WO2010138622A2

WO2010138622A2 - Pivoting installation system and method for an offshore wind

Info

Publication number: WO2010138622A2
Application number: PCT/US2010/036241
Authority: WO
Inventors: Peter Graham Harris
Original assignee: Technip France
Priority date: 2009-05-29
Filing date: 2010-05-26
Publication date: 2010-12-02
Also published as: WO2010138622A3

Abstract

The disclosure provides a method and system for installing an offshore wind turbine assembly independent of cranes and derricks. The system includes a support structure with a centrally disposed receptacle for the wind turbine assembly, a wind turbine assembly having a tower, turbine, and blades, and a transportation structure, such as a barge, to transport the wind turbine assembly to the support structure. The barge offloads the wind turbine assembly by placing the tower into a receptacle on the support structure. The receptacle is disposed below an elevation of the barge. The remainder of the wind turbine assembly is pivoted about the receptacle using the barge or winch cables into an upright position and secured to the support structure. The invention eliminates the need for offshore crane services for the installation of the wind turbine assembly tower, turbine or blades, and works with either fixed or floating support structures.

Description

[0001] TITLE OF THE INVENTION

[0002] Pivoting Installation System and Method for an Offshore Wind

Turbine

[0003] CROSS REFERENCE TO RELATED APPLICATIONS [0004] This application claims the benefit of U.S. Provisional Application

No. 61/182,558, filed May 29, 2009, titled "PIVOTING INSTALLATION SYSTEM AND METHOD FOR AN OFFSHORE WIND."

[0005] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0006] Not applicable.

[0007] REFERENCE TO APPENDIX

[0008] Not applicable.

[0009] BACKGROUND OF THE INVENTION

[0010] Field of the Invention.

[0011] The disclosure relates generally to a system and method for offshore wind turbine installation. More specifically, the disclosure relates to a system and method for a pivoting installation of an offshore wind turbine.

[0012] Description of the Related Art.

[0013] The use of offshore wide turbines is becoming an increasingly feasible and desirable form of power generation. In implementing the concept of windmills, generally bigger is better-the larger the turbine motor, the more power is generated. Thus, massive structures are being and have been built. Some of these structures are 50 meters (m) to 100 m tall and weigh 500 metric tonnes or more, and larger ones may be made in the future.

[0014] Typically, wind turbines installed offshore involve the use of cranes to lift the tower, turbine, and turbine blades into position, such as shown in DE

10332383 B4. Offshore crane barges and services can be expensive. When considering multiple turbine units, the multiple lifts, and crane assets deployed, it can add considerable cost to the offshore installation when compared to land- based installation, and therefore affect overall commercial viability of the offshore wind turbine installation.

[0015] One known alternative to the use of offshore cranes is disclosed in

US Publ. No. 2004/0169376. US Publ. No. 2004/0169376 teaches that a wind turbine is preassembled on a floating structure with the blades connected to the turbine and the turbine connected to the tower. The floating structure is transported in an upright orientation with the telescopic support compacted to the site of installation. The floating structure is ballasted and becomes a gravity base that supports the preassembled wind turbine, and the telescopic support is deployed to a full length. A challenge with this kind of procedure can be the instability during the transportation and cost of installing, maintaining, and later moving the wind turbine.

[0016] Another known system, GB 2344843, states that it is a gravity securing system for a piece of offshore generating equipment such as a wind turbine consisting of gravity legs arranged in a star pattern on the seabed and connected to a mast 3 stabilized by tensioned cables. The latter are attached to the legs at points 3e along their length. It can be installed by utilizing the legs as hulls of a transportation vessel, launching the system, with the legs arranged alongside one another with the mast, turbine and associated winching equipment on board, and then towing the complete system out to the installation site for sinking the legs thereat, after the legs have been arranged into the configuration required by the seabed contours. Addition of a further pair of buoyancy hulls 2 for temporarily supporting the mast 3 facilitate raising the mast and turbine as a result of sinking the legs, the temporary pair of buoyancy hulls providing a fulcrum.

[0017] There remains a need for an improved system and method for installing a wind turbine that is generally assembled prior to the installation.

[0018] BRIEF SUMMARY OF THE INVENTION [0019] The disclosure provides a method and system for installing an offshore wind turbine assembly onto a separate offshore support structure, independent of cranes and derricks. The system includes an offshore support structure to support the installed wind turbine assembly, a wind turbine assembly having a tower, turbine, and blades, and a transportation structure, such as a barge, to transport the wind turbine assembly to the support structure. The offshore support structure can be a triangular tubular steel jacket style configuration forming a pyramidal shape with a centrally disposed receptacle adapted to receive an end of the tower. The offshore support structure can be formed in other shapes as well. The receptacle is generally disposed at the bottom of the offshore support structure. In some embodiments, the receptacle can be movable between a high position on the support structure and a low position to facilitate at least one method of installation. The offshore support structure also can include a floatation tank at each corner to allow the structure to be floated and towed to the installation site. If the offshore support structure is to be submerged at the site, the floatation tanks can be ballasted with water, cement, or high-density mud. The floatation tanks can also be used as pile guides to secure the offshore support structure into position. One leg of the offshore support structure can have a double member to act as a guide for the tower as the tower is pivoted and lowered into position during installation. The top of the offshore support structure incorporates a clamp to capture and secure the tower when erected into the offshore support structure.

[0020] In general, the barge offloads the wind turbine assembly by placing the tower into the receptacle on the offshore support structure. The receptacle is disposed below an elevation of the barge. The remainder of the wind turbine assembly is pivoted about the receptacle using the barge or winch cables into an upright position and secured to the support structure. The invention eliminates the need for offshore crane services for the installation of the wind turbine assembly tower, turbine or blades, and works with either fixed or floating support structures.

[0021] This installation process is reversible and so this becomes an efficient and less costly way compared to conventional crane methods to manage major repairs, change outs of equipment, upgrades or decommissioning. As technology rapidly advances, the ability to upgrade wind turbine assemblies to develop more electricity may be an important feature which could be more viable given the disclosure herein compared to conventional and expensive crane installation methods.

[0022] The disclosure provides a method of installing a wind turbine assembly having a tower at an offshore installation site into an offshore support structure having a receptacle disposed at a first elevation and a clamp disposed at a second elevation different from the first elevation, the wind turbine assembly having a tower, the method comprising: positioning an offshore support structure at an offshore installation site; transporting the wind turbine assembly to the installation site; elevating at least a portion of the wind turbine assembly; inserting a portion of the tower into the receptacle on the offshore support structure at the installation site; pushing the tower with a barge into at least a partially upright position after the tower is inserted into the receptacle on the offshore support structure; and pivoting the wind turbine assembly relative to the offshore support structure into an upright position while the tower is engaged with the receptacle.

[0023] The disclosure also provides a system for installing a wind turbine assembly at an offshore installation site into an offshore support structure, comprising: an offshore support structure having a receptacle at a first elevation and a clamp at a second elevation different from the first elevation; the wind turbine assembly having a tower, a turbine coupled to the tower, and at least one blade coupled to the turbine; a barge adapted to support the wind turbine assembly during transportation to the offshore installation site; means for inserting a portion of the tower into the receptacle on the offshore support structure; and means for pivoting the wind turbine assembly about the receptacle into an upright position.

[0024] The disclosure further provides an offshore support structure for a wind turbine assembly having a tower for installation to the offshore support structure at an offshore installation site, comprising: a plurality of legs coupled together that are uncoupled to the wind turbine assembly prior to the installation at the offshore installation site; a plurality of floatation tanks coupled to the legs; a receptacle coupled to the legs at a first elevation and adapted to receive a portion of the tower of the wind turbine assembly when the tower is disposed in a non- vertical position; and a clamp coupled to the legs at a second elevation different from the first elevation, the clamp being disposed in vertical alignment with the receptacle, the clamp being adapted to couple the tower to the framework when the tower has been pivoted relative to the offshore support structure to a vertical position at the installation site.

[0025] BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE

DRAWINGS

[0026] Figure 1 is a top view schematic diagram illustrating an exemplary embodiment of a wind turbine assembly installed on a transportation barge.

[0027] Figure 2 is a side view schematic diagram illustrating an exemplary embodiment of a wind turbine assembly installed on the transportation barge.

[0028] Figure 3 is a perspective view schematic diagram illustrating an exemplary embodiment of the offshore support structure to which the wind turbine assembly is installed.

[0029] Figure 3A is a perspective view schematic diagram illustrating an alternative receptacle for the offshore support structure of Figure 3 or Figure 3A to which the wind turbine assembly is installed.

[0030] Figure 4 is a side view schematic diagram illustrating the wind turbine assembly on the barge adjacent to the offshore support structure of Figure 3 to be installed thereon.

[0031] Figure 5 is a side view schematic diagram illustrating the wind turbine assembly on the barge with a tower inserted into a receptacle on the offshore support structure.

[0032] Figure 5A is a side view schematic diagram illustrating the wind turbine assembly in an near upright position with a tower inserted into a receptacle on the offshore support structure. [0033] Figure 6 is a side view schematic diagram illustrating the wind turbine assembly installed to the offshore support structure in an upright position.

[0034] Figure 7 is a perspective view schematic diagram illustrating another exemplary embodiment of the offshore support structure.

[0035] Figure 7A is a perspective view schematic diagram illustrating an alternative receptacle for the offshore support structure of Figure 7.

[0036] Figure 8 is a side view schematic diagram illustrating the wind turbine assembly on the barge adjacent to the offshore support structure of Figure 7 or Figure 7A to be installed thereon.

[0037] Figure 9 is a side view schematic diagram illustrating the wind turbine assembly on the barge with a tower inserted into a receptacle in an elevated position on the offshore support structure.

[0038] Figure 10 is a side view schematic diagram illustrating the wind turbine assembly on the barge with a tower inserted into the receptacle and the receptacle in a lowered position on the offshore support structure.

[0039] Figure 10A is a side view schematic diagram illustrating the wind turbine assembly in an near upright position with a tower inserted into a receptacle on the offshore support structure and the receptacle in a lowered position on the offshore support structure.

[0040] Figure 1 1 is a side view schematic diagram illustrating the wind turbine assembly installed to the offshore support structure in an upright position.

[0041] Figure 12 is a side view schematic diagram illustrating the wind turbine assembly installed to the offshore support structure in an upright position with the tower secured to the receptacle.

[0042] DETAILED DESCRIPTION

[0043] The Figures described above and the written description of specific structures and functions below are not presented to limit the scope of what Applicant has invented or the scope of the appended claims. Rather, the Figures (not necessarily to scale) and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present inventions will require numerous implementation-specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation, location and from time to time. While a developer's efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of skill in this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. Lastly, the use of a singular term, such as, but not limited to, "a," is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, "top," "bottom," "left," "right," "upper," "lower," "down," "up," "side," and the like are used in the written description for clarity in specific reference to the Figures and are not intended to limit the scope of the invention or the appended claims.

[0044] The disclosure provides a method and system for installing an offshore wind turbine assembly onto a separate offshore support structure, independent of cranes and derricks. The system includes a support structure with a centrally disposed receptacle for the wind turbine assembly, a wind turbine assembly having a tower, turbine, and blades, and a transportation structure, such as a barge, to transport the wind turbine assembly to the support structure. The barge offloads the wind turbine assembly by placing the tower into a receptacle on the support structure. The receptacle is disposed below an elevation of the barge. The remainder of the wind turbine assembly is pivoted about the receptacle using the barge or winch cables into an upright position and secured to the support structure. The invention eliminates the need for offshore crane services for the installation of the wind turbine assembly tower, turbine or blades, and works with either fixed or floating support structures.

[0045] Figure 1 is a top view schematic diagram illustrating an exemplary embodiment of a wind turbine assembly installed on a transportation barge. Figure 2 is a side view schematic diagram illustrating an exemplary embodiment of a wind turbine assembly installed on the transportation barge. The figures will be described in conjunction with each other. A wind turbine assembly 1 generally includes a tower 2, a turbine 3 coupled to the tower, and a plurality of blades 4, 5, 6 coupled to the turbine. The wind turbine 3 can include, but is not limited to, a wind generator, a wind turbine, a wind power unit (WPU), a wind energy converter (WEC), or an aerogenerator. The turbine 3 generally has a horizontal axis of rotation about which a plurality of the blades rotate. Present commercial embodiments of wind turbine assemblies often use three blades. However, the number of blades can vary. As described above in the background section, such commercial wind turbine assemblies can be massive structures that are, for example, 50 meters (m) to 100 m tall and weigh 500 metric tonnes or more. The tower 2 is designed of sufficient height and strength to support the stationary and dynamic loading of the other components, and when installed at the site, the blades and turbine will be at or above water level. The turbine 3 is used to convert the rotational energy of the blades into electrical energy. The blades are aerodynamically designed to efficiently use wind currents to cause the turbine to rotate.

[0046] A transportation barge 7 is used to transport the wind turbine assembly to the installation site. The term "barge" is used broadly herein and is meant to include any device that can be used to transport the wind turbine assembly to the site and support the wind turbine assembly 1 during the launching and upending process to install the wind turbine assembly to the offshore support structure, as described herein. The barge 7 includes a barge supporting structure 8 which can be a ramp, skid, boom, or other structures to support and offload the wind turbine assembly 1. The wind turbine assembly 1 is generally installed in a non-vertical position on the barge 7, that is, less than 45 degrees to the horizontal, and generally will be substantially horizontal. The tower 2 of the wind turbine assembly 1 can be clamped on the barge supporting structure 8 by clamps 9, 10. In at least one embodiment, these clamps 9, 10 can slide along the barge supporting structure 8 as the wind turbine assembly 1 is installed. The barge supporting structure 8 can rotate about the barge 7 around an axis of rotation 1 1 during the installation process. A barge offloading structure 12 or "catcher" can be mounted at an end, such as the end facing the offshore support structure when at the installation site. This barge offloading structure 12 can include a pulley, roller, or a very hard skid with advantageously a low coefficient of friction in order to provide lateral support and stability during the launching and upending operations. One or more winches 28 can be coupled to the barge 7 with winch lines to secure and/or pull the barge to the offshore support structure, described below. A winch 28A can also be coupled to the barge 7 and used to upright the tower during one or more phases of the installation, as described below.

[0047] Figure 3 is a perspective view schematic diagram illustrating an exemplary embodiment of the offshore support structure to which the wind turbine assembly is installed. In at least one embodiment, the offshore structure 13 can be formed as a framework of members that have a pyramidal type of shape that rises from a base to a central location at the top of the offshore support structure. The offshore support structure is generally a separate structure from the wind turbine assembly 1 and can be fixed and generally mounted to the seabed, or floating and generally moored to a location. In at least some embodiments, the number of sides can be three. However, the offshore support structure 13 can be formed from other numbers of sides of four, five, and so forth. In general, it is advantageous to have at least three sides to be able to provide support for the wind turbine assembly in all three orthogonal (x, y, z axes) directions. The top of the offshore support structure that supports the tower of the wind turbine assembly, described below, is generally vertically centered between the sides to provide uniform loading, but can be offset from the center if appropriate.

[0048] A plurality of floatation tanks 14, 15, 16 can be coupled around the periphery of the offshore support structure 13. Generally, the floatation tanks will be disposed at each corner of the structure. The floatation tanks allow the offshore structure 13 to be floated in shallow water and towed to an installation site. A plurality of legs 17, 18, 19 can be coupled between the bottom of the offshore support structure and the top of the structure. The legs can be spread apart from each other on one end of the legs and coupled together on another end of the legs. The legs 17, 18, 19 will generally extend from the floatation tanks 14, 15, 16 to the top to define the previously referenced pyramidal shape. The top of each leg 17, 18, 19 can be coupled together directly or through an intermediate member. At least one of the legs, such as leg 17, can be formed in at least two leg portions 17A, 17B. The leg portions 17A, 17B can be used to laterally constrain movement of the tower of the wind turbine assembly between the leg portions, as the tower is positioned to engage the receptacle and the other components of the wind turbine assembly are upended to a vertical position during installation.

[0049] In at least one embodiment, a clamp 20 can be advantageously disposed at an elevation, such as the top of the legs 17, 18, 19 to assist in coupling the legs together. The clamp 20 can be used to capture and secure the tower 2 of the wind turbine assembly 1 , described in Figures 1 , 2, in a vertical position to the offshore support structure. The term "clamp" is used broadly herein and is intended to refer to any device or method of securing a portion of the tower to the offshore support structure at a different elevation than the receptacle described below. For example, the clamp 20 can include a first clamp portion 2OA fixedly coupled to the legs 17, 18, 19. A second clamp portion 2OB can be hingeably coupled to the first clamp portion 2OB about a hinge portion 2OC. When the tower of wind turbine assembly is installed so that it is placed adjacent the first clamp portion 2OA, the second clamp portion 2OB can be rotated and fixedly coupled to the first clamp portion 2OB to secure the tower therebetween.

[0050] A receptacle 21 can be disposed at a different elevation than the elevation of the clamp 20, such as at the bottom of the support structure 13, when the tower is installed to the offshore support structure 13. The receptacle 21 is used to receive and secure a portion of the tower, such as a bottom end of the tower 2, during and after installation. In at least one embodiment, the receptacle can be fixedly coupled in such position. In other embodiments, the receptacle can be slidably coupled to the support structure 13, as described in more detail below.

[0051] A plurality of links 22, 23, 24, generally rigid in design, can be used to laterally couple the floatation tanks 14, 15, 16. The links 22, 23, 24 can also position the receptacle 21 in a fixed lateral relationship to the offshore support structure.

[0052] The offshore support structure has been described and shown so that the floatation tanks 14, 15, 16 and the receptacle 21 are at a lower elevation and the convergence of the legs 17, 18, 19 with the clamp 20 are at an upper elevation on the offshore support structure. Other variations in keeping within the objective of providing a structure to support the wind turbine assembly can include inverting the offshore support structure so that the floatation tanks 14, 15, 16 are disposed at an upper elevation and the legs 17, 18, 19 converge at a lower elevation. The receptacle 21 could be disposed at the convergence of the legs at the lower elevation, and the clamp 20 could be disposed between the floatation tanks. The method described herein and variations thereof for installing the wind turbine assembly are similar in that the tower engages the receptacle, the wind turbine assembly is upended, and the tower is secured into position at a different elevation than the receptacle on the offshore support structure. Other shapes of the offshore support structure, fixed and floating, can be used.

[0053] Figure 3A is a perspective view schematic diagram illustrating an alternative receptacle for the offshore support structure of Figure 3 to which the wind turbine assembly is installed. The receptacle can be designed to rotate about a portion of the offshore support structure 13. For example, the receptacle 21 A illustrated in Figure 3A can include an opening 21 B having a size and depth suitable for the lower end of the tower 2. The receptacle 21 A can be pivotally coupled to the offshore support structure at a rotatable connection 21 C. Thus, the end of the tower 2 can be inserted into the receptacle 21 A at an angle and as the tower 2 is pivoted to a vertical position, the receptacle can correspondingly pivot with the tower. [0054] Figure 4 is a side view schematic diagram illustrating the wind turbine assembly on the barge adjacent to the offshore support structure of Figure 3 to be installed thereon. Figure 5 is a side view schematic diagram illustrating the wind turbine assembly on the barge with a tower inserted into a receptacle on the offshore support structure. Figure 5A is a side view schematic diagram illustrating the wind turbine assembly in an near upright position with a tower inserted into a receptacle on the offshore support structure. Figure 6 is a side view schematic diagram illustrating the wind turbine assembly installed to the offshore support structure in an upright position. The figures will be described in conjunction with each other.

[0055] In operation, the offshore support structure 13 can be deployed in a floating condition after fabrication into shallow water for towing to the offshore site. After arrival at the site, the floatation tanks 14, 15, 16 can be ballasted with water, cement, or high density mud to allow at least a portion of the offshore support structure to sink to a subsea elevation. After settling into position, the floatation tanks can be used as pile guides to insert one or more piles 25 to secure the offshore support structure 1 to the seabed 26.

[0056] The tower 2, turbine 3, blades 4, 5, 6 can be assembled onshore to form the wind turbine assembly 1. The wind turbine assembly 1 can be lifted onto the barge 7 and secured to the barge supporting structure 8, such as a ramp, in a horizontal position. The barge 7 can be towed to site by tugs and moored adjacent to the submerged offshore support structure 13.

[0057] The barge 7 can be anchored on the seabed 26 by mooring lines 27 from the winch 28. Additional winch lines can be deployed and attached to appropriate places on the offshore support structure 13. For example, a winch line can be routed through the structure 13 and back to the tower 2 to extend more efficiently pulling forces during the latter stages of the installation, described below in reference to Figure 5A. Further, a pull-in line 32 can routed from the winch 28A, through a pulley 34 coupled to the offshore support structure 13, through a pulley 33 adjacent the receptacle 21 (or receptacle 21 A), and then routed to the bottom of the tower 2. As the winch 28A pulls the line 32, the tower end is pulled and otherwise directed to engage the receptacle 21 between the two leg portions 17A and 17B of the leg 17 to laterally guide the tower during the installation.

[0058] The barge supporting structure 8 for the wind turbine assembly can be raised and the tower 2 is pulled off and launched. The clamps 9, 10 can slide along the barge supporting structure 8 (or allow the wind turbine assembly 1 to slide along the barge supporting structure) sufficiently to allow the bottom of the tower 2 to engage the receptacle 21. The wind turbine assembly can also be stabilized and supported by the barge offloading structure 12 as the wind turbine assembly is offloaded.

[0059] After the tower 2 engages the receptacle 21 , the tower 2 is raised by a combination of pulling in on the mooring lines 27 and other winch wires coupled between the barge 7 and to the offshore support structure 13, so that the barge effectively pushes the tower into a more upright orientation, while the tower pivots about the receptacle 21 in the base of the offshore support structure 13. The means of pivoting the tower is independent of the use of cranes and helps avoid additional expense to the installation.

[0060] The clamps 9, 10 can be unlocked from the tower 2. If appropriate, the barge supporting structure 8 can be further raised. Eventually in the pivoting process, the tower 2 may leave the barge supporting structure 8 and is supported by the barge offloading structure 12 at the end of the barge 7. By continuing to pull in on the winch wires and mooring lines, the barge 7 and the barge offloading structure 12 can push or otherwise direct the tower to be raised and effectively lifted to a vertical position by the action of the barge being pulled towards the structure and the winch wires. The bottom of the tower 2 is constrained in the receptacle 21 all the way to the vertical position.

[0061] In some installations, the barge 7 may be unable to approach the offshore support structure 13 sufficiently for the barge to place the tower 2 into an upright final position (for example, by the barge being pulled toward the offshore structure and thereby pushing the tower to a final position). Thus, a line 32A can be used to pull the tower to the final position, shown in Figure 5A. The line 32A can be the above referenced pull-in line 32 that is redirected and coupled to an upper portion of the tower rather than a lower end of the tower shown in Figure 4. The line 32A can be routed from the winch 28A, through a pulley 34A coupled to the offshore support structure 13 and to the tower 2. The winch 28A can be used for retracting the line 32A and pulling the tower 2 to a final position. It is to be understood that the location of the winch 28A is exemplary and the winch can be placed on other structures and locations having the ability to pull the tower into one or more positions.

[0062] When the tower 2 is in the final position and generally vertically disposed, the tower can engage the clamp 20, specifically the first clamp portion 2OA. The second clamp portion 2OB of the clamp 20 can be locked around the tower 2 in order to secure it on the offshore structure 13. Intermediate clamps can be incorporated into the structure if required for additional structure support. The mooring lines, winch wires, and other lines can be released and the barge transported to a different location with the wind turbine assembly being installed in position.

[0063] The system and method of installing the wind turbine assembly could likewise be performed in a corresponding order to reverse the installation of the wind turbine assembly. Having the ability to disassembly the wind turbine assembly without the use of additional vessels and/or cranes offers many advantages, including but not limited to, allowing for mobility of the wind turbine assembly 2, and allowing for maintenance or repair of the wind turbine assembly 2. Thus, the system and method described herein becomes a less costly way to effect major repairs, change outs of equipment, upgrades or decommissioning.

[0064] Figure 7 is a perspective view schematic diagram illustrating another exemplary embodiment of the offshore support structure. Similar to an exemplary embodiment described above, the offshore support structure 13 can be a pyramidal shaped structure with the floatation tanks 14, 15, 16 fixed at the bottom of the legs 17, 18, 19. The top of each leg 17, 18, 19 can be connected by a portion of the clamp 20. The clamp 20 is used to capture and secure the tower 2 of the wind turbine assembly 1 in a vertical position. An optional fourth floatation tank 29 can be coupled at the bottom of the offshore support structure 13 by a plurality of links 22, 23, 24 coupled to the floatation tanks 14, 15, 16.

[0065] The receptacle 21 , which receives the bottom of the tower 2, can be movable in elevation. For example, the receptacle can be disposed at a high elevation when the tower is inserted into the receptacle to facilitate placement and then as the tower is pivoted into a vertical position and rotated about the receptacle, the receptacle can slide down to a low elevation different from the elevation of the clamp. The receptacle can be moveable along a guide rail 30, where the guide rail can include vertical parallel guide rail portions 3OA, 3OB disposed laterally from each other to maintain an alignment of the receptacle with the structure 13. A top of the guide rail 30 can be coupled to the top of the legs 17, 18, 19, or the clamp 20. The bottom of the guide rail 30 can be coupled to the floatation tank 29, or one or more of the links 22, 23, 24.

[0066] Figure 7A is a perspective view schematic diagram illustrating an alternative receptacle for the offshore support structure of Figure 7. The receptacle 21 A can be designed to pivot about a portion of the offshore support structure 13 as it is lowered along the guide rail 30. For example, the receptacle 21 A illustrated in Figure 7A can include an opening 21 B having a size and depth suitable for the lower end of the tower 2. The receptacle 21 A can be pivotally coupled to the offshore support structure at a rotatable connection 21 C of a receptacle guide base 21 D. The receptacle guide base 21 D in turn can slide along the guide rail 30. Thus, the bottom end of the tower 2 can be inserted into the rotatable receptacle 21 A at an angle and secured thereto. As the tower 2 is raised to a vertical position, the receptacle 21 A can correspondingly pivot with the tower, and also be lowered along the guide rail 30. To assist in lowering the receptacle, a line can be coupled to the receptacle guide base 21 D of the receptacle 21 A, as described below in reference to Figure 9.

[0067] Figure 8 is a side view schematic diagram illustrating the wind turbine assembly on the barge adjacent to the offshore support structure of Figure

7 to be installed thereon. Figure 9 is a side view schematic diagram illustrating the wind turbine assembly on the barge with a tower inserted into a receptacle in an elevated position on the offshore support structure. Figure 10 is a side view schematic diagram illustrating the wind turbine assembly on the barge with a tower inserted into the receptacle and the receptacle in a lowered position on the offshore support structure. Figure 1 OA is a side view schematic diagram illustrating the wind turbine assembly in an near upright position with a tower inserted into a receptacle on the offshore support structure and the receptacle in a lowered position on the offshore support structure. Figure 1 1 is a side view schematic diagram illustrating the wind turbine assembly installed to the offshore support structure in an upright position. The figures will be described in conjunction with each other.

[0068] The operation using this embodiment is similar to the operation described above, except that the receptacle 21 (or receptacle 21 A) can initially be set along the guide rail 30 in a generally elevated position in the structure 13 as shown in Figure 8. The barge 7 with the wind turbine assembly 1 in a horizontal position can be towed on the installation site and anchored on the seabed 26. The tower 2 can be launched off of the barge sufficiently to allow the bottom of the tower 2 to engage the receptacle 21 in the elevated position, as shown in Figure 9. The clamps 9, 10 can slide along the barge supporting structure 8 as the wind turbine assembly 1 is installed.

[0069] As the tower 2 is raised off the barge, pivoting about the receptacle

21 , the receptacle can slide along the guide rail 30 to a lower elevation, as shown in Figure 10. Further, a line 32B can be routed from the winch 28A, through a pulley 33 coupled to the offshore support structure 13 adjacent a final location of the receptacle 21 and then routed to the receptacle 21 in the elevated position. As the winch 28A pulls the line 32B, the receptacle 21 and the bottom of the tower 2 are pulled downward toward the final location of the receptacle with the tower. In the final position, the tower 2 is oriented generally into a vertical final position and secured with the clamp 20 to the offshore structure 13, as shown in Figure 1 1.

[0070] Similar to the procedure described in Figure 5A, in some installations, the barge 7 may be unable to approach the offshore support structure 13 sufficiently for itself to place the tower 2 to a final position (for example, by the barge being pulled toward the offshore structure and thereby pushing the tower to a final position). Thus, a line 32A can be used to pull the tower to the final position, as shown in Figure 1 OA. The line 32A can be routed from the winch 28A, through a pulley 34B coupled to a gravity base 37, the offshore support structure 13, or a combination thereof. The line 32A can be coupled to an upper portion of the tower 2. The winch 28A can be used for retracting the line 32A and pulling the tower 2 to a final position. It is to be understood that the location of the winch 28A is exemplary and the winch can be placed on other structures and locations having the ability to pull the tower into one or more positions.

[0071] Figure 12 is a side view schematic diagram illustrating the wind turbine assembly installed to the offshore support structure in an upright position with the tower secured to the receptacle. In one or more of the embodiments herein, including the stationary receptacle and the sliding receptacle embodiments, which each can include the different receptacle configurations 21 , 21 A, shuttering arrangements can be incorporated to grout or otherwise secure the completed tower in position for additional stability. For example, as shown in Figure 12, a sleeve or other securing element 35 can be placed around the tower 2 by divers or an ROV. The securing element 35 can be placed at a convenient elevation shown in dotted lines and lowered to a position that surrounds the receptacle 21 (or receptacle 21 A, described above) and tower 2. The securing element 35 can be of multiple parts to aid in surrounding the receptacle and tower. In other embodiments, the securing element can be added to the tower prior to inserting the tower into the receptacle. In such embodiments, a clearance may be needed for the securing element as the tower passes between the leg portions 17A, 17B, shown in Figure 3 and other figures. A material such as grout or concrete can be placed into the sleeve to secure the tower 2 with the receptacle 21 (or receptacle 21 A).

[0072] Other and further embodiments utilizing one or more aspects of the inventions described above can be devised without departing from the spirit of Applicant's invention. For example, the other configurations of the offshore support structure can be formed with different numbers of sides and shapes including structures with rectangular, square, and circular bases, and structures that are mono piles (single leg having a receptacle), cubic, cylindrical and other shapes. The orientation of the support structure can vary as well. The offshore support structure can be a floating structure, a moored structure, or a fixed submerged structure fixed to the seabed. The winch wires can be coupled to just the offshore support structure, the seabed, or a combination thereof. The lines can be coupled to other pulling elements than winches. The lines can be placed at other positions. Other variations are possible.

[0073] Further, the various methods and embodiments of the wind turbine assembly and method of installing the same can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice-versa. Also, various aspects of the embodiments could be used in conjunction with each other to accomplish the understood goals of the disclosure. Unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising," should be understood to imply the inclusion of at least the stated element or step or group of elements or steps or equivalents thereof, and not the exclusion of a greater numerical quantity or any other element or step or group of elements or steps or equivalents thereof. The device or system may be used in a number of directions and orientations. The term "coupled," "coupling," "coupler," and like terms are used broadly herein and may include any method or device for securing, binding, bonding, fastening, attaching, joining, inserting therein, forming thereon or therein, communicating, or otherwise associating, for example, mechanically, magnetically, electrically, chemically, operably, directly or indirectly with intermediate elements, one or more pieces of members together and may further include without limitation integrally forming one functional member with another in a unity fashion. The coupling may occur in any direction, including rotationally.

[0074] The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions.

[0075] The inventions have been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by the Applicant, but rather, in conformity with the patent laws, Applicant intends to fully protect all such modifications and improvements that come within the scope or range of equivalent of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A method of installing a wind turbine assembly having a tower at an offshore installation site into an offshore support structure having a receptacle disposed at a first elevation, the method comprising: positioning an offshore support structure at an offshore installation site; transporting the wind turbine assembly to the installation site; elevating at least a portion of the wind turbine assembly; inserting a portion of the tower into the receptacle on the offshore support structure at the installation site; pushing the tower with a barge into at least a partially upright position after the tower is inserted into the receptacle on the offshore support structure; and pivoting the wind turbine assembly relative to the offshore support structure into an upright position while the tower is engaged with the receptacle.

2. The method of claim 1 , wherein the offshore structure further comprises a clamp disposed at a second elevation different from the first elevation of the receptacle and the method further comprises securing the wind turbine assembly with the clamp to the offshore support structure in the upright position

3. The method of claim 1 , further comprising: floating the offshore support structure to the installation site with floatation tanks coupled around the structure; sinking the structure to a seabed; and securing the structure to the seabed.

4. The method of claim 1 , wherein transporting the wind turbine assembly comprises loading the wind turbine assembly in non-vertical position on a barge supporting structure coupled to a barge and wherein elevating at least the portion of the wind turbine assembly comprises rotating the barge supporting structure with the portion about an axis of rotation relative to the barge.

5. The method of claim 1 , wherein inserting the portion of the tower into the receptacle comprises guiding the tower through at least two leg portions of at least one of the legs, the leg portions being laterally disposed on both sides of the tower.

6. The method of claim 1 , wherein inserting the portion of the tower into the receptacle comprises inserting the portion into the receptacle when the receptacle is in a first elevation and wherein pivoting the wind turbine assembly about the receptacle comprises sliding the receptacle from the first elevation to a second elevation that is lower than the first elevation.

7. A system for installing a wind turbine assembly at an offshore installation site into an offshore support structure, comprising: an offshore support structure having a receptacle at a first elevation; the wind turbine assembly having a tower, a turbine coupled to the tower, and at least one blade coupled to the turbine; a barge adapted to support the wind turbine assembly during transportation to the offshore installation site; means for inserting a portion of the tower into the receptacle on the offshore support structure; and means for pivoting the wind turbine assembly about the receptacle into an upright position.

8 The system of claim 7, further comprising a clamp disposed at a second elevation different from the first elevation of the receptacle and adapted to secure the wind turbine assembly to the offshore support structure in the upright position.

9. The system of claim 7, further comprising at least one floatation tank coupled to the offshore support structure, the floatation tank being adapted to allow the offshore support structure to be floated to the installation site.

10. The system of claim 7, wherein the floatation tank is adapted to be ballasted to allow at least a portion of the offshore support structure to sink to a subsea elevation.

1 1. The system of claim 7, wherein the barge comprises a barge supporting structure coupled to the barge and adapted to support the wind turbine assembly on the barge during transportation of the wind turbine assembly to the installation site and further adapted to rotate about an axis of rotation relative to the barge during installation of the wind turbine assembly to the offshore support structure.

12. The system of claim 7, wherein the offshore support structure comprises a plurality of legs spread apart from each other on one end of the legs and coupled together on another end of the legs.

13. The system of claim 1 1 , wherein at least one of the legs comprises at least two leg portions, the leg portions being laterally disposed and adapted to laterally constrain movement of the tower of the wind turbine assembly between the leg portions as the tower is positioned to engage the receptacle.

14. The system of claim 7, wherein the receptacle is adapted to change elevations during installation of the wind turbine assembly and further comprising a guide rail slidably coupled with the receptacle and adapted to guide the receptacle as the receptacle changes elevations.

15. An offshore support structure for a wind turbine assembly having a tower for installation to the offshore support structure at an offshore installation site, comprising: a plurality of legs coupled together that are uncoupled to the wind turbine assembly prior to the installation at the offshore installation site; a plurality of floatation tanks coupled to the legs; a receptacle coupled to the legs at a first elevation and adapted to receive a portion of the tower of the wind turbine assembly when the tower is disposed in a non-vertical position; and a clamp coupled to the legs at a second elevation different from the first elevation, the clamp being disposed in vertical alignment with the receptacle, the clamp being adapted to couple the tower to the framework when the tower has been pivoted relative to the offshore support structure to a vertical position at the installation site.

16. The structure of claim 15, wherein the floatation tank is adapted to be ballasted to allow at least a portion of the offshore support structure to sink to a subsea elevation.

17. The structure of claim 15, wherein the legs are spread apart from each other on one end of the legs and coupled together on another end of the legs.

18. The structure of claim 15, wherein at least one of the legs comprises at least two leg portions, the leg portions being laterally disposed and adapted to laterally constrain movement of the tower of the wind turbine assembly between the leg portions as the tower is positioned to engage the receptacle.

19. The structure of claim 15, wherein the receptacle is adapted to change elevations during installation of the wind turbine assembly and further comprising the receptacle being slidably coupled to a guide rail, the guide rail adapted to guide the receptacle as the receptacle changes elevations.