall buoyancy and stability of the power generating apparatus). Embodiments having more than one turbine assembly may be prone to instability during movement of the turbine assemblies, which instability may be limited by applying mechanical control over the rate and in some cases symmetry of movement. The powered mechanism may comprise position measurement apparatus, operable to detect the position of the powered mechanism, and thus the/each turbine assembly. The powered mechanism may be associated with a controller operable to control the powered mechanism, based on information received from the position measurement apparatus. This may for example facilitate synchronisation of the movement of two or more turbine assemblies and/or assist in maintaining the stability of the power generating apparatus.

The turbine assembly may optionally be retained in the first position by a cable extending for example between the nacelle and a location on the buoyancy vessel or another turbine assembly.

Movement towards one or more of the first or second position may be damped.

Motion may be mechanically damped, for example by a buffer. Each turbine assembly may comprise a buffer, or a component thereof. A turbine assembly may be buffered against the buoyancy vessel, or (where there are two or more symmetrically disposed turbine assemblies) against another turbine assembly.

Motion may be “damped” by varying the buoyancy of the turbine assembly, as it approaches a respective position. This may be achieved for example by the provision of more than one, or a series, of ballast tanks, which may be selectively filled or emptied so as to vary the buoyancy force as a turbine assembly approaches the first or second position, as the case may be.

Motion may in some embodiments be damped using a powered mechanism, for example which may act as a “brake” to movement toward the first and/or second position.

A powered mechanism for assisting movement between the first and second positions may in some circumstances be used to brake or damp motion in the opposite direction.

The turbine assembly may be pivotally moveable around a hinge arrangement.

The power generating apparatus may comprise any suitable type of hinge arrangement, for example a pin-joint or bushing. The hinge arrangement may comprise a single hinge or multiple hinges, e.g. two or more hinges arranged along an axis. The hinge arrangement may comprise one or more journal bearings, fibre bearings or the like. The hinge arrangement may be water lubricated.

The hinge arrangement may be above or below the waterline. For example, the hinge arrangement may be below the waterline in the first position and in the second position.

The hinge arrangement may form part of the turbine assembly, or part of the buoyancy vessel. The turbine assembly may be coupled to the buoyancy vessel via the hinge arrangement. For example, the turbine assembly may comprise a part of the hinge arrangement, such as one or other of a padeye or a hinge clevis, and the buoyancy vessel may comprise a complimentary part of the hinge arrangement.

The turbine assembly may alternatively be coupled to the buoyancy vessel by a separate coupling arrangement, such as a flange coupling or the like. In such embodiments, the hinge arrangement may be inboard of the coupling arrangement (i.e. forming part of the buoyancy vessel) or outboard of the hinge arrangement (i.e. forming part of the support structure of the turbine assembly).

The turbine assembly may pivot around an axis that is generally parallel to a longitudinal axis of buoyancy vessel.

The hinge arrangement and/or secondary hinge arrangement where present may for example comprise a latch or be associated with a latch or a component part thereof.

A hinge arrangement may be associated with more than one latch, for example to enable the turbine assembly to be retained in each of two positions between which a hinge arrangement can move.

The power generating apparatus may comprise any suitable type of latch or latches. For example, the apparatus may comprise a magnetic latch between a permanent or electro magnet and corresponding material attracted thereto. The apparatus may comprise a mechanical or electromechanical latch, for example comprising a shear pin.

In the first position the turbine assembly may extend below, and optionally to the side of (i.e. extending diagonally below), the buoyancy vessel. In the second position, the turbine assembly may extend generally to the side of the buoyancy vessel.

Within the context of this disclosure, the baseline of the buoyancy vessel is defined as the lowest point of the buoyancy vessel (when the buoyancy vessel is floating on a body of water).

The bow is the front portion of the buoyancy vessel and the stern is the rear portion of the buoyancy vessel. However, it should be understood that within the context of this disclosure, the terms bow and stern may be interchangeable.

The beam of the buoyancy vessel is the overall width of the buoyancy vessel measured at the widest point of the nominal waterline.

The waterline of the buoyancy vessel may be defined as the location on the hull or body of the buoyancy vessel where the air-water interface occurs (when the buoyancy vessel is floating on a body of water). The draught of the buoyancy vessel is defined as the distance between the baseline and the waterline of the buoyancy vessel (when the buoyancy vessel is floating in a body of water, as in normal use).

The freeboard of the buoyancy vessel is defined as the difference between the total height of the buoyancy vessel and the draught. The freeboard is measured from the waterline to the uppermost portion of the buoyancy vessel (viewed when the buoyancy vessel is floating on a body of water). The draught and freeboard combined give the height of the buoyancy vessel.

The buoyancy vessel may have any suitable configuration. However, in some embodiments, the buoyancy vessel is elongate and may be generally cylindrical, so as to provide limit hydrodynamic drag and wave loading. A generally cylindrical (in cross section) buoyancy is inherently extremely strong and may be of particular benefit in adverse weather conditions, such as may be encountered in the marine environment.

The buoyancy vessel may be elongate and generally cylindrical. The buoyancy vessel may taper at the bow end and/or stern end. The buoyancy vessel may comprise a substantially conical end at the bow and/or stern region. Without wishing to be bound by theory, providing a buoyancy vessel with tapering or conical ends decrease the drag of the buoyancy vessel.

The buoyancy vessel may comprise a keel.

The platform may be integral with the buoyancy vessel. Alternatively, the platform may be fixable to the buoyancy vessel. The platform may be fixed to the buoyancy vessel by any suitable means, such as welding or bolting. In embodiments in which the platform is bolded to the buoyancy vessel, the buoyancy vessel may comprise mounts configured to receive the platform. The platform may then be bolted to the mounts of the buoyancy vessel.

Providing a power generating apparatus with a separate platform may minimise the manufacture costs, since the platform may be manufactured separately from the buoyancy vessel and subsequently mounted thereto. For example, the platform may be mounted and attached to the buoyancy vessel when the buoyancy vessel is floating over a body of water. This method of manufacture may also enable the use of a different (perhaps cheaper, more visually appealing, lighter or less slippery) material for the platform and for the buoyancy vessel. Providing a platform that is attachable to the buoyancy vessel may facilitate repairs of the whole or parts of the platform in situ without the need to remove the entire apparatus from the water for repair. The platform may be located on the upper portion of the buoyancy vessel. The platform may be coupled to the upper surface of the buoyancy vessel, for example by welding or by means of mounts. In embodiments in which the buoyancy vessel has a curved cross-section, the platform may define a plane parallel to tangential plane to the uppermost point of the buoyancy vessel. The platform may define a plane parallel to tangential plane to the air draught of the buoyancy vessel. For the avoidance of doubt, the uppermost point of the buoyancy vessel is the highest point of the buoyancy vessel above the waterline (when the power generating apparatus is floating on a body of water). The air draught is the distance from the surface of the water to the highest point on the buoyancy vessel. The platform may be coupled directly to the upper surface of the buoyancy vessel. The platform may be vertically spaced from the upper surface of the buoyancy vessel. The platform may be mounted above the upper surface of the buoyancy vessel and at distance therefrom, for example by means of supports or struts.

When the power generating apparatus is in the second position, the platform may be substantially parallel to the water surface. When the power generating apparatus is in the first position and the turbine arrangement is not generating power, the platform may be substantially parallel to the water surface. When the power generating apparatus is in the first position and the turbine arrangement is generating power, the platform may be not parallel to the water surface, for example a portion of the platform may be submerged below the water surface. When the power generating apparatus is in the first position and the turbine arrangement is generating power, the bow or stern section of the platform may be partially submerged below the water surface. When the power generating apparatus is in the first position and the turbine arrangement is generating power, the buoyancy vessel and the platform may be disposed at an angle of from about 0.2° to about 5° from the water surface. In use, all or most of the platform may remain above the waterline of the buoyancy vessel.

The platform may be a deck of the buoyancy vessel. The platform may be a floating pier bridge.

The platform may comprise one or more planks. The platform may be manufactured as a single section. The platform may be manufactured as multiple sections. In embodiment in which the platform comprises more than one section, the sections may be mounted on the buoyancy vessel as to provide an continuous platform. The sections may be bolted or welded together. Adjacent sections may not be coupled to each other, but coupled to the buoyancy vessel leaving substantially no gaps or parting lines between sections. The surfaces of adjacent sections of the platform may be flush or levelled.

In embodiments in which the power generating apparatus comprises a powered mechanism to move the turbine assembly between the first and second positions, the powered mechanism may be disposed below the platform. The powered mechanism may be stored below the platform by any suitable means.

For example, the platform may comprise a removable portion, such as a hatch. The platform may define one or more sealable openings. The openings may be reversibly sealed by any suitable means. For example, the platform may comprise an openable portion, such as a hatch or door. The removable portion (e.g. hatch or door) may form part of the platform. The removable portion (e.g. hatch or door) may be a section of the platform. The removable portion (e.g. hatch or door) may be flush with the rest of the platform.

Beneficially, providing a platform with an openable or removable portion may provide access to the surface or area below the platform and/or an area inside the buoyancy vessel, while maintaining a continuous (uninterrupted) surface to walk. In embodiments in which the platform comprises a removable portion, the platform may enable embodiments in which components of the power generating apparatus are stored below the platform when said elements are not required.

In embodiments in which the powered mechanism of the power generating apparatus is a ram with an associated mechanical linkage, the ram may extend from the buoyancy vessel or may be coupled to the buoyancy vessel below the platform. The ram and/or the mechanical linkage may not intersect the platform. The ram or mechanical linkage may not interrupt or cross the path defined by the platform in the first position, the second position or any position therebetween. The ram and/or the mechanical linkage may be disposed outboard from the platform (e.g. in the first position, the second position or any position therebetween.

Providing a continuous platform is advantageous as it minimises the risk of falls by avoiding trip hazards. In addition, it results in a more aesthetically pleasing device which can blend better in the environment and have lower visual impact. The platform may be flat.

The platform may extend along at least half of the length of the buoyancy vessel. The platform may extend substantially along the entire length of the buoyancy vessel. The platform may substantially extend from the bow of the buoyancy vessel to the stern of the buoyancy vessel. The platform may be longer than the buoyancy vessel. The platform may extend from about 5/10^th to 10/10^th of the length of the buoyancy vessel. In other words, the length of the platform may be from about 50% to about 100% of the length of the buoyancy vessel. For example, the length of the platform may be from about 50% to about 99%, or from about 55% to about 99%, or from about 50% to about 90%, or from about 60% to about 100%, or from about 60% to about 90%, or from about 60% to about 80%, or from about 60% to about 70%, or from about 70% to about 100%, or from about 70% to about 90%, or from about 70% to about 80%, or from about 80% to about 100%, or from about 80% to about 90%, or from about 90% to about 100% of the length of the buoyancy vessel.

The platform may be elongate. The platform may be substantially rectangular. The platform may be substantially oval. The platform may define any shape or form. The platform may comprise straight edges. The platform may comprise curved edges. The platform may comprise wavy edges. Independently of the shape of the platform, the platform may extend substantially along the entire length of the buoyancy vessel. Providing a platform that extends substantially along the whole length of the buoyancy vessel is advantageous because it enables a passenger or user to safely access the entire length of the platform. This may be desirable, for example for servicing different parts of the power generation apparatus, for raising or lowering the anchor or anchors, or for accessing one or more fittings or cleats to tie ropes or chains, for example to assist embarking and disembarking the power generation apparatus from another vessel, or to tie the power generation apparatus to a tow vessel.

The platform may cover substantially the entire upper surface of the buoyancy vessel. The platform may be substantially as wide as the beam of the buoyancy vessel. In other words, the width of the platform may be substantially the same as the beam of the buoyancy vessel. The platform may be wider than the beam of the buoyancy vessel. The width of the platform may be from about 70% to about 120% of the beam of the buoyancy vessel. The width of the platform may be from about 70% to about 90%, or from about 70% to about 80%, or from about 80% to about 90%, or from about 75% to about 85%, or from about 80% to about 100%, or from about 90% to about 100%, or from about 90% to about 120%, or from about 100% to about 120%, or from about 100% to about 110%, or from about 110% to about 120% of the beam of the buoyancy vessel.

Providing a wide platform is beneficial as more passengers can board the power generating apparatus. Furthermore, providing a wide platform may increase the safety of the power generating apparatus since the distance between the platform and a pontoon or the deck of another vessel can be decreased, therefore facilitating boarding the power generating apparatus and possibly obviating the need for stairs to access the platform from another vessel or pontoon. Moreover, providing a wide platform enables the powered mechanism for moving the turbine assembly between the first and second positions to be located or hidden below the platform. For example, in embodiments having a ram and associated linkage, the ram may be located or coupled to the buoyancy vessel below the platform.

In embodiments in which the platform is elongate (i.e. longer than it is wide), the platform may have a longitudinal axis that is substantially parallel to the longitudinal axis of the buoyancy vessel. In embodiments in which the platform is elongate, the platform may comprise two long sides and two short sides. The edges of the platform that are disposed on the long sides may be the long edges. The long edges may be substantially parallel to the longitudinal axis of the buoyancy vessel. The edges of the platform that are disposed on the short sides may be the short edges.

The platform may comprise any suitable means for accessing the platform. For example, the platform may comprise stairs, a ramp, a gangway, a ladder or the like for accessing the platform from another vessel, pontoon or pier.

The platform may comprise a plate extending downwards from an edge of the platform. In some embodiments, the platform may comprise two plates extending downwards from the long edges of the platform. In some embodiments, the platform may comprise two plates extending downwards from the short edges of the platform. In some embodiments, the platform may comprise two plates extending downwards from the long edges of the platform and two plates extending downwards from the short edges of the platform. The plate or plates may extend from an edge of the platform towards the water surface. When the power generating apparatus is floating on a body of water , the plate or plates may remain above the water surface. The plate may be a rigid skirt, rigid shroud or shield.

The plate may extend generally downwards and to a side of the platform. The plate may be disposed at an angle from about 20° to about 90° from a plane containing the platform. The plate may be disposed at an angle from about 20° to about 50°, or from about 30° to about 50°, or from about 35° to about 45°, or from about 40° to about 50°, or from about 45° to about 55°, or from about 30° to about 60°, or from about 40° to about 70°, or from about 70° to about 90° from a plane containing the platform. In preferred embodiments, the plate may extend downwards (i.e. towards the water surface) and may be disposed at an angle of about 45° from a plane containing the platform.

The plate may be integral with the platform. Alternatively, the plate may be attached to the platform by any suitable means, such as welding or bolting. The plate may comprise a single member. Alternatively, the plate may comprise more than one member. The plate may be elongate. The plate may be rectangular.

The plate may be continuous. The plate may be discontinuous. The plate may define one or more apertures or holes. In some embodiments, the plate may multiple holes. The plate may define multiple holes scattered along the width of the plate. The plate may define multiple holes scattered along the length of the plate. The plate may define multiple holes scattered along the width and length of the plate. The holes may define any suitable pattern. For example, the holes may define a grid, or a random pattern, or geometric shapes or the like.

The deck may comprise a buoyancy aid. In some embodiments, the deck may comprise multiple buoyancy aids. The buoyancy aid or aids may be configured to be disposed substantially above the waterline. For example, the deck may comprise solid foam, an inflatable element or the like. The buoyancy aid may be located below the platform, In preferred embodiments, the buoyancy aid may be located below the plate or plates.

Providing a platform with a plate or plates extending from an edge of the platform towards the water is advantageous because it reduces the loading from waves or water currents (e.g. river currents) and side winds. This is particularly important on power generating apparatuses having wide platforms since platforms that are substantially as wide as or wider than the beam of the buoyancy vessel experience increased wave loading from waves hitting the bottom surface of the platform. In addition, the plate or plates can host and conceal one or more buoyancy aids of the power generating apparatus. This may increase the buoyancy of the apparatus above the waterline, and therefore improve its roll stability. The plate or plates hold in place and conceal the buoyancy aid or aids, thus maintaining the aesthetic appeal of the power generating apparatus while improving its roll stability. This is particularly advantageous in embodiments in which the buoyancy aid comprises or consists of solid foam, as the manufacturing cost of the buoyancy aid can be kept to a minimum while maintaining its functionality and aesthetic appeal.

Plates angled about 45° with respect to the platform are optimal for minimising the loading on the buoyancy vessel. The presence of the plate or plates provides an even face along the length of the platform and may reduce the wave loading by reducing the impact experienced by the buoyancy vessel from crashing waves.. Providing plates defining apertures or holes allows water to flow through said apertures, thus reducing the load from water flow impacting on the side plates.

In embodiments in which the platform comprises one or more plates, the platform and plates may conform to the perimeter of the buoyancy vessel. The platform and the plate or plates may “hug” or surround the perimeter of the buoyancy vessel. This is advantageous as it provides all the safety benefits of having a deck of platform for the power generating apparatus, while maintaining a low profile and enabling the buoyancy vessel to be manufactured in any suitable shape. In preferred embodiments, the buoyancy vessel may be substantially cylindrical. This may minimise the manufacturing costs while providing maximal buoyancy. Providing a platform (and side plate or plates in some embodiments) disposed at a short distance above the upper surface of the buoyancy vessel (hugging the buoyancy vessel) maintains a low profile.

For the avoidance of doubt, within the context of this application, the dimensions of the platform refer to the dimensions of the surface or deck disposed over the buoyancy vessel (without including the plate or plates).

The platform and/or side plate (where present) may comprise any suitable material, such as wood, stainless steel, plastic, concrete, polyurethane foam, polystyrene foam. The platform may comprise an anti-slip coating. For example, the platform comprise a coating comprising one or more of: fiberglass cloth, a polyester, epoxy resin, silica spheres, rubber, beads, nut shells, fillers, sand, an anti-skid additive and the like. The platform may comprise a non-skid coating. The platform may comprise a textured surface.

The platform and/or side plate or plates (where present) may comprise one or more fittings for securing a rope or chain to the buoyancy vessel. The fitting or fittings may be located on the upper surface of the platform, or on the side plates. The platform and/or side plate or plates may comprise one or more cleats or mooring posts. For example, the platform and/or side plate or plates may comprise one or more fittings (e.g. cleats or mooring posts) at the stern and/or at the bow of the buoyancy vessel. The platform and/or side plate or plates (where present) may comprise one or more fittings, mooring posts or cleats along the length of the buoyancy vessel, for example near a ramp or stairs. Without wishing to be bound by theory, the decreased visual impact of power generation apparatus according to the invention is advantageous as it can ease the consenting process for the deployment of floating tidal or river power generation technology, thus increasing the available sources of renewable energy generation and helping to achieve the targets for carbon emission reduction around the globe. Furthermore, the power generation apparatus according to the invention looks more streamlined than prior art industrial-looking apparatuses, thus increasing the public acceptance of this technology.

Furthermore, the power generating apparatus according to the invention has a flatter profile thanks to the increased length of the platform along the length of the buoyancy vessel. The increased width to cover most or all of the beam of the buoyancy vessel, the extended length along most or all of the length of the buoyancy vessel and the side plates (where present), all confer the power generating apparatus with an even profile. This even profile minimises the wind loading along the length and width of the hull, thus prevents or at least minimises yawing movement of the power generating apparatus as a result of wind loading. In addition, the platform enables the equipment of the power generating apparatus (e.g. powered mechanism, cables, and the like) to be stowed beneath the platform. This provides a “cleaner” surface with minimal drag profile and increased safety as there are no or minimal trip hazards.

The support structure of the turbine assembly may be coupled to the nacelle at its outboard end and coupled to the buoyancy vessel at its inboard end. The turbine assembly may be coupled or connected to the buoyancy vessel outboard of the platform. The turbine assembly may be coupled or connected to the buoyancy vessel below the platform.

The support structure may be coupled to the buoyancy vessel at at least two vertically spaced locations. The support structure may be movably coupled to the buoyancy vessel at the inboard end of the support structure at at least two vertically spaced locations. The support structure may be pivotally coupled to the buoyancy vessel. The support structure may be movably and/or pivotally coupled to the buoyancy vessel at one or more upper connection point or points disposed closer to the waterline (when the power generation apparatus is floating on a body of water) than the one or more lower connection points of the support structure to the buoyancy vessel. The support structure may be pivotally coupled to the buoyancy vessel at one or more locations that are configured to remain below the waterline when the apparatus is floating on a body of water. The support structure may be movably and/or pivotally coupled to the buoyancy vessel at one or more locations (upper connection point or points) that are configured to remain above the waterline when the apparatus is floating on a body of water. Connecting the support structure to the buoyancy vessel at vertically spaced locations maximises the mechanical advantage for moving the turbine assembly between the first and second positions.

The support structure of the turbine assembly may be pivotally connected to the buoyancy vessel at one or more pivot points. The support structure may be pivotally connected to the buoyancy vessel by means of a ram with a corresponding mechanical linkage arrangement or arrangements. The mechanical linkage may be coupled to the buoyancy vessel at one end and to the support structure at the other end. The mechanical linkage may also be associated with a ram.

In some embodiments, the support structure may be indirectly coupled to the buoyancy vessel at an upper connection point by means of a mechanical linkage and it may be directly coupled to the buoyancy vessel at a lower connection point that is vertically separated from the upper connection point. The upper connection point may be above (at a greater height on the buoyancy vessel) the lower connection point, when the apparatus is viewed in its normal configuration floating on a body of water. The lower connection point may be a pivot point. The support structure may be directly connected to the buoyancy vessel at the lower connection point by any suitable means, for example a hinge arrangement.

In embodiments in which the top portion is connected to the buoyancy vessel by means of a ram and associated linkage arrangement and arrangements, the top portion of the support structure may be pivotally connected to one end of a linkage arrangement and the other end of the linkage arrangement may be connected to the buoyancy vessel. The linkage arrangement may also be connected to the ram. The ram may be connected to the buoyancy vessel at two points. One of the connection points of the ram to the buoyancy vessel may be the connection point of the linkage arrangement to the buoyancy vessel. The other connection point of the ram to the buoyancy vessel may be disposed below the connection point of the linkage arrangement to the buoyancy vessel. The connection point of the linkage arrangement to the buoyancy vessel may be above the waterline.

The upper connection point or points of the support structure to the buoyancy vessel may be vertically and horizontally offset from the lower connection point or points of the support structure to the buoyancy vessel.

The upper connection point or points of the support structure to the buoyancy vessel may be configured to be located above the waterline when the power generating apparatus is floating on a body of water. The upper connection point or points of the support structure to the buoyancy vessel may be configured to be located just above the waterline when the power generating apparatus is floating on a body of water. The upper connection point or points of the support structure to the buoyancy vessel may be located above a horizontal cross-sectional plane containing the longitudinal axis of the buoyancy vessel. That is, the upper connection point or points of the support structure to the buoyancy vessel may be located on the upper half of the buoyancy vessel. The upper connection point or points of the support structure to the buoyancy vessel may be configured to be located at a distance above a longitudinal axis of the buoyancy vessel of from about 5% to about 50% of the total height of the buoyancy vessel. For example, the upper connection point or points of the support structure to the buoyancy vessel may be configured to be located at a distance above a longitudinal axis of the buoyancy vessel of from about 5% to about 45%, or about 5 to about 40%, or about 5% to about 30%, or about 5% to about 20%, or about 5% to about 10%, or about 30% to about 50%, or about 30% to about 40%, or about 10% to about 40%, or about 10% to about 30%, or about 10% to about 20%, or about 10% to about 45% of the total height of the buoyancy vessel. The upper connection point or points of the support structure to the buoyancy vessel may be associated with a ram and associated linkage mechanism.

Providing connection points of the turbine assembly to the buoyancy vessel that are vertically spaced but at a low height of the buoyancy vessel enables greater clearance at the top of the buoyancy vessel for providing a wide platform without the turbine assemblies, powered mechanism or any associated connection components interfering with the platform. Specifically, locating the upper connection point or points of the turbine assembly to the buoyancy vessel close to the waterline leaves a great area on the top portion of the buoyancy vessel on which a platform can be placed. This in turn allows wide platforms to be fitted while the turbine arrangement and any powered mechanism (e.g. hydraulic ram and associated mechanical linkage) is disposed outboard of the platform.

The lower connection point or points of the support structure to the buoyancy vessel may be configured to be disposed above the waterline or below the waterline of the buoyancy vessel and vertically distanced from the upper connection point or points of the support structure to the buoyancy vessel.

The lower connection point or points of the support structure to the buoyancy vessel may be located at a distance above a baseline of the buoyancy vessel of from about 5% to about 60% of the total height of the buoyancy vessel. For example, the lower connection point or points of the support structure to the buoyancy vessel may be located at a distance above a baseline of the buoyancy vessel of from about 5% to about 55%, or from about 5% to about 50%, or from about 5% to about 40%, or from about 5% to about 30%, or from about 5% to about 20%, or from about 5% to about 10%, or from about 10% to about 50%, or from about 10% to about 40%, or from about 10% to about 30%, or from about 10% to about 20%, or from about 20% to about 60%, or from about 20% to about 40%, or from about 20% to about 30%, or from about 30% to about 60%, or from about 30% to about 50%, or from about 30% to about 40%, of the total height of the buoyancy vessel.

The lower connection point or points of the support structure to the buoyancy vessel may be disposed at or towards the baseline of the buoyancy vessel. The lower connection point or points of the support structure to the buoyancy vessel may be located below a horizontal cross-sectional plane containing the longitudinal axis of the buoyancy vessel. That is, the lower connection point or points of the support structure to the buoyancy vessel may be located on the lower half of the buoyancy vessel. The lower connection point or points of the support structure to the buoyancy vessel may be associated with hinge arrangement.

The lower connection point or points of the support structure to the buoyancy vessel may be disposed between the baseline of the buoyancy vessel and the upper connection point or points of the support structure to the buoyancy vessel. The lower connection point or points of the support structure to the buoyancy vessel may be vertically separated from the upper connection point or points of the support structure to the buoyancy vessel by a distance of from about 50% to about 100% of the total height of the buoyancy vessel. The lower connection point or points of the support structure to the buoyancy vessel may be vertically separated from the upper connection point or points of the support structure to the buoyancy vessel by a distance of from about 50% to about 75%, or from about 50% to about 60%, or from about 60% to about 80%, or from about 70% to about 90%, or from about 75% to about 90%, or from about 80% to about 100%, or from about 90% to about 100% of the total height of the buoyancy vessel.

The connection lower point or points of the support structure to the buoyancy vessel may be vertically separated from the upper connection point or points of the support structure to the buoyancy vessel by a distance of from about 1/6^th to about 1/13^th of the average length of the support structure from the inboard end to the outboard end. The lower connection point or points of the support structure to the buoyancy vessel may be vertically separated from the upper connection point or points of the support structure to the buoyancy vessel by a distance of from about 1/6^th to about 1/10^th, or from about 1 /7^th to about 1/9^th, or from about 1 /6^th to about 1/8^th, or from about 1 /9^th to about 1/11^th, or from about 1 /8^th to about 1/10^th, or from about 1/10^th to about 1/13^th, or from about 1/11^th to about 1/13^th, or from about 1 /9^th to about 1/10^th, or from about 1/12^th to about 1/13^th of the average length of the support structure from the inboard end to the outboard end.

The upper connection point or points of the support structure to the buoyancy vessel may define a pull point or pull points of the turbine assembly for moving the turbine assembly between the first position and the second position. The lower connection point or points of the support structure to the buoyancy vessel may define a pivot point or pivot points of the turbine assembly with respect to the buoyancy vessel.

Providing a low pivot point with respect to the pull point of the turbine assembly increases the mechanical advantage experienced at the pull point of the turbine assembly, thus minimising the force required to move the turbine assembly between the first position and second positions. This in turn enables the use of smaller engines. This also increases the flexibility for scalability of the apparatus. For example, it enables the use of bigger rotor blades than would otherwise have been possible to employ in apparatuses with turbine assemblies configured to move between different positions. Furthermore, lowering the hinge point of the turbine assembly may also have a beneficial effect on the roll stability of the power generating apparatus.

The lower connection point or points of the support structure to the buoyancy vessel may be located at a distance from the baseline of the buoyancy vessel from about 1/18^th to about 1 /4^th of the total perimeter of the buoyancy vessel. For example, the lower connection point or points of the support structure to the buoyancy vessel may be located at a distance from the baseline of the buoyancy vessel of about 1 /18^th, or about 1 /17^th, or about 1 /16^th, or about 1 /15^th, or about 1 /14^th , or about 1 /13^th, or about 1 /12^th, or about 1/11^th, or about 1/10^th, or 1 /9^th, or about 1 /8^th or about 1 /7^th, or about 1 /6^th, or about 1 /5^th, or about 1 /4^th of the total perimeter of the buoyancy vessel.

In embodiments in which the power generating apparatus comprises two turbine assemblies symmetrically disposed about the buoyancy vessel, the lower connection point or points of the first support structure may be separated from the corresponding lower connection point or points of the second support structure by a distance covering from about 1/7^th to about 1/2 of the perimeter of the buoyancy vessel. The lower connection point or points of the support structure may be separated by a distance covering from about 1/7^th to about 1/5^th, or from about 1/6^th to about 1/4^th, or from about 1/5^th to about 1 /3^rd, or from about 1 /3^rd to about %, or from about 1 /7^th to about 1 /3^rd, or from about 1 /5^th to about %, or from about 1 /6^th to about 1 /3^rd of the perimeter of the buoyancy vessel. For example, symmetrically arranged lower connection point or points of two support structures to the buoyancy vessel may be separated by a distance covering about 1 /7^th, or about 1 /6^th, or about 1 /5^th, or about 1 /4^th, or about 1 /3^rd of the total perimeter of the buoyancy vessel.

In some embodiments the support structure may be movably or pivotally connected to the buoyancy vessel (whether directly or indirectly via a mechanical linkage) at a single upper connection point. The support structure may be pivotally connected to an outboard end of a mechanical linkage and the mechanical linkage may be pivotally connected at its inboard end to the buoyancy vessel. The mechanical linkage may define two or more pivot points. The connection point to the buoyancy vessel of the mechanical linkage associated with the support structure may be a pull point. The pull point may be the upper connection point of the support structure to the buoyancy vessel. Translational and/or rotational motion of the support structure with respect to the buoyancy vessel may occur as a result of pulling action by a powered mechanism (e.g. hydraulic ram and/orwinch). In those embodiments, the support structure may be connected to the buoyancy vessel (whether directly or indirectly) at two or more horizontally spaced lower connection points. In those embodiments, the upper connection point of the support structure to the buoyancy vessel may be vertically and horizontally offset from the lower connection points of the support structure to the buoyancy vessel.

In some embodiments the support structure may be movably or pivotally connected to the buoyancy vessel (whether directly or indirectly via a mechanical linkage) at a single lower connection point. The support structure may be pivotally connected to an outboard end of a mechanical linkage and the mechanical linkage may be pivotally connected at its inboard end to the buoyancy vessel. The mechanical linkage may define two or more pivot points. The connection point to the buoyancy vessel of the mechanical linkage associated with the support structure may be a push point. The push point may be the lower connection point of the support structure to the buoyancy vessel. Translational and/o rotational motion of the support structure with respect to the buoyancy vessel may occur as a result of pushing action by a powered mechanism (e.g. hydraulic ram and/orwinch). In those embodiments, the support structure may be connected to the buoyancy vessel (whether directly or indirectly) at two or more horizontally spaced upper connection points. In those embodiments, the lower connection point of the support structure to the buoyancy vessel may be vertically and horizontally offset from the upper connection points of the support structure to the buoyancy vessel.

Without wishing to be bound by theory, providing multiple connection points of the support structure to the buoyancy vessel which are vertically and/or horizontally offset from each other may provide a better distribution of the load on the buoyancy vessel and a better grip. Horizontal spacing the connection points of the support structure to the buoyancy vessel provides mechanical advantage for resisting the thrust force. Vertically spacing the connection points of the support structure to the buoyancy vessel provides mechanical advantage for moving the turbine Figure 1 shows a perspective view of a portion of a power generating apparatus according to the invention viewed from the bottom.

The power generating apparatus may be manufactured from any suitable material, such as steel or low density materials. The support structure of the turbine assembly may be manufactured of any suitable material, such as steel, reinforced concrete, low density materials such as carbon fibre and the like.

The platform may comprise a safety barrier. The safety barrier may be disposed around all or part of the perimeter of the platform. The safety barrier may comprise one or more gates to allow access to the platform from a different vessel or pontoon. The safety barrier may be disposed at or near the edge of the platform. The one or more gates may be lockable to prevent unwanted opening while there are passengers or users on board. The safety barrier may take any suitable shape or form. The safety barrier may comprise at least platform engaging member and at least one protective member disposed substantially The safety barrier may be selected from a panel, a wall, a railing, a banister, a guard, or the like. The safety barrier may be fixed to the platform. The safety barrier may be removable from the platform. The safety barrier may be stowable, for example stowable under the platform.

The safety barrier may be movable from a first position to a second position. The first position may be a deployed position. In the deployed position the safety barrier may substantially extend above the platform, for example to prevent accidental falls from the platform to the water. The second position may be a stowed position. In the second position the safety barrier may be stored under and/or recessed into the platform or it may extend substantially under the platform. In some embodiments, the platform comprises more than one section. In those embodiments all sections may be movable between the stowed and deployed positions simultaneously. Alternatively, the sections may be movable between the stowed and deployed positions independently. That is, one or more sections may be in the deployed position while one or more sections of the safety barrier remain in the stowed position.

The height of the safety barrier above the platform may be variable. For the avoidance of doubt, the height of the safety barrier may be measured as the vertical distance from the upper surface of the platform (viewed when installed on the power generating apparatus on its normal use, e.g. floating on a body of water) to the highest point of the safety barrier. In the first position, the safety barrier may extend higher above the platform than in the second position. The height of the safety barrier may variable by any suitable means. For example, the safety barrier may be telescopic, or slidable, or foldable.

The safety barrier may be moved from the first position to the second position by pushing the safety barrier downwards so that most of the safety barrier is concealed. For example, the height of the safety barrier may be decreased in the second position by storing portions of the safety barrier within itself (e.g. safety barrier with telescopic legs). The safety barrier may decrease in height in the second position, for example by folding the safety barrier over itself. Foldable safety barriers may comprise one or more hinge points about which the safety barrier can be folded. The safety barrier may decrease in height in the second position by sliding along guides. The guides may be located above the platform. At least part of the guides may be disposed below the platform. In embodiments in which at least part of the guides are disposed below the platform, the safety barrier may be stowable or partially stowable under the platform.

The safety barrier may be pivotably movable between the first and the second positions. For example, the safety barrier may be vertically rotatable about a pivot axis. The safety barrier may be pivotally movable between the first and second positions by any suitable means, such as a hinge arrangement comprising a hinge clevis and a hinge padeye. The pivot axis may be disposed at or near the surface of the platform. In the first position, the safety barrier may extend above the surface of the platform. In the second position, the safety barrier may extend on the surface of the platform, slightly above the surface of the platform or below the surface of the platform.

In some embodiments, the safety barrier is rotatable about 90 degrees about a pivot axis to move between the first position and the second position. In the first position, the safety barrier may extend vertically upwards from the upper surface of the platform. In the first position the safety barrier may be contained in a plane that is substantially perpendicular to a plane containing the platform. In the second position, the safety barrier may extend substantially parallel to the surface of the platform. In the second position the safety barrier may be contained in a plane that is substantially parallel to a plane containing the platform. In the second position, the safety barrier may rest on the surface of the platform.

In other embodiments, the safety barrier may be rotatable about a pivot axis from about 90 degrees to about 180 degrees to move the safety barrier between the first position and the second position. In the second position the safety barrier may be contained in a plane that is substantially perpendicular to a plane containing the platform. In the second position, the safety barrier may rest on the surface of the platform. In order to stow the safety barrier (i.e. to move the safety barrier from the first position to the second position), a user rotates the safety barrier about a pivot axis such that the uppermost portion of the safety barrier in the first position becomes the lowermost portion of the safety barrier in the second position (if the safety barrier is rotated from about 95 degrees to about 180 degrees between the first and second positions). In those embodiments the safety barrier may be stowed below the platform. For example, the safety barrier may be stowed in a space under the platform that may be coverable with a lid or a removable section of the platform. The safety barrier may be rotatable over an edge of the platform such that the safety barrier is stowed below the platform.

The safety barrier may comprise a latch, or a component part of a latch, by which the safety barrier may be latched in the first and/or the second position.

Providing a stowable safety barrier enables providing the required safety features when there are users on board of the power generating apparatus, while minimising the visual impact of the power generating apparatus when there is nobody on board the apparatus.

In addition, stowing the safety barrier when there are no users on board the power generating apparatus may minimise the impact of over washing waves and wind on the roll stability of the power generating apparatus, and it may also protect the safety barrier from damage from the wave loading.

The power generating apparatus is typically anchored in its final position. Any suitable anchoring arrangement may be employed, for example conventional cables between an anchoring structure (typically a concrete block) on the bed of a body of water, and suitable fixings at or near one or both ends of the buoyancy vessel. Also suitable is a rotatable anchor such as described in EP2300309 (Scotrenewables Tidal Power Limited).

The power generating apparatus may typically comprise various additional apparatus. The skilled addressee will also appreciate that the location or distribution of such additional apparatus may be varied without departing from the scope of the invention.

For example, the power generating apparatus may comprise apparatus as required to harvest energy, to convert this into electrical energy and/or to transform, store and/or transmit such electrical to an electrical distribution system.

The power generating apparatus may also comprise apparatus required to vary buoyancy, by selectively flooding and venting ballast tanks.

A turbine assembly, or its nacelle and/or support structure, may comprise one or more ballast tanks. The buoyancy vessel may itself be provided with a ballasting system (comprising ballast tanks, desirably front and rear), by which the trim of the power generating apparatus may be adjusted, in some embodiments automatically. The ballasting system may be used to compensate for the varying forces applied by a river or tidal flow impinging on the turbine rotor or other parts of the turbine assembly.

The power generating apparatus may comprise a conduit for delivering air to a ballast tank (to increase buoyancy). In order to flood a ballast tank, the power generating apparatus may comprise an inlet or inlet conduit between the surrounding water and the ballast tank. In order to flood/vent a ballast tank, the apparatus may comprise a vent conduit or vent manifold to selectively release air/water from the ballast tank. An outlet of the vent conduit/manifold may be positioned above the water surface.

The apparatus means for delivering air to and/or pumping water from, a ballast tank is most typically situated on the buoyancy vessel. Such apparatus may comprise for example a source of compressed air (e.g. a cylinder or a compressor), or connections for connecting thereto. Selectively operable valves for operating a variable buoyancy system may be located on the buoyancy vessel and/or in the turbine assembly. Such apparatus may comprise one or more pumps.

The nacelle may comprise an electrical generator. Advantageously, this may be an in-line generator, optionally a direct-drive generator (i.e. lacking a gearbox). The generator may be any suitable type of generator; most typically comprising an electrical rotor and stator, the electrical rotor typically being driven by the turbine rotor. Electricity may alternatively also be generated indirectly from fluid circulated under the action of the turbine rotor.

It may be desirable for the turbine rotor to comprise variable-pitch rotor blades. For example, feathering the rotor blades during storm conditions may reduce loads applied through the turbine assembly and prevent damage.

Accordingly, the nacelle (and/or the turbine rotor in particular) may comprise a pitch adjustment arrangement. Various means are known in the art for adjusting turbine blade pitch, both in relation to wind and marine/water turbines. For example, the turbine rotor may comprise a rotor blade (or blades) rotatably mounted to a hub around an axis along the rotor blade, the pitch being adjustable by way of a worm gear or a pinion coupled to a planary gear or slew ring.

The pitch adjustment arrangement may be electromechanically actuated. The pitch adjustment arrangement may be housed in the rotor. Examples of turbine blade pitch adjustment are described in GB996182, CN202266366 or GB2348250 or WG2009004420, to which the skilled reader is directed.

The turbine rotor may be configured to reverse the pitch of the rotor blades. The rotor blades may be rotatable through 180 degrees or 360 degrees. The facility to reverse the pitch of rotor blades may enable energy to be harvested regardless of the direction of the water flow, without changing the position of the power generating apparatus as a whole. The pitch may be revered so as to harvest energy when the direction of a tidal stream changes. It may also be desirable to adjust the pitch in response to variations in water flow.

It is to be understood that reference herein to the water surface, and references thereto components being submerged or above the water surface, refer to the power generating apparatus when floating on a body of water. Moreover, the precise position of the water line (i.e. water surface in relation to the power generating apparatus) may depend on water salinity, temperature, loading on the vessel and the like. The position of the water line of a buoyant apparatus may be readily determined by those skilled in the art, by observation or calculation.

Preferred and optional features of each aspect of the invention correspond to preferred and optional features of each other aspect of the invention.

Example embodiments of the invention will now be described with reference to the following drawings in which:

Figure 1 shows a perspective view of a portion of a power generating apparatus according to an embodiment of the invention viewed from the bottom.

Figures 2A and 2B show a perspective view of the apparatus of Figure 1 viewed from the top when floating in a body of water with the turbine assembly in the first position and in the second position respectively.

Figures3A and 3B show perspective enlarged views of the platform of the apparatus of Figure 1 viewed from different angles.

Figure 4 shows a schematic representation of a front view of a buoyancy vessel with a platform according to an embodiment of the invention.

Figures 5A and 5B, are line drawings of a bottom view and a perspective view of a power generating apparatus according to an embodiment of the invention .

Figure 6 shows a perspective view of the apparatus of Figure 1 viewed from the bottom when floating in a body of water with the turbine assembly in the first position.

Figure 7 shows a rendered top view of the apparatus of Figures 5A and 5B in the second position.

Figure 8 shows a side view of the apparatus of Figure 8 with the turbine assembly in the first position.

Figure 9 shows a side view of a prior art power generating apparatus in a similar position to that shown in Figure 8.

Figure 10 shows a perspective view of the apparatus of Figure 8 in the second position. Figure 1 1 shows a perspective view of a portion of the apparatus of Figure 9 with the turbine assembly in the second position.

Figure 12 shows a front view of the apparatus of Figures 9 and 11 with the turbine assembly in the first position.

Figure 13 shows a front view of the apparatus of Figures 8 and 10.

Detailed Description of Example Embodiments

Figure 1 shows a perspective view of a portion of a power generating apparatus 100 according to the invention viewed from the bottom. The power generating apparatus 100 comprises an elongated buoyancy vessel 1 10 having two identical turbine assemblies 120, 120’ symmetrically disposed about the longitudinal axis of the buoyancy vessel 110. In Figure 1 the turbine assemblies 120, 120’ are shown in the first position in which the nacelle 124, 124’ are configured to be fully submerged below the waterline (when the power generating apparatus is floating on a body of water). For the avoidance of doubt, features described in respect of any of the components of turbine assembly 120 also apply to the turbine assembly 120’.

Each turbine assembly 120, 120’ has a support structure 122, 122’ coupled to a nacelle 124, 124’ at the outboard end of the support structure 122, 122’. The nacelle 124, 124’ comprises a rotor 126, which in this embodiment has two rotor blades (but it may have any number of blades in other embodiments). In this embodiment, the support structure 122, 122’ is an open support structure, but in other embodiments the support structure may be a closed support structure.

The platform 190 is disposed on the upper portion of the buoyancy vessel 1 10 and it may be coupled thereto by any suitable means (e.g. bolting or welding). The platform 190 comprises an upper surface (not shown) which acts as a deck of the buoyancy vessel 110 and two side plates 194 (only one shown) that are disposed at an angle of from about 20° to about 90° from the plane of the platform. The platform also comprises a safety railing 198.

In this embodiment, each turbine assembly 120, 120’ is connected to the buoyancy vessel at three connection points 152a, 152b and 154. Connection point 154 is the upper connection point and connection points 152a and 152b are the lower connection points. Upper connection point 154 is vertically spaced from lower connection points 152a and 152b.

The support structure 122 is directly connected to the buoyancy vessel 110 at the lower connection points 152a, 152b by means of a hinge arrangement. The connection is movable and the turbine assembly can pivot about lower connection points 152a, 152b. The support structure 122 is indirectly connected to the buoyancy vessel 110 at the upper connection point 154 by means of a mechanical linkage 140. The mechanical linkage 140 is coupled to the buoyancy vessel 110 at its inboard end (at upper connection point 154) and to the support structure 122 at its outboard end 156. Connection 156 defines a pivot point about which the support structure 122 can rotate with respect to the linkage arrangement 140. Connection 154 defines a pivot point about which the linkage arrangement 140 can rotate with respect to the buoyancy vessel 110.

The mechanical linkage 140 is associated with or coupled to a ram 130. The ram 130 is connected to the buoyancy vessel 110 at two points. The higher of the two connection points of the ram to the buoyancy vessel 110 is the connection point 154 of the linkage arrangement 140 to the buoyancy vessel 110. The other (lower) connection point of the ram 130 to the buoyancy vessel 110 is disposed below the connection point 154 of the linkage arrangement 140 to the buoyancy vessel 110. The distance between the outboard end 156 and the inboard end 154 of the mechanical linkage arrangement 140 is variable by operation of the hydraulic ram 130.

Upper connection point 154 is configured to be disposed closer to the waterline (when the power generation apparatus 100 is floating on a body of water) than the lower connection points 152a, 152b of the support structure 122 to the buoyancy vessel 110. The upper connection point 154 of each of the support structures 120, 120’ to the buoyancy vessel 110 is configured to be located just above the waterline (when the power generating apparatus is floating on a body of water). The upper connection point 154 is located above a horizontal cross-sectional plane containing the longitudinal axis of the buoyancy vessel 110. That is, the upper connection point 154 is located on the upper half of the buoyancy vessel 110. The upper connection point 154 is located above the longitudinal axis of the buoyancy vessel 110 at a distance of from about 5% to about 50% of the total height of the buoyancy vessel 110. Locating upper connection point 154 as close to the highest point of the buoyancy vessel 110 as possible (i.e. as close to 50% above the longitudinal axis of the buoyancy vessel as possible) is advantageous as it maximises the mechanical advantage for moving the turbine assemblies 120, 120’ between the first and second positions.

On the other hand, providing connection points 154, 152a, 152b of the turbine assembly 120 to the buoyancy vessel 100 that are vertically spaced but at a low height of the buoyancy vessel 110 (e.g. as close as possible to 5% above the longitudinal axis of the buoyancy vessel) enables a greater clearance at the top of the buoyancy vessel 110 for providing a wide platform 190 without the hydraulic ram 130, linkage arrangement 140 or support structure 122 interfering with the platform 190.

In this embodiment, the lower connection points 152a, 152b ofthe support structure 122 to the buoyancy vessel 110 are disposed below the waterline of the buoyancy vessel 110 when the apparatus is floating on a body of water. In other words, the lower connection points 152a, 152b are disposed at or towards the baseline 112 of the buoyancy vessel (and are therefore located below a horizontal cross-sectional plane containing the longitudinal axis ofthe buoyancy vessel or on the lower half ofthe buoyancy vessel 110). However, in other embodiments, the lower connection points 152a, 152b of the support structure 122 to the buoyancy vessel 110 may be disposed at the waterline or just above the waterline (from about 5% to about 60 % of the total height of the buoyancy vessel above the baseline of the buoyancy vessel).

The lower connection points 154a, 154b of each support structure 122, 122’ to the buoyancy vessel 110 are vertically separated from the upper connection point 154 of the support structure 122 to the buoyancy vessel 110 by a distance of from about 50% to about 100% of the total height of the buoyancy vessel. For example, the vertical distance between upper connection point 154 and lower connection points 152a, 152b may be from about 50% to about 75%, or from about 50% to about 60%, or from about 60% to about 80%, or from about 70% to about 90%, or from about 75% to about 90%, or from about 80% to about 100%, or from about 90% to about 100% of the total height of the buoyancy vessel 110.

The lower connection points 154a, 154b of each support structure 122 to the buoyancy vessel 110 are vertically separated from the upper connection point 154 of the support structure 122 to the buoyancy vessel 110 by a distance of from about 1 /6^th to about 1/13^th of the average length of the support structure from the inboard end to the outboard end. For example, the vertical distance between upper connection point 154 and lower connection points 152a, 152b may be from about 1 /6^th to about 1/10^th, or from about 1/7^th to about 1/9^th, or from about 1/6^th to about 1/8^th, or from about 1/9^th to about 1/11^th, or from about 1 /8^th to about 1/10^th, or from about 1/10^th to about 1/13^th, or from about 1/1 1^th to about 1/13^th, or from about 1/9^th to about 1/10^th, or from about 1/12^th to about 1/13^th of the average length of the support structure 122 from the inboard end to the outboard end.

The upper connection point 154 of the support structure 122 to the buoyancy vessel 110 define a pull point of the turbine assembly 120 for moving the turbine assembly 120 between the first position and the second position. The lower connection points 152a, 152b of the support structure 122 to the buoyancy vessel 110 define pivot points of the turbine assembly 120 with respect to the buoyancy vessel 1 10.

Providing low pivot points 152a, 152b with respect to the pull point of the turbine assembly increases the mechanical advantage experienced at the pull point 154 of the turbine assembly 120, thus minimising the force required to move the turbine assembly 120 between the first position and second positions. This in turn enables the use of smaller engines. This also increases the flexibility for scalability of the apparatus. For example, it enables the use of bigger rotor blades than would otherwise have been possible to employ in apparatuses with turbine assemblies configured to move between different positions. Furthermore, lowering the hinge points 152a, 152b of the turbine assembly 120 may also have a beneficial effect on the roll stability of the power generating apparatus 100. The lower connection points 152a, 152b of the support structure 122 to the buoyancy vessel 110 are located at a linear distance from the baseline 112 of the buoyancy vessel from about 1/18^th to about 1 /4^th of the total perimeter of the buoyancy vessel. For example, the lower connection points 152a, 152b are located at a linear distance from the baseline 112 of the buoyancy vessel of about 1/18^th, or about 1/17^th, or about 1/16^th, or about 1/15^th, or about 1/14^th, or about 1/13^th, or about 1/12^th, or about 1/11^th, or about 1/10^th, or 1 /9^th, or about 1 /8^th or about 1 /7^th, or about 1 /6^th, or about 1 /5^th, or about 1 /4^th of the total perimeter of the buoyancy vessel 110.

The lower connection points 152a, 152b of the first support structure 122 are separated from the corresponding lower connection points 152a’, 152b’ of the second support structure 122’ by a distance covering from about 1/7^th to about 1/2 of the perimeter of the buoyancy vessel. The lower connection 152a of the first support structure 122 is separated from the lower connection point 152a’ of the second support structure 122’ by a distance covering from about 1 /7^th to about 1 /5^th, or from about 1 /6^th to about 1/4^th, or from about 1 /5^th to about 1/3^rd, or from about 1/3^rd to about %, or from about 1 /7^th to about 1/3^rd, or from about 1 /5^th to about %, or from about 1 /6^th to about 1 /3^rd of the perimeter of the buoyancy vessel. The same applies to the distance between connection points 152b and 152b’. For example, symmetrically arranged lower connection points 152a and 152a’ and connection points 152b and 152b’ of the two support structures 122 and 122’ to the buoyancy vessel 110 may be separated by a distance covering about 1 /7^th, or about 1 /6^th, or about 1 /5^th, or about 1 /4^th, or about 1 /3^rd of the total perimeter of the buoyancy vessel.

Figures 2A and 2B show a perspective view of the apparatus 100 of Figure 1 viewed from the top when floating in a body of waterwith the turbine assembly in the first position (Figure 2A) and in the second position (Figure 2B). As appreciated in these figures, the platform 190 is elongate and in this embodiment is rectangular, although it may have any other shape. The longitudinal axis of the platform 190 is parallel to the longitudinal axis of the buoyancy vessel 110 (disposed directly under the platform 190).

The platform 190 is flat and it extends substantially along the entire length of the buoyancy vessel 110. For example, the platform 190 may extend from about 5/10^th to 10/10^th of the buoyancy vessel. In other words, the length of the platform 190 may be from about 50% to about 100% of the length of the buoyancy vessel 110.

Providing a platform that extends substantially along the whole length of the buoyancy vessel is advantageous because it enables a passenger or user to safely access the entire length of the platform.

The platform 190 covers substantially the entire upper surface of the buoyancy vessel 110. The platform 190 is a wide deck for the buoyancy power generating apparatus 100. The width of the platform 190 may be from about 70% to about 120% of the beam of the buoyancy vessel. The width of the platform 190 may be from about 70% to about 90%, or from about 70% to about 80%, or from about 80% to about 90%, or from about 75% to about 85%, or from about 80% to about 100%, or from about 90% to about 100%, or from about 90% to about 120%, or from about 100% to about 120%, or from about 100% to about 110%, or from about 110% to about 120% of the beam of the buoyancy vessel 110.

As observed in these figures, the connection point 154 of the mechanical linkage 140 associated with the ram 130 and the support structure 122 of the turbine assembly 120 is connected outboard of the platform. The mechanical linkage 140 and ram 130, even in the second position shown in Figure 2B do not interfere with the platform 190 (they do not intersect the platform). Therefore, this is advantageous because it results in a continuous platform with no trip hazards, which minimises the risk of falls. In addition, it results in a more aesthetically pleasing device which can blend better in the environment and have lower visual impact.

The platform 190 has two side plates 194 (only one is visible) which extend downwards from each of the longitudinal edges of the platform 190 towards the water surface. The plates 194 in this embodiment are rectangular, but they may have any other suitable shape or form. The plates 194 in this embodiment are disposed at an angle of 45° with respect to the surface of the platform 190. However, in other embodiments, the plates may be disposed at an angle from about 20° to about 90° from the plane of the platform 190. In this embodiment the plates have sections coupled together or attached to the platform leaving virtually no gaps between sections. The plates 194 may also be continuous.

The plates 194 can be integral with the platform or fixedly coupled thereto (e.g. by welding or bolting). As better observed in Figure 2B, the plates define multiple holes 195 scattered along the width and length of the plate.

Providing a platform 190 with plates 194 extending from the longitudinal edges of the platform 195 towards the water is advantageous because it reduces the loading from waves or water currents (e.g. river currents) and side winds. This is particularly advantageous for power generating apparatus 100, which has a wide platform 190, since platforms that are substantially as wide as or wider than the beam of the buoyancy vessel experience increased wave loading from waves hitting the bottom surface of the platform. Disposing the plates 194 at an angle of about 45° with respect to the platform are optimal for minimising the loading on the buoyancy vessel. The presence of the plate or plates provides an even face along the length of the platform and may reduce the wave loading by reducing the impact experienced by the buoyancy vessel from crashing waves. Providing plates defining apertures or holes allows water to flow through said apertures, thus reducing the load from water flow impacting on the side plates. Providing plates 194 defining apertures or holes 195 allows water to flow through said apertures 195, thus reducing the load from water flow impacting on the side plates 194.

The platform 190 may comprise any suitable material, such as wood, stainless steel, plastic, concrete, polyurethane foam, polystyrene foam. The platform may comprise an anti-slip coating. For example, the platform comprise a coating comprising one or more of: fiberglass cloth, a polyester, epoxy resin, silica spheres, rubber, beads, nut shells, fillers, sand, an anti-skid additive and the like. The platform may comprise a non-skid coating. The platform may comprise a textured surface.

The side plates comprise multiple fittings 197, for tying ropes or chains, for example to assist embarking and disembarking the power generation apparatus from another, and/or for mooring to the tidal site or to a quay side. The fittings 197 may be mooring posts or mooring points for mooring to a quayside. In this embodiment the fittings are disposed on the side plates to minimise trip hazards on the walkway of the platform 190. However, the fittings 197 may be located on the upper surface of the platform 190 instead.

The platform comprises stairs 196 to enable users to gain access to the platform, for example from another vessel as shown in Figure 2B. The stairs 196 are disposed between sections of the side plate 194, but they may also be mounted on the side plate in embodiments in which the side plate is a continuous plate.

The platform 190 comprises a safety barrier 198, which in this embodiment is a railing or banister disposed at or near the edge of the platform 190. The safety barrier 198 is disposed around most of the perimeter of the platform 190, except on the stairs 196 in order to allow access to the platform 190, for example from a different vessel or pontoon. Although not shown here, the safety barrier may comprise one or more gates around the stairs 196. The gates may be reversibly lockable to allow access to the platform 190 but prevent falls from the platform 190 once the gate is closed.

The safety 198 barrier may be fixed to the platform 190, or it may be removable and/or storable under the platform 190. The safety barrier may be movable from a first position to a second position. The first position may be a deployed position. In the deployed position the safety barrier may substantially extend above the platform (as shown), for example to prevent accidental falls from the platform to the water. The second position may be a stowed position (not shown). In the second position the safety barrier may be stored under the platform 190, or recessed into the platform 190, or it may extend substantially under the platform 190.

The height of the safety barrier 198 above the platform 190 may be variable. For the avoidance of doubt, The height of the safety barrier may be measured as the vertical distance from the upper surface of the platform 190 to the highest point of the safety barrier. In the first position, the safety barrier 198 may extend higher above the platform than in the second position. The height of the safety barrier 198 may variable by any suitable means. For example, the safety barrier may be telescopic, or slidable, or foldable.

The safety barrier 198 may be moved from the first position to the second position by pushing the safety barrier downwards so that most of the safety barrier is concealed. For example, the height of the safety barrier 198 may be decreased in the second position by storing portions of the safety barrier within itself (e.g. safety barrier with telescopic legs). The safety barrier 198 may decrease in height in the second position, for example by folding the safety barrier over itself. Foldable safety barriers 198 may comprise one or more hinge points about which the safety barrier can be folded. The safety barrier 198 may decrease in height in the second position by sliding along guides. The guides may be located above the platform 190. At least part of the guides may be disposed below the platform. In embodiments in which at least part of the guides are disposed below the platform 190, the safety barrier 198 may be stowable or partially stowable under the platform 190. The safety barrier 198 may be pivotably movable between the first and the second positions. For example, the safety barrier 198 may be rotatable about a pivot point by means of a hinge arrangement comprising a hinge clevis and a hinge padeye.

The safety barrier 198 may comprise a latch, or a component part of a latch, by which the safety barrier may be latched in the first and/or the second position.

Providing a stowable safety barrier 198 enables providing the required safety features when there are users on board of the power generating apparatus, while minimising the visual impact of the power generating apparatus when there is nobody on board the apparatus.

As discussed above, the upper connection point 154 of the turbine arrangement 120, 120’ to the buoyancy vessel 110 (by means of the mechanical linkage 140) remains above the water surface but close to the water surface. When the turbine arrangement is in the first position they are fully submerged under the water, with only the first link of the linkage arrangement extending above the water surface (see Figure 2A). In the second position, at least a part of the nacelle projects above the water surface (see Figure 2B). The hydraulic ram 130 and upper connection point 154 of the turbine arrangements to the buoyancy vessel 110 remain below the platform 190.

Figures 3A and 3B show perspective enlarged views of the platform of the apparatus of Figure 1 viewed from different angles. As better seen in these figures, the platform 190 has two side plates 194 extending downwards from the long edges of the platform 190 towards the water. The side plates 194 are integral or welded to the platform 190 in this embodiment, but they may be fixedly coupled thereto by any suitable means.

Figure 4 shows a schematic representation of a front view of a buoyancy vessel with a platform according to an embodiment of the invention. Features in common with the power generating apparatus of Figure 1 are provided with like reference numerals, incremented by 100.

As shown in Figures 3A and 3B and in the schematic representation of Figure 4, the side plates 194, 294 are disposed at an angle a of about 45° from platform 190, 290. The platform 190, 290 is mounted on the buoyancy vessel 210 by any suitable means. For example, the buoyancy vessel 210 may comprise mounts configured to receive the platform. The platform 190, 290 may then be bolted to the mounts of the buoyancy vessel. As seen on Figure 3A, the plates 194 may define a recess 193 to accommodate the linkage arrangement 140 at the upper connection point 154 to the buoyancy vessel 110. Recess 193 enables rotational movement of the linkage arrangement 140 about pivot point 154 when moving between the first and second positions of the turbine arrangement.

Figure 5A shows a bottom view and Figure 5B shows a perspective view of an apparatus 200 according to an embodiment of the invention. Features in common with the power generating apparatus of Figure 1 are provided with like reference numerals, incremented by 200.

As seen in Figure 5A, power generating apparatus 300 comprises an elongated buoyancy vessel 310 having two identical turbine assemblies 320, 320’ symmetrically disposed about the longitudinal axis of the buoyancy vessel 310. In Figure 5A the turbine assemblies 320, 320’ are shown in the second position. For the avoidance of doubt, features described in respect of any of the components of turbine assembly 320 also apply to the turbine assembly 320’.

Each turbine assembly 320, 320’ has a support structure 322, 322’ coupled to a nacelle 324, 324’ at the outboard end of the support structure 322, 322’. The nacelle 324, 324’ comprises a turbine 326, which in this embodiment has two rotor blades (but it may have any number of blades in other embodiments). In this embodiment, the support structure 322, 322’ is an open support structure, but in other embodiments the support structure may be a closed support structure.

In this embodiment, each turbine assembly 320, 320’ is connected to the buoyancy vessel at three connection points 352a, 352b and 354 (shown in Figure 5B). Connection point 354 is the upper connection point and connection points 352a and 352b are the lower connection points. Upper connection point 354 is vertically and horizontally spaced from lower connection points 352a and 352b.

The support structure 322 (and 322’) is directly connected to the buoyancy vessel 310 at the lower connection points 352a, 352b (and 352a’, 352b’) by means of a hinge arrangement. The connection is movable and the turbine assembly 320 (320’) can pivot about lower connection points 352a, 352b (and 352a’, 352b’).

The support structure 322 is indirectly connected to the buoyancy vessel 310 at the upper connection point 354 by means of a mechanical linkage 340. The mechanical linkage 340 is coupled to the buoyancy vessel 310 at its inboard end (at upper connection point 354) and to the support structure 322 at its outboard end 356. Connection 356 defines a pivot point about which the support structure 322 can rotate with respect to the linkage arrangement 340. Connection 354 defines a pivot point about which the linkage arrangement 340 can rotate with respect to the buoyancy vessel 310.

The mechanical linkage 340 is associated with or coupled to a ram 330. The ram 330 is connected to the buoyancy vessel 310 at three points. The higher of the three connection points of the ram 330 to the buoyancy vessel 310 is the connection point 354 of the linkage arrangement 340 to the buoyancy vessel 310. The other (lower) connection points of the ram 330 to the buoyancy vessel 310 are disposed below the connection point 354 of the linkage arrangement 340 to the buoyancy vessel 310. The distance between the outboard end 356 and the inboard end 354 of the mechanical linkage arrangement 340 is variable by operation of the hydraulic ram 330.

As seen in Figure 5A, the lower connection point 352b from turbine assembly 320 is separated from the corresponding lower connection point 352b’ of turbine assembly 320’ by a distance covering from about 1/7^th to about 1/2 of the perimeter of the buoyancy vessel. The same applies to the distance between lower connection point 352a and 352a’. Lower connection points 352a, 352a’, 352b and 352b’ are located at a distance from the baseline 312 of the buoyancy vessel from about 1/18^th to about 1/4^th of the total perimeter of the buoyancy vessel 310. For example, the lower connection points 352a, 352a’, 352b and 352b’ of the support structures 322, 322’ to the buoyancy vessel may be located at a distance from the baseline 312 of the buoyancy vessel 310 of about 1/18^th, or about 1/17^th, or about 1/16^th, or about 1/15^th, or about 1/14^th , or about 1/13^th, or about 1/12^th, or about 1/11^th, or about 1/10^th, or 1 /9^th, or about 1/8^th or about 1/7^th, or about 1/6^th, or about 1/5^th, or about 1/4^th of the total perimeter of the buoyancy vessel 310.

Figure 5B shows a perspective view of the apparatus of Figure 5A in the first position. As better seen in Figure 5B, The platform 390 is disposed on the upper portion of the buoyancy vessel 310 and it may be coupled thereto by any suitable means (e.g. bolting or welding). The platform 390 comprises an upper surface which acts as a deck of the buoyancy vessel 310 and two side plates 394 (only one shown) that are disposed at an angle of from about 20° to about 90° from the plane of the platform. The platform also comprises a safety which is not shown in the Figure as it is in the stowed position.

As better observed in Figure 5B, the buoyancy vessel 310 is elongate and generally cylindrical and it tapers at the bow end and/or stern end. The buoyancy vessel may comprise a substantially conical end at the bow and/or stern region. Without wishing to be bound by theory, providing a buoyancy vessel with tapering or conical ends may decrease the drag of the buoyancy vessel.

The platform comprises towing points 399 at the bow end and stern end of the platform 390 to connect the power generating apparatus to another vessel for towing between locations. The side plates comprise multiple fittings 397, for tying ropes or chains, for example to assist embarking and disembarking the power generation apparatus from another.

Figure 6 shows a perspective view of the apparatus 100 of Figure 1 viewed from the bottom when floating in a body of water with the turbine assembly in the first position. In this figure it can be appreciated how the connection points of the turbine assembly to the buoyancy vessel 110 are low on the buoyancy vessel and the ram and turbine assemblies are submerged in the water in the first position. Figure 7 shows a top rendered view of the apparatus of Figures 5A and 5B in the second position. In this figure it can be better appreciated that the platform 390 extends along the entire length of the buoyancy vessel 310 and provides an uninterrupted walkway for users to reach all areas of the buoyancy vessel. The platform 390 and side plates define multiple holes or apertures in a grid pattern. The turbine assemblies 320, 320’ extend symmetrically at either side of the buoyancy vessel 310 and they are connected to the buoyancy vessel (not visible in this view) outboard of the platform 390.

Figure 8 shows a side view of the power generating apparatus 300 of Figure 7 with the turbine assembly in the first position. In this figure is possible to observe how the upper connection point 354 linkage mechanism 340 associated with the support structure 322 to the buoyancy vessel 310 is vertically and horizontally offset from the lower connection points 152a, 152b of the support structure 322 to the buoyancy vessel 310. In this embodiment, the lower connection points 352a, 352b are located in the bottom half of the buoyancy vessel 310 (below a horizontal cross-sectional plane containing the longitudinal axis of the buoyancy vessel 310), near the baseline 314 of the buoyancy vessel 310, while the upper connection point 354 is located on the upper half of the buoyancy vessel 310.

In contrast, Figure 9 shows a side view of a prior art power generating apparatus disclosed in EP3559440, with the turbine assembly also in the first position. The apparatus 400 of Figure 9 has a turbine assembly 420 having an closed support structure 422, a nacelle 424 having a turbine 426. In contrast with the embodiment of Figure 8, the support structure 422 is connected to the buoyancy vessel 410 at a higher position within the buoyancy vessel 410 (all the connection points of the support structure to the buoyancy vessel are located in the upper half of the buoyancy vessel, or above a horizontal cross-sectional plane containing the longitudinal axis of the buoyancy vessel). The location of the upper connection point 354 lower on the buoyancy vessel 310 of apparatus 300 compared to apparatus 400 enables the use of a wider platform 390 that provides an uninterrupted walkway for users. In addition, providing lower pivot points 352a, 352bwith respect to the pull point 354 ofthe turbine assembly increases the mechanical advantage experienced at the pull point of the turbine assembly, thus minimising the force required to move the turbine assembly between the first position and second positions. This in turn enables the use of smaller engines. This also increases the flexibility for scalability of the apparatus.

Figure 10 shows a perspective view of a portion of the apparatus of Figure 8 in the second position. Figure 11 shows a perspective view of a portion of the apparatus of Figure 9 with the turbine assembly in the second position. In Figure 10, upper connection point 354 of the support structure 322 to the buoyancy vessel 310 is associated with a ram 330 and therefore acts as a pull point. Lower connection points 352a, 352 b of the support structure to the buoyancy vessel 310 act as pivot points about which the support structure 322 can rotate to effect the vertical movement between the first and second positions of the turbine assemblies. In the second position shown in Figure 10, the ram 330 and associated mechanical linkage 340 do not intersect the platform 390 and the platform provides a continuous walkway for a user. Similarly, in Figure 1 1 , upper connection point 454 of the support structure 420 to the buoyancy vessel 410 that is associated with a ram 430 and therefore acts as a pull point. Connection points 452a, 452 b of the turbine assemblies 420 to the buoyancy vessel 410 act as pivot points about which the turbine assemblies can rotate to effect the vertical movement between the first and second positions.

In the view shown in Figures 10 and 11 it can be appreciated the greater vertical distance present in apparatus 300 between the “pull point” located at upper connection point 354 of the turbine assemblies 320, 320’ to the buoyancy vessel 110 and the “pivot points” located at lower connection points 152a, 152b, compared to the vertical distance between “pull point” 454 and pivot points 452a, 452b of the power generating apparatus 400 of Figure 11 .

Figure 12 shows a front view of the apparatus 400 of Figures 9 and 1 1 with the turbine assemblies in the first position. Figure 13 shows a front view of the apparatus 300 of Figures 8 and 10 in the first position. In the view of apparatus 300 shown in Figure 13 it can be observed that the “pivot” connection point 352a of the support structure 320 to the buoyancy vessel 310 is disposed towards the baseline 312 of the buoyancy vessel 310. The lower connection points 352a, 352a’ of the turbine assemblies 320, 320’ to the buoyancy vessel 310 are located at a distance from the baseline 312 of the buoyancy vessel 310 from about 1/14^th to about 1/8^th of the total perimeter of the buoyancy vessel. Each lower connection point 352a/b of the first turbine assembly 320 to the buoyancy vessel is disposed close to the corresponding lower connection point 352a/b’ of the other turbine assembly 320’. Lower connection points 352a/b are separated from lower connection points 352a/b’ by a distance covering from about 1 /7^th to about 1/2 of the perimeter of the buoyancy vessel. In contrast, as shown in Figure 12, the “pivot” connection points 452a/b and 452a/b’ of power generating apparatus 400 are disposed in the upper half of the buoyancy vessel 410 and the connection points 452a/b of the first of the turbine assemblies 420 to the buoyancy vessel 410 are separated from the corresponding connection points 452a/b’ of the second turbine assembly 420’ to the buoyancy vessel 410 by a distance of about half or greater than half of the perimeter of the buoyancy vessel. For the avoidance of doubt, the distance between connection points 452a/b and the corresponding connection points 452a/b’ is the distance measured on the underside of the buoyancy vessel. Also, as shown in Figure 13, the platform 390 and side plates 394 conform to the contour of the buoyancy vessel 310 (i.e. the platform and side plates hug the upper surface of the buoyancy vessel 310, thus providing a low profile platform).

As discussed above, the connection arrangement of the turbine assemblies 320 to the buoyancy vessel 310 of power generating apparatus 300 confers a greater mechanical advantage than the connection arrangement of power generating apparatus 400, thus enabling greater scalability of the support structures and/or turbines, as well as the use of less power to actuate the turbine assemblies 320 between the first and second positions. The power generating apparatuses shown in the figures may be manufactured from any suitable material, such as steel or low density materials. The support structure of the turbine assembly may be manufactured of any suitable material, such as steel, reinforced concrete, low density materials such as carbon fibre and the like. In preferred embodiments, the support structure of the turbine assembly is manufactured from carbon fibre in order to further reduce the weight of the support structure and improve scalability or enable the use of less power for moving the turbine assemblies between the first and second positions.

Whilst the invention has been described in connection with the foregoing illustrative embodiments, various modifications, additions and alterations may be made to the invention by one skilled in the art without departing from the scope of the claimed invention.

For example, in the described embodiments the power generating apparatus has a single buoyancy vessel with two turbine assemblies symmetrically disposed about the buoyancy vessel. However, in some embodiments the power generating apparatus may comprise a different number of buoyancy vessels, for example connected tethered to each other.

The platform in the exemplified embodiments has side plates, but embodiments according to the invention may comprise a platform without side plates, or with side plates configured differently.

The power generating apparatus may have only one turbine assembly, or for example three, four, five, six, seven, eight or any suitable number of turbine assemblies.

The turbines of the exemplified embodiments have two rotor blades. However, in other embodiments the turbines may have any number of rotor blades, for example three or four.

In the exemplified embodiments the turbine assemblies are movably coupled to the buoyancy vessel closer to one of the stern or bow section of the buoyancy vessel, however the terms stern and bow may be interchangeable in these embodiments, and the turbine assemblies may be coupled at any location along the length of the buoyancy vessel.

Although in the exemplified embodiments the turbine assemblies are coupled to the buoyancy vessel, the turbine assembly or assemblies may be coupled to any other suitable load bearing structure that is supported by the buoyancy vessel.

Claims

1. A power generating apparatus for extracting energy from flowing water, comprising: a buoyancy vessel; a platform integral with or coupled to the buoyancy vessel, wherein the platform extends along at least half of the length of the buoyancy vessel; and a turbine assembly comprising a turbine rotor mounted to a nacelle, and a support structure; the turbine assembly being pivotally moveable between a first position and a second position; wherein, when the power generating apparatus is floating on a body of water, in the first position the nacelle is configured to be fully submerged below the water surface, and in the second position at least a part of the nacelle is configured to project above the water surface.

2. The power generating apparatus according to claim 1 , wherein the power generating apparatus comprises a powered mechanism to move the turbine assembly between the first and second positions, and wherein the powered mechanism is disposed below the platform.

3. The power generating apparatus according to claim 2, wherein the powered mechanism is a ram and associated mechanical linkage, optionally wherein the ram and associated mechanical linkage are disposed outboard from the platform.

4. The power generating apparatus according to any preceding claim, wherein the platform comprises an openable portion, optionally wherein the openable portion is a hatch or door.

5. The power generating apparatus according to claim 4 when depending from claim 2, wherein the powered mechanism is stored below the hatch or door.

6. The power generating apparatus according to any preceding claim, wherein the length of the platform is from about 50% to about 100% of the length of the buoyancy vessel.

7. The power generating apparatus according to any preceding claim, wherein the platform covers substantially an entire upper surface of the buoyancy vessel, optionally wherein the width of the platform is from about 70% to about 120% of the beam of the buoyancy vessel.

8. The power generating apparatus according to any preceding claim, wherein the platform comprises a plate extending downwards from an edge of the platform, optionally wherein the platform is elongate and comprises two plates, each plate extending downwards from a long edge of the platform.

37

9. The power generating apparatus according to claim 8, wherein the plate is disposed at an angle from about 20° to about 90° from a plane containing the platform, optionally wherein the plate is disposed at an angle of about 45° from a plane containing the platform.

10. The power generating apparatus according to claim 8 or 9, wherein the plate defines one or more apertures or holes, optionally wherein the plate defines multiple holes scattered along the width and length of the plate.

11. The power generating apparatus according to any preceding claim, wherein the support structure of the turbine assembly is movably coupled to the buoyancy vessel at one or more upper connection point or points and at one or more or more lower connection point or points, and wherein the lower connection point or points is vertically separated from the upper connection point or points by a distance of from about 50% to about 100% of a height of the buoyancy vessel.

12. The power generating apparatus according to any preceding claim, wherein, when the power generating apparatus is floating on a body of water, the upper connection point or points of the support structure to the buoyancy vessel are configured to be located above the waterline, optionally wherein the upper connection point or points of the support structure to the buoyancy vessel are configured to be located at a distance above a longitudinal axis of the buoyancy vessel of from about 5% to about 50% of the total height of the buoyancy vessel.

13. The power generating apparatus according to any preceding claim, wherein the lower connection point or points of the support structure to the buoyancy vessel are disposed at a distance above a baseline of the buoyancy vessel of from about 5% to about 60% of the total height of the buoyancy vessel.

14. The power generating apparatus according to any preceding claim, wherein the lower connection point or points of the support structure to the buoyancy vessel are located at a distance from the baseline of the buoyancy vessel from about 1/18^th to about 1/4^th of the total perimeter of the buoyancy vessel.

15. The power generating apparatus according to any preceding claim, comprising two turbine assemblies symmetrically disposed about the buoyancy vessel.

16. The power generating apparatus according to claim 15, wherein the lower connection point or points of a first support structure of a first turbine assembly may be separated from a corresponding lower connection point or points of a second support structure of a second turbine assembly by a distance covering from about 1 /7^th to about 1/2 of the perimeter of the buoyancy vessel.

38

17. The power generating apparatus according to any preceding claim, wherein the platform comprises a safety barrier, optionally wherein the safety barrier is disposed at or near an edge of the platform.

18. The power generating apparatus according to claim 17, wherein the safety barrier is movable from a first position in which the safety barrier extends above the platform to a second position in which the safety barrier is stored under and/or recessed into the platform or the safety barrier extends substantially under the platform.

19. The power generating apparatus according to claim 18, wherein the safety barrier is rotatable about a pivot axis from about 90 degrees to about 180 degrees to move the safety barrier between the first position and the second position.