WO2010003416A1

WO2010003416A1 - Offshore construction

Info

Publication number: WO2010003416A1
Application number: PCT/DK2009/000157
Authority: WO
Inventors: Henning Baltzer Rasmussen
Original assignee: Foot Foundation AS
Current assignee: Foot Foundation AS
Priority date: 2008-07-09
Filing date: 2009-06-26
Publication date: 2010-01-14
Anticipated expiration: 2011-01-09

Abstract

The present invention relates to an offshore construction comprising a base construction (1) for foundation of tower elements where said base construction (1) comprises a lower section (2), a middle section (3) and an upper section (4), where said middle section (3) comprises one or more of the following modules: accommodation module (5), workshop module (6), engineering module (7), storage module (8), ballast module (9) and/or service module. The present invention furthermore relates to an offshore construction comprising a tower element where the upper end is arranged for mounting of wind turbine wings, a turbine element arranged to extract energy from wind interacting with the wings, and a wave energy module arranged to interact with water waves where the turbine module furthermore is arranged to extract energy from waves interacting with the wave energy module.

Description

Offshore construction

Scope of the invention

The present invention relates in a first aspect to a base construction for foundation of tower elements, where said base construction comprises a lower section, a middle section and an upper section.

The present invention relates in a second aspect to a specially made float construction for balancing a floating base construction for offshore constructions during landing of the base construction and tower element. The present invention relates in a third aspect to a method for balancing a floating base construction and/or an offshore construction.

The present invention relates in a fourth aspect to a base construction and a tower element whose upper end is arranged for mounting of wind turbine wings and where the base construction comprises a wave energy module arranged to interact with water waves.

The present invention relates in a fifth aspect to a base construction with a number of modules where one or more of said modules are provided with a number of holes in the outer cladding such that a stream of water can pass through the module. , The present invention relates in a sixth aspect to a base construction with a number of modules coupled with a number of wires extending from the foot pile and possibly all the way up into the tower element.

Background of the invention Today, great costs are connected with the foundation of tower elements for e.g. offshore wind turbines as this requires large special machines which must be transported out to sea and require fair weather for a longer period of time.

A foundation process can be interrupted by a change in weather which makes it impossible to use the special machines placed on barges or ships as the waves hinder the precision of the working processes which is required to establish a foundation which is durable for the erection of a tower element or for the use of wave energy.

A lot of manpower is required for maneuvering the machines and the ships which makes the manpower costs run quite high and thereby the time factor is very crucial for the foundation process. Where fair weather results in a short foundation process, changing weather can result in a difficult foundation process with several stops where manpower and ships are unable to do anything. When the foundation process is paused due to bad weather, all crew members must stay on the ships which can be a trying experience and very costly. A holt in the foundation process can cost millions per day and at the same time makes time tables difficult. Today different systems are used for foundation of seabased tower elements, for instance mono piles, suction tubs, tripoles or gravitation foundations. They all have the disadvantages mentioned above concerning great costs and the risk of inconvenient stops in the foundation process due to bad weather.

In connection with a base construction for the establishment of a foundation for a tower element, time and manpower can be saved in connection with offshore foundation of tower elements such as for example seabased wind turbines, wave energy systems and the like.

In this connection it will be possible with the present invention to further save on manpower and additionally be independent of the weather as it will be financially profitable to assemble the base construction and the tower element on land, in floating dock and/or in dock as the access to machines and cranes is easier and it is easier to quality-control the different construction parts, assemblies and working processes.

A further advantage will be the saving on ship transport since the assembled entity (base construction and tower element) can be transported in one go in comparison to the situation where the base construction and the tower element are transported in more rounds which means a dependency on fair weather for all processes (transportation and in situ assembly).

Mounting of wave energy modules on offshore wind turbines has the advan- tage that one construction can be used to extract energy from respectively water waves and wind. It is thereby possible to save on especially landing and mounting of the construction because just one and not two constructions is to be mounted. Wave energy modules mounted on offshore constructions are known from for example ES 2 182 702 A1 and DE 20 2005 013 165 U1. When an offshore construction is placed on for example a seabed where there are water currents, the phenomenon "scaring" can occur, i.e. the speed of the water current is increased around the bottom part of the offshore construction, and a turbulent current is created whereby the water current carries seabed material with it which causes an excavation of the seabed in front of/under/around the bottom part. This causes instability in the offshore construction as well as a strain on the existing foundation. The solution to this problem with conventional methods it to either dig out a large area around the bottom part of the offshore construction into which concrete is cast or to lower a large amount of rocks around the bottom part of the offshore construction such that a stone barrier is created which prevents the movement of sand and pebbles. Both methods are costly in materials and take time to carry out.

Another problem connected to an offshore construction which for example is placed in water is the substantial impact of the surface waves on the offshore construction when these break against the offshore construction at the sea surface. In order to solve this problem offshore constructions of massive dimensions and heav- ier foundations are used.

It is commonly known that offshore constructions are made in a certain dimension in order to resist all the influences that exist at sea, such as salt water, the impact from the wind, the impact from waves and currents. This has the effect that with larger tower elements it is necessary to either increase the dimension of the outer cladding of the tower element or to make heavier constructions in order to resist all these different forces, especially the wave force, or to establish heavier foundations.

Purpose of the invention It is the purpose of the first aspect of the present invention to indicate a module for foundation of tower elements which ensures a safe and fast foundation of a tower element regardless of the weather and without use of expensive special vessels.

This is achieved with a base construction for foundation of tower elements where said base construction comprises a lower section, a middle section and an upper section where said middle section comprises one or more of the following section modules: accommodation module, workshop module, engineering module, storage module, ballast module and/or service module.

It is the purpose of the second aspect of the present invention to indicate a specially made float construction which ensures a safe and fast establishment/dismounting of a tower element regardless of the weather and without using expensive special machines and vessels.

This is achieved with a specially made float construction for balancing a floating base construction for offshore constructions during landing of the base con- struction and tower element, where said specially made float construction comprises a number of flotation elements, a moveable fitting which encloses the base construction such as a gyro fitting and connection items where the flotation elements are connected with the moveable fitting and the base construction through said connection items.

It is the purpose of the third aspect of the present invention to indicate a method of balancing a floating base construction and/or offshore construction. This is achieved with a method comprising the following steps: providing a construction comprising a number of flotation elements, a moveable fitting and connection items, where the flotation elements are connected to the moveable fitting and base construction/tower element through the connection items; suspending the base construction and/or tower element in the specially made float like a pendulum such that the moveable fitting can be moved along a vertical plane of the base construction and/or tower element such that it is possible to raise and lower the base construction and/or tower element in relation to the weather, position above the seabed and during placement of the base construction and/or tower element at the desired position, and landing the base construction and/or tower element to an offshore site. It is the purpose of the fourth aspect of the present invention to indicate an offshore construction which uses the available energy sources at the construction even more efficiently.

This is achieved with a base construction and a tower element, whose upper end is arranged for mounting wind turbine wings, and where the base construction comprises a wave energy module arranged for interaction with water waves, and which furthermore comprises a common transformer module arranged to both extract energy from wind interacting with the wings and from waves interacting with the wave energy module. The construction can thereby be manufactured smaller and cheaper and it will also be easier and faster to transport to the erection site. An increased production is achieved due to the synenergy between the use of the wind and waves which creates a larger energy production from stochastic energy sources with fewer resources. The construction is cost efficient and maintenance friendly.

It is the purpose of the fifth aspect of the present invention to counter the above-mentioned problems with scaring and impact from waves. This is achieved with a base construction with a number of modules in which one or more of said modules are provided with a number of holes in the outer cladding such that a water stream can pass through the module.

It is the purpose of the sixth aspect of the present invention to develop a system for mutual fastening of the modules of the base construction as well as stabi- lization of the tower element during heavy impact from the forces of nature such as weather, wind and waves. This is achieved with a base construction with a number of modules which are coupled to a number of wires extending from the foot pile and possibly all the way up into the tower element.

Description of the invention

In order to ensure a safe and fast foundation of a tower element, a base construction can be manufactured on land, in floating dock or in dock and subsequently be towed out to the desired position at sea. It is very advantageous that the entire base construction can be assembled on land and in certain cases also the tower element, where it is easy to use ordinary machines and where the weather is not so important.

Another advantage is the fact that the base construction comprises a middle section which comprises one or more of the following modules; accommodation module, workshop module, engineering module, storage module, ballast module and service module which makes it possible to transport everything out to sea in one go and with a minimum of manpower for the maneuvering of the towing vessel as there is no need for large special vessels for transportation of machines and materials.

An accommodation module can be used by the crew during the foundation process or during service or maintenance stops due to bad weather or long-term work.

A workshop module can comprise the special machines and measuring equipment to be used for the foundation process or can be used as machine workshop for service and maintenance of the tower element.

An engineering module can for instance comprise hydraulic and air com- pressors, power generators, freshwater plants, purifying plants, ventilation plants, electrical controls and the like.

A storage module can comprise all the materials to be used during the foundation process, for instance drill pipes, reinforcement bars and casting compound. Furthermore, the storage module can comprise spare part storage for components for the tower element and a freshwater depot.

A ballast module can comprise a number of ballast tanks which can be used for stabilization of the module during towing from land to sea and for lowering of the module onto the underlying layer when the desired position has been reached. Furthermore, the ballast module can be made such that it can be used for storing left- over material, garbage and the like.

In order to establish a foundation with the use of the base construction it can comprise a number of working channels extending from said upper section to said lower section and which have been arranged for working an underlying layer. These working channels are especially suited for a foundation process which comprises the use of pile foundation as described in detail in WO03/062539 / WO2006/024294. By referring to these two applications, the applications are considered as incorporated in their entirety into the present application.

When the base construction has been towed to the desired position it is important that the position is maintained both vertically and horizontally until the foundation process has been completed. Therefore, said bottom section may be provided with a number of adjustable arms for fixating said base construction to said underly- ing layer. These adjustable arms can either be driven by hydraulics or air pressure such that they can be pushed into the underlying layer completely or partly after which the base construction cannot move to the side. A possible embodiment of the adjustable amis has been used on for instance diggers comprising a number of arms which are folded out when the digger is positioned correctly. Thus the digger rests on the arms instead of the wheels and is thereby more stabile during power transmission from the shovel. The adjustable arms may be reusable and are disconnected from the bottom section when the foundation process is completed.

When the base construction is fixated at the desired position it is important that the base construction is stabile on the underlying layer. Therefore said lower section may comprise a number of unidirectional casting channels arranged to press out an casting compound such that potential unevenness in the underlying layer is removed and the base construction supports on the entire lower section. The casting (purifying layer/alignment layer) is preferably to ensure that the foundation does not slide/tilt when influenced by the impact from push and pull forces which occur during the foundation process and which later arise from the tower element. The casting channels are preferably performed as unidirectional channels such that water and the like cannot enter the base construction. The casting channels may be connected to one of said modules where the casting compound is mixed and pushed out through the casting channels by for instance air pressure or hydraulics. In order to move between said modules, said service module extends preferably completely or partially through said middle section thus providing access to the individual modules. The service module can for instance comprise a ladder, an elevator, a staircase, a hoisting device such that it is possible to transport spare parts, materials and crew from the upper section down to the different modules of the middle section. For safety reasons the service module can comprise a number of closing mechanisms which ensure that each individual module is separated in a wa- ter-proof manner from the remaining modules. These closing mechanisms may for instance be waterproof hatches.

When the base construction is anchored to the underlying surface, as for example the seabed, it is preferred that there is access to the base construction for delivery of crew, food, tools, spare parts, oil and the like in connection with the foundation process and/or for service and maintenance of the tower element. Therefore, said upper section may be provided with a service platform such that it is possible to either board the service platform with a vessel from the seaside or from the air. This platform is used in the foundation process for protection of the construction crew and later for inspection of the coupling of the tower element and of the base construction and the assemblies of the modules of the base construction.

In connection with the foundation process said working channels are used which comprise openings distributed on the upper section. In order to use a machine for all working channels, said upper section may be provided with a completely or partially rotating machine tool which may be arranged to perform a number of working processes on said underlying layer through said working channels. The machine tool is preferably to perform one or more of the following working processes: flush or drill a channel/a cavity in the underlying layer, lower reinforcement bars in the channel/cavity and pressing out a casting compound into the channel/cavity. When offshore constructions are established, an evaluation of the environmental impact is preferably carried out which maps out the influence of the offshore construction on the surrounding environment. But an evaluation of the environmental impact can cause the foundation process of the offshore construction to become very costly if it turns out that parts of the underlying layer must be removed/deposited and/or purified. With the present invention only material from the foot pile foundation process must be removed/deposited; alternatively the material may be stored in the ballast module. Because said ballast module comprises a number of sections for storing material from said underlying layer, it is possible to avoid transporting large amounts of underlying layer away from the position of the base construction, while at the same time not harming the surrounding environment by establishing a foundation in the form of a base construction cf. the present invention.

It is a basic principle of the present invention that the entire base construction is manufactured on land/in floating dock or in dock and subsequently is towed out to the desired position at sea. The base construction is to be easy to manufacture and assemble. Therefore, the base construction is made from concrete and/or steel, for example pre-cast concrete elements which subsequently are assembled into the base construction itself or a steel framework clad with steel plates or a steel framework with concrete elements.

The base construction is reusable, as it is possible if the module has been arranged in the wrong place or when the tower element ceases to function to dis- mount the connections of the base construction to the foot piles, after which the base construction can be freed and is ready to be towed to another position, for example with a specially made float according to the present invention.

The establishment of foot piles can alternatively take place from within the base construction with mini equipment through the working channels. This may be relevant where it is desirable to bring a tower element or the like which is connected to the base construction on land, which does not leave space for a machine toot on the upper section.

In an alternative embodiment the base construction may be provided with a number of buoyancy and/or stabilization elements on the outside of the base con- struction, for example fastened to one or more of the three sections of the base construction. This may be necessary for safety reasons or other legal requirements. In order to ensure a safe transportation of a base construction and/or a tower element a specially made float is used which comprises a number of flotation elements, a moveable fitting which encloses the base construction such as a gyro fitting and connection items where the flotation elements are connected with the moveable fitting and the foundation module through said connection items.

Said flotation element may be a container which partially or completely encloses the base construction/tower element and may be a container with a durable form of for example iron, steel or a similar material or may be a rubber balloon which can be inflated before mounting. Said flotation elements may be a number of containers which may be mutually moveably connected such that a power impact may be transported from one flotation element to the next flotation element. As a result an impact from waves can be absorbed by the flotation elements while at the same time keeping the base construction and tower element uninfluenced by the wave move- ments.

In order to reduce the impact of the waves on said flotation elements, they may during the transportation trim be lowered into the water, for example 5-10 meters below the sea surface. In order to ensure that the flotation elements remain in this position during transportation, said flotation elements may be provided with a stabilization system for buoyancy adjustment. The stabilization systems can quickly and in relation to the impact from waves and currents ensure that the flotation elements are maintained in a certain position. Furthermore, the stabilization system can be used when placing the base construction on seabeds. The flotation elements are trimmed such that they (together with the base construction) slowly sink towards the seabed such that the base construction is placed slowly and surely on the location where the tower element is to be established. A stabilization system may be provided in connection with each flotation element such that one stabilization system only trims one flotation element. Alternatively, a stabilization system may be connected to all float elements such that the trim of the flotation elements is controlled collectively.

The collective or individual trimming possibility of the flotation elements as well as the possibility of trimming the base construction makes it possible to carry out a foundation during difficult weather which increases the operation window for foundation significantly.

A number of cylinders may be provided between the flotation elements and the base construction which may absorb forces and thereby act as movement damp- eners. To further secure the base construction/tower element against rough sea during transportation, said flotation elements may be provided with a number of stabilization items and/or support items. The stabilization items, which may be adjustable, will hinder heeling of the base construction/tower element, as they consist of plates, net or the like which must displace a certain amount of water in order to move.

The support items can be used as legs/spears during placement of the base construction on the seabed and thus ensure that the base construction remains at the desired position while the foundation process/anchoring takes place.

Said moveable fittings mounted on the base construction/tower element causes the base construction/tower element to "hang" like a pendulum in the water. This means that even though the flotation elements are influenced by waves and currents, the base construction/tower element will be in a substantially vertical position during the entire transport. In order to hang the base construction/tower element like a pendulum in the specially made float, said moveable fittings can be mounted/dismounted around said base construction/tower element. It is important that the moveable fitting is placed on the base construction/tower element, such that the centre of rotation of the pendulum movement is above sealevel and sufficiently high to avoid heeling of the base construction/tower element.

Said moveabte fittings may be provided with a number of movement items for vertical movement along said base construction/ tower element which in praxis means that all wave and current movements are absorbed in the flotation elements and do not influence the position of the base construction/tower element. The move- merit items may be one or more of the following: rollers, wheels, gearwheels, bearings or the like.

In order for the moveable fitting and the flotation elements to have the stabilizing effect, they are preferably connected to the base construction/tower element by using connection items, which at one end are connected to the upper end of the base construction/tower element and through the movable fitting at the other end are connected to the flotation elements. Said connection items may be one or more of the following: wires, telescopic poles and/or fixed poles which in themselves or through fittings are tensioned out continuously while at the same time absorbing and/or equalizing the different forces which waves and currents influence the flotation elements with. At the same time the moveable fitting and the connection items ensure that impact from the transport is absorbed without influencing the position of the base construction/tower element.

Alternatively the specially made float can be used for dismounting and transporting existing offshore constructions which may be transported in their entirety or in smaller parts. This makes it financially profitable to reuse tower elements and much cheaper to repair/maintain these on land.

A first preferred embodiment for balancing a floating base construction and/or an offshore construction comprises the following steps: providing a construc- tion comprising a number of flotation elements, a moveable fitting and connection items, where the flotation elements are connected to the moveable fitting and base construction/tower element through the connection items; suspending the base construction and/or tower element in the specially made float like a pendulum such that the moveable fitting can be moved along a vertical plane of the base construction and/or tower element such that it is possible to raise and lower the base construction and/or tower element in relation to the weather, position above the seabed and during placement of the base construction and/or tower element at the desired position and; landing the base construction and/or tower element to an offshore site.

Another preferred embodiment for balancing a floating base construction and/or an offshore construction comprising the following steps; landing the base construction to the offshore site through the specially made float, after which the base construction is fastened to the seabed and subsequent landing of the tower element to the offshore site through the specially made float after which the tower element is fastened to the upper section of the base construction. In a preferred embodiment the base construction/tower element are arranged such that the extracted wind and wave energy is lead to a common generator module and preferably have a common cabling etc. In another preferred embodiment the base construction/tower element comprises a platform or landing stage where the wave energy module is mounted on the platform, preferably the platform comprises an underside which through tilted angles or arches is arranged to act as ice breaker capable of twisting ice at the water sur- face down below itself. In this a multi platform is achieved which can be used for a number of purposes such as landing stage, work bridge, ice breaker, wave damp- ener, flotation element holder and/or stabilization element. The platform is preferably made from a substantially massive unit of a heavy material such as concrete or steel. Thereby the platform will be better able to absorb forces inflicted by waves hitting against it or ice at the water surface.

In a third preferred embodiment the wave energy module comprises at least one flotation element for instance in the form of a pontoon, preferably the flotation elements are arranged to float on top of the water surface in order to follow the surface movement of the waves and are arranged around a lower section of the tower such that they furthermore function as wave breakers and/or dampeners reducing the impact of the waves on the base construction. In a preferred further development of this embodiment the flotation element(s) are arranged on a swingable arm, preferably the arm can be moved from a horizontal to a tilted position.

In a fourth preferred embodiment several flotation elements have been fas- tened to the platform, and a platform part of the platform is arranged to rotate around the base construction/tower element, preferably in a circular movement in order to place the floatation elements optimally in relation to a given wave direction, preferably the flotation elements are arranged such that they meet the wave movement in a half-circle. In a fifth preferred embodiment the flotation element(s) are arranged to be filled with ballast, preferably in the form of water, in order to be placed on a seabed or the like for further support of the entire offshore construction, for example during rough weather or during mounting of the base construction/tower element.

In a sixth preferred embodiment the construction furthermore comprises en- ergy modules for extracting energy from tidal movements and/or solar energy, where these energy modules also have been connected to the common transformer module, as all energy preferably is transformed to kinetic energy which drives a common generator module, preferably the tower element comprises an elevated water reservoir functioning as energy reservoir by using extracted energy to pump water to a higher height of fall for storage and later for driving a common generator module in the form a common turbine. An extremely high energy output is achieved on the basis of a relatively cheap construction. With a turbine a utilization factor of 85-90% can be achieved with simple pump technology. Small energy losses may occur in gears, transformers, cables etc.

In a seventh preferred embodiment the base construction/tower element comprises a wave energy module in the form of a wave planing system, which com- prises a channel system, which starts at the upper openings of the base construction/tower element and continues through the base construction/tower element to lower openings in the base construction/tower element, where at the lower part of the channel system a generator module is installed in the form of a turbine arranged such that when in operation it floats inside the base construction/tower element such that it is arranged to follow a water surface inside the base construction/tower element in order to optimize a height of fall of water from waves penetrating through the upper openings in the tower and where the lower openings preferably are in the form of trap doors preventing water from flowing in during wave crests, but allowing water to flow out during wave vales. Alternatively, the water access to the wave energy modules can take place through holes in the base construction as described in fig. 19-21.

In a preferred embodiment of the present invention the base construction is in a lower module close to the seabed provided with a number of holes in the outer cladding which allow water to penetrate through the lower part of the tower element. By this there is only a minimal increase in the speed of the water current and the materials of the seabed are not carried along with the water current and thereby scaring is avoided.

Holes are placed on the outer cladding of the base construction such that across from a hole in one side is placed a hole in the other side of the outer cladding which decreases the resistance and thereby reduces the formation of a turbulent current. The holes can be placed symmetrically around the tower element, such that it is not important how the sea current runs. In areas where the sea current runs in a constant direction or where only juxtaposed sea currents occur (by placement in tidal areas) the holes can be placed on the sides of the tower element facing towards the sea current.

The holes in the outer cladding may have different dimensions and forms. It just has to be taken into consideration that the number, size and placement of the holes do not reduce the strength of the base construction significantly.

In another preferred embodiment of the present invention the base construc- tion is arranged with an upper module at the sea surface preformed with a number of holes in the outer cladding which allow water to flow through the upper part of the base construction. A reduction of the impact of the waves on the base construction is thus achieved. A reduction of the wave impact makes it possible to maintain/reduce the dimension of the outer cladding of the base construction as well as reducing the number of foot piles which constitute the foundation for the base construction/tower element. This causes a large reduction in the costs for transportation, foundation and placement of offshore constructions.

The holes in the outer cladding of the base construction can, besides from leading the water through the base construction, alternatively be coupled to the previously described energy module in which a turbine/generator is placed.

In a third preferred embodiment of the present invention the base construc- tion is provided with modules with holes both at the sea surface and at the seabed.

In order to ensure an approximately laminar water flow around the lower part of the base construction, this can be provided with a partially or completely enclosing casing placed over the module with holes. The water flow will always seek the easiest route with the least resistance. The casing ensures that the water flow/water layer over the partly or completely enclosing casing does not seek down towards the module with holes where the resistance is less, which prevents an increase and/or formation of a turbulent water current at the seabed from taking place and thereby the development of scaring around the seabed /lower part of the base construction. Furthermore, the casing causes a layering of the water flow. In an embodiment of the present invention the casing is tilted such that the water flow is lead upwards. This results in an underpressure under the casing and an overpressure above the casing such that the speed of the water flow will increase over the casing but the speed of the water flow below the casing will be reduced.

In a preferred embodiment of the present invention the modules of the base construction are coupled with a number of wires extending from the foot piles up through the base construction and possibly all the way up into the tower element. This makes it possible to tension the wires such that they hold the modules together even during heavy influences from for instance wind and waves.

The wires are fastened/cast into the foot pile and extend through channels up to the lower part/upper part of the tower element which makes it possible to reduce the dimensions of the assembly flanges/bolts since the pressure distribution on for instance the concrete part is much improved.

The wires can be divided into different pieces such that they can extend in sections which hold one or more modules together. The wire gathering can take place using different types of locking arrangements which ensure that the wire stays tensioned. In an embodiment of the present invention the wire is lead through channels from the foot pile and to the tower element and subsequently arranged along a flange established on the inside of the outer cladding of the tower element.

In a preferred embodiment of the present invention each individual wire is fastened in one or more places in an adjustable arrangement which can be adjusted in the longitudinal direction of the wire. This makes it possible to adjust the tensioning of the wire in relation to the power impact the base construction/tower element is subjected to.

As an example, impact from the wind on the base construction/tower ele- ment from the west may result in a tensioning of the wires facing west such that the moment from the impact of the wind is evened out in the west side of the base construction/tower element.

The adjustable arrangement may be a screw arrangement, a hydraulic arrangement or the like which ensures a tensioning of the wire in its longitudinal direc- tion.

By establishing a control on all these adjustable arrangements and connecting them with power measurers on the base construction/tower element it is possible to counter the different impacts from wind, current and waves.

By continuously adjusting the wires to counter the forces on the base con- struction/tower element it is possible to stabilize the base construction/tower element as well as to avoid an increase in the dimensions of the base construction/ tower element/foundation when increasing the height of the tower element.

The alternative to wires may be cables, pull rods etc. It must be items which can absorb the pull forces.

In order to float-out the base construction and/or tower element safely, one or more of the modules of the base construction are provided with an air and waterproof cell division. This has however many different advantages:

•During floating-out the separate cells can be used as trim tanks. • When placing the base construction and/or tower element on a seabed with poor carrying capacity, the separated cells can be used for buoyancy by filling them with air. This reduces the strain on the seabed and pile foundation and thereby it is possible to reduce the number of foot piles.

• In extreme weather the separated cells can be used as ballast by filling them with water. This causes the base construction and/or tower element to push harder against the seabed.

• By a heavy force impact on the base construction and/or tower element the separated cells can be used as staυilizers by filling them with water in the side of the base construction and/or tower element which is impacted by the force.

Even though the third aspect of the present invention is solely defined in the description and not included in the claims, the right to seek protection for this aspect both separately and in combination with the other aspects of the invention is reserved.

Short description of the figures

The present invention with be described in the following in more detail with reference to the accompanying drawing in which fig. 1 shows a cross-section seen from the side of a base construction and a cross-section through the base construction seen from below, fig. 2 shows a perspective view of the base construction, fig. 3 shows a traditional towing of the base construction, fig. 4-6 show a foundation process in cross-section seen from the side, fig. 7 shows a cross-section of an offshore construction (base construction and tower element) towed by a specially made float, fig. 8-10 show cross-sections of the offshore construction (base construction and tower element) towed by a specially made float, fig. 8a-8b show cross-sections of an alternative moveable fitting in two different positions, fig. 11 shows a cross-section of a base construction with flotation elements and platforms, fig. 12 shows a view seen from above of the base construction, fig. 13 shows a cross-section of the base construction with alternative flotation elements, fig. 14-15 show cross-sections of a base construction with a turbine, fig. 16 shows a cross-section of a base construction with wings, fig. 17 shows a cross-section of a base construction using solar energy, fig. 18 shows a cross-section of a base construction with groove arms, fig. 19 shows a cross-section of a base construction with modules with holes, fig. 20 shows a cross-section of a base construction through a module with holes, fig. 21 shows a cross-section of a base construction with flotation elements, fig. 22 shows a coupling of the modules of the base construction and tower element, fig. 23 shows a casting in a foot pile, fig. 24 shows an adjustable arrangement for wires.

Detailed description of the invention

In fig. 1 is shown a cross-section of a base construction 1 comprising a lower section 2, a middle section 3 and an upper section 4. The middle section 3 is shown in this embodiment with an accommodation module 5, a workshop module 6, an engineering module 7, a storage module 8 and a ballast module 9. The base construction 1 is placed such that the lower section 2 supports on an underlying layer 11. On the upper section 4 a machine tool 16 is provided which has access to the working channels 10.

In fig. 2 is shown a perspective view of the base construction 1 without clad- ding. It is possible to see that the working channels 10 are placed along the outer circumference of the base construction 1. Furthermore, a service platform 15 is arranged in connection with the upper section 2.

In fig. 3 is shown a towing of the base construction 1 using a towboat 17. The ballast module (not shown) of the base construction 1 is partially or completely filled such that the base construction 1 is stabilized during towing.

In fig. 4-6 is shown a foundation process where the ballast module 9 is filled up such that the base construction 1 abuts against the underlying layer 11. A number of adjustable arms 12 fixate and adjust the base construction 1 to the underlying layer 11. A purifying layer of for instance concrete is cast under the lower section 2 such that the base construction 1 stands vertically and stable on the underlying layer 11. The machine tool 16 bores for a foot pile 19, lowers reinforcement and casts concrete in the bore 18 via working channel 10. After hardening of the foot piles 19 the machine tool 16 and the adjustable arms 12 are removed and the base construction 1 is then ready for mounting of a tower element (not shown in fig. 1-6). The base construction 1 can alternatively be floated out lying horizontally. In this case boring or flushing for foot piles can take place from the inside of the base construction 1. It is possible to mount a work adaptor on top.

In fig. 7 is shown a specially made float 31 according to an embodiment of the present invention which is used for landing an offshore construction which com- prises a base construction 1 and a tower element 33 (here shown with a wind turbine). The float 31 is used in this embodiment for balancing during landing of a base construction 1 and a tower element 33 which have been assembled on land prior to the floating-out. The float 31 comprises a number of flotation elements 34, a move- able fitting 35 (here shown in the form of a gyro fitting) and connection items 36 where the flotation elements 34 are connected to the gyro fitting 35 and the base construction 1 by the connection items 36. The gyro fitting 35 can comprise relief wheels for abutments against the tower element 33. Flotation elements 34 are provided with stabilization items 38 which prevent heeling of the float 31. The gyro fitting 35 ensures that the tower element 33/base construction 1 is suspended in the float 31 like a pendulum. Furthermore, the gyro fitting 35 is provided with a number of movement items 37 which ensure that the gyro fitting 35 can be moved along the vertical plane of the tower element 33 making it possible to raise and lower the tower element 33/base construction 1 in relation to the weather, position over the seabed and during placement of the tower element 33/base construction 1 at the desired position. As an alternative to landing a complete offshore construction in one go, parts of the offshore construction can also be landed separately.

In fig. 8-10 the described float 31 is used for practicing of another embodiment where a part 32a of a floating base construction 1 is floated-out to the offshore site for the offshore construction first, see fig. 8. The part 32a of the base construction 1 is then fastened to the seabed using pile foundation 39 (fig. 10). Wings, na- celle and another part 32b of the base construction 1 , more precisely a number of modules, are mounted to the tower element 33. Tower element 33 etc. is landed separately, see fig. 9, then tower element 33 etc. is mounted on the already landed and fastened part 32a of the base construction 1. In this embodiment the tower element 33 and a part 32a of the base construction 1 are thus not assembled on land before transport, but first on the offshore site. This is an advantage because the tower element 33 and the base construction 1 in large dimensions will be considerably easier to control during transport when they are divided into parts. The gyro fitting 35 ensures here that the tower element 31 and the part 32a of the base construction 1 each are suspended in the float 31 like a pendulum. Regarding the embodiment shown i fig. 8-10 it is furthermore noted that the part 32b in this case corresponds to a number of modules 5, 6, 7, 8. This makes it possible and extremely easy to transport the tower element 33 alone with the part 32b of the base construction 1, wings and nacelle to service on land for example for servicing/replacement of the transformer or other parts of the part 32b or the other parts of the tower element 33, including wing parts. It also makes it possible to transport the tower element 33 alone with the fixed parts to another offshore site if for in- stance the offshore site in question only is desirable for energy extraction during parts of the year. Then the upper side of the part 32a can be sealed with a hatch or the like until the remaining tower element 33 is to be mounted on top of it again.

As an alternative to a gyro fitting 35 a new and in itself inventive enclosing moveable fitting 35a, shown in fig. 8a and 8b, can be used. This fitting 35a comprises two holders 35b corresponding to the gyre fitting 35 above, which is intended for connection with the connection items 36 mentioned above. Between the two holders 35b a number of poles which can be pressed together in the form of hydraulic cylinders 35c which at their free end comprise gliding elements, wheels or the like are fastened to each holder 35b. Fig. 8a shows the fitting 35a enclosing the tower element 33 as the tower element 33 is in a vertical standing position and the fitting 35a is envisioned as a part of a float 31. In fig. 8b the tower element 33 has moved due to for example rough weather such that it is now in a tilted position. During the movement to the tilted position the surface of the tower element 33 glides/rolls to- ward the gliding elements or the wheels placed at the respective free ends of the hydraulic cylinders 35c, and the length of the cylinders 35c continuously changes in order to adapt to the movement of the tower.

In other embodiments of the present invention it is possible to land for example the tower element 33, wings and nacelle separately and not necessarily through the float 31 according to the present invention. The base construction 1 and the tower element 33 can also be landed in smaller parts.

Fig. 11 to 17 show different embodiments of a base construction 32 according to the present invention. The offshore construction comprises a base construction 32 and a tower element 33 where only the base construction 32 is shown in the fig- ures. The base construction 32 and the tower element 33 correspond in all embodiments shown in fig. 11 to 17 to the corresponding base construction 1 and tower element 33 in the embodiments described above, see fig 1 to 10. The offshore construction is thus intended for foundation through a base construction 32. The upper end of the tower element 33 (not shown) is thus arranged for mounting of wind tur- bine wings via a nacelle. Furthermore, each embodiment comprises a wave energy module 40 of different kinds arranged for interaction with water waves. Finally, all embodiments comprise a common transformer module (not shown) arranged to both extract energy from wind interacting with the wings and from waves interacting with the wave energy module 40. Preferably the extracted wind and wave energy is fur- thermore lead to a common generator module (not shown). Fig. 11 and 12 show a first embodiment where the wave energy module 40 comprises flotation elements 41 of the type used in the commercially available "Wave Star Energy" system. The flotation elements 41 are arranged to float on top of the water surface in order to follow the surface movement of the waves and are arranged around a lower section of the tower element, more precisely around the base construction 32 such that they furthermore act as wave breakers and/or dampeners which decrease the impact of the waves on the base construction 32. In the shown embodiments the flotation elements 41 are substantially formed as a half-circle, i.e. they are rounded at the bottom and have a flat, circular surface. An arm 42 is fas- tened to the flat surface through a hinge. The arm 42 can comprise two linear arm parts which meet near the center of the circular surface of the flotation element 41 and extend from this point in an angle of perhaps 5-10° for fastening of both arm parts onto a platform 43 which comprises the functions from service platform 15 described in relation to the embodiment according to fig. 1 above. A stiffening connec- tion part may be provided between the two arm parts. The arm 42 is swingable and moveable from an angle of about -20° in relation to horizontal and to an angle of about 120° in relation to horizontal, see fig. 11 where the two outer positions are shown with a punctured line. The flotation elements 41 can have other shapes than the halfcircle-shape, preferably they are approximately halfcircle-shaped, but oblong in the plane of the water surface such that they achieve an ellipse-shaped surface. Preferably the flotation elements are then tumable around the arm 42 such that it is possible to adjust them such that their longitudinal axis is parallel to a given wave crest. Thus greater use of the wave energy is achieved.

In fig. 11 three horizontal lines are shown which represent different wave heights. The waves thus cause the flotation elements 41 to move up and down because they float on top and thereby follow the water surface. The arm 42 can thus transfer wave energy to the construction.

The platform 43 is shaped as a circular ring (see fig. 12) with a beak-shaped cross-section (see fig. 11). The platform 43 thus has an underside 44 which by using tilted angles or arches is arranged to act as ice breaker capable of twisting ice at the water surface down below itself. The platform 43 is made as a substantially massive entity of a heavy material such as reinforced concrete. Thus the platform 43 will be able to better absorb the forces caused by waves beating against it or ice at the water surface. The platform 43 can furthermore advantageously be used as landing stage during mounting and maintenance of the offshore construction. As is best seen in fig. 12, 12 flotation elements 41 are in the present embodiment placed in a circular pattern with a uniform distance to each other and to the platform 43. An upper platform part of the platform 43 can be arranged to be able to turn around the base construction 32 preferably in a circular movement for the pur- pose of placing the flotation elements 41 optimally in relation to a given wave direction.

One or more of the flotation elements 41 can advantageously be used as flotation element(s) 34 in the construction according to the other aspect of the invention for the purpose of carrying out the method according to the third aspect of the invention, see description above of fig. 7 to 10. In other words, the flotation elements 41 are lowered for contact with the water surface in a constant relationship to the tower in order to provide buoyancy during transport of the tower element 33 and/or base construction 32. The flotation elements 41 can thus function as supplement to other flotation elements 34 or the flotation elements 41 can constitute the flotation elements 34 on their own. One or more flotation elements 41 can furthermore be arranged to be filled with ballast, preferably in the form of water, in order to communicate with the seabed 45 for further support of the offshore construction, for example during rough weather or during mounting of the base construction 32/tower element (not shown). An example of such an embodiment is shown in fig. 13 which sub- stantially corresponds to fig. 11 , but where the arm 42 is arranged with two joints.

During mounting or in rough weather one of the joints can be lead to abut against the seabed as illustrated.

Fig. 14 and 15 show a third embodiment where a module 46 of the base construction 32 comprises a turbine 47 of a wave planing system. Module 46 is sur- rounded by the platform 43 and comprises a channel system 48 which has an upper opening in the form of a ring-shaped groove 49 where the sides are constituted by a inner side and a bottom side of the platform 43 and an outer side of the base construction 32. From the groove 49 the channel system 48 continues through openings distributed around the circumference of the base construction 32 and are gathered in a central channel 50 in the bottom part of which the turbine 47 is installed. From the turbine 47 the channel system 48 extends back out of the offshore construction through openings 52 in the base construction 32. The turbine 47 is placed such that it floats inside the base construction 32 while in operation. The central channel 50 of the channel system 48 is limited to the side by a ring-shaped float plate 47a, and the turbine 47 is at the bottom of the part 50 fastened to this flotation element 47a. The float plate 47a constitutes an upper limitation of a section part 46a of module 46, where this module part will be filled with water while in operation. The float plate 47a thus floats on the surface of a water surface of the water in the section part 46a in order to optimize a height of fall of the water penetrating into the channel system 48 through the groove 49 or directly through holes in the base construction 32 (fig. 19- 21). The lower openings 52 comprise trap doors which prevent water from coming in during wave crests, but which allows water to come out during wave vales. The lower openings 52 can furthermore have a shape which becomes narrower away from the base construction 32, and they can also be tilted toward the bottom which ensures that water is more likely to run out than in through the openings 52. Fig. 14 shows a wave crest situation where a wave has flushed up over the upper curved surface of the platform 43 whereby the channel 48 is filled with water through the groove 49. Correspondingly fig. 15 shows a wave vale situation where the water surface is in a position where the water can be emptied out of the channel system 48 through the lower openings 52. Thus the energy from the height of fall of the water between wave crests and wave vales can be exploited as the water falls through and thereby drives the turbine 47. In fig. 14 the water from the overflowing wave has just begun to flow into the channel system 48 after the channel system and thereby the section part 46a has been emptied through the openings 52 at the last wave vale. The section part 46a is thus of small volume and the float plate 47a and thereby the turbine 47 are near the bottom of the section part 46a. The height of fall of the water through the central channel 50 (the upper end of which is fastened) is therefore large. In fig. 15 most of the water that has penetrated through the groove 49 has run through the central channel 50 and the volume of section part 46a has increased because the increased amount of water in module 46 pushes the float plate 47a upwards. The central channel 50 and the height of fall of the water have therefore decreased. The lower openings 52 comprise openings at different heights and are distributed around the circumference of the tower which is why water from the section part 46a throughout the entire wave vale motion is let out through the trap doors of the openings. Thus a variable height of fall and a continuous driving of the turbine are achieved, whereby a greater exploitation of the energy and a continuous energy production is achieved. This water planing system is preferably connected with the transformer module of the wind turbine and may be provided at the same time as one or more of the other energy exploitation systems described here, including a Wave Star Energy system according to fig. 11 to 13. Fig. 16 shows a fourth embodiment where the wave planing system according to fig. 14 and 15 is combined with a commercially available Wave Dragon sys- tern. This comprises a number of erect wings 51 arranged to rotate around the tower, preferable through a rotatable platform part in order to face a given wave direction. Thereby the water from the waves is lead to a greater height of fall through the groove 49 or possibly through holes in the base construction 1/tower element 33 (fig. 19-21) and to the turbine 47 whereby a greater efficiency is achieved.

Fig. 17 shows a fifth embodiment which substantially corresponds to the embodiment according to fig. 11 and 12. Here reflectors have been arranged on the circular surface of the flotation elements 41, which are capable of reflecting sunlight to the solar cells 54 provided on the outside of the tower in the entire circumference of the tower. The flotation elements 41 are arranged with adjustment means capable, preferably through ballast tanks, of rotating the flotation elements 41 around a horizontal axis depending on the angle of the sunlight in order to follow the movement of the sun and/or movement of the water such that an optimum use of the solar energy is achieved. Alternatively or additionally the solar cells 54 can comprise solar collec- tors. The use of the solar energy can be combined with any of the other energy exploitation forms described here. Alternatively or additionally corresponding reflectors may be provided which are tensioned between the flotation elements 41 or which float on the surface of the water. Alternatively the reflectors may be replaced by solar cells or solar collectors. Fig. 18 shows a sixth embodiment which is a combination of the embodiment shown in fig. 11 with the embodiment shown in fig. 14. Here is thus provided both a wave energy module 40 comprising floaters 41 and a wave energy module comprising a floating turbine 47 or a height adjustable turbine with channel system. On the platform 43 groove arms 60 are furthermore provided which are hinged to the platform 43 at one end and at the other free end comprise shovels 61. The grove arms 60 abut against the flotation elements 41 and the flotation elements 41 will during the influence of waves glide back and fourth against a lower part of the grove arms 60 and thereby bring the grove arms 60 to tip up and down with the movement of the waves. The grove arms 60 will thus during wave vales bring the shovels 61 below the water surface. When the grove arms subsequently are raised during wave crests, the water lifted by the shovels 61 will run through a groove in each groove arm 60 towards the groove 49 and thereby into the channel system 48 in order to contribute to the driving of the turbine 47.

In other not shown embodiments the offshore construction comprises ac- cording to the fourth aspect of the invention modules for extracting energy from tidal movements where these energy modules also can be connected to the common transformer module.

All the energy extracted through the different methods described above is preferably transformed to kinetic energy which drives the common generator module. Preferably the base construction 32/tower element 33 comprise an elevated water reservoir for example in one of the higher modules of base construction 32 where this reservoir acts as energy reservoir by using the extracted energy to pump water to a higher height of fall for storage and later for driving a common generator module in the form a common turbine, for example in the form of the turbine 47. Thus a more uniform energy production is achieved. It is an option to use a closed pump/turbine system which comprises fresh water.

In the water reservoir or in specially designed cavities and tanks for this purpose for example placed in one or more of the modules of the base construction it is possible as a supplement or as an alternative to split water into oxygen and hydrogen for the purpose of storing energy. This split can advantageously be preformed using the energy extracted via one or more of the methods mentioned above.

The machine tool 16 placed on the upper section 4 according to the embodiment shown in fig. 5 above can correspondingly be used to mount each of the energy modules used in accordance with the fourth aspect of the invention. Fig. 19 shows a base construction 1 where the module 106 comprises a number of holes 100a, 100b, 100c, 100d in the outer cladding 101. The holes 100a, 100b are placed both in an upper module 106 such that the waves 107 flushing in over module 106 are lead through. The holes 100c, 10Od are placed in a lower module 108 such that the sea current 109 hitting the lower module 108 is lead through without forming a turbulent current causing entrainment/scaring of the seabed 110. The casing 126 is arranged just above module 108 such that the sea current 109 is lead through the holes 100c, 100d and the sea current over the casing 126 is prevented from finding a way down to module 108.

Figure 20 shows a cross-section of module 108 where the holes 100d allow the sea current 109 to pass through module 108. The internal construction 111 built to provide strength to module 108 is furthermore arranged with a number of holes 112 or is a non-massive plate 113.

Figure 21 shows a base construction 1 where wave raisers 114 and wave floaters 115 are arranged in connection with the upper module 106. In this combina- tion the holes 100a, 100b will contribute to leading the water to the generator arrangement 116 whereby the wave energy is used to the maximum. Figure 22 shows the coupling of the modules 118, 119 to the foot pile 117 using wire 104 which is cast/fastened to foot pile 117.

Figure 23 shows a casting of wire 104 in foot pile 117. It is shown here that wire 104 is unlayed with two windings such that "4" wires extend from the foot pile 107 and up. The wire 104 is wound around a transverse element 120 arranged on a lower side of a plate element 121. Alternative casts may be used and in principle a number of uplays of the wire 104 can be performed depending on the desired strength of the wire coupling.

Figure 24 shows a wire 104 finished at an adjustable arrangement 122 con- sisting of a flange 124 mounted on the inside of the outer casing 123 and an adjustable end part 125 moveable in the longitudinal direction of the wire 104 whereby the wire 104 is tightened. Alternative adjustable arrangement may be used.

Claims

Patent claims

1. Base construction (1) for foundation of tower elements (33), where said base construction (1) comprises a lower section (2), a middle section (3) and an upper section (4), characterized in that said middle section (3) comprises one or more of the following modules

- accommodation module (5)

- workshop module (6)

- engineering module (7) - storage module (8)

- ballast module (9) and/or

- service module.

2. Base construction (1) according to claim 1, characterized in that said base con- struction (1) furthermore comprises a number of working channels (10), which extend from said upper section (4) to said lower section (2) and is arranged for working an underlying layer (11).

3. Base construction (1) according to any of the previous claims, characterized in that said lower section (2) is provided with a number of adjustable arms (12) for fixating said base construction (1) on said underlying layer (11).

4. Base construction (1) according to any of the previous claims, characterized in that the lower section (2) comprises a number of unidirectional casting channels (13) arranged for pressing out a casting compound.

5. Base construction (1) according to any of the previous claims, characterized in that said service module extends completely or partially through said middle section

(3).

6. Base construction (1) according to any of the previous claims, characterized in that said upper section (4) is provided with a service platform (15).

7. Base construction (1) according to any of the previous claims, characterized in that said upper section (4) is provided with a completely or partially rotating machine tool (16) arranged to perform a number of working processes on said underlying layer (11) through said working channels (10).

8. Base construction (1) according to any of the previous claims, characterized in

S that said ballast module (9) comprises a number of sections for storing material from said underlying layer (11).

9. Base construction (1) according to any of the previous claims, characterized in that said base construction (1) is made from concrete and/or steel. 0

10. Base construction (1) according to any of the previous claims, characterized in that one or more modules (5, 6, 7, 8, 9) of said base construction (1) are made with an air- and waterproof cell division.

11. Base construction (1) according to any of the previous claims, characterized in that the base construction (1) in one or more places is provided with a number of holes (100a, 100b) in the outer cladding (101) such that a water current (102, 103) can pass through the base construction (1).

12. Base construction (1) according to any of the previous claims, characterized in that the base construction (1) may be provided with a completely or partially enclosing casing (126).

13. Base construction (1) according to any of the previous claims, characterized in that the module (5, 6, 7, 8, 9) of the base construction (1) is coupled to a number of wires (104) extending from the foot pile (104) to the tower element (105).

14. Base construction (1) according to any of the previous claims, characterized in that each individual wire (104) is fastened in one or more places to an adjustable arrangement (105).

15. Offshore construction comprising a base construction (32) according to any of the previous claims and a tower element (33), whose upper end is arranged for mounting of wind turbine wings, and a wave energy module (40) arranged for interac- tioπ with water waves, characterized in that it comprises a common transformer module arranged to both extract energy from wind interacting with the wings and from waves interacting with the wave energy module (40), preferably the construction is arranged such that the extracted wind and wave energy is transferred to a common generator module.

16. Offshore construction according to claim 15, characterized in that the base construction (32) comprises a platform (43) or landing stage, and where the wave energy module (40) is mounted on the platform (43), preferably the platform comprises an underside which through tilted angles or arches is arranged to act as ice breaker capable of twisting the ice at the water surface down below itself.

17. Offshore construction according to any of the previous claims 15-16, characterized in that the wave energy module (40) comprises at least one flotation element (41) for instance in the form of a pontoon, preferably the flotation elements (41) are arranged to float on top of the water surface in order to follow the surface movement of the waves and are arranged around a lower section of the base construction (1 ) such that they furthermore function as wave breakers and/or dampeners reducing the impact of the waves on the base construction (32), preferably the flotation elements) (41) are arranged on a swingable arm, more preferred the arm (42) is move- able from a horizontal to a tilted position.

18. Offshore construction according to any of the previous claims 15-17, characterized in that several flotation elements (41) are fastened to the platform (43), preferably a platform part (51) arranged to be turned around the base construction (32), preferably in a circular movement such that it is placed optimally in relation to a given wave direction, preferably the flotation elements (41) are arranged such that they meet the wave movement in a half-circle, more preferred 8 to 16 of the flotation elements are distributed in a half-circle or in a circle around the base construction (32).

19. Offshore construction according to any of the previous claims 15-18, character- ized in that the flotation elements) (41) are arranged to be filled with ballast, preferably in the form of water, in order to be placed on a seabed or the like for further support of the offshore construction, for example during rough weather or during mounting of the base construction (1).

20. Offshore construction according to any of the previous claims 15-19, characterized in that the base construction (32) furthermore comprises energy modules for extracting energy form tidal movements and/or solar energy, where these energy modules also are connected to the common transformer module as all energy preferably is transformed to kinetic energy which drives a common generator module.

21. Offshore construction according to any of the previous claims 15-20, character- ized in that the base construction (32) comprises an elevated water reservoir functioning as energy reservoir by using extracted energy to pump water to a higher height of fall for storage and later for driving a common generator module.

22. Offshore construction according to any of the previous claims 15-21 , character- ized in that the base construction (32) comprises a wave energy module (40) in the form of a wave planing system comprising a channel system (48), which starts at the upper openings of the base construction (32) and continues through the base construction (32) to lower openings (52) in the tower, where at the lower part of the channel system a generator module has been installed in the form of a turbine (47) arranged such that it floats inside the base construction (32) while in operation such that it is arranged to follow a water surface inside the base construction (32) in order to optimize a height of fall of water from waves penetrating through the upper openings in the base construction (32), and where the lower openings (52) preferably are in the form of trap doors preventing an inflow of water during wave crests, but allow- ing water to flow out during wave vales.

23. Float (31) for balancing a floating base construction (32) according to any of the previous claims 15-22 and/or a tower element (33) during landing of the base construction (32) and/or tower element (33), characterized in that the construction (31) comprises a number of flotation elements (34), a moveable fitting which encloses the module such as a gyro fitting (35) and connection items (36) where the flotation elements (34) are connected with the moveable fitting and the foundation module through the connection items (36).

24. Float (31) according to claim 23, characterized in that said number of flotation elements (34) are mutually moveably connected.

25. Float (31) according to any of the previous claims 23-24, characterized in that said flotation elements (34) are provided with a stabilization system for buoyancy adjustment.

26. Float (31) according to any of the previous claims 23-25, characterized in that said flotation elements (34) are provided with a number of stabilization items (38) and/or support items.

27. Float (31 ) according to any of the previous claims 23-26, characterized in that said moveable fitting (35) can be mounted/dismounted around said tower module (33).

28. Float (31) according to any of the previous claims 23-27, characterized in that said moveable fitting (35) is provided with a number of movement items (37) for vertical movement along said tower element (33).

29. Float (31) according to any of the previous claims 23-28, characterized in that said connection items (36) are one or more of the following: wires, telescopic poles and/or fixed poles.

30. Method of balancing a floating base construction (32) and/or tower element (33) comprising the following steps:

- providing a float (31) comprising a number of flotation elements (34), a moveable fitting (35) and connection items (36), where the flotation elements (34) are connected to the moveable fitting and the base construction (32) through the connection items (36).

- suspending the base construction (32) and/or tower element (33) in the float (31) like a pendulum such that the moveable fitting (35) can be moved along a vertical plane of the base construction (32) and/or tower element (33) such that it is possible to raise and lower the base construction (32) and/or tower element (33) in relation to the weather, position above the seabed and during placement of the base construction (32) and/or tower element (33) at the desired position, and

- landing the base construction (32) and/or tower element (33) to an offshore site.

31. Method of balancing a floating base construction (32) and/or an offshore construction comprising the following steps; landing the base construction (32) to the offshore site through the specially made float (31), after which the base construction (32) is secured to the seabed and subsequent landing of the tower element (33) to the offshore site through the specially built float (1 ) whereafter the tower element (33) is fastened to the upper section of the base construction (32).