Method for assembling a floating offshore wind vessel using a mobile offshore assembly facility

Abstract

A method and apparatus for assembling a floating offshore wind vessel is described. The method manufactures the floating offshore wind vessel at an intermediate offshore location. Subcomponents of the floating offshore wind vessel are transported to a first offshore location before being assembled into a completed offshore wind vessel. The completed offshore wind vessel is transported to a second offshore location that is part of the wind field. The subcomponents are assembled on a semi-submersible vessel, such as a floating drydock.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate generally to a method for manufacturing a floating offshore wind power installation. More particularly, the method is directed to manufacturing a floating offshore wind turbine using a mobile offshore assembly facility. [Background technology]

[0002] Offshore wind developments in shallow waters are growing in number and competing with other traditional energy production methods. As competition for shallow water wind development sites increases, so does the demand for floating offshore wind developments that can be deployed in deeper waters. Floating offshore wind developments do not utilize fixed foundation structures and therefore can be deployed in significantly deeper waters in areas with greater wind energy potential.

[0003] Floating offshore wind vessels are currently manufactured in onshore shipyard facilities. Onshore shipyard facilities are expensive to build and maintain and often involve significant upfront capital costs. The upfront capital costs include purchasing land fronting the sea, which may be in densely populated areas, permitting costs, construction costs of the facility, and decommissioning costs after the facility's usefulness has been exhausted. Onshore shipyard facilities also disrupt the local environment and communities around the shipyard facility.

[0004] It is therefore desirable to reduce the manufacturing costs of floating offshore wind vessels and the utilization of onshore shipyard facilities.

[0005] So that the above-recited features of the present disclosure may be understood in detail, a more particular description of the present disclosure briefly summarized above may be made by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that since the present application may admit of other equally effective embodiments, the accompanying drawings only illustrate exemplary embodiments and therefore should not be considered limiting in scope. [Brief description of the drawings]

[0006] [Figure 1A-1C] 1A-1D are schematic plan views of an offshore construction facility and wind field during various stages of construction according to embodiments described herein. [Fig. 2A-2F] 1A-1D are schematic plan views of an offshore construction facility during various stages of wind power vessel assembly according to embodiments described herein. [Figure 3A-3B] FIG. 2C is a schematic side view of the offshore construction facility of FIGS. 2A-2F during assembly of a turbine blade on a wind power vessel assembly according to a first embodiment described herein. [Figure 4A-4B] 1A-1D are schematic side views of a partially assembled wind power ship assembly during various stages of floating the wind power ship assembly according to embodiments described herein. [Figure 5A-5B] FIG. 2C is a schematic side view of the offshore construction facility of FIGS. 2A-2F during assembly of a turbine blade on a wind power vessel assembly according to a second embodiment described herein. [Figure 6A-6B] FIG. 1 is a perspective view of an assembled wind vessel being wet towed away from a semi-submersible vessel and the hull being wet towed towards a jack-up rig according to various embodiments described herein. [Figure 7] 1 is a flow diagram of a method for manufacturing an offshore wind floating vessel at an offshore vessel building facility according to embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] For ease of understanding, like reference numbers have been used, where possible, to designate like elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0008] The present disclosure is directed to methods and apparatus for manufacturing a floating offshore wind vessel. More specifically, embodiments described herein are directed to the use of a mobile offshore wind vessel facility during assembly of the floating offshore wind vessel. The mobile offshore wind vessel facility includes a jack-up rig, a semi-submersible vessel, and one or more transfer vessels. The jack-up rig and the semi-submersible vessel are utilized at a first offshore location to manufacture the offshore wind vessel before it is transported to a wind field. The mobile offshore wind vessel facility is completed offshore, reducing dependency on onshore facilities during manufacture of the offshore wind turbines.

[0009] The mobile offshore wind ship facility allows for the use of local labor and supporting services during construction of the offshore wind field. The mobile offshore wind ship facility can be relocated and deployed throughout the area near the offshore wind field under construction. Therefore, the offshore wind ship assembly facility is reusable, significantly reducing start-up construction costs for new offshore wind field facilities.

[0010] The mobile offshore wind ship facility may include a semi-submersible vessel (e.g., a dry dock), a self-elevating mobile offshore crane platform, and a large capacity crane, and may operate with one or more transfer vessels. Multiple wind ship sub-components are delivered disassembled by the transfer vessels to the mobile offshore wind ship facility where they are assembled into the floating offshore wind ship.

[0011] The semi-submersible vessel provides a stable and versatile floating foundation for construction of the hull and / or base of the floating offshore wind vessel and installation of wind turbine components such as the nacelle and wind turbine blades. The semi-submersible vessel may also facilitate transport of the floating offshore wind vessel to a holding location for vessel launch prior to deployment to the wind field. The semi-submersible vessel may optionally include one or more spud legs and corresponding lifting units to provide additional stability during construction of the floating offshore wind vessel and / or during installation of the wind turbine components. In operation, the lifting units extend the spud legs until contact is made between the spud legs and the seabed, allowing the semi-submersible vessel to be supported by the ocean, increasing stability against metocean effects.

[0012] The self-elevating mobile offshore crane platform is a jack-up rig and is equipped with a large capacity crane for the assembly of floating offshore wind power vessels and other installation operations. The self-elevating mobile offshore crane platform can be configured for float-up lift operations. The self-elevating mobile offshore crane platform is optimized for lifting and holding capacity, adjustable deck height, adjustable leg length, open deck space, under deck storage, and accommodation space for crew and other personnel.

[0013] The one or more transfer vessels include dry tow vessels and transfer barges. The one or more transfer vessels carry and transport completed floating offshore wind vessels and / or disassembled sub-components of floating offshore wind vessels from an overseas manufacturing site and / or a domestic facility to the mobile offshore wind vessel facility. The one or more transfer vessels additionally carry and / or transport completed floating offshore wind vessels to the wind field for deployment.

[0014] 1A-1C are schematic plan views of an offshore construction facility 150 and the wind field 140 during various stages of construction of the wind field 140. The offshore construction facility 150 is located at a first offshore location. The first offshore location is located adjacent to the shore 102. The shore 102 may include a shipyard or dock 104 from which a transfer vessel 106 may be loaded and unloaded. The transfer vessel 106 is configured to transfer and / or transport multiple wind farm sub-components to the offshore construction facility 150.

[0015] The offshore construction facility 150 includes a jack-up rig 152, a semi-submersible vessel 154, and a component transfer vessel 156. The offshore construction facility 150 is in a shallow water area 110. A floating offshore wind vessel 158 is assembled on the semi-submersible vessel 154 using the jack-up rig 152 and a number of wind vessel sub-components disposed on the component transfer vessel 156. The shallow water area 110 has a water depth of less than about 500 feet, such as less than about 250 feet, such as less than about 400 feet, such as less than about 300 feet, such as less than about 400 feet. A first offshore location of the offshore construction facility 150 has a first water depth. The first water depth is less than about 500 feet, such as less than about 400 feet, such as less than about 300 feet, such as less than about 250 feet, such as less than about 150 feet, such as less than about 100 feet, such as less than about 75 feet. The water depth is generally determined by the unladen draft at the construction site. The offshore construction facility is further located at a distance D less than about 10 miles from the coast 102, such as less than about 6 miles from the coast 102, such as less than about 5 miles from the coast.

[0016] The wind field 140 is located at a second offshore location. The wind field 140 includes a plurality of floating offshore wind vessels 142. The wind field 140 is located in a deep water region 130. The deep water region 130 has a greater depth than the shallow water region 110. The deep water region 130 is a region having a water depth greater than about 200 feet, such as greater than about 300 feet, such as greater than about 400 feet, such as greater than about 500 feet, such as greater than about 600 feet. Between the deep water region 130 and the shallow water region 110 is a transition region 120. The transition region 120 has a water depth between the water depths of the shallow water region 110 and the deep water region 130.

[0017] FIG. 1B further illustrates a second transfer vessel 144 utilized to transfer the completed floating offshore wind vessel 158 from the offshore construction facility 150 in the shallow water area 110 to the wind field 140. The second transfer vessel 144 is a wet towing vessel or a transfer barge. The second transfer vessel 144 may be the same as the transfer vessel 106 or the component transfer vessel 156. The floating offshore wind vessel 158 may be wet towed behind the second transfer vessel 144 towards the wind field 140. In some embodiments, a dry towing vessel appropriately sized to meet the floatation stability requirements for offshore transportation of the completed floating offshore wind vessel 158 may transfer the completed floating offshore wind vessel 158 from the offshore construction facility 150 to the wind field 140.

[0018] 1C illustrates the offshore construction facility 150, the transition area 120, and the wind field 140 as the semi-submersible vessel 154 is also utilized to transfer a completed floating offshore wind vessel 158 from the offshore construction facility 150 to the transition area 120. The completed floating offshore wind vessel 158 is assembled at the offshore construction facility 150 prior to moving the semi-submersible vessel 154 to the transition area 120. The semi-submersible vessel 154 is then ballasted and the completed floating offshore wind vessel 158 is offloaded at the transition area 120. The completed floating offshore wind vessel 158 may then be wet towed from the transition area 120 to the wind field 140 by another vessel, such as the second transfer vessel 144.

[0019] 2A-2F are schematic plan views of an offshore construction facility 150 during various stages of wind vessel assembly. The offshore construction facility includes a jack-up rig 152, a semi-submersible vessel 154, and a component transfer vessel 156. The jack-up rig 152 is configured to transfer wind vessel sub-components from the component transfer vessel 156 to the semi-submersible vessel 154. The jack-up rig 152 further supports assembly of the wind vessel on the semi-submersible vessel 154 after transfer of one or more wind vessel sub-components from the component transfer vessel 156. FIG. 2A is a first plan view of the offshore construction facility 150 before the wind vessel sub-components are moved from the component transfer vessel 156 to the semi-submersible vessel 154.

[0020] The jack-up rig 152 includes a crane 200. The crane 200 is a high capacity crane. In some embodiments, a high capacity crane may surround and / or couple to the adjustable legs 206 of the jack-up rig 152, or two or more lower capacity cranes may surround and / or couple to two or more of the adjustable legs 206 of the jack-up rig 152. The crane 200 is configured to utilize a high speed line (auxiliary hoist) for light loads and a main hoist for heavy loads. The crane 200 is located on or above the rig's main deck 208. The main deck 208 is the top surface of the jack-up rig 152, which may be, for example, a multi-leg jack-up rig (e.g., a tripod rig, a four-legged rig, etc.). A crane base 204 is disposed on and / or across the main deck 208. The crane arms 202 extend outward from the crane base 204 such that the crane arms 202 extend radially outward from a central axis defined by the crane base 204. The crane arms 202 extend around the periphery of the jackup rig 152 and outward from the main deck 208 of the jackup rig 152. The crane arms 202 may also be referred to as the boom or jib of the crane 200. A plurality of adjustable legs 206 are disposed across the body and main deck 208 of the jackup rig 152. The plurality of adjustable legs 206 are configured to enable raising and lowering of the jackup rig 152 relative to the seabed. The plurality of adjustable legs 206 are coupled to a portion of the seabed below the jackup rig 152.

[0021] The semi-submersible vessel 154 includes an assembly deck 230, a number of spud legs 231, a number of lifting units 232, and a gantry crane 286. The assembly deck 230 is configured to be a flat or nearly flat surface in the center of the semi-submersible vessel 154. The assembly deck 230 is where the wind turbines are configured to be constructed. In some embodiments, the assembly deck 230 is large enough to support the simultaneous construction of two or more wind turbines. The number of lifting units 232 are disposed at each corner of the semi-submersible vessel 154. The number of lifting units 232 are configured to extend the spud legs 231 towards the seabed to provide stability to the semi-submersible vessel 154 and to allow the assembly deck 230 to be raised relative to the seabed (e.g., raised above ocean water level and / or lowered below ocean water level). In some embodiments, the plurality of lifting units 232 are configured to extend the spud legs 231 to allow the assembly deck 230 to be raised to a height where the draft is less than the floating draft where the legs are not in contact with the seabed. In Figures 2A-2F, the spud legs 231 are in contact with the seabed and the assembly deck 230 of the semisubmersible vessel 154 is disposed above ocean water level. When the semisubmersible vessel 154 is generally rectangular or when the assembly deck 230 has a rectangular shape, four lifting units 232 and corresponding spud legs 231 may be implemented, one lifting unit 232 located at each corner of the rectangular semisubmersible vessel 154.

[0022] Each lifting unit 232 is configured to assist in balancing and stabilizing the semisubmersible vessel 154. Additionally, other configuration modules, such as one or more tower cranes 280, may be coupled to and / or surround one or more of the lifting units 232. The housing of the lifting unit 232 may also include and / or provide structural support for generators and pumps for ballasting and unballasting the semisubmersible vessel 154. A gantry crane 286 is disposed between two edges of the assembly deck 230 and is configured to be movable along the length of the semisubmersible vessel 154 and the assembly deck 230.

[0023] The gantry crane 286 includes two or more girders 288 disposed across the width of the assembly deck 230 of the semisubmersible vessel 154 to form a bridge across the assembly deck 230. The girders 288 include a drive girder and an idler girder. The drive girder includes one or more actuators, or a driver coupled thereto. The actuators and / or drivers are configured to actuate a trolley 290 between the girders 288. End tacks are disposed at either end of the girders 288. The end tacks assist in moving the gantry crane 286 along the length of the assembly deck 230 and include one or more actuators and / or one or more wheels. The trolley 290 is disposed between the girders 288 and configured to actuate along the length of the girder 288 during assembly of the wind power vessel. The trolley 290 includes a hoist, a trolley drive, an upper block, and a hood block. The semi-submersible vessel 154 is of any shape or size suitable for use during assembly of a wind power vessel. The semi-submersible vessel 154 may therefore be oval or circular in shape.

[0024] The component transfer vessel 156 includes a transfer vessel deck 210. The transfer vessel deck 210 is the upper deck of the component transfer vessel 156. The transfer vessel deck 210 is a generally planar surface configured to receive a number of wind power vessel sub-components. The wind power vessel sub-components may include, but are not limited to, a number of lower columns 212, a number of upper columns 218, a number of lower braces 216, a number of upper braces 214, one or more wind power vessel column components 220, a nacelle 222, and a number of turbine blades 224. The number of lower columns 212 and the number of lower braces 216 form a hull base. The number of upper columns 218 and the number of upper braces 214 form an upper support base. The combination of each of the lower columns 212, the number of lower braces 216, the number of upper columns 218, and the number of upper braces 214 forms the hull of the wind power vessel. One or more wind power ship column components 220 form the hull column. In general, the transfer vessel deck 210 may receive, store, and / or transport sub-components associated with a wind power ship of any type or design. The above wind power ship sub-components are therefore described only as exemplary components that may be implemented using the offshore construction facility 150.

[0025] The lower column 212 and upper column 218 are configured to include a volume therein that allows the assembled wind vessel to float and allows for control of the buoyancy of the wind vessel. The wind vessel described herein is a semi-submersible wind turbine. Other types of wind vessels, such as ballast stabilized / spar buoy wind turbines, buoyancy stabilized / barge wind turbines, or tension leg / mooring line stabilized wind turbines, may be manufactured using methods and components similar to those described herein.

[0026] FIG. 2B is a second plan view of the offshore construction facility 150 after moving a plurality of lower columns 212 from the component transfer vessel 156 onto the semisubmersible vessel 154. The lower columns 212 are moved into place using one or more combinations of the cranes 200, the gantry cranes 286, and one or more optional tower cranes 280 coupled to and / or surrounding the lifting units 232. FIG. 2C is a third plan view of the offshore construction facility 150 after moving a plurality of lower braces 216 onto the semisubmersible vessel 154 and assembling the lower braces 216 with the lower columns 212 to form a hull base. The lower braces 216 are moved into place using one or more combinations of the cranes 200, the gantry cranes 286, and the optional tower cranes 280.

[0027] FIG. 2D is a fourth plan view of the offshore construction facility 150 after transferring the upper columns 218 and upper braces 214 from the component transfer vessel 156 onto the semisubmersible vessel 154. The upper columns 218 and upper braces 214 are assembled onto the vessel base to form the hull 250. The upper columns 218 and upper braces 214 are moved into place using one or more combinations of the cranes 200, the gantry cranes 286, and the optional tower cranes 280. FIG. 2E is a fifth plan view of the offshore construction facility 150 after transferring one or more wind power ship column components 220 from the component transfer vessel 156 onto the semisubmersible vessel 154. The wind power ship column components 220 are moved into place using one or more combinations of the cranes 200, the gantry cranes 286, and the optional tower cranes 280. The wind ship column components 220 are assembled as a single column on one of the upper columns 218. FIG. 2F is a sixth plan view of the offshore construction facility 150 after the nacelle 222 has been moved from the component transfer vessel 156 onto the semisubmersible vessel 154. The nacelle 222 is moved into place using one or more combinations of the cranes 200, the gantry cranes 286, and the optional tower cranes 280. The nacelle 222 is placed on the column formed by the wind ship column components 220. The combination of the hull 250, the wind ship column components 220, and the nacelle 222 forms a first portion 270 of the floating offshore wind ship.

[0028] In some embodiments, the semi-submersible vessel 154 is also utilized as a component transfer vessel 156. In this embodiment, the semi-submersible vessel 154 is utilized to both transfer the wind vessel sub-components to the offshore construction facility 150 and to construct the wind vessel. In this embodiment, the semi-submersible vessel 154 is utilized to assemble the wind vessel on the semi-submersible vessel 154 without removing the wind vessel sub-components from a separate component transfer vessel 156. It is contemplated that the semi-submersible vessel 154 may be Jones Act compliant to facilitate operation in U.S. waters.

[0029] 3A and 3B are schematic side views of the offshore construction facility of FIGS. 2A-2F during assembly of turbine blade 224 on first portion 270 of floating offshore wind vessel. As shown in FIGS. 3A and 3B, turbine blade 224 is assembled on first portion 270 as it is disposed on semisubmersible vessel 154. As shown, lifting unit 232 and corresponding spud legs 231 raise assembly deck 230 and first portion 270 of floating offshore wind vessel above water level 310 and out of water 312. Assembly deck 230 and first portion 270 are disposed in air 314.

[0030] Each of the turbine blades 224 is configured to be attached to one of a plurality of mounting surfaces 306a, 306b, 306c on the rotor hub 304 of the nacelle 222. Each of the plurality of mounting surfaces 306a, 306b, 306c is disposed on a different side of the rotor hub 304. The plurality of mounting surfaces 306a, 306b, 306c includes a first mounting surface 306a, a second mounting surface 306b, and a third mounting surface 306c. As shown in FIG. 3A, the first turbine blade 224 is coupled to the first mounting surface 306a. One or more hooks or hoist lines 302 are configured to couple to the first turbine blade 224 and enable lifting of the first turbine blade 224 during assembly with the first portion 270 of the floating offshore wind vessel.

[0031] In various embodiments, the partially assembled wind vessel (e.g., including first portion 270 assembled on hull 250) may be floated by a dry towing vessel and placed on assembly deck 230 of semisubmersible vessel 154 for final installation of wind turbine components (e.g., turbine blades 224). In some embodiments, the partially assembled wind vessel includes a lower platform (e.g., hull 250), hull column 220, and (optionally) a nacelle 222, and turbine blades 224 are assembled on the partially assembled wind vessel on assembly deck 230 to form a completed wind vessel 350.

[0032] FIG. 3B illustrates the floating offshore wind vessel after assembling each of the turbine blades 224 onto the rotor hub 304. Thus, the first turbine blade 224 is attached to the first mounting surface 306a, the second turbine blade 224 is attached to the second mounting surface 206b, and the third turbine blade 224 is attached to the third mounting surface 206c. The rotor hub 204 is rotated as the turbine blades 224 are assembled thereon. One or a combination of the turbine blades 224 and the nacelle 222 is referred to as the second part of the wind vessel. Once the turbine blades 224 are assembled onto the rotor hub 304, a completed wind vessel 350 is formed. The completed wind vessel 350 is a completed offshore wind vessel.

[0033] 4A and 4B are schematic side views of an assembled wind power vessel first part 270 during various stages of floating the wind power vessel first part 270. As shown in Fig. 4A, the wind power vessel first part 270 is disposed on the assembly deck 230, which is disposed above the water level 310 and out of the water 312. The wind power vessel first part 270 is assembled in the position shown in Fig. 4A. After assembly of the first part 270, the lifting unit 232 retracts the spud legs 231 away from the seabed, causing the semi-submersible vessel 154 to be at least partially submerged such that the assembly deck 230 is below the water level 310, as shown in Fig. 4B. By moving the assembly deck 230 below the water level 310, the first part 270 of the wind power vessel is placed in the water 312 and then floated from the assembly deck 230 into the water 312. Submerging the assembly deck 230 below the water level 310 separates the first part 270 of the wind power vessel from the assembly deck 230 and the semi-submersible vessel 154.

[0034] 5A and 5B are schematic side views of the offshore construction facility of FIGS. 2A-2F during assembly of the turbine blades 224 on the first portion 270 of the wind power vessel. Assembly of the turbine blades 224 on the first portion 270 is similar to the assembly shown in FIGS. 3A and 3B, except that the turbine blades 224 are attached to the rotor hub 304 after the first portion 270 is floated from the semi-submersible vessel 154 such that the first portion 270 is partially submerged in the water 312. In some embodiments, prior to attachment of the turbine blades 224 to the first portion 270, the first portion 270 is ballasted and / or tied to the seabed to provide additional stability. Thus, Figures 3A and 3B illustrate a first embodiment of how to assemble the completed wind power vessel 350, and Figures 4A, 4B, 5A, and 5B illustrate a second embodiment of how to assemble the completed wind power vessel 350. The first embodiment floats the completed wind power vessel 350 from the semi-submersible vessel 154 after the turbine blades 224 are attached. The second embodiment floats the first part 270 of the wind power vessel from the semi-submersible vessel 154 before adding the turbine blades 224 to form the completed wind power vessel 350. As shown in Figure 5A, the first turbine blade 224 is attached to the first mounting surface 306a. As shown in Figure 5B, the second turbine blade 224 and the third turbine blade 224 are attached to the second mounting surface 306b and the third mounting surface 306c, respectively. Therefore, when each of the turbine blades 224 is attached to the rotor hub 304, the completed wind vessel 350 is already floating in the water 312. The completed wind vessel 350 is utilized as the floating offshore wind vessel 158.

[0035] 6A and 6B are perspective views of an assembled wind vessel being wet towed away from the semisubmersible vessel 154 and a hull 250 being wet towed towards a jack-up rig 152. The hull 250 may include, for example, a number of lower columns 212, a number of upper columns 218, a number of lower braces 216, and a number of upper braces 214.

[0036] As shown in Figure 6A, the hull 250 is wet towed to the semisubmersible vessel 154 and placed on the assembly deck 230, which is at least partially submerged below the water level 310, similar to the position of the assembly deck 230 shown in Figure 4B. Prior to assembly of the wind farm vessel subcomponents, the hull 250 may be ballasted and / or coupled to the assembly deck 230, which is submerged to provide stability during subsequent assembly of the wind farm vessel components. One or more wind farm vessel column components 220, a nacelle 222, and a number of turbine blades 224 may then be assembled on the hull 250 to form a completed wind farm vessel 350. Alternatively, the lifting unit 232 may extend the spud legs 231 toward the seabed to raise the assembly deck 230 above the water level 310 so that the hull 250 rests in a stable position above the assembly deck 230, similar to the position of the assembly deck 230 shown in FIG. 4A. One or more wind power ship column components 220, the nacelle 222, and the plurality of turbine blades 224 may then be assembled on the hull 250 to form a completed wind power ship 350. The completed wind power ship 350 may then be wet towed away from the semisubmersible vessel 154, and the new hull 250 may be wet towed toward the assembly deck 230. Transferring the pre-assembled hull 250 to the semisubmersible vessel 154 for final assembly of the wind turbine components may increase overall throughput compared to assembling the hull 250 itself on the semisubmersible vessel 154.

[0037] As shown in FIG. 6B, the hull 250 is wet towed to the jack-up rig 152 but is not placed on the assembly deck. Instead, the hull 250 may be ballasted and / or tied to the seabed to provide stability for subsequent assembly of the wind power vessel components. One or more wind power vessel column components 220, a nacelle 222, and a number of turbine blades 224 may then be assembled on the hull 250 to form a completed wind power vessel 350. The completed wind power vessel 350 may then be wet towed away from the jack-up rig 152 and the new hull 250 may be wet towed to the jack-up rig 152.

[0038] FIG. 7 is a flow diagram of a method 700 for manufacturing a floating offshore wind vessel, such as one of the completed wind vessel 350 or floating offshore wind vessel 158, at an offshore vessel building facility, such as offshore vessel building facility 150. The method 700 is utilized to assemble the floating offshore wind vessel at an intermediate location, such as at a first offshore location, before moving the floating offshore wind vessel to a second offshore location that is in deeper water or further from shore. By assembling the floating offshore wind vessel at an offshore site, capital expenditures for development of onshore shipyard infrastructure are reduced. Local labor and supporting services are also more fully utilized with offshore wind vessel assembly. Assembling the floating offshore wind vessel at an offshore location further avoids development of land onshore, which often requires government agency approvals, permits, impact studies, and construction costs. Land-based infrastructure construction can also have adverse effects on local communities and the environment.

[0039] During a first operation 702 of method 700, a jackup rig, such as jackup rig 152, is installed at a first offshore location. Installing the jackup rig includes transporting the jackup rig to the first offshore location before lowering one or more adjustable legs, such as adjustable legs 206, into the ocean and coupling the jackup rig to a portion of the ocean floor below the jackup rig. The jackup rig may be transported to the first offshore location and forms part of the offshore construction facility 150. The depth of the ocean at the first offshore location is shallow enough to allow the jackup rig to be installed such that the water is shallow enough to allow the jackup rig and crane platform to be above the water level and the bottom of the adjustable legs 206 contact the ocean floor. The jack-up rig may be transported from a different offshore location, such as an onshore location (eg, a seaport or harbor) or a previous offshore construction site.

[0040] After the jack-up rig is installed, a semi-submersible vessel, such as semi-submersible vessel 154, is positioned adjacent to the jack-up rig during operation 704. The semi-submersible vessel is transferred from a different location. The different location can be a different offshore location, such as an onshore location or a previous offshore construction site. The combination of the jack-up rig and the semi-submersible vessel forms an offshore construction facility. After the second operation 704, the spud legs, such as spud legs 231, of the semi-submersible vessel are extended toward the ocean floor during operation 706. The spud legs are optional and provide stability to the assembly deck of the semi-submersible vessel during assembly of the wind power vessel. After extension of the spud legs, the assembly deck of the semi-submersible vessel can be positioned above the ocean water level, as described in connection with Figures 2A-2F, or the assembly deck of the semi-submersible vessel can be positioned below the ocean water level, as described in connection with Figure 6A.

[0041] After operation 706, the one or more wind vessel components are transferred to the first offshore location adjacent to the jack-up rig during operation 708. The one or more wind vessel components include one or a combination of each of the lower columns 212, the upper columns 218, the lower braces 216, the upper braces 214, the one or more wind vessel column components 220, the nacelle 222, and the turbine blades 224. It is contemplated that additional components may be transferred to facilitate completion of the wind turbine. In some embodiments, the one or more wind vessel components transferred to the first offshore location adjacent to the jack-up rig include a pre-assembled hull 250, one or more wind vessel column components 220, the nacelle 222, and the turbine blades 224, as described in connection with FIGS. 6A and 6B.

[0042] In some embodiments, each of the one or more wind vessel components are transferred to the first offshore location using a single transfer vessel. In other embodiments, multiple transfer vessels are utilized, with each transfer vessel carrying a different component. In some embodiments, the semi-submersible vessel includes multiple wind vessel sub-components already positioned thereon during the second operation 704, such that the semi-submersible vessel is transferred from port with the wind vessel sub-components to the first offshore location.

[0043] After operation 708, the hull of the wind vessel, such as hull 250, is optionally assembled during operation 710. The hull of the wind vessel includes the portion of the wind vessel that maintains the buoyancy of the wind vessel. The hull of the wind vessel is assembled using one of a crane on a jack-up rig, a gantry crane on the semi-submersible vessel, and one or more optional tower cranes coupled to or surrounding the lifting unit of the semi-submersible vessel. Alternatively, as described in operation 708, the hull of the wind vessel may be transported to the first offshore location in a pre-assembled form, thereby not requiring assembly in operation 710.

[0044] After operation 710, the hull column and nacelle are assembled onto the hull of the wind vessel during operation 712. The hull column and nacelle are placed onto the hull of the wind vessel, and the hull of the wind vessel is placed onto the assembly deck of the semi-submersible vessel. The assembly of the hull column, nacelle, and hull of the wind vessel is a lower vessel assembly, such as first portion 270. The hull column and nacelle are similarly assembled onto the hull using one of a combination of cranes on a jack-up rig, a gantry crane, and any tower crane.

[0045] After assembling the lower vessel assembly, the semi-submersible vessel is at least partially submerged during operation 714 to float the lower vessel assembly. Operation 714 is optional and is performed only in embodiments in which the wind vessel is floated prior to installation of one or more turbine blades, such as in the embodiments of Figures 4A, 4B, 5A, and 5B. Floating the lower vessel assembly includes submerging an assembly deck, such as assembly deck 230, below the water level of the ocean. Thus, the assembly deck is submerged in the water and the lower vessel assembly is at least partially submerged. Partially submerging the lower vessel assembly allows the lower vessel assembly to be floated from the assembly deck, and one of the semi-submersible vessel or the lower vessel assembly is moved such that the lower vessel assembly is no longer disposed above the semi-submersible vessel.

[0046] After one or both of operations 712 and 714, a plurality of turbine blades are attached to the lower vessel assembly during operation 716. The attachment of the plurality of turbine blades forms a wind vessel assembly, such as completed wind vessel 350. An embodiment of the assembly of the turbine blades onto the wind vessel assembly is illustrated in Figures 3A, 3B, 5A, 5B, 6A, and 6B. The turbine blades are attached to the rotor hub. The turbine blades are assembled onto the rotor hub and the lower vessel assembly using one of a combination of a crane on a jack-up rig, a gantry crane, and any tower crane.

[0047] In embodiments in which the lower vessel assembly was not floated during operation 714, the semi-submersible vessel is at least partially submerged during operation 718 after assembling the turbine blades on the lower vessel assembly during operation 716. Operation 718 is performed in embodiments in which the wind vessel is floated after being fully assembled, such as the embodiment of Figures 3A and 3B. Floating the fully assembled wind vessel is similar to floating the lower vessel assembly in operation 714.

[0048] After fully assembling and floating the wind vessel during operations 714, 716, 718, the wind vessel assembly is transferred to a second offshore location during operation 720. The second offshore location is a wind field location, such as wind field 140. The second offshore location can be in a deep water area, such as deep water area 130. Transferring the completed wind vessel to the second offshore location is performed after the wind vessel is assembled to allow assembly of the wind vessel at an offshore location while still benefiting from good stability and weather protection closer to the coastline in shallow waters. Thus, the benefits of offshore assembly are utilized while reducing the variability introduced by assembly at a deeper water location.

[0049] The transfer of the completed wind power ship is performed using a transfer vessel. The transfer vessel may be any one of a semi-submersible vessel, a transfer barge, a wet towing vessel (e.g., an offshore service vessel or "OSV"), or a dry towing vessel. The completed wind power ship may be disposed on the transfer vessel or towed behind the transfer vessel to a second offshore location. Since towing the completed wind power ship is slower than transferring the wind power ship sub-components in a disassembled state, transferring the completed wind power ship from the offshore location further allows for a shorter delivery time for each completed wind power ship compared to transferring the completed wind power ship from shore.

[0050] Method 700 is part of a larger method of constructing a floating offshore wind field. Each of the wind farm vessel sub-components is manufactured off-site at one or more onshore locations. A first plurality of wind farm vessel sub-components is manufactured at one or more onshore locations before the first plurality of wind farm vessel sub-components are transported to the first offshore location as described in method 700. The first plurality of wind farm vessel sub-components are assembled into a first floating offshore wind vessel at the first offshore location and transported from the first offshore location to a second offshore location as described in method 700. Either after or simultaneously with the manufacture and assembly of the first offshore wind vessel and the wind farm vessel sub-components, a second plurality of wind farm vessel sub-components is manufactured and transported to the first offshore location. A second plurality of wind farm vessel sub-components undergo a similar process as the first plurality of wind farm vessel sub-components and are assembled into a second floating offshore wind vessel at the first offshore location before being transported to the second offshore location. The second floating offshore wind vessel and the first floating offshore wind vessel are both positioned in the wind field. Additional floating offshore wind vessels are manufactured and assembled in a similar manner and transported to the wind field to complete the wind farm.

[0051] Each of the one or more onshore locations may be at a different location and may specialize in one or more of the wind farm vessel sub-components. In some embodiments, each of the one or more wind farm vessel sub-components is manufactured separately and then transported to a port close to the wind field, from which the one or more wind farm vessel sub-components are transported to the first offshore location for assembly.

[0052] While the above is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope of the disclosure, the scope of which is determined by the claims that follow.

Claims

1. A method for assembling a floating offshore wind power vessel, comprising the steps of: Delivering a plurality of wind power vessel subcomponents to a first offshore location; Assembling a first portion of a wind power vessel on a semi-submersible vessel at the first offshore location; assembling a second portion of the wind power vessel onto the first portion at the first offshore location to form a completed wind power vessel; partially submerging the semi-submersible vessel to float at least the first portion of the wind power vessel; transporting the completed wind power ship from the first offshore location to a second offshore location; A method comprising:

2. The method of claim 1 , wherein the second portion of the wind power vessel is attached to the first portion of the wind power vessel on the semi-submersible vessel.

3. The second part of the wind power ship Floating the first part of the wind power vessel; ballasting the first part of the wind power vessel; coupling the first portion of the wind power vessel to a seabed; 2. The method of claim 1, further comprising attaching the wind power vessel to the first part after at least one of:

4. 2. The method of claim 1, wherein the first offshore location has a first water depth and the second offshore location has a second water depth, the first water depth being shallower than the second water depth.

5. The method of claim 4 , wherein the first water depth is less than about 150 feet.

6. The method of claim 5 , wherein the second water depth is greater than about 100 feet.

7. The method of claim 1 , wherein the semi-submersible vessel is a floating dry dock.

8. The method of claim 1 , wherein a jack-up rig is at the first offshore location and configured to assemble the wind power vessel onto the semi-submersible vessel.

9. The method of claim 8 , wherein the jack-up rig comprises one or more cranes.

10. A method for assembling a floating offshore wind power vessel, comprising the steps of: assembling at least a portion of a wind power vessel from a plurality of wind power vessel subcomponents on an assembly deck of a semi-submersible vessel at a first offshore location; submerging the assembly deck of the semi-submersible vessel to float the wind power vessel; transporting the completed wind power ship from the first offshore location to a second offshore location; A method comprising:

11. The method of claim 10 , wherein the plurality of wind farm vessel sub-components are transported in a disassembled state to the first offshore location using a component transfer vessel.

12. The wind power ship sub-component comprises: A lower platform; Hull column, Nasser and Multiple turbine blades and The method of claim 10 comprising:

13. The method of claim 10 , wherein the wind power vessel subcomponent comprises a plurality of turbine blades.

14. The method of claim 10, wherein the completed wind power vessel is transported to the second offshore location after floating the wind power vessel.

15. 11. The method of claim 10, wherein assembling the wind power vessel on the assembly deck includes utilizing a jack-up rig located adjacent to the semi-submersible vessel at the first offshore location, a gantry crane located on the semi-submersible vessel, and a tower crane located on the semi-submersible vessel.

16. 16. The method of claim 15, wherein the jackup rig comprises a high capacity crane and a plurality of adjustable legs coupled to a portion of the seabed below the jackup rig.

17. The method of claim 10, wherein the wind power vessel is a floating offshore wind turbine.

18. 11. The method of claim 10, wherein the first offshore location has a first water depth less than 150 feet and the second offshore location has a second water depth, the first water depth being shallower than the second water depth.

19. dry towing a partially assembled wind vessel to the semisubmersible vessel, the partially assembled wind vessel including at least a lower platform and a hull column; placing the partially assembled wind power vessel on the assembly deck of the semisubmersible vessel; Further comprising: and assembling the at least a portion of the wind power vessel includes assembling a plurality of turbine blades on the partially assembled wind power vessel. The method of claim 10.

20. 1. A method of constructing a floating offshore wind field, comprising: manufacturing a first plurality of wind power vessel subcomponents at one or more onshore locations; delivering the first plurality of wind power vessel subcomponents to a first offshore location; assembling the first plurality of wind farm vessel subcomponents into a first floating offshore wind vessel at a first offshore location; Transporting the first floating offshore wind vessel from the first offshore location to a second offshore location; manufacturing a second plurality of wind power vessel subcomponents at the one or more onshore locations; delivering the second plurality of wind power vessel subcomponents to the first offshore location; assembling the second plurality of wind farm vessel subcomponents into a second floating offshore wind vessel at the first offshore location; transporting the second floating offshore wind power vessel from the first offshore location to the second offshore location; A method comprising:

21. The assembling of the first plurality of wind farm vessel sub-components into the first floating offshore wind vessel comprises: assembling a first portion of the first floating offshore wind vessel on a semi-submersible vessel; assembling a second portion of the first floating offshore wind vessel onto the first portion to form a completed first floating offshore wind vessel; partially submerging the semi-submersible vessel to float at least the first portion of the wind power vessel, wherein a jack-up rig is utilized during assembly of the first portion and the second portion; 21. The method of claim 20, comprising:

22. the first plurality of wind vessel sub-components comprises a hull, and prior to assembling the first plurality of wind vessel sub-components into the first floating offshore wind vessel, the method further comprises: ballasting the hull; connecting said hull to the seabed; 21. The method of claim 20, further comprising at least one of:

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