Floating Foundation for Wind Turbines and Method for Manufacturing a Floating Foundation for Wind Turbines

Abstract

A method for manufacturing a floating foundation for a wind turbine, wherein the floating foundation comprises load carrying structures and a plurality of air pontoons attached to the load carrying structures, is disclosed. The method includes cutting one or more fiber-reinforced composite structures, such as wind turbine blades, into a plurality of smaller pieces comprising fiber-reinforced composite, molding the air pontoons from the smaller pieces, and attaching the air pontoons to the load carrying structures.

Claims

1. A method for manufacturing a floating foundation for a wind turbine, the floating foundation comprising load carrying structures and a plurality of air pontoons attached to the load carrying structures, wherein each air pontoon is attached to a base portion of the load carrying structures, wherein the method comprises: a) cutting one or more fiber-reinforced composite structures into a plurality of smaller pieces comprising fiber-reinforced composite material; b) molding the air pontoons from the smaller pieces; and c) attaching the air pontoons to the load carrying structures, wherein the step of molding the air pontoons from the smaller pieces comprises: filling a quantity of smaller pieces and resin into a mold; closing the mold; opening the mold; and removing the molded air pontoon from the mold, wherein mechanical properties of the smaller pieces are determined prior to molding the air pontoon and wall thicknesses of the air pontoon are selected such that a mechanical strength of the air pontoon is equal to or above a predefined selected level.

2. The method according to claim 1, further comprising adding additional fibers into the mold in order to increase the mechanical strength of the air pontoon.

3. The method according to claim 1, further comprising manufacturing the floating foundation as a plurality of modular components, wherein the modular components are configured to be attached to each other by mechanical structures.

4. A floating foundation for a wind turbine, the floating foundation comprising load carrying structures and a plurality of air pontoons attached to the load carrying structures, wherein the air pontoons are made from recycled one or more fiber-reinforced composite structures, wherein the floating foundation is manufactured in a manner, in which a) one or more fiber-reinforced composite structures are cut into a plurality of smaller pieces comprising fiber-reinforced composite material; b) the air pontoons are molded from the smaller pieces; and c) the air pontoons are attached to the load carrying structures, wherein mechanical properties of the smaller pieces are determined prior to molding the air pontoon and wall thicknesses of the air pontoon are selected such that a mechanical strength of the air pontoon is equal to or above a predefined selected level.

5. The floating foundation according to claim 4, wherein each air pontoon comprises a plurality of air pontoon segments that are attached to each other.

6. The floating foundation according to claim 4, wherein the air pontoons are air-filled.

7. The floating foundation according to claim 4, wherein the air pontoons are hermetically sealed.

8. The floating foundation according to claim 4, wherein each air pontoon comprises an attachment portion that is arranged and configured to be brought into engagement with a corresponding attachment member arranged at a base portion.

9. The floating foundation according to claim 8, wherein the base portion is made of reinforced and pre-tensioned concrete.

10. The floating foundation according to claim 8, wherein the base portion comprises several base portion segments that are configured to be mechanically attached to each other by fastening structures that are integrated in the base portion, wherein the floating foundation is configured to be arranged in: a) a first disassembled configuration, in which the base portion segments of the base portion and the air pontoons have not been attached to each other; and b) a second assembled configuration, in which the base portion segments of the base portion and the air pontoons have been attached to each other to form an assembled floating foundation.

11. The floating foundation according to claim 5, wherein the air pontoons are hermetically sealed.

12. The floating foundation according to claim 6, wherein the air pontoons are hermetically sealed.

13. The floating foundation according to claim 9, wherein the base portion comprises several base portion segments that are configured to be mechanically attached to each other by fastening structures that are integrated in the base portion, wherein the floating foundation is configured to be arranged in: a) a first disassembled configuration, in which the base portion segments of the base portion and the air pontoons have not been attached to each other; and b) a second assembled configuration, in which the base portion segments of the base portion and the air pontoons have been attached to each other to form an assembled floating foundation.

14. The floating foundation according to claim 5, wherein each air pontoon comprises an attachment portion that is arranged and configured to be brought into engagement with a corresponding attachment member arranged at a base portion.

15. The floating foundation according to claim 14, wherein the base portion is made of reinforced and pre-tensioned concrete.

16. The floating foundation according to claim 14, wherein the base portion comprises several base portion segments that are configured to be mechanically attached to each other by fastening structures that are integrated in the base portion, wherein the floating foundation is configured to be arranged in: a) a first disassembled configuration, in which the base portion segments of the base portion and the air pontoons have not been attached to each other; and b) a second assembled configuration, in which the base portion segments of the base portion and the air pontoons have been attached to each other to form an assembled floating foundation.

17. The floating foundation according to claim 15, wherein the base portion comprises several base portion segments that are configured to be mechanically attached to each other by fastening structures that are integrated in the base portion, wherein the floating foundation is configured to be arranged in: a) a first disassembled configuration, in which the base portion segments of the base portion and the air pontoons have not been attached to each other; and b) a second assembled configuration, in which the base portion segments of the base portion and the air pontoons have been attached to each other to form an assembled floating foundation.

18. The floating foundation according to claim 7, wherein each air pontoon comprises an attachment portion that is arranged and configured to be brought into engagement with a corresponding attachment member arranged at a base portion.

19. The floating foundation according to claim 18, wherein the base portion is made of reinforced and pre-tensioned concrete.

20. The floating foundation according to claim 18, wherein the base portion comprises several base portion segments that are configured to be mechanically attached to each other by fastening structures that are integrated in the base portion, wherein the floating foundation is configured to be arranged in: a) a first disassembled configuration, in which the base portion segments of the base portion and the air pontoons have not been attached to each other; and b) a second assembled configuration, in which the base portion segments of the base portion and the air pontoons have been attached to each other to form an assembled floating foundation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The contents of this disclosure will become more fully understood from the detailed description given herein below. The accompanying drawings are given by way of illustration only, and thus, they are not limitative of the present invention. In the accompanying drawings:

[0070] FIG. 1 shows a side view of a floating foundation according to an embodiment;

[0071] FIG. 2 shows another side view of the floating foundation shown in FIG. 1;

[0072] FIG. 3 shows a close-up view of the load carrying structures of the floating foundation shown in FIG. 1 and FIG. 2;

[0073] FIG. 4 shows a top view of the perspective view of the floating foundation shown in FIG. 1 and FIG. 2;

[0074] FIG. 5 shows a perspective top view of a segmented air pontoon of a floating foundation according to an embodiment;

[0075] FIG. 6 shows a perspective top view of a segmented air pontoon of a floating foundation according to an embodiment;

[0076] FIG. 7 shows a perspective top view of a segmented air pontoon of a floating foundation according to an embodiment;

[0077] FIG. 8 shows a schematic view of steps of a method according to an embodiment;

[0078] FIG. 9 shows a schematic view of a step of a method according to an embodiment;

[0079] FIG. 10A shows a cross-sectional view of an air pontoon attached to a base portion of a floating foundation according to an embodiment;

[0080] FIG. 10B shows a first cross-sectional close-up view of a portion of the air pontoon shown in FIG. 10A;

[0081] FIG. 10C shows a second cross-sectional close-up view of a portion of the air pontoon shown in FIG. 10A;

[0082] FIG. 11A shows a cross-sectional view of a floating foundation shown in FIG. 1 and FIG. 2; and

[0083] FIG. 11B shows a close-up cross-sectional view of the floating foundation shown in FIGS. 10A-10C.

DETAILED DESCRIPTION

[0084] Referring now in detail to the drawings for the purpose of illustrating embodiments of the present invention, a floating foundation 2 is illustrated in FIG. 1.

[0085] FIG. 1 is a schematic side view of a floating foundation 2 according to an embodiment. The floating foundation 2 comprises load carrying structures formed as a base portion 28 and a centrally arranged tubular member 24 protruding upwardly from the base portion 28. A plurality of cross members 26 extend between the base portion 28 and the tubular member 24. The cross members 26 support the tubular member 24 by transferring horizontal loads to the base portion 28.

[0086] The floating foundation 2 comprises a plurality of air pontoons 8 that are attached to a base portion 28. The air pontoons 8 are manufactured from fiberglass recycled from wind turbine blades.

[0087] The base portion 28 is fixed to anchor members 34, 34, 34 by wires 32, 32, 32. The anchor members 34, 34, 34 are arranged on or fixed to the seabed. A tower 22 of a wind turbine 4 is attached to the tubular member 24. The wind turbine 4 comprises blades 10.

[0088] FIG. 2 illustrates another side view of the floating foundation 2 shown in FIG. 1. The floating foundation 2 is floating in water. The air pontoons 8 provide upward forces that keep the floating foundation 2 floating in the water. It can be seen that the base portion 28 is arranged below the water level 30.

[0089] FIG. 3 illustrates a close-up view of the load carrying structures 24, 26, 28 of the floating foundation shown in FIG. 1 and FIG. 2. The base portion 28 comprises three base segments that are attached to and protrude from a central connection portion 36. A support portion 38 is arranged at the distal end of each base segment of the base portion 28. Each of the support portions 38 is arranged and configured to receive an air pontoon 8. Attachment of the air pontoons 8 to the support portions 38 may be carried out by using various types of engaging fixation structures provided at the support portions 38 and at the air pontoons 8. In an embodiment, attachment of an air pontoon 8 to a support portion 38 may be carried out by screwing one or more screws into a corresponding number of bores extending through the support portion 38 and through a portion of the underlying air pontoon 8.

[0090] It can be seen that a wire 32, 32, 32 is attached to each support portion 38. In an embodiment, a wire 32, 32, 32 is attached to the bottom portion of each support portion 38.

[0091] A cross member 26 extends between the tubular member 24 and each base segment of the base portion 28. Each cross member 26 is fixed to the top side of the base segment to which it is attached. The point of fixation is placed adjacent to the support portion 38. Hereby, it is possible to apply a long cross member 26. In an embodiment, the angle between the cross member 26 and the tubular member 24 is about 45 degrees. It can be seen that a tower 22 has been received by the tubular member 24.

[0092] FIG. 4 illustrates a top view of the perspective view of the floating foundation 2 shown in FIG. 1, FIG. 2 and FIG. 3. It can be seen that the floating foundation 2 comprises three base segments that are evenly distributed around the central portion of the floating foundation 2. Accordingly, the angle between adjacent base segments is 120 degrees.

[0093] FIG. 5 illustrates a perspective top view of a segmented air pontoon 8 of a floating foundation according to an embodiment. The air pontoon 8 initially comprises a plurality of air pontoon segments 40 (see the left side of FIG. 5) that are joined to form an air pontoon 8 (shown on the right side of FIG. 5). Each air pontoon segment constitutes an eighth of a cylinder.

[0094] In an embodiment, the air pontoon segments 40 are equally sized.

[0095] It is possible to vary the number of air pontoon segments 40.

[0096] FIG. 6 illustrates a perspective top view of a segmented air pontoon 8 of a floating foundation according to an embodiment. The segmented air pontoon 8 comprises three layers. Each layer 41 comprises four air pontoon segments 40 shaped as quarters of a cylinder. At the left side, three layers 41 of segments 8 are spaced from each other. At the right side, the air pontoon segments 40 have been attached to each other.

[0097] In an embodiment, the air pontoon segments 40 are equally sized.

[0098] FIG. 7 illustrates a perspective top view of a segmented air pontoon 8 of a floating foundation according to an embodiment. The segmented air pontoon 8 comprises three layers. Each layer 41 comprises two air pontoon segments 40 shaped as semi cylinders. At the left side, three layers of segments 8 are spaced from each other. At the right side, the segments have been attached to each other. It may be an advantage that the air pontoon segments 40 are equally sized.

[0099] For all segments shown in FIG. 5, FIG. 6 and FIG. 7 it is possible to attach the air pontoon segments 40 to each other by glue, for example. In an embodiment, the air pontoon segments 40 are attached to each other during a molding process.

[0100] The molding process may comprise the following steps: [0101] Opening a mold; [0102] Placing the air pontoon segments 40 in a mold; [0103] Closing the mold; [0104] Injecting resin into the mold; and [0105] Opening the mold and removing the molded air pontoon 8.

[0106] FIG. 8 illustrates a schematic view of the steps of a method according to an embodiment.

[0107] In the first step, a wind turbine blade 10 is cut into smaller pieces using a cutting tool 42. In an embodiment, the cutting tool 42 is used to cut the wind turbine blade 10 into pieces having a length that is 2 meters or less. The cutting tool 42 may be any tool that is suitable for cutting the wind turbine into smaller pieces. In an embodiment, the cutting tool 42 is a power saw.

[0108] In the second step, the pieces that are cut during the first step are cut into smaller pieces 12 using a cutting device 44. In an embodiment, the smaller pieces 12 may have a length in the range 5-50 mm.

[0109] In the third step, the smaller pieces 12 that are cut during the second step are used to mold an air pontoon. As shown in FIG. 8, the molding of the air pontoon 8 is produced by molding a plurality of air pontoon segments that can be joined to form an air pontoon. Each air pontoon segment is molded by sandwiching smaller pieces 12 between two spaced apart mats 46, 46 and adding resin 20 to the smaller pieces 12. In an embodiment, glass fibers or other types of fibers (aramid fibers or carbon fibers) are added in order to increase the strength of the air pontoon.

[0110] In the fourth step, pressure is provided to form the air pontoon segment or the air pontoon. Heating and/or ultraviolet light may be used to accelerate the curing process.

[0111] FIG. 9 illustrates a schematic view of a step of a method according to an embodiment. Small pieces 12 of recycled wind turbine blades and resin are injected into a mold 14 having a first mold portion 16 and a second mold portion 18. When the air pontoon segment 40 has cured, the mold 14 is opened and the air pontoon segment 40 is removed from the mold 14. The method may comprise further steps, in which a plurality of air pontoon segments 40 are joined to form an air pontoon. An air pontoon 8 may comprise air pontoon segments of different shapes.

[0112] FIG. 10A illustrates a cross-sectional view of an air pontoon 8 attached to a support portion 38 that is arranged in the distal end of each base portion segment of a base portion of a floating foundation 2 according to an embodiment. FIG. 10B illustrates a first cross-sectional close-up view of a portion of the air pontoon 8 shown in FIG. 10A. FIG. 10C illustrates a second cross-sectional close-up view of a portion of the air pontoon 8 shown in FIG. 10A.

[0113] The air pontoon 8 comprises a plurality of air-filled air pontoon segments 40. The air pontoon segments 40 are joined to form an air pontoon 8 constituting a one-piece body. The air pontoon 8 comprises an attachment portion 48 provided with a through bore 54. The underlying support portion 38 is provided with a threaded bore 50 that is arranged and configured to receive a screw 52 provided with a corresponding outer thread.

[0114] In FIG. 10A and in FIG. 10B, the screw 52 has not yet been screwed into the threaded bore 50 in the support portion 38.

[0115] In FIG. 10C, however, the screw 52 has been screwed into the threaded bore 50 in the support portion 38. Hereby, the screw 52 is used to fix the attachment portion 48 and thus the air pontoon 8 to the support portion 38.

[0116] It is important to emphasize that the air pontoon 8 can be attached to the support portion 38 in various other ways.

[0117] FIG. 11A illustrates a cross-sectional view of a floating foundation 2 shown in FIG. 1 and FIG. 2. FIG. 11B illustrates a close-up cross-sectional view of the floating foundation 2 shown in FIGS. 10A-10C.

[0118] The floating foundation 2 comprises load carrying structures formed as a base portion 28 and a centrally arranged tubular member 24 protruding upwardly from the base portion 28. The load carrying structures correspond to the one shown in and explained with reference to FIG. 1 and FIG. 2. The load carrying structures include a plurality of cross members 26 that are arranged and configured to support the tubular member 24 by transferring horizontal loads to the base portion 28. The cross members 26 extend between the base portion 28 and the tubular member 24.

[0119] The floating foundation 2 comprises a plurality of air pontoons 8 that are manufactured from fiberglass recycled from wind turbine blades. The air pontoons 8 are attached to a base portion 28.

[0120] The base portion 28 is attached to anchor members 34, 34 by wires 34, 34. The anchor members 34, 34, 34 are configured to be arranged on or fixed to the seabed. The floating foundation 2 comprises a tubular member 24 that is arranged and configured to receive a tower 22 of a wind turbine. It can be seen that a tower 22 of a wind turbine has been received by and thus is attached to the tubular member 24.

[0121] Each of the air pontoons 8 comprises a plurality of segments that are joined to constitute the air pontoon 8. In an embodiment, the segments of the air pontoons 8 are filled with a media having a lower density than water. In a n embodiment, the segments of the air pontoons 8 are air-filled. It is important that each air pontoon 8 is sealed in order to prevent water from entering into the air pontoon 8.

[0122] In an embodiment, each air pontoon 8 is hermetically sealed.

LIST OF REFERENCE NUMERALS

[0123] 2 Floating foundation [0124] 4 Wind turbine [0125] 6 Load carrying structure [0126] 8 Air pontoon [0127] 10 Wind turbine blade [0128] 12 Small pieces [0129] 14 Mold [0130] 16 First mold portion [0131] 18 Second mold portion [0132] 20 Resin [0133] 22 Tower [0134] 24 Tubular member [0135] 26 Cross member [0136] 28 Base portion [0137] 30 Water level [0138] 32, 32, 32 Wire [0139] 34, 34, 34 Anchor member [0140] 36 Central connection portion [0141] 38 Support portion [0142] 40 Air pontoon segment [0143] 41 Layer [0144] 42 Cutting tool [0145] 44 Cutting device [0146] 46, 46 Mat [0147] 48 Attachment portion [0148] 50 Attachment member [0149] 52 Fixation structure [0150] 54 Attachment member