Patent Application
20250092857
This invention relates in general to floating platforms. In particular, this invention relates to embodiments of improved floating offshore wind turbine (FOWT) platforms that have a lower weight and are easier to manufacture and assemble than known FOWT platforms.
Wind turbines for converting wind energy to electrical power are known and provide an alternative energy source for power companies. On land, large groups of wind turbines, often numbering in the hundreds of wind turbines, may be placed together in one geographic area. Siting these large groups of wind turbines may have limitations near dense population centers if they generate undesirably high levels of noise, or they may be viewed as aesthetically unpleasing. An optimum wind resource may not be available to these land-base wind turbines due to obstacles such as hills, woods, and buildings.
Groups of wind turbines may also be located offshore, but near the coast at locations where water depths allow the wind turbines to be fixedly attached to a foundation on the seabed. Over the ocean, the flow of air to the wind turbines is not likely to be disturbed by the presence of various obstacles (i.e., as hills, woods, and buildings) resulting in higher mean wind speeds and more power. The foundations required to attach wind turbines to the seabed at these near-coast locations can be accomplished at relatively shallow depths, such as a depth of up to about 45 meters.
The U.S. National Renewable Energy Laboratory has determined that winds off the U.S. Coastline over water having depths of 30 meters or greater have an energy capacity of about 3,200 TWh/yr. This is equivalent to about 90 percent of the total U.S. energy use of about 3,500 TWh/yr. The majority of the offshore wind resource resides between 37 and 93 kilometers offshore where the water is over 60 meters deep. Fixed foundations for wind turbines in such deep water are not likely economically feasible. This limitation has led to the development of floating platforms for wind turbines. Known floating wind turbine platforms may be anchored to the seabed with mooring lines and provide some stability to the tower and turbine against external loading from wind, waves, and current, as well as loading associated with the dynamics of the wind turbine mounted thereon.
Some known FOWT platforms may be formed from steel and are based on technology developed by the offshore oil and gas industry. Other known FOWT platforms may include components formed from pre-stressed or reinforced concrete, FRP, steel, or combinations of pre-stressed reinforced concrete, FRP, and steel. There remains however, a need to provide an improved FOWT platform particularly with the ever increasing size of potential turbines which have reached 15 MW and may be larger.
This application describes various embodiments of an improved FOWT platform. In one embodiment, a semi-submersible wind turbine platform is capable of floating on a body of water and supporting a wind turbine, and includes a center column, at least three tubular bottom beams extending radially outward of a first axial end of the center column, the center column configured to have a tower attached to a second axial end thereof, outer columns, wherein a first axial end of each outer column attached to a distal end of one of the bottom beams, and top beams, one of which extends between a second axial end of each outer column and the second axial end of the center column.
Various advantages of the invention will become apparent to those skilled in the art from the following detailed description, when read in view of the accompanying drawings.
The present invention will now be described with occasional reference to the illustrated embodiments of the invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein, nor in any order of preference. Rather, these embodiments are provided so that this disclosure will be more thorough, and will convey the scope of the invention to those skilled in the art.
The embodiments of the invention disclosed below generally provide improvements to FOWT platform that include, but are not limited to, reducing the complexity, overall weight, cost, and performance, and simplifying the construction, of the FOWT platform relative to known FOWT platforms.
As used herein, the term parallel is defined as in a plane substantially parallel to the horizon. The term vertical is defined as substantially perpendicular to the plane of the horizon.
The embodiments of the improved FOWT platforms described and illustrated herein are suitable for commercial scale floating turbines with a power capacity within the range of about 6 MW to about 25 MW. The improved FOWT platforms described and illustrated herein may also be suitable for commercial scale floating turbines with a power capacity greater than about 25 MW. Advantageously, the improved FOWT platforms described and illustrated herein may be manufactured at a lower cost relative to conventional, known FOWT platforms, and are easier to construct and deploy than conventional, known FOWT platforms for a new generation of large wind turbines.
Referring to the drawings, particularly to
In the illustrated embodiment, the wind turbine tower 14 is tubular and may have any suitable outside diameter and height. In the illustrated embodiment, the outside diameter of the wind turbine tower 14 has a uniform diameter. Alternatively, the outside diameter of the wind turbine tower 14 may taper from a first diameter at its base to a second, smaller diameter at its upper end. The wind turbine tower 14 may be formed from any desired material, including but not limited to steel, concrete, fiber reinforced polymer (FRP) composite material, and a composite laminate material. If desired, the wind turbine tower 14 may be formed in any number of sections 14A.
The wind turbine 16 may be conventional and may include a rotatable hub 18. At least one rotor blade 20 is coupled to, and extends outward from, the hub 18. The hub 18 is rotatably coupled to an electric generator (not shown). The electric generator may be coupled via a transformer (not shown) and an underwater power cable (not shown) to a power grid (not shown). In the illustrated embodiment, the hub 18 has three rotor blades 20. In other embodiments, the hub 18 may have more or less than three rotor blades 20.
The illustrated foundation 12 is formed from three bottom beams 22 that extend radially outwardly from a keystone 23, connect radial or outer columns and a center column, provide heave resistance, and may provide buoyancy. An interior or center column 24 is mounted to the keystone 23, and three outer columns 26 are mounted at or near the distal ends of the bottom beams 22. The center column 24 and outer columns 26 extend upwardly and perpendicularly to the bottom beams 22 and may also provide buoyancy. Additionally, the center column 24 supports the wind turbine tower 14. Alternatively, the foundation 12 may be constructed with four bottom beams 22, each having one of the outer columns 26 mounted at or near the distal ends of each bottom beam 22.
The illustrated center column 24 and the outer columns 26 are formed from pre-stressed reinforced concrete. Alternatively, the center column 24 and the outer columns 26 may be formed from high performance concrete, FRP, steel, or combinations of pre-stressed reinforced concrete, high performance concrete, FRP, and steel. If desired, the center column 24 and the outer columns 26 may be formed in sections.
Radial support or top beams 28 are connected to the center column 24 and each of the outer columns 26, spreading the forces among the columns. The top beams 28 are configured as substantially axially loaded members and extend substantially horizontally between upper ends of the center column 24 and each outer column 26. In the illustrated embodiment, the top beams 28 are formed of tubular steel having an outside diameter of about 4 ft (1.2 m). Alternatively, the top beams 28 may be formed from FRP, pre-stressed reinforced concrete, or combinations of pre-stressed reinforced concrete, FRP, and steel.
The top beams 28 are further designed and configured substantially not to resist the bending moment of the base of the tower 14, and do not carry a bending load. Rather, the top beams 28 receive and apply tensile and compressive forces between the center column 24 and the outer columns 26.
In the embodiments illustrated herein, the wind turbine 16 is a horizontal-axis wind turbine. Alternatively, the wind turbine may be a vertical-axis wind turbine (not shown). The size of the wind turbine 16 will vary based on the wind conditions at the location where the floating wind turbine platform 10 is anchored and the desired power output. For example, the wind turbine 16 may have an output of about 5 MW. Alternatively, the wind turbine 16 may have an output within the range of from about 1 MW to about 25 MW. Additionally, if desired, the wind turbine 16 may have an output greater than about 25 MW.
The illustrated keystone 23 is formed from pre-stressed reinforced concrete, and may include an internal central cavity (not shown). Any desired process may be used to manufacture the keystone 23, such as a spun concrete process or with conventional concrete forms. Alternatively, other processes such as those used in the precast concrete industry may also be used. The concrete of the keystone 23 may be reinforced with any conventional reinforcement material, such as high tensile steel cable and high tensile steel reinforcement bars or REBAR. Alternatively, the keystone 23 may be formed from high performance concrete, FRP, steel, or combinations of pre-stressed reinforced concrete, high performance concrete, FRP, and steel.
The illustrated bottom beams 22 are formed from pre-stressed reinforced concrete as described above. Alternatively, the bottom beams 22 may be formed from high performance concrete, FRP, steel, or combinations of pre-stressed reinforced concrete, high performance concrete, FRP, and steel. The bottom beams 22 may be formed having a length within the range of about _ m to about _ m.
If desired, one or more first ballast chambers (not shown) may be formed in each bottom beam 22. Also, one or more second ballast chambers (not shown) may be formed in each outer column 26.
Referring now to
The illustrated foundation 32 is formed from three bottom beams 34 configured as steel tubes that extend radially outwardly from a lower portion of a center column 36, rather than a keystone, connect the radial or outer columns and a center column, provide heave resistance, and provide buoyancy. Three outer columns 38 are mounted at or near the distal ends of the bottom beams 34. The center column 36 and outer columns 38 extend upwardly and perpendicularly to the bottom beams 34 and also provide buoyancy. Additionally, the center column 36 supports the wind turbine tower 14. The foundation 32 includes the top beams 28 that are connected to the center column 36 and each of the outer columns 38. Disk-shaped heave plates 40 may be attached to a base portion of each of the outer columns 38. The center column 36 and the outer columns 38 may be formed and configured in the same manner as described above regarding the center column 24 and the outer columns 26. Also, if desired, the foundation 32 may be constructed with four bottom beams 34, each having one of the outer columns 26 mounted at or near the distal ends of each bottom beam 34.
It will be understood that a diameter of the tubular bottom beams 34 may be determined based on a size of the wind turbine 16 to be mounted on the wind turbine tower 14, and the environmental conditions. Advantageously, the tubular bottom beams 34 may be formed from sections of the tubular material similar to those used to form the wind turbine tower 14, and/or the tubular bottom beams 34 may be formed using similar manufacturing equipment used to form the wind turbine tower 14. The tubular bottom beams 34 are configured to substantially carry the bending, shear, and torsion forces between the center column 36 and the radially arranged outer columns 38.
Referring now to
The illustrated foundation 52 includes a center column and three trusses 54 that extend radially outwardly from the center column 56 to each of three outer columns 58. The illustrated trusses 54 include an elongated first truss member 54A that extends between a base of the center column 56 and a base of each outer column 58. Each truss 54 further includes a pair of second truss members 54B. One of the second truss members 54B extends between a mid-point of the first truss member 54A and the center column 56 and a second one of the second truss members 54B extends between the mid-point of the first truss member 54A and one of the outer columns 58. Three additional first truss members 54A extend between the center column 56 and each of the outer columns 58. The trusses 54, including the first and second truss members 54A and 54B, may be formed from steel, such as steel tube.
Top support beams 60 extend between the outer columns 58. Similarly, bottom support beams 62 also extend between the outer columns 58. In the illustrated embodiment, the trusses 54 are formed from steel. The top and bottom support beams 60 and 62, respectively, are formed from steel tube.
The center column 56 and outer columns 58 extend upwardly and perpendicularly to the top and bottom support beams 60 and 62, respectively. Additionally, the center column 56 supports the wind turbine tower 14. Disk-shaped heave plates 64 may be attached to a base portion of each of the outer columns 58.
The steel trusses 54 are configured to carry the bending, shear, and torsion forces between the center column 56 and the radially arranged outer columns 58. The top and bottom steel support beams 60 and 62, respectively, are configured to provide torsional support for the outer columns 58.
Also, if desired, the foundation 52 may be constructed with four outer columns 58, wherein each outer column 58 is connected to an adjacent outer column 58 by the top support beams 60 and the bottom support beams 62, and to the center column 56 by one of the trusses 54, described above.
Referring now to
The illustrated foundation 72 is formed from three bottom T-beams 74 that extend radially outwardly from center column 76. The illustrated T-beams 74 are formed from pre-stressed reinforced concrete as described above. Alternatively, the bottom T-beams 74 may be formed from FRP, steel, or combinations of pre-stressed reinforced concrete, FRP, and steel.
Three outer columns 78 are mounted at or near the distal ends of the bottom T-beams 74. The center column 76 and outer columns 78 extend upwardly and perpendicularly to the bottom T-beams 74 and also provide buoyancy. Additionally, the center column 76 supports the wind turbine tower 14. Top support beams 80 extend between the outer columns 76. Similarly, bottom support beams 82 also extend between the outer columns 76. Radially extending top beams 83 are connected to the center column 76 and each of the outer columns 78. In the illustrated embodiment, the top and bottom support beams 80 and 82, and the radially extending top beams 83 are formed from steel tube.
The center column 76 and outer columns 78 extend upwardly and perpendicularly to the top and bottom support beams 80 and 22, respectively.
The bottom T-beams 74 are configured to carry the bending and shear forces between the center column 76 and the radially arranged outer columns 78. The top and bottom steel support beams 80 and 82 are configured to provide torsional support for the outer columns 78. This embodiment of the FOWT platform 70 does not require heave plates, such as the heave plates 40 or 64, although heave plates may be provided.
Also, if desired, the foundation 72 may be constructed with four bottom T-beams 74, each having one of the outer columns 78 mounted at or near the distal ends of each bottom T-beams 74.
Referring now to
The illustrated foundation 92 includes a center column 96 and three trusses 94 that extend radially outwardly from the center column 96 to each of three outer columns 98. In the illustrated embodiment, the trusses 94 are a hybrid concrete-steel construction wherein a first truss member or bottom chord is formed as a prestressed reinforced concrete T-beam 95. Each T-beam 95 extends between a base of the center column 96 and a base of each outer column 98. Each truss 94 further includes a pair of second truss members 95A. One of the second truss members 95A extends between a mid-point of the T-beam 95 and the center column 96 and a second one of the second truss members 95A extends between the mid-point of the T-beam 95 and one of the outer columns 98. Three third truss members 97 extend radially between the center column 96 and each of the outer columns 98. The second truss members 95A and the third truss members 97, may be formed from steel, such as steel tube.
Top support beams 100 extend between the outer columns 96. Similarly, bottom support beams 102 also extend between the outer columns 96. In the illustrated embodiment, the second truss members 95A and the third truss members 97 are formed from steel. The top and bottom support beams 100 and 102, respectively, are formed from steel tube.
The center column 96 and outer columns 98 extend upwardly and perpendicularly to the top and bottom support beams 100 and 102, respectively. Additionally, the center column 96 supports the wind turbine tower 14.
The hybrid concrete-steel trusses 94 are configured to carry the bending and shear forces between the center column 96 and the radially arranged outer columns 98. The top and bottom steel support beams 100 and 102 are configured to provide torsional support for the outer columns 98. This embodiment of the FOWT platform 90 may be provided with heave plates, such as the heave plates 40 or 64.
The embodiments of the FOWT platforms 30, 50, 70, and 90, illustrated in
Referring now to
The foundation 112 is formed from two elongated buoyant bottom beams 114 that are similar to, but longer than, the bottom beams 22 shown in
Top support beams 118 extend between the three columns 116A and 116B. Similarly, a bottom support beam 120 also extends between the distal ends of the bottom beams 114. Thus, the top and bottom support beams 118 and 120, respectively, brace the top and bottom of the outer columns 116. In the illustrated embodiment, the top and bottom support beams 118 and 120 are formed from steel tube.
The longer bottom beams 114 are configured to carry the bending, shear, and torsion forces between the vertex of the connect3ed bottom beams 114 and the outer columns 116B, and provide additional buoyancy and heave resistance. The top and bottom steel support beams 118 and 120 are also configured to provide torsional support for the outer columns 116B.
Referring now to
Thus, the foundation 132 is formed from the two bottom beams 134 that are similar to, but may have a different length than, the bottom beams 114 shown in
Top support beams 138 extend between the three columns 136A and 136B. Similarly, a bottom support beam 140 also extends between the distal ends of the bottom beams 134. Thus, the top and bottom support beams 138 and 140, respectively, brace the top and bottom of the outer columns 136B. In the illustrated embodiment, the top and bottom support beams 138 and 140 are formed from steel tube.
The bottom beams 134 are configured to carry the bending, shear, and torsion forces between the vertex of the connected bottom beams 134 and the outer columns 136B. The top and bottom steel support beams 138 and 140 are also configured to provide torsional support for the outer columns 136B.
Referring now to
Thus, the foundation 152 is formed from two of the T-beams 154 that are connected together at a 60-degree angle. A first column 156A is mounted to the two connected bottom beams 154 at the vertex defined thereby. Two additional or outer columns 156B are mounted at or near the distal ends of the T-beams 154. The outer columns 156B extend upwardly and perpendicularly to the T-beams 154 and also provide buoyancy. Additionally, the first column 156A mounted at the vertex of the two T-beams 154 supports the wind turbine tower 14. The T-beams 154 may have a length within the range of about _ m to about _ m. If desired, the foundation 152 may be formed from two of the T-beams 154 that are connected together at a 90-degree angle.
Top support beams 158 extend between the three columns 156A and 156B. Similarly, a bottom support beam 160 also extends between the distal ends of the T-beams 154. Thus, the top and bottom support beams 158 and 160, respectively, brace the top and bottom of the outer columns 156B. In the illustrated embodiment, the top and bottom support beams 158 and 160 are formed from steel tube.
The T-beams 154 are configured to carry the bending, shear, and some torsion forces between the first column 156A (at the vertex of the connected T-beams 154) and the outer columns 156B. The top and bottom steel support beams 158 and 160 are also configured to provide torsional support for the outer columns 156B.
Referring now to
The foundation 172 includes two trusses 174 that extend outwardly from a first of three columns 176A to each of a second and third, or outer columns 176B. A top support beam 178 extends between the two outer columns 176B. Similarly, a bottom support beam 180 also extends between the outer columns 176B. In the illustrated embodiment, the trusses 174 are a hybrid concrete-steel construction wherein a first truss member or bottom chord is formed as a prestressed reinforced concrete T-beam 175. The top and bottom support beams 178 and 180 are formed from steel tube.
The illustrated foundation 172 is formed from two of the trusses 174 that are connected together at a 60-degree angle. If desired, the foundation 172 may be formed from two of the trusses 174 that are connected together at a 90-degree angle.
Each truss 174 further includes a pair of second truss members 175A. One of the second truss members 175A extends between a mid-point of the T-beam 175 and the first column 176A, and a second one of the second truss members 175A extends between the mid-point of the T-beam 175 and one of the outer columns 176B. Two third truss members 177 extend between the first column 176A and each of the outer columns 176B. The second truss members 175A and the third truss members 177 may be formed from steel, such as steel tube.
The hybrid concrete-steel trusses 174 are configured to carry the bending and shear forces between a lower end of the first column 176A and the outer columns 176B. The top and bottom steel support beams 178 and 180, and the trusses 174, including the concrete T-beams 175, are configured to provide torsional support for the outer columns 176B.
Referring now to
Thus, the foundation 192 is formed from the three trusses 194 that extend between each of three columns, including a first column 196A and two outer columns 196B. In the illustrated embodiment, the trusses 194 are a hybrid concrete-steel construction wherein a first truss member or bottom chord is formed as a prestressed reinforced concrete T-beam 195.
Each truss 194 further includes a pair of second truss members 195A. One of the second truss members 195A extends between a mid-point of the T-beam 195 and one of the columns 196A or 196B, and a second one of the second truss members 195A extends between the mid-point of the T-beam 195 and an adjacent one of the columns 196A or 196B. Third truss members 198 also extend between each of the columns 196A and 196B. The second truss members 195A and the third truss members 198 may be formed from steel, such as steel tube.
The illustrated foundation 192 is formed wherein each of the trusses 194 are connected together at a 60-degree angle. If desired, the foundation 192 may be formed wherein the trusses 194 connected at the first column 196A are connected at a 90-degree angle.
The hybrid concrete-steel trusses 194 are configured to carry the bending and shear forces between lower ends of the connected columns 196A and 196B. The third truss members 198, and the trusses 194, including concrete T-beams 195, are configured to provide torsional support for the first and outer columns 196A and 196B, respectively.
The embodiments of the FOWT platforms 110, 130, 150, 170, and 190, illustrated in
The principle and mode of operation of the invention have been described in its preferred embodiments. However, it should be noted that the invention described herein may be practiced otherwise than as specifically illustrated and described without departing from its scope.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/038161 | 7/25/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63224988 | Jul 2021 | US |
