Autonomous mobile offshore wind turbine

Abstract

The Autonomous Mobile Offshore Wind Turbine (AROWT) includes a floating hull, a lifting keel extending outward from the underside of the hull, ballast, a propeller attached to a portion of the hull, and a wind turbine attached to the upper side of the hull. When deployed on the water, the AROWT moves in a figure-of-eight station-keeping pattern and includes a wind turbine with a rated power output of 5 MW to 25 MW, a rated wind speed of 8 m / s to 20 m / s, a wind turbine blade diameter within 100 m to 300 m, a lifting keel depth of 30 m to 100 m, a ratio of hull speed to wind speed of 0.1 to 0.3, a ratio of pattern beam to wind turbine blade diameter of 0.5 to about 5.0, and a ratio of pattern beam to pattern surge of 0.02 to about 0.1.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 322,791, filed March 23, 2022, the disclosure of which is incorporated herein by reference. [Background technology]

[0002]

[0002] The present invention relates generally to floating wind turbine platforms. In particular, the present invention relates to an improved autonomous roaming offshore wind turbine (AROWT) that is free to chase wind energy anywhere in the ocean.

[0003]

[0003] Wind turbines for converting wind energy into electricity are known and provide an alternative energy source to power companies. On land, large groups of wind turbines, often hundreds of wind turbines, may be located together in one area. These large groups of wind turbines may produce annoyingly high levels of noise and may look aesthetically unpleasing. Obstacles such as hills, forests, and buildings may prevent optimal air flow from being available for these land-based wind turbines.

[0004]

[0004] Groups of wind turbines may also be located offshore, but at deeper waters near shore where the wind turbines can be fixedly attached to foundations on the seabed. Offshore, the airflow to the wind turbines is less likely to be disturbed by the presence of various obstacles (i.e. hills, forests, buildings, etc.), resulting in higher average wind speeds and greater power output. The foundations required to attach wind turbines to the seabed at such close-to-shore locations are relatively expensive and can only be achieved at relatively shallow depths, such as up to about 45 meters.

[0005]

[0005] The National Renewable Energy Laboratory has determined that wind from the U.S. coastline in waters with depths of 30 meters or more has an energy capacity of about 3,200 TWh / year. This is equivalent to about 90 percent of the U.S. total energy use, which is about 3,500 TWh / year. The majority of offshore wind sources are located 37 to 93 kilometers offshore, in water depths of more than 60 meters. At such depths, fixed foundations for wind turbines may not be economically feasible. This constraint has led to the development of floating platforms for wind turbines.

[0006]

[0006] Known floating offshore wind turbines (FOWTs) can capture abundant high-energy winds in deep waters, but they require expensive foundations, moorings, and anchors, and have high operation and maintenance costs. The National Renewable Energy Laboratory (NREL) estimates that the operation and maintenance, foundations, electrical infrastructure, assembly, and installation alone exceed 68% of the levelized cost of energy (LCOE) of a FOWT.

[0007]

[0007] It is therefore desirable to provide a floating wind turbine platform that can move autonomously, thus eliminating the need for floating wind power farms that must be operated as fixed power plants. Summary of the Invention [Means for solving the problem]

[0008]

[0008] The present invention relates to an improved autonomous mobile offshore wind turbine (AROWT) that can freely chase wind energy anywhere in the ocean. In one embodiment, the AROWT includes a floating hull, a lifting keel extending outward from the underside of the hull, ballast, a propeller attached to a portion of the hull, and a wind turbine attached to the upper side of the hull. When deployed on the water, the AROWT includes a wind turbine that moves in a figure-of-eight station-keeping pattern and has a rated power of 5MW to 25MW, a rated wind speed of 8m / s to 20m / s, a wind turbine blade diameter within 100m to 300m, a lifting keel depth of 30m to 100m, a ratio of hull speed to wind speed of 0.1 to 0.3, a ratio of pattern beam to wind turbine blade diameter of 0.5 to about 5.0, and a ratio of pattern beam to pattern surge of 0.02 to about 0.1.

[0009]

[0009] In a second embodiment, the AROWT includes a floating hull, a lifting keel extending outward from the underside of the hull, ballast, a propeller attached to a portion of the hull, and a wind turbine attached to the upper side of the hull. When deployed on the water, the AROWT includes a wind turbine that moves in a figure-of-eight station-keeping pattern and has a rated power of 5MW to 25MW, a rated wind speed of 8m / s to 20m / s, a wind turbine blade diameter within 100m to 300m, a lifting keel depth of 30m to 100m, a ratio of hull speed to wind speed of 0.05 to 0.5, a ratio of pattern beam to wind turbine blade diameter of 0.5 to about 10.0, and a ratio of pattern beam to pattern surge of 0.01 to about 0.5.

[0010]

[0010] In a third embodiment, the AROWT includes a floating hull, a lifting keel extending outward from the underside of the hull, ballast, a propeller attached to a portion of the hull, and a wind turbine attached to the upper side of the hull. When deployed on the water, the AROWT includes a wind turbine that moves in a figure-of-eight station-keeping pattern and has a rated power of 5MW to 25MW, a rated wind speed of 8m / s to 20m / s, a wind turbine blade diameter within 100m to 300m, a lifting keel depth of 30m to 100m, a ratio of hull speed to wind speed of 0.05 to 0.5, a ratio of pattern beam to wind turbine blade diameter of 0.5 to about 10.0, and a ratio of pattern beam to pattern surge of 0.01 to about 1.0.

[0011] In a fourth embodiment, the AROWT includes a floating hull, a lifting keel extending outward from the underside of the hull, ballast, a propeller mounted on a portion of the hull, and a wind turbine mounted on the upper side of the hull. When deployed on water, the AROWT moves in a figure-of-eight upwind movement pattern at an upwind movement speed.

[0012] In a fifth embodiment, the AROWT includes a floating hull, a lifting keel extending outward from the underside of the hull, ballast, a propeller mounted on a portion of the hull, and a wind turbine mounted on the upper side of the hull. When deployed on water, the AROWT moves in a figure-of-eight downwind movement pattern at a downwind movement speed.

[0013] The various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of an autonomous mobile offshore wind turbine (AROWT) according to the present invention. [Diagram 2]

[0015] FIG. 2 is an elevation view of the AROWT shown in FIG. 1. [Diagram 3]

[0016] FIG. 3 is a diagram of a first embodiment of a position holding pattern of the AROWT shown in FIGS. 1 and 2. [Figure 4]

[0017] FIG. 3 is a diagram of a second embodiment of a station-keeping pattern, showing the AROWT shown in FIGS. 1 and 2 in an upwind movement pattern. [Diagram 5]

[0018] FIG. 3 is a diagram of a third embodiment of a station-keeping pattern, showing the AROWT shown in FIGS. 1 and 2 in a downwind movement pattern. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015]

[0019] Referring now to the drawings, Figures 1 and 2 show a first embodiment of an Autonomous Mobile Offshore Wind Turbine (AROWT) 10 in accordance with the present invention. The larger AROWT 10 embodiment described herein is configured to operate independently such that it is free to chase wind energy anywhere in the ocean, including international waters. Thus, the use of AROWT 10 has the potential to significantly increase the capture of renewable energy around the world.

[0016]

[0020] The AROWT 10 includes a foundation or hull 11 including an elongated torpedo-shaped float, equipment, and storage tank that defines an upper hull 12 having a pair of vertically oriented control fins 14, a lifting keel 16, and an elongated torpedo-shaped ballast pod 18. The upper hull 12 can include one or more internal compartments (not shown), such as floating compartments that can be filled or partially filled with water to control buoyancy and stability. The floating compartments in the upper hull 12 may be used as ballast tanks or may be used to store liquid fuels, such as hydrocarbons, hydrogen, ammonia, etc., generated by energy captured by production equipment (not shown) on board the AROWT 10 and a conventional wind turbine 24, such as a 15 MW wind turbine, mounted on the top end of the upper hull 12. The floating compartments in the upper hull 12 advantageously provide the majority of the internal volume required to maintain the buoyancy and stability of the entire AROWT 10 system. It will be understood that the lifting keel 16 and ballast pod 18 may also include one or more internal compartments (not shown) that can be used to store liquid fuels, such as hydrocarbons, hydrogen, ammonia, etc., produced by production equipment (not shown) onboard the AROWT 10.

[0017]

[0021] The lifting keel 16 is aligned with the longitudinal axis A of the upper hull 12 and extends outwardly (downwardly as viewed in FIGS. 1 and 2) from the upper hull 12. In the embodiment of the AROWT 10 shown in FIGS. 1 and 2 and having a 15 MW wind turbine 24, the lifting keel 16 has a vertical length of about 50 m. Alternatively, the lifting keel 16 may have a vertical length in the range of about 10 m to about 100 m. As used herein, the lifting keel 16 is defined as the main central longitudinal structural member and subsea lifting surface of the AROWT 10, and is located at or near the lowest point of the upper hull 12. The lifting keel 16 extends outwardly from the lower outer surface of the upper hull 12 and provides hydrodynamic lift that acts against the thrust of the wind turbine 24 generating a net force that drives the AROWT 10 in a desired predetermined pattern. The hull 11, including the upper hull 12, the lifting keel 16 and the ballast pods 18, may be formed from metals such as steel, marine grade composite materials, and marine grade concrete materials.

[0018]

[0022] The ballast pod 18 is attached to the distal end of the lifting keel 16 and includes a thruster or propeller 20 at its aft end. For use with the illustrated 15 KW wind turbine 24, the propeller 20 may have a diameter in the range of about 0.5 m to about 5 m, may have a size of about 0.02 percent to about 0.05 percent of the diameter of the wind turbine blades 28 described below, and may be designed and configured to generate a thrust force of about 8 percent to about 40 percent of the rated power of the wind turbine 24. The ballast pod 18 provides stability and additional hydrodynamic drag. The ballast pod 18 may include one or more internal ballast compartments (not shown) that may be filled or partially filled with heavy ballast material (not shown) to provide stability. The ballast material may be a movable material, such as gravel or stones, that is placed therein permanently or semi-permanently, or may be a combination of water and other heavy solid ballast materials, such as iron ore, lead, steel, and aggregates, such as sand and stone. The ballast material may also be integral to the ballast pod 18, for example, the ballast pod 18 may be formed from metals, such as steel, marine grade composite materials, and marine grade concrete materials. The ballast in the ballast pod may be a combination of water and other heavy solid ballast materials, such as iron ore, aggregates (sand, stone), lead, steel, and the like.

[0019]

[0023] The upperhull 12 also supports a conventional wind turbine tower 22, described below. The wind turbine tower 22 extends outwardly (upwardly as viewed in FIGS. 1 and 2) from the upperhull 12 opposite the lifting keel 16 and includes a conventional wind turbine 24 mounted at its upper end. The wind turbine 24 is structured and arranged to be able to yaw, thereby allowing the orientation of the wind turbine 24 to be changed relative to the direction of the longitudinal axis A of the upperhull 12.

[0020]

[0024] In the illustrated embodiment, the tower 22 is tubular with an outer wall defining a hollow interior space and may have any suitable outer diameter and height. For example, for the 15 MW wind turbine 24 shown in FIGS. 1 and 2, the tower 22 may have a height of about 150 m. It will be appreciated that the height of the tower 22 may vary based on the size of the wind turbine 24 attached to the tower 22. In the illustrated embodiment, the outer diameter of the tower 22 tapers from a first diameter at its base to a second, smaller diameter at its top. The illustrated tower 22 may be formed from a fiber reinforced polymer (FRP) composite material. Non-limiting examples of other suitable composite materials include glass and carbon FRP. The tower may also be formed from a composite laminate material. Alternatively, the tower 22 may also be formed from concrete or steel. The tower 22 may be formed in any number of sections (not shown).

[0021]

[0025] In the embodiment shown herein, the wind turbine 24 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 24 may vary based on wind conditions at the location or locations where the AROWT 10 operates and the desired power output. For example, the wind turbine 24 may have a power output of about 15 MW. Alternatively, the wind turbine 24 may have a rated power output in the range of about 1 MW to about 25 MW capable of operating at wind speeds of about 4 m / s to 20 m / s.

[0022]

[0026] The wind turbine 24 includes a rotatable hub 26. At least one wind turbine blade 28 is coupled to and extends outwardly from the hub 26. The hub 26 is rotatably coupled to a nacelle 30, which is mounted to the rear of the wind turbine 24 and houses electrical and mechanical components of the wind turbine 24, such as a generator (not shown). The generator may be coupled to equipment (not shown) within the upper hull 12. In the illustrated embodiment, the hub 26 has three wind turbine blades 28 attached thereto defining a wind turbine blade diameter. In other embodiments, the hub 26 may have more or less than three wind turbine blades 28. The wind turbine blade 28 may have a diameter within a range of about 50 m to about 300 m.

[0023]

[0027] The upper hull 12 is semi-submersible and is structured and configured to float semi-submerged in water. The upper hull 12 of the AROWT 10 may float only partially submerged (not shown), or completely submerged, such that the waterline W of the water in which the AROWT 10 floats is at the base of the tower 22, as shown in Figures 1 and 2.

[0024]

[0028] Although not shown, a simpler embodiment of the AROWT 10 may include a wind turbine 24 and its associated tower 22 mounted on top of the hull, including a keel lifting surface similar to the upper hull 12 and lifting keel 16, and one or more independently driven propellers similar to the propeller 20, but mounted at the aft hull.

[0025]

[0029] Advantageously, the generated power provided by AROWT10, for example with a modern 10-15 MW upwind horizontal axis wind turbine, can be used for multiple purposes. The generated power can be used for, for example, carbon sequestration, hydrogen production, and / or the production of carbon-free liquid ammonia (NH3), the primary chemical used to make fertilizer, or other desired products. AROWT10 is configured to slowly navigate the ocean and use autonomous navigation techniques and novel navigation principles to seek out the most productive winds to enhance energy capture.

[0026]

[0030] The modified keel-shaped configuration of the hull 11 of the AROWT 10 provides sufficient stability to resist overturning moments from wind forces, allows for efficient navigation and energy harvesting, and allows for on-board storage of produced fuel. Although the hull 11 is shown as having a keel-shaped configuration, it will be understood that the foundation may have other semi-submersible configurations.

[0027]

[0031] Referring now to FIG. 3, one embodiment of a station-keeping pattern for the AROWT 10 is shown. As shown, the AROWT 10 maximizes energy capture and resists turbine thrust without a mooring system. In FIG. 3, the AROWT 10 is shown in a figure-of-eight station-keeping pattern 40. In the illustrated embodiment, the pattern beam 42 is defined as the width of the station-keeping pattern generally transverse to the wind direction indicated by WS. The pattern surge 44 is defined as the range of movement of the AROWT 10 within the path 40 of the wind direction WS. The vessel speed is indicated by arrow 46, the thrust of the wind turbine 24 is indicated by arrow 48, and the lifting force of the lifting keel 16 is indicated by arrow 50. The pattern beam 42 may be further defined as a distance equal to between about 0.5 times and about 10 times the diameter of the wind turbine blade 28. The pattern beam 42 may also be defined as a distance greater than about 10 times the diameter of the wind turbine blade 28. In operation, the ratio of vessel speed 46 to wind speed WS is in the range of about 0.1 to about 0.3. Alternatively, the ratio of vessel speed 46 to wind speed WS may be in the range of about 0.05 to about 0.5. In operation, the ratio of pattern surge 44 to pattern beam 42 may be in the range of about 0.02 to about 0.1. Alternatively, the ratio of pattern surge 44 to pattern beam 42 may be in the range of about 0.01 to about 0.5, or in the range of about 0.01 to about 1.0.

[0028]

[0032] As used herein, AROWT movement patterns, including holding patterns, upwind movement patterns, and downwind movement patterns, consist of movement patterns generally in the shape of a figure eight pattern, with the paths of the AROWT 10 intersecting somewhere near the midpoint of the pattern. When in the energy producing region of the pattern, the general movement of the AROWT 10 is somewhat downwind, and when in the tacking portion of the pattern, the AROWT 10 moves generally upwind.

[0029]

[0033] Referring again to FIG. 3, the thrust of the propeller 20 is indicated by arrows 52. In the figure-of-eight station-keeping pattern 40 shown in FIG. 3, the vector of the wind turbine 24 has a small drag component indicated by arrows 54 that adds to the drag of the AROWT 10. The propeller 20 is required to counter these drag forces 54. However, the wind turbine 24 will see a slight increase in apparent wind, which will increase its power output to compensate for some of the propeller 20 power required. With forward speed, the lifting keel 16 generates a keel lift 50 that counteracts the turbine thrust 48, minimizing downwind motion and maximizing relative wind speed, increasing energy capture. When moving briefly upwind, energy is used by the propeller 20 to rotate the hull 11.

[0030]

[0034] Using the hydro / aero vector model of AROWT 10 shown in Figures 1 and 2, using a commercially available 15 MW wind turbine 24, and assuming a 70 percent efficient propeller 20, it has been shown that a figure-of-eight station-holding pattern 40 as shown in Figure 3 requires only 10-15 percent consumption of the wind turbine 24's energy in an optimally configured system (represented by AROWT 10) with realistic performance. AROWT 10 can be further optimized by traveling longer distances, reducing wind turbine power while making turns, vectoring wind turbine thrust 48 using yaw, optimizing route path 40 and vessel speed 46 with weather fluctuation control feedback, etc. Thus, it has been shown that the system efficiency of AROWT 10 can be substantially improved by optimization in the proposed endeavor.

[0031]

[0035] The unique combination of the AROWT 10 configuration combined with the novel station-keeping pattern 40 shown in FIG. 3 allows the AROWT 10 to generate significant energy, i.e., power, from the wind turbine 24 and control the AROWT 10 without the use of mooring lines or anchors. Although this pattern 40 and the directional maneuvers using the lifting keel 16, wind turbine 24, and propeller 20 are similar in principle to the operation of a sailing vessel, the operation of the vectoring elements including the lifting keel 16, propeller 20, and wind turbine 24 is significantly different from the tacking maneuver of conventional sailing. This difference is because the primary forces provided by the wind turbine 24, including the thrust in the downwind direction, are significantly different from the lift force of the sail perpendicular to the wind. Thus, the station-keeping pattern 40 shown in FIG. 3 and the alternative embodiments shown in FIG. 4 and FIG. 5 and described below are novel and unique for the AROWT 10 system to operate successfully and generate power. Although the AROWT 10 operating in the position keeping pattern 40 shown in FIG. 3 has been described as operating without the use of mooring lines or anchors, it will be understood that the AROWT 10 may be anchored and operated in alternative embodiments of the position keeping pattern 40, or the movement patterns shown in FIGS. 4 and 5.

[0032]

[0036] In the embodiment of the station keeping pattern 40 shown in Figure 3, the AROWT 10 is shown to be on the water and does not have a permanent mooring that attaches the AROWT 10 to the seabed. The illustrated figure-of-eight pattern 40 may have the following characteristics: a wind turbine 24 having a rated power of about 5 MW to about 25 MW, a rated wind speed WS of 8 m / s to about 20 m / s, a wind turbine blade diameter in the range of about 100 m to about 300 m, a lifting keel 16 depth of about 30 m to about 100 m, a ratio of vessel speed 46 to wind speed WS of about 0.1 to about 0.3, a ratio of pattern beam 42 to wind turbine blade diameter of 0.5 to about 5.0, and a ratio of pattern beam 42 to pattern surge 44 of 0.02 to about 0.1, which defines an optimal ratio of pattern beam 42 to pattern surge 44.

[0033]

[0037] Alternatively, the figure-eight pattern 40 shown in FIG. 3 may have the following characteristics: a wind turbine 24 having a rated power of about 5 MW to about 25 MW; a rated wind speed WS of 8 m / s to about 20 m / s; a wind turbine blade diameter in the range of about 100 m to about 300 m; a lifting keel 16 depth of about 30 m to about 100 m; a ratio of hull speed 46 to wind speed WS of about 0.05 to about 0.5; a ratio of pattern beam 42 to wind turbine blade diameter of 0.5 to about 10.0; and a ratio of pattern beam 42 to pattern surge 44 of 0.01 to about 0.5, which defines a ratio of operating pattern beam 42 to pattern surge 44.

[0034]

[0038] In addition, the figure-eight pattern 40 shown in FIG. 3 may have the following characteristics: a wind turbine 24 having a rated power of about 5 MW to about 25 MW; a rated wind speed WS of 8 m / s to about 20 m / s; a wind turbine blade diameter in the range of about 100 m to about 300 m; a lifting keel 16 depth of about 30 m to about 100 m; a ratio of hull speed 46 to wind speed WS of about 0.05 to about 0.5; a ratio of pattern beam 42 to wind turbine blade diameter of 0.5 to about 10.0; and a ratio of pattern beam 42 to pattern surge 44 of 0.01 to about 1.0, which defines a ratio of functional pattern beam 42 to pattern surge 44.

[0035]

[0039] 4, a second embodiment of a station keeping pattern for the AROWT 10 is shown. As shown, the AROWT 10 maximizes energy capture without a mooring system and resists turbine thrust. In FIG. 4, the AROWT 10 is shown in a figure-of-eight upwind migration pattern 60. Pattern 60 is similar to pattern 40, except that the AROWT 10 moves upwind at an upwind migration speed 62. The illustrated upwind migration pattern 60 can be used when the ratio of net upwind vessel speed to wind speed WS is in the range of about 0.001 to about 0.2. Alternatively, the illustrated upwind migration pattern 60 can be used when the ratio of net upwind vessel speed to wind speed WS is in the range of about 0.001 to about 0.4.

[0036]

[0040] Referring now to FIG. 5, a third embodiment of a station keeping pattern for the AROWT 10 is shown. As shown, the AROWT 10 maximizes energy capture and resists turbine thrust without a mooring system. In FIG. 5, the AROWT 10 is shown in a figure-of-eight downwind movement pattern 70. Pattern 70 is similar to pattern 60, except that the AROWT 10 moves downwind at a downwind movement speed 72. The illustrated downwind movement pattern 70 can be used when the ratio of net downwind vessel speed to wind speed WS is in the range of about 0.001 to about 0.2. Alternatively, the illustrated upwind movement pattern 70 can be used when the ratio of net downwind vessel speed to wind speed WS is in the range of about 0.001 to about 0.4.

[0037]

[0041] Advantageously, AROWT10 can produce more energy than other offshore wind turbines. Although AROWT10 may lose some power produced to be able to provide the power required to operate its propellers 20, and may also lose some power associated with the production of chemical fuels, these losses can be offset because AROWT10 can access better winds far offshore, adapt to seasonal weather changes, avoid unfavorable weather, and avoid waycrossing and transmission losses. In addition, the cost of energy produced by AROWT10 may be significantly reduced because most government permits, offshore construction, power grids, transformers, converters, moorings, and anchors associated with conventional floating offshore wind turbines (FOWTs) are not required. Referring to the example of onboard NH3 production, energy can be produced at a capital cost approximately 40% lower than conventional offshore wind energy production. AROWT10 will also enable energy production in areas where moored offshore wind is unavailable, i.e. at very deep depths, beyond approximately 1500m, the depth of most of the world's oceans.

[0038]

[0042] The purified seawater can be advantageously electrolyzed to hydrogen (H2) and then to the denser NH3 for easier storage on board. A service vessel can be dispatched at designated times and locations throughout the year when and where ocean conditions are favorable to retrieve the stored NH3. A small modular NH3 plant can be mass produced to reduce costs and can be integrated into one or more floating sections (not shown) of the upper hull 12. This concept could be a very low-cost way to produce carbon-free NH3 while eliminating the hazardous siting concerns associated with onshore NH3 production. NH3 is not only a source of energy but also a large source of chemical fertilizer, and the United States already has significant pipeline transportation infrastructure for NH3. In addition, the potential revenue from NH3 generation is tied to the world market price of NH3, which is currently derived from methane and coal supplies. Using the AROWT 10 for NH3 production could change the reliance on fossil fuels as feedstock for NH3 production.

[0039]

[0043] Traditionally, it has been understood that FOWT farms must be geographically fixed power plants, but the floating but autonomously mobile AROWT10 described herein can significantly reduce or eliminate many of the costs associated with fabricating, installing, and operating offshore wind facilities. Significantly, AROWT10 can achieve significant reductions in energy generation costs by eliminating expensive foundations, moorings, and anchors, and the associated geotechnical work and their installation, using lighter and more efficient hulls or foundations compared to fixed FOWTs, no longer requiring electrical cable infrastructure, reducing permitting costs by, for example, shifting oversight and regulatory control from the Bureau of Ocean Energy Management (BOEM) to the Coast Guard, and increasing capacity factors resulting from being able to navigate autonomously to high-energy wind areas.

[0040]

[0044] Additionally, the AROWT10 has several environmental advantages over known technologies such as known FOWTs, including having fewer competing issues - for example, potentially eliminating fishing disputes - having no anchors, electrical cables, or other equipment that may be left at sea after the project's life is over, and having a lighter hull with less material.

[0041]

[0045] The principles and modes of operation of this invention have been explained and illustrated in its preferred embodiment, however, it will be understood that the invention can be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.

Claims

1. 1. An autonomous mobile offshore wind turbine (AROWT), comprising: A floating vessel; a lifting keel extending outwardly from the underside of the hull; Ballast and A propeller attached to a portion of the hull; a wind turbine mounted on an upper side of the hull opposite the underside of the hull; and Equipped with When deployed on the water, the AROWT moves in a figure-of-eight positioning pattern; When moving in the figure-of-eight position holding pattern, the AROWT A wind turbine having a rated power output of 5 MW to 25 MW; A rated wind speed of 8m / s to 20m / s; - a wind turbine blade diameter in the range of 100m to 300m; Lifting keel depth of 30m to 100m; A ratio of vessel speed to wind speed between 0.1 and 0.3; a pattern beam to wind turbine blade diameter ratio of 0.5 to about 5.0; a pattern beam to pattern surge ratio of 0.02 to about 0.1; Including, AROWT.

2. 2. The AROWT of claim 1, wherein the AROWT floats on water and has no moorings attaching the AROWT to the ocean floor.

3. 2. The AROWT of claim 1, wherein the floating hull includes a tank defining an upper hull, the lifting keel extending outwardly from an underside of the upper hull.

4. The wind turbine and the production equipment in the floating vessel convert liquid ammonia (NH ３ ) and placing the NH ３ The AROWT of claim 1 configured to store

5. 10. The AROWT of claim 1, further comprising an elongated, torpedo-shaped ballast pod attached to a distal end of said lifting keel.

6. The AROWT of claim 5 , further comprising a propeller attached to an aft end of the ballast pod.

7. 1. An autonomous mobile offshore wind turbine (AROWT), comprising: A floating vessel; a lifting keel extending outwardly from the underside of the hull; Ballast and A propeller attached to a portion of the hull; a wind turbine mounted on an upper side of the hull opposite the underside of the hull; and Equipped with When deployed on the water, the AROWT moves in a figure-of-eight positioning pattern; When moving in the figure-of-eight position holding pattern, the AROWT A wind turbine having a rated power output of 5 MW to 25 MW; A rated wind speed of 8m / s to 20m / s; - a wind turbine blade diameter in the range of 100m to 300m; Lifting keel depth of 30m to 100m; A ratio of vessel speed to wind speed between 0.05 and 0.5; a ratio of pattern beam to wind turbine blade diameter between 0.5 and 10.0; A pattern beam to pattern surge ratio of 0.01 to 0.5; Including, AROWT.

8. 8. The AROWT of claim 7, wherein the AROWT floats on water and has no moorings attaching the AROWT to the ocean floor.

9. 8. The AROWT of claim 7, wherein the floating hull includes a tank defining an upper hull, and the lifting keel extends outwardly from an underside of the upper hull.

10. The wind turbine and the production equipment in the floating vessel convert liquid ammonia (NH ３ ) and placing the NH ３ The AROWT of claim 9 configured to store

11. 8. The AROWT of claim 7, further comprising an elongated, torpedo-shaped ballast pod attached to a distal end of the lifting keel.

12. The AROWT of claim 11 , further comprising a propeller attached to an aft end of the ballast pod.

13. 1. An autonomous mobile offshore wind turbine (AROWT), comprising: A floating vessel; a lifting keel extending outwardly from the underside of the hull; Ballast and A propeller attached to a portion of the hull; a wind turbine mounted on an upper side of the hull opposite the underside of the hull; and Equipped with When deployed on the water, the AROWT moves in a figure-of-eight positioning pattern; When moving in the figure-of-eight position holding pattern, the AROWT A wind turbine having a rated power output of 5 MW to 25 MW; A rated wind speed of 8m / s to 20m / s; - a wind turbine blade diameter in the range of 100m to 300m; Lifting keel depth of 30m to 100m; A ratio of vessel speed to wind speed between 0.05 and 0.5; a pattern beam to wind turbine blade diameter ratio of 0.5 to 10.0; A ratio of pattern beam to pattern surge of 0.01 to 1.0; Including, AROWT.

14. 14. The AROWT of claim 13, wherein the AROWT floats on water and has no moorings attaching the AROWT to the ocean floor.

15. 14. The AROWT of claim 13, wherein the floating hull includes a tank defining an upper hull, and the lifting keel extends outwardly from an underside of the upper hull.

16. The wind turbine and the production equipment in the floating vessel convert liquid ammonia (NH ３ ) and placing the NH ３ The AROWT of claim 15 configured to store

17. 14. The AROWT of claim 13, further comprising an elongated, torpedo-shaped ballast pod attached to a distal end of the lifting keel.

18. 20. The AROWT of claim 17, further comprising a propeller attached to an aft end of the ballast pod.

19. 1. An autonomous mobile offshore wind turbine (AROWT), comprising: A floating vessel; a lifting keel extending outwardly from the underside of the hull; Ballast and A propeller attached to a portion of the hull; a wind turbine mounted on an upper side of the hull opposite the underside of the hull; and Equipped with When deployed on water, the AROWT moves in a figure-eight upwind movement pattern at an upwind movement speed.

20. 20. The AROWT of claim 19, wherein the ratio of net upwind vessel speed to wind speed WS is in the range of 0.001 to 0.

2.

24. 20. The AROWT of claim 19, wherein the ratio of net upwind vessel speed to wind speed WS is in the range of 0.001 to 0.

4.

22. 1. An autonomous mobile offshore wind turbine (AROWT), comprising: A floating vessel; a lifting keel extending outwardly from the underside of the hull; Ballast and A propeller attached to a portion of the hull; a wind turbine mounted on an upper side of the hull opposite the underside of the hull; and Equipped with When deployed on water, the AROWT moves in a figure-eight downwind movement pattern at a downwind movement speed.

23. 23. The AROWT of claim 22, wherein the ratio of net downwind vessel speed to wind speed WS is in the range of 0.001 to 0.

2.

24. 23. The AROWT of claim 22, wherein the ratio of net downwind vessel speed to wind speed WS is in the range of about 0.001 to 0.4.

Images