FLOATING STRUCTURE FOR WIND TURBINE AND METHOD OF INTALLING SAME

Abstract

Floating construction comprising: a flotation base including at least one essentially hollow body selectively fillable with ballast, where the maximum horizontal dimension of the flotation base is greater than the maximum vertical dimension of the flotation base; a building supported by said flotation base, comprising preferably a telescopic tower; downward impelling means; and at least three retaining cables, the corresponding upper ends thereof being attached to said flotation base, preferably at peripheral positions of the flotation base, and the corresponding lower ends thereof being attached to said downward impelling means, such that said retaining cables are tensioned and exert on said flotation base a downward force that increases the stability of the floating construction. And the installation method for this floating construction.

Claims

1. Floating substructure for wind turbine, characterised in that it comprises comprising: a flotation base including at least one essentially hollow body selectively fillable with ballast, where the maximum horizontal dimension of the flotation base is greater than the maximum vertical dimension of the flotation base, a telescopic shaft, supported by said flotation base, comprising at least two segments, including a base segment and a head segment, downward impelling means, and at least three retaining cables, the corresponding upper ends thereof being attached to said flotation base, preferably at peripheral positions of the flotation base, and the corresponding lower ends thereof being attached to said downward impelling means, such that said retaining cables are taut and exert on said flotation base a downward force; and in that wherein in the installed condition either said shaft is semi-emerged and said flotation base is submerged, or said shaft is emerged and said flotation base is semi-submerged.

2. Floating substructure for wind turbine according to claim 1, characterised by further comprising at least one stay the upper end of which is joined to the telescopic shaft and the lower end of which is joined to the flotation base, and in that wherein at least one of said stays is inclined with respect to the vertical such that the lower end of the stay is farther from the central vertical axis of the shaft than the upper end of the stay.

3. Floating substructure according to claim 2, characterised in that wherein at least one of said stays is formed by the prolongation of a corresponding retaining cable, in which case the flotation base comprises at least one deflection element that allows bending the alignment of the retaining cable and the upper end of the retaining cable is finally attached to the shaft; and characterised in that wherein said deflection element is farther from the central vertical axis of the shaft than said upper end of the retaining cable

4. Floating substructure for a wind turbine according to any of the preceding claims, characterised in that claim 1, wherein the flotation base is: a structure that comprises a single body, essentially closed, in the form of a box, or a structure comprising at least two essentially box-like closed bodies, said bodies being joined to each other directly or by means of a structure.

5-10. (canceled)

11. Floating substructure for a wind turbine according to any of the previous claims, characterised in that claim 1, wherein said downward impelling means comprise attachment means to the seabed.

12. Floating substructure for a wind turbine according to claim 11, wherein 11, characterised in that such attachment means comprise: driven piles, anchored micropiles, anchored bulbs of hardening material or anchored suction buckets which can resist the upward force transmitted to them by the retaining cables, or at least one massive element resting on the seabed that can resist, due to its own weight, the upward force applied thereto by the retaining cables.

13-18. (canceled)

19. Floating substructure for a wind turbine according to any of the preceding claims, characterised in that it comprises claim 1, further comprising at least one extensor arm projected laterally outward from the perimeter of the body or of the group of bodies of the flotation base and in that wherein at least one of said retaining cables is attached by their upper end to a corresponding extensor arm.

20. Floating substructure for a wind turbine according to claim 2, wherein claim 19, characterised in that at least one of the stays is attached at its lower end to a corresponding extensor arm projected laterally outward from the perimeter of the body or of the group of bodies of the flotation base, and wherein at least one of said retaining cables is attached by their upper end to a corresponding extensor arm.

21-24. (canceled)

25. Installation method for a floating substructure for a wind turbine according to any of the previous claims, characterised in that it comprises claim 1, comprising the following steps in any order technically possible: a) manufacturing the flotation base on-shore or in-shore, b) dry manufacturing the telescopic shaft, including at least one base segment and one head segment, c) forming on-shore or in-shore a transport unit, buoyant and free standing, that comprises the flotation base, the telescopic shaft in the retracted condition and at least part of the wind turbine means joined to the head segment of said telescopic shaft, according to the following sub-steps: c1) placing the telescopic shaft in retracted condition on the flotation base, c2) attaching at least part of the wind turbine means to the head segment, c3) attaching the extensor arms, if applicable, to the flotation base, c4) attaching the stays, if applicable, to the flotation base, c5) attaching the wave energy harness means, if applicable, to the flotation base, d) transporting or towing said buoyant and free-standing transport unit in a self-buoyant manner to the site, the flotation base remaining semi-submerged and the telescopic shaft in a retracted condition remaining fully emerged during transport, the installation method according to the present invention also being characterised in that it comprises further comprising, after step a) and/or after the fabrication or construction of the downward impelling means, in an indifferent order, the steps: e) attaching one end of each of the retaining cables to the flotation base, f) attaching the other end of each of the retaining cables to said downward impelling means, the installation method according to the present invention also characterised in that it comprises further comprising, before step d), the step: g) placing the flotation base on the body of water at the site; the installation method according to the present invention also characterised in that it comprises further comprising, after steps e) and f), the steps: p) submerging the flotation base to the desired depth for the installed condition, h) applying by the retaining cables a downward force on the flotation base; this force being generated by the impelling means; the installation method according to the present invention also characterised in that it comprises further comprising, after step c) and preferably before step h), the step: i) extending the telescopic shaft together with the wind turbine means; the installation method according to the present invention also characterised in that it comprises further comprising, after step d), the step: j) attaching to the substructure, if applicable, the means for maintaining the lateral position; and the installation method according to the present invention also characterised in that it comprises further comprising, before step h), the step: k) attaching to the seabed, if applicable, the attachment means to the seabed.

26. Installation method according to claim 25, characterised in that wherein the floating substructure comprises attachment means which include at least one massive element provisionally abuttable to the flotation base, and wherein at least one of said abuttable massive elements forms part of the transport unit and is transported together with the flotation base and the telescopic shaft, and once at the site it is ballasted and let down from the flotation base until it reaches the weight and position required for the installed condition of the substructure.

27. Installation method according to any one of claims 25 to 26, characterised in that it also comprises 25, further comprising, after step c) and before step h), the step: m1) provisionally attaching flotation stabiliser means to the floating substructure; and in that it also comprises further comprising, after step h) and after step 1p), the step: m2) removing the flotation stabiliser means from the floating substructure.

28. Installation method according to claim 27, wherein 27, characterised in that said flotation stabiliser means comprise at least one among: at least three floats attached to the flotation base at a relatively fixed position, each float having sufficient height to remain always partially emerged throughout step 1p), and/or at least two floats connected to the flotation base by launching means that are extended as the depth of the flotation base descends during step 1p), each float having a buoyancy such that it remains at the surface throughout step 1p), and/or at least one barge connected to the flotation base by launching means that are extended as the depth of the flotation base descends during step 1p), each barge having a buoyancy such that it remains at the surface throughout step 1p), and/or at least one support vessel equipped with launching means that attach the vessel to the flotation base, at least three floats that are connected to one another and comprise sliding or guiding means, such that they allow the shaft to slide during the ballasting and/or descent of the flotation base while the floats remain at the surface.

29. Installation method according to any one of claims 25 to 28, characterised in that it also comprises claim 25, further comprising, before step h), the steps: n1) manufacturing on-shore or in-shore at least one concrete box with the downward impelling means and placing it in the body of water of the site, n2) transporting or towing said concrete box in a self-buoyant manner to the site, n3) ballasting said concrete box such that it is submerged to its operational depth; and characterised in that it also comprises further comprising, after step n3), the step: n4) ballasting said concrete box such that its weight increases to the value desired for the installed condition.

30. Installation method according to any one of claims 25 to 29, characterised in that it also comprises claim 25, further comprising, before step h), the step: o) placing on the flotation base traction means for the retaining cables; such that the installation method according to the present invention can also comprise further comprising in step h) and/or step p): actuating said traction means for the retaining cables to vertically move the flotation base.

31-37. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0095] These and other features and advantages of the present invention will become apparent in view of the following non-limiting description of an embodiment of the invention, made with reference to the accompanying drawings, where:

[0096] FIG. 1 shows a schematic plan view with a partial cross-section of a transportation unit with a shaft in the retracted condition, with wind turbine means;

[0097] FIG. 2 shows a schematic plan view with a partial cross-section of a floating substructure attached to the seabed using cables and piles, with wind turbine means;

[0098] FIG. 3 shows a schematic plan view with a partial cross-section of a floating substructure attached to the seabed using cables and massive elements, with extensor arms, with wind turbine means;

[0099] FIG. 4 shows a schematic plan view with a partial cross-section of a floating substructure attached to the seabed using cables and a massive element, with wind turbine means;

[0100] FIG. 5 shows a schematic plan view with a partial cross-section of a floating substructure attached to the seabed using cables and piles, with extensor arms and stays, with wind turbine means;

[0101] FIG. 6 shows five schematic plan views with partial cross-sections representing respective embodiments that include different stabilisation means used during the installation method;

[0102] FIG. 7 shows two schematic plan views with partial cross-sections representing respective embodiment stages with stabilisation means used during the installation method;

[0103] FIG. 8 shows three schematic plan views with a partial cross-section of respective steps in an installation method for a floating substructure attached to the seabed using cables and a massive element, with wind turbine means;

[0104] FIG. 9 shows a schematic perspective view of a floating substructure attached to the seabed using cables and piles, with a floating substructure having several bodies, with a non-telescopic shaft and wind turbine means;

[0105] FIG. 10 shows a schematic perspective view of a floating substructure attached to the seabed using cables and piles, with another floating substructure having several bodies and with stays, with wind turbine means; and

[0106] FIG. 11 shows a schematic view of a portion of a floating substructure, specifically a flotation base that includes a pressurised gas chamber and Wells type turbines, as well as extensor arms.

DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

[0107] With reference to the accompanying figures, all of which show a floating construction which, in installed condition, according to the present invention, comprises: a floating base 2, which includes at least one body with an essentially hollow enclosure 25, the maximum horizontal dimension of which is greater than its maximum vertical dimension; a building supported by said flotation base 2; downward impelling means; and at least three retaining cables 8 the corresponding upper ends of which are joined to said flotation base 2 and the corresponding lower ends of which are joined to said downward impelling means: In addition, in FIGS. 1-8, 10 and 11 the building that forms part of the floating construction comprises a telescopic shaft 3 where the wind turbine means 7 shown are an accessory that is optional and/or interchangeable with other accessories, depending on the use of the floating construction, illustrated only by way of example to describe the embodiments of the invention. In the case of FIGS. 1 to 11, the flotation base 2 has dimensions allowing to ensure the stable self-buoyancy of the assembly comprising the flotation base 2 itself, the telescopic shaft 3 in retracted condition and at least part of the wind turbine means 7 placed on the head of said shaft.

[0108] However, FIGS. 1, 6 and 7 show floating substructures in which said downward impelling means and said retaining cables 6 have not been attached to form the complete floating substructure 7 according to the invention, since it shows stages of the installation method for the floating substructure 1 are shown previous to the installed condition.

[0109] Specifically, FIG. 1 shows a transport unit 9 in a transportation stage of an embodiment of the installation method according to the present invention, where a self-buoyant and free-standing transport unit 9, formed by a floating base 2, a telescopic shaft 3 in folded condition supported by said flotation base 2, and wind turbine means 7 joined to the head segment 32 of said telescopic shaft 3 is towed by a tug boat 28. In the transportation stage shown in FIG. 1, the downward impelling means and the retaining cables 8 are transported separately from said transport unit 9 and attached subsequently to the transport unit 9.

[0110] FIG. 6 shows a transport unit 9 in a descending condition corresponding to an embodiment of the installation method according to this invention, in particular during the step of ballasting the flotation base 2 just before applying precisely retaining cables 8 connected by their lower end to downward impelling means. FIG. 6 shows five views representing respective embodiments of stabilisation means 27 used in the installation method. Such stabilisation means 27 are intended for stabilising the transport unit 9 during the tasks of applying the downward impelling means and the retaining cables 8 to the transport unit 9, as well as during the ballasting and descent of the flotation base 2 to its operating depth. These stabilisation means 27 are optional in the installation method and, in any case, are preferably detachable and reusable such that they are not part of the floating substructure 1 in its installed condition.

[0111] More specifically, in the embodiment shown in view 6(a), the stabilisation means 27 comprise three floats attached to the flotation base 2 at a relatively fixed position, each float having sufficient height to remain always partially emerged throughout the step of ballasting and descent of the floating substructure 1 to its operating depth. In this embodiment, two tug boats would be connected to the flotation base 2 of the floating substructure 1 at diametrically opposite points, to increase control in the positioning of the floating substructure 1.

[0112] In the embodiment shown in view 6(b), the stabilisation means 27 comprise three floats connected to one another and comprising guiding means 33 with the shaft that maintain their relative plan position with the flotation base 2 (the drawing only shows two floats due to the type of view used), each float having a motorised reel comprising launching means 29; in this case said launching means 29 consist in a rope attached at its free end to the flotation base 2, such that said motorised reel pays out rope during the ballasting and descent of the floating substructure 1 to its operating depth. Said rope is pre-stressed.

[0113] In the embodiment shown in view 6(c), the stabilisation means 27 comprise a single float partially surrounding the base section 4, the float having a U-shaped geometry in plan view, and comprising traction means 31, which in this case consist in three motorised reels, each of which comprise a rope attached at its free end to the flotation base 2, such that each one of said motorised reels pays out rope until the floating substructure 1 is ballasted and descends to its operational depth.

[0114] In the embodiment shown in view 6(d), the stabilisation means 27 comprise two barges or vessels that have a motorised reel each comprising a rope attached at its free end to the flotation base 2 (in this embodiment, in particular to a respective extensor arm 19) such that said motorised reel pays out rope as the floating substructure 1 is ballasted and descends to its operational depth.

[0115] Finally, in the embodiment shown in view 6(e), the stabilisation means 27 comprise three floats (although the cross sectional view only shows two) connected to the flotation base 2 via extensor arms 39 which in this case are provisional, and also comprise support vessels 27 provided with launching means 29. In this case, the floats remain emerged during part of the ballasting procedure for the flotation base 2 from but not in the final stages of the ballasting procedure.

[0116] FIG. 7 shows a transport unit 9 in a descending condition corresponding to an embodiment of the installation method according to this invention, in particular during the step of ballasting the flotation base 2 just before applying precisely retaining cables 8 connected by their lower end to downward impelling means. FIG. 7 shows two views representing respective embodiment stages of stabilisation means 27 used in the installation method. Such stabilisation means 27 are intended for stabilising the transport unit 9 during the tasks of applying the downward impelling means and the retaining cables 8 to the transport unit 9, as well as during the ballasting and descent of the flotation base 2 to its operating depth. These stabilisation means 27 are optional in the installation method and, in any case, are preferably detachable and reusable such that they are not part of the floating substructure 1 in its installed condition.

[0117] In the embodiment shown in view 7(a), the stabilisation means 27 comprise three floats that are connected to one another and comprise sliding or guiding means 33, such that they allow the shaft to slide during the ballasting and/or descent of the flotation base 2 while the floats 27 remain at the surface (the drawing only shows two floats due to the type of view used). In this embodiment stage the flotation base 2 is semi-submerged during the transport operation.

[0118] The embodiment shown in view 7(b), shows a subsequent embodiment stage, wherein the flotation base 2 is submerged, while the floats 27 remain at the surface, such that the shaft slides during the ballasting and/or descent of the flotation base 2.

[0119] Reference will now be made to FIGS. 2 to 5, each one of which shows a different embodiment of a floating substructure 1 according to the invention.

[0120] FIG. 2 shows wind turbine means 7 supported by an extended telescopic shaft 3 formed by four tubular segments, that is, a base segment 4 and three superposition segments 5, 32, of which one is the head segment. In turn, the telescopic shaft 3 rests by its base segment 4 on a flotation base 2. In this embodiment the shaft is semi-emerged and the flotation base 2 is submerged, together forming part of a floating substructure 1 for a wind turbine. From the peripheral area of said flotation base 2 emerge three retaining cables 8 (of which only two are visible due to the view shown). These retaining cables 8 are attached by their end opposite the end attached to the flotation base 2 to downward impelling means that consist in attachment means to the seabed which, in this embodiment, are driven piles 12, anchored to the seabed. Said cables extend between the flotation base 2 and the corresponding pile adopting a certain inclination to improve their behaviour regarding horizontal actions that may act upon the floating substructure 1. In this embodiment, the flotation base 2 has different compartments that may be ballasted differentially, allowing to generate a non-uniform distribution of the ballast that counteracts, at least partially, external actions such as waves, sea currents, etc. The ballast material 14 can be a liquid material, a solid material or a mixture of both.

[0121] FIG. 3 shows wind turbine means 7 supported by an extended telescopic shaft 3 formed by four tubular segments, that is, a base segment 4 and three superposition segments 5, 32. In turn, the telescopic shaft 3 rests by its base segment 4 on a flotation base 2. In this embodiment the shaft is semi-emerged and the flotation base 2 is submerged, together forming part of a floating substructure 1 for a wind turbine. From the peripheral area of said flotation base 2 emerge three retaining cables 8 (of which only two are visible due to the view shown). Specifically, in this embodiment the flotation base 2 comprises three extensor arms 19 that extend laterally out of said flotation base 2 and from each of said extensor arms 19 leaves a corresponding retaining cable 8. These retaining cables 8 are attached by their end opposite the end attached to the flotation base 2 to downward impelling means that consist in attachment means to the seabed which, in this embodiment, are massive elements resting on the seabed for each cable, in the form of hollow concrete boxes 34. The interior of the boxes 34 is filled with ballast material 14, by which said boxes 34 are anchored to the seabed by gravity. Said cables extend vertically between the flotation base 2 and the corresponding box 34. The flotation base 2 also includes a pressurised gas chamber 22 that is explained in more detail below. In this embodiment, the flotation base 2 is not ballasted.

[0122] In this embodiment, the cables may be arranged at an angle to the vertical such that the lower end of each cable is farther from the central vertical axis 10 of the shaft than the upper end of the same cable, without thereby departing from the scope of the invention.

[0123] FIG. 4 shows wind turbine means 7 supported by an extended telescopic shaft 3 formed by four tubular segments, that is, a base segment 4 and three superposition segments 5, 32. In turn, the telescopic shaft 3 rests by its base segment 4 on a flotation base 2. In this embodiment the shaft is semi-emerged and the flotation base 2 is submerged, together forming part of a floating substructure 1 for a wind turbine. From the peripheral area of said flotation base 2 emerge three retaining cables 8 (of which only two are visible due to the view shown). These retaining cables 8 are attached by their end opposite the end attached to the flotation base 2 to downward impelling means that consist in attachment means to the seabed which, in this embodiment, comprise a massive element resting on the seabed, in the form of a hollow concrete box 34 common to all cables. The interior of the common box 34 is filled with ballast material 14, by which said common box 34 is anchored to the seabed by gravity. Said cables extend vertically between the flotation base 2 and said common box 34. In this embodiment, the flotation base 2 is ballasted, allowing to generate a non-uniform distribution of the ballast that counteracts, at least partially, external actions such as waves, sea currents, etc.

[0124] In this embodiment, the cables may be arranged at an angle to the vertical such that the lower end of each cable is farther from the central vertical axis 10 of the shaft than the upper end of the same cable, without thereby departing from the scope of the invention.

[0125] FIG. 5 represents wind turbine means 7 supported on an extended telescopic shaft 3 formed by two tubular segments, a base segment 4 in this case made from concrete and a head segment 32, in this case metallic. In turn, the telescopic shaft 3 rests by its base segment 4 on a flotation base 2. In this embodiment the shaft is emerged and the flotation base 2 is semi-submerged, together forming part of a floating substructure 1 for a wind turbine. From the peripheral area of said flotation base 2 emerge three retaining cables 8 (of which only two are visible due to the view shown). Specifically, in this embodiment the flotation base 2 comprises three extensor arms 19 that extend laterally out of said flotation base 2 and from each of said extensor arms 19 leaves a corresponding retaining cable 8. These retaining cables 8 are attached by their end opposite the end attached to the flotation base 2 to downward impelling means that consist in attachment means to the seabed which, in this embodiment, are driven piles 12, anchored to the seabed. Said cables extend vertically between the flotation base 2 and the corresponding pile. In this embodiment, the flotation base 2 is not ballasted.

[0126] In addition, the floating substructure 1 includes three stays 20, each of which starts at a corresponding extensor arm 19 and is joined by its other end to the upper end of the base segment 4 of the shaft of the floating substructure 1. In fact, in this embodiment three strands are provided, each of which is attached on one end to its corresponding pile 12 and on the other end to the upper end of the base segment 4 of the shaft of the floating substructure 1. Each of said strands passes through a deflection element 21 placed at the free end of a respective extensor arm 19, such that each strand is divided into a bottom segment reaching from an extensor arm 19 to the corresponding pile 12 and an upper segment that extends from an extensor arm 19 to the upper end of the base segment 4 of the shaft of the floating substructure 1. Then each of said lower segments forms each of said retaining cables 8, and each of said upper segments forms each one of said stays 20. Said deviation element 21 in this embodiment is a plastic element with a curved face that allows the cable to deflect, adopting a suitable bending radius.

[0127] With reference to FIG. 8, it shows intermediate stages of the installation method of the embodiment of FIG. 4. FIG. 8(a) shows a transport unit 9 in a transportation stage, where a self-buoyant and free-standing transport unit 9, formed by a floating base 2, a telescopic shaft 3 in folded condition supported by said flotation base 2, and wind turbine means 7 joined to the head segment 32 of said telescopic shaft 3 is towed by a tug boat 28. In this embodiment, the downward impelling means comprise attachment means to the seabed consisting in an abuttable massive element intended to rest on the seabed, in the form of a hollow concrete box 34 common to all cables, the plan view of which coincides substantially with the plan of the flotation base 2. In this transport stage, said common box 34 is abutted on the lower flat surface of said transport unit 9 and is transported together with it. Said common box 34 is abutted to the flotation base 2 in this transport stage via the retaining cables 8 or via any known fastening means which can be released once this transport stage is completed.

[0128] In fact, once the transport stage illustrated in view 8(a) is completed and prior to the moored condition illustrated in view 8(b), the common box 34 is ballasted so that it descends until resting on the seabed, at the same time as the retaining cables 8 that attach said common box 34 to the flotation base 2 are paid out.

[0129] View 8(b) then shows the transport unit 9 with the abuttable massive element in its moored and ballasted condition, where the retaining cables 8 are totally paid out and the common box 34 is resting on the seabed, and the flotation base 2 is substantially floating at the surface of the water.

[0130] After this and before the installed condition illustrated in view 8(c), traction means 31 for the retaining cables 8 are used that haul in a predetermined amount of cable, which causes the descent of the flotation base 2 to its operating depth since the ballasted common box 34 remains anchored to the seabed due to its weight. Said traction means 31 are in this case heavy-lift strand jacks that are operated from accessible cabins inside the flotation base 2.

[0131] The view 8(c) thus shows the floating substructure 1 according to this invention in said installed condition, where the cables are paid out in the precise measure so that the flotation base 2 is located at its operating depth, and the common box 34 rests on the seabed. In this case the shaft of the floating substructure 1 is semi-emerged and the flotation base 2 is submerged.

[0132] Said traction means 31 can already be applied initially to the floating substructure 1 and optionally be used to pay out the retaining cable 8 during the ballasting stage for the common abuttable box 34. Similarly, said cables can already be applied initially to the common box 34 and be collected during the transport stage via cable collection means 30.

[0133] In the embodiment according to the invention of FIG. 8, the massive element, abutting or transported independently, provides the required stability through the retaining cables 8 during the ballasting process of the flotation base 2, even if the flotation base 2 is fully submerged. For this reason, the installation process can be performed without having to use flotation stabilisation means 27.

[0134] FIGS. 9 and 10 show corresponding embodiments of a floating substructure 1 for a wind turbine according to the present invention, in which the flotation base 2 is formed by a plurality of hollow bodies. Specifically, FIG. 9 shows an embodiment of a floating substructure 1 for a wind turbine according to the present invention in which the flotation base 2 is formed by a main hollow body and two additional hollow bodies, all hollow bodies joined to each other by lattice type structures; and FIG. 10 shows an embodiment of the floating structure 1 for a wind turbine according to the present invention in which the flotation base 2 is formed by a main hollow body and three additional hollow bodies, each one of the additional hollow bodies being joined to the main hollow body by a bar type structure which in this case is also formed by a prismatic hollow body.

[0135] In the embodiment of FIG. 9, the main hollow body is disc shaped and supports on it a non-telescopic tubular shaft 40 which in turn supports the wind turbine means 7, and the additional hollow bodies are arranged such that they form a triangular layout with the main hollow body. In this embodiment, the retaining cables 8 each emerge one from each hollow body and are attached by their end opposite the end attached to the flotation base 2 to downward impelling means that consist in attachment means to the seabed which, in this embodiment, are driven piles 12, anchored to the seabed.

[0136] In turn, in the embodiment of FIG. 10 the main hollow body is disc shaped and supports the shaft of the floating substructure 1, and the additional hollow bodies are arranged around said main hollow body at positions equidistant to each other and to said main body. In this embodiment, the retaining cables 8 each emerge one from each one of the additional hollow bodies and are attached by their end opposite the end attached to the flotation base 2 to downward impelling means that consist in attachment means to the seabed which, in this embodiment, are driven piles 12, anchored to the seabed.

[0137] The floating substructure 1 of this embodiment also comprises three stays 20, each of which arise from each one of the additional hollow bodies and are joined to the upper end of the base segment 4 of the shaft of the floating substructure 1. Preferably the lower end of a stay 20 of a floating construction according to the present invention will be joined to the flotation base 2 of the floating structure at a position close to or aligned with the point of union of the upper end of one of the retaining cables 8 to the flotation base 2.

[0138] In this embodiment the segments of the telescopic shaft 3 are formed by prefabricated half-segments which, joined at vertical joints 38, form essentially cylindrical segments of the shaft. Similarly, formed between said cylindrical segments are horizontal joints 37 along the shaft.

[0139] The tower segments formed by half-segments can be preassembled in dry dock and/or in port to form full segments, and then the full segments attached to the flotation base 2, as an intermediate step also applicable to other offshore substructures that use telescopic towers such as that described in the present invention.

[0140] Lastly, FIG. 11 shows a detailed view of an embodiment of a floating substructure 1 according to the present invention, specifically a flotation base 2 with extensor arms 19 that includes a pressurised gas chamber 22 and Wells type turbine 23 to harness wave power and which correspond to the gas chamber 22 of the embodiment in FIG. 3.

[0141] More specifically, the peripheral wall of the flotation base 2 is extended downward such that a cavity facing downward is defined. This cavity initially contains air which is trapped when the flotation base 2 is placed in the body of water of the site. In addition when the flotation base 2 is submerged said trapped air is compressed, forming said pressurised gas chamber 22. Alternatively or additionally, air or any other pressurised gas can be introduced in said pressurised gas chamber 22. In addition, the flotation base 2 is compartmentalised. Each compartment has an opening in the end wall and, in corresponding with each such opening, a Wells type turbine 23. In addition, the compartments also have an opening in each partition wall between compartments. The partitions between compartments also extend downward such that said pressurised gas chamber 22 is also compartmentalised.

[0142] The power generation system of a Wells type turbine 23 is based on the OWC (oscillating water column) technology, which relies on the pressure changes generated by waves on the air chamber 22 that drive air through the Wells type turbines 23.

[0143] The presence of Wells type turbines 23 in the embodiments of the present invention to generate power from waves in which the floating construction is a floating substructure 1 for a wind turbine is particularly appropriate as all the infrastructure provided for evacuating the power generated by the wind turbine is already present.

[0144] In addition, the pressurised gas chamber 22 can comprise means for controlling and regulating the volume and/or pressure of the gas contained in said pressurised gas chamber 22, in order to regulate or help regulate the depth of the floating substructure 1 and to adjust or help adjust the resonant frequency of the gas chamber 22 to improve the efficiency of the oscillating water column system.

[0145] Naturally, the principal of the present invention remaining the same, the embodiments and constructive details may vary considerably from those described and represented for illustration purposes and in a non-limiting sense, without thereby departing from the scope of the present invention as defined in the accompanying claims.

[0146] For example, by way of illustration, in light of the teachings of this document it would be obvious for a person skilled in the art that the turbine means could comprise up-wind or down-wind turbines, as well as any number of blades, not being limited to three blades as shown for illustration purposes.

[0147] Also for purposes of illustration, although the present document refers to cables used to connect the downward impelling means and the flotation base, a person skilled in the art will understand that instead of cables these can be chains, rods, slings or the like, without thereby departing from the scope of the invention.

[0148] Also for purposes of illustration, a person skilled in the art in view of the teachings of the present document will find it obvious that the lateral extensions referred to herein as arms can be coupled or even integrated in a lateral extension in the form of a continuous crown or as crown arcs, or in any other type of structure, without thereby departing from the scope of the invention. Similarly, it will be obvious for a person skilled in the art in view of the teachings of the present document that although essentially circular shapes are preferred for many of the elements comprised in the invention such as the shafts, hollow bodies or boxes, many other shapes are possible without departing from the scope of the invention, such as square or rectangular shapes, or regular and irregular polygons.

[0149] Known techniques may be used to regulate the volume and/or weight of the ballast material of the massive elements, such as those analogous to that used in submarines to control depth.