System for generating electricity from underwater ocean streams

Abstract

A system for generating electricity from an underwater stream to generate electricity for an electric grid or to produce hydrogen includes an underwater turbine. The underwater turbine includes an upper pontoon, a lower pontoon, and a pylon structure extending between and interconnecting the upper and lower pontoons. The underwater turbine also includes a single propeller assembly rotatably coupled to the lower pontoon. Rotation of the propeller operates a generator to generate electricity. The underwater turbine can be moored to the seabed via a mooring weight. An optional friction winch is operable to raise or lower the underwater turbine relative to the seabed.

Description

[Technical Field]

[0001] (Incorporation by reference of any application claiming priority) Any application for which a foreign or domestic priority claim is identified in an Application Data Sheet filed with this application is hereby incorporated by reference under 37 CFR 1.57.

[0002] The present disclosure relates to systems and methods for generating electricity from renewable energy sources, and more particularly to systems for generating electricity from underwater ocean streams. [Background technology]

[0003] Electricity generation from renewable energy sources is increasing to reduce dependence on fossil fuels for energy generation. Renewable sources such as sunlight and wind are common. However, such energy sources are intermittent, as electricity from solar power can only be generated during the day, and electricity from wind can only be generated when the wind is blowing. Summary of the Invention

[0004] According to one aspect of the present disclosure, a system and method are provided for continuously generating electricity from a renewable energy source, namely, an underwater ocean stream.

[0005] According to one aspect of the present disclosure, a system and method for generating electricity from underwater ocean streams using underwater turbines is provided.

[0006] According to one aspect of the present disclosure, a system and method for producing hydrogen via electricity generated from an underwater ocean stream using an underwater turbine is provided.

[0007] In some aspects, the technology described herein relates to a system for generating electricity from an underwater ocean stream, the system including an underwater turbine including an upper pontoon, a lower pontoon, a pylon structure extending between and interconnecting the upper pontoon and the lower pontoon, and a single propeller assembly having a plurality of blades rotatably coupled to the lower pontoon and configured to rotate by force from the underwater ocean stream flowing along the lower pontoon and past the propeller assembly.

[0008] In some aspects, the technology described herein relates to a system for generating electricity from an underwater marine stream, the system including an underwater turbine including an upper pontoon, a lower pontoon, a pylon structure extending between and interconnecting the upper pontoon and the lower pontoon, and a single propeller assembly having a plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from the underwater marine stream flowing along the lower pontoon and past the propeller assembly, the upper pontoon exerting a vertical buoyancy force on the lower pontoon, rotation of the propeller assembly generating electricity via a generator in the lower pontoon, the upper pontoon configured to automatically generate a counter moment opposite to a moment generated by rotation of the propeller assembly to prevent roll motion of the underwater turbine about an axis of the lower pontoon, and configured to facilitate alignment of the lower pontoon with the underwater marine stream flowing along the lower pontoon and past the propeller assembly.

[0009] In some aspects, the technology described herein relates to a system for generating electricity from an underwater marine stream, the system including an underwater turbine including an upper pontoon, a lower pontoon, a pylon structure extending between and interconnecting the upper pontoon and the lower pontoon, a single propeller assembly having a plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from the underwater marine stream flowing along the lower pontoon and past the propeller assembly, and a cable extending between a pulley on the lower pontoon and a mooring weight configured to be placed on the seabed, wherein a buoyancy force exerted on the lower pontoon by the upper pontoon, a drag force exerted on the lower pontoon and the propeller assembly by the stream, and a tension force exerted by the cable are configured to intersect at a center of the lower pontoon to prevent pitch of the lower pontoon and to facilitate alignment of the lower pontoon with the underwater stream flowing along the lower pontoon and past the propeller assembly.

[0010] In some aspects, the technology described herein provides an underwater turbine system for generating electricity from an underwater ocean stream, the system including: an upper pontoon; a lower pontoon; a pylon structure extending between and interconnecting the upper pontoon and the lower pontoon; a single propeller assembly having a plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from the underwater ocean stream flowing along the lower pontoon and past the propeller assembly; and a cable extending between a pulley on the lower pontoon and a mooring weight configured to be placed on the seabed. and a cable, the position of which is adjustable laterally in a direction parallel to the axis of the lower pontoon, wherein the buoyancy force exerted on the lower pontoon by the upper pontoon, the drag force exerted on the lower pontoon and the propeller assembly by the stream, and the tension applied to the pulley by the cable are configured to intersect at a central position of the lower pontoon to prevent pitch of the lower pontoon and facilitate alignment of the lower pontoon with the underwater stream flowing along the lower pontoon and past the propeller assembly, and the position of the pulley is adjustable to maintain the intersection of the forces at the central position.

[0011] In some aspects, the technology described herein relates to a system for generating electricity from an underwater stream, including a plurality of underwater turbines, each of which includes an upper pontoon, a lower pontoon, a pylon structure extending between and interconnecting the upper pontoon and the lower pontoon, and a single propeller assembly having a plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from the underwater ocean stream flowing along the lower pontoon and past the propeller assembly. The upper pontoon also applies a vertical buoyancy force to the lower pontoon. Rotation of the propeller assembly generates electricity via a generator in the lower pontoon. The upper pontoon is configured to automatically generate a counter moment opposite to a moment generated by rotation of the propeller assembly to prevent roll motion of the underwater turbine about the axis of the lower pontoon, and is configured to facilitate alignment of the lower pontoon with the underwater ocean stream flowing along the lower pontoon and past the propeller assembly. The system also includes a plurality of underwater turbines and a junction box operably coupled to each of the plurality of underwater turbines via electrical cables connecting the junction box to the plurality of underwater turbines, the junction box configured to transmit electricity generated by the plurality of underwater turbines via current collecting cables. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic front perspective view of an underwater turbine for generating electricity from an ocean stream;

[0013] [Figure 1A] 2 is a schematic side view of an underwater turbine for generating electricity from the marine stream of FIG. 1.

[0014] [Figure 1B] 2 is a schematic partial cross-sectional view of an underwater turbine for generating electricity from the marine stream of FIG. 1.

[0015] [Figure 1C] 2 is a schematic, partially exploded view of a pylon structure and pontoons of an underwater turbine for generating electricity from the marine stream of FIG. 1.

[0016] [Figure 1D] 2 is a schematic partial assembly view of a pylon structure and pontoons of an underwater turbine for generating electricity from the marine stream of FIG. 1.

[0017] [Figure 1E] 2 is a schematic cross-sectional view of an upper pontoon of an underwater turbine for generating electricity from the marine stream of FIG. 1.

[0018] [Figure 2] FIG. 2 is a schematic front view of the underwater turbine of FIG. 1.

[0019] [Figure 3] 1 is a schematic partial cross-sectional side view of a bottom pontoon of an underwater turbine for generating electricity from an ocean stream.

[0020] [Figure 3A] 4 is a schematic partial cross-sectional side view of a bottom pontoon of an underwater turbine for generating electricity from the marine stream of FIG. 3.

[0021] [Figure 3B] 4 is another schematic partial cross-sectional side view of the bottom pontoon of the underwater turbine for generating electricity from the marine stream of FIG. 3.

[0022] [Figure 3C] 4 is a schematic exploded perspective view of a bottom pontoon of an underwater turbine for generating electricity from the marine stream of FIG. 3. FIG.

[0023] [Figure 4] 1 is a schematic cross-sectional view of a pitch control mechanism for an underwater turbine for generating electricity from an ocean stream.

[0024] [Figure 4A] 5 is another schematic diagram of the pitch control mechanism of the underwater turbine for generating electricity from the marine stream of FIG. 4.

[0025] [Figure 4B] 5 is another schematic cross-sectional view of the pitch control mechanism of the underwater turbine for generating electricity from the marine stream of FIG. 4.

[0026] [Figure 5] 1 is a schematic front perspective view of an underwater turbine for generating electricity from an ocean stream;

[0027] [Figure 6] FIG. 6 is a schematic rear perspective view of the underwater turbine of FIG. 5.

[0028] [Figure 7] FIG. 1 is a partial cross-sectional view of an underwater turbine.

[0029] [Figure 8] FIG. 8 is an enlarged partial cross-sectional view of the bottom pontoon of the underwater turbine of FIG. 7.

[0030] [Figure 9A] 1 is a schematic diagram of an underwater turbine in use;

[0031] [Figure 9B] FIG. 9B is a close-up view of a weight and cable used with the underwater turbine of FIG. 9A.

[0032] [Figure 10A] 1 is a schematic front perspective view of another underwater turbine for generating electricity from an ocean stream. FIG.

[0033] [Figure 10B]FIG. 10B is a schematic side view of the underwater turbine of FIG. 10A.

[0034] [Figure 11A] FIG. 10B is a schematic rear view of the underwater turbine of FIG. 10A.

[0035] [Figure 11B] FIG. 10B is a schematic diagram of the underwater turbine of FIG. 10A.

[0036] [Figure 11C] FIG. 10B is a schematic partial view of a bottom pontoon of an underwater turbine for generating electricity from the marine stream of FIG. 10A.

[0037] [Figure 12] 10B is a schematic partial view of an upper pontoon of an underwater turbine for generating electricity from the marine stream of FIG. 10A.

[0038] [Figure 13A] 10B is a schematic partial side view of the internal components of the bottom pontoon of the underwater turbine for generating electricity from marine streams of FIG. 10A, with the outer housing of the bottom pontoon excluded.

[0039] [Figure 13B] 10B is a schematic partial cross-sectional side view of a bottom pontoon of an underwater turbine for generating electricity from the marine stream of FIG. 10A.

[0040] [Figure 14A] 10B is a schematic partial cross-sectional side view of a bottom pontoon of an underwater turbine with folded blades for generating electricity from the marine stream of FIG. 10A and disposed within a storage or shipping container. FIG.

[0041] [Figure 14B] 10B is a schematic end view of a bottom pontoon of an underwater turbine with folded blades for generating electricity from the marine stream of FIG. 10A and disposed within a storage or shipping container. FIG.

[0042] [Figure 14C] 10B is a schematic end view of the folded blades of a propeller assembly for an underwater turbine for generating electricity from an ocean stream of FIG. 10A. FIG.

[0043] [Figure 14D] 10B is a schematic end view of deployed blades of a propeller assembly for an underwater turbine for generating electricity from an ocean stream of FIG. 10A. FIG.

[0044] [Figure 15] 1 is a schematic diagram of an underwater turbine used to generate electricity.

[0045] [Figure 16] FIG. 1 is a schematic diagram of an underwater turbine operably coupled to an electrolyzer system to produce hydrogen.

[0046] [Figure 17A] FIG. 1 is a schematic diagram of an underwater turbine in a modular farm layout used to generate energy.

[0047] [Figure 17B] FIG. 1 is another schematic diagram of an underwater turbine in a modular farm layout used to generate energy.

[0048] [Figure 17C] FIG. 1 is another schematic diagram of an underwater turbine in a modular farm layout used to generate energy.

[0049] [Figure 17D] FIG. 1 is another schematic diagram of an underwater turbine in a modular farm layout used to generate energy. DETAILED DESCRIPTION OF THE INVENTION

[0050] 1-1E illustrate an underwater turbine 100 (e.g., a system) for use in generating electricity from an ocean stream (i.e., the Gulf Stream off the coast of Florida). The underwater turbine 100 includes an upper pontoon 110 and a lower pontoon 120 interconnected by a pylon structure 130 and a propeller assembly 140 having a plurality (e.g., three) of blades 145. The upper pontoon 110 and the lower pontoon 120 have rounded edges (e.g., the upper pontoon 110 and the lower pontoon 120 have a circular cross section) to advantageously reduce drag on the turbine. In one implementation, the pylon structure 130 includes two sheet metal pieces 133A, 133B connected to the upper pontoon 110 and the lower pontoon 120 via fasteners 134 (e.g., rivets, screws, bolts, welts, etc.). The sheet metals 133A, 133B can be thin, e.g., 2 mm to 5 mm thick, which can facilitate or improve the hydrodynamics of the underwater turbine 100. Additionally, the sheet metals 133A, 133B can have a width W of approximately 900 mm to approximately 1500 mm, e.g., 1250 mm. Advantageously, the pylon structure 130 makes the underwater turbine 100 more hydrodynamic, allowing water to pass through the opening 133C between the two sheets of metal 133A, 133B (e.g., reducing the effect of ocean current forces acting on the underwater turbine 100). Additionally, the underwater turbine 100 is buoyant, and the upper pontoon 110 selectively provides at least 50% (e.g., 60%, 70%, 100%) of the buoyancy of the underwater turbine 100, applying a buoyancy F1 to the underwater turbine 100 (e.g., above the pylon structure 130 and the lower pontoon 120). However, as described further below, the buoyancy of the upper pontoons 110 is selectively adjustable to facilitate the ascent of the underwater turbine 100 (e.g., by increasing the buoyancy of the upper pontoons 110) or the descent of the underwater turbine 100 (e.g., by decreasing the buoyancy of the upper pontoons 110). In one implementation, the upper pontoons 110 are at least partially hollow and can be filled with either or both of air and seawater.As shown in FIG. 1, neither the upper pontoon 110 nor the lower pontoon 120 have wings extending laterally from the surface of the pontoons 10,20.

[0051] 1-1B, the upper pontoon 110 and the lower pontoon 120 can have the same shape or profile (e.g., transverse or cross-sectional shape, substantially the same length, same outer diameter), which can advantageously reduce manufacturing costs (e.g., using a single mold to fabricate the upper pontoon 110 and the lower pontoon 120). Furthermore, by having the same shape or profile, the upper pontoon 110 and the lower pontoon 120 can experience the same amount of drag (e.g., the same drag force) from the stream S (e.g., an underwater marine stream). The upper pontoon 110 and the lower pontoon 120 can also be made of the same material. For example, in one implementation, the upper pontoon 110 and the lower pontoon 120 can be made of concrete. Advantageously, constructing the upper pontoon 110 and the lower pontoon 120 out of concrete allows the upper pontoon 110 and the lower pontoon 120 to withstand greater compressive forces from being underwater without having to be pressurized to exert a counterforce from within the upper pontoon 110 and the lower pontoon 120 against the compressive forces exerted by being underwater. Optionally, the upper pontoon 110 and the lower pontoon 120 can be coated with a concrete sealant to inhibit (e.g., prevent) water from penetrating the outer layer of the upper pontoon 110 and the lower pontoon 120. Referring to FIG. 3C , the lower pontoon 120 can have a wall thickness W2 of about 50 mm to about 200 mm, for example, 100 mm. In one implementation, the upper pontoon 120 can have a wall thickness equal to the wall thickness of the lower pontoon 120.

[0052] 1B , the lower pontoon 120 may include three compartments: a first compartment 152A, a second compartment 152B, and a third compartment 152C. The first compartment 152A may include an electric motor 154 (and optionally a gearbox), bearings 151 (see FIG. 3A ), a generator 150, and a shaft 156. The second compartment 152B may include a pitch control mechanism 170. Additionally, the third compartment 152C may include a pump (e.g., hydraulic 196 and / or electric 197). The operation of the listed components and compartments is further described below.

[0053] 1C-1D show a cross section of the upper pontoon 110, in which a sheet metal 133A (or 133B) is secured to the upper pontoon 110 via fasteners 134 (e.g., rivets, screws, bolts, welts, etc.). The upper pontoon 110 may have a recess 134A designed to receive a portion of the sheet metal 133A. Advantageously, this can improve the hydrodynamics of the sheet metal 133A, 133B by reducing drag because the sheet metal 133A, 133B is flush (e.g., even, level, etc.) with the surface of the upper pontoon 110. Therefore, resistance or turbulence at the interface between the sheet metal 133A (or 133B) and the upper pontoon 110 can be reduced (e.g., prevented). Although not shown, the lower pontoon 120 may also have a similar recess designed to receive a portion of the sheet metal 133A (or 133B) to improve the hydrodynamics of the underwater turbine 100.

[0054] 1E shows a cross section of the upper pontoon 110, which is hollow at ambient pressure (e.g., atmospheric pressure) and operably connected to a pump 135. The pump 135 of the upper pontoon 110 can be selectively operated to supply water OW to the hollow shell of the upper pontoon 110 to increase the weight of the upper pontoon 110 (e.g., decrease the buoyancy of the upper pontoon 110). Advantageously, this increases the weight of the underwater turbine 100 (e.g., decrease the buoyancy of the underwater turbine 100), causing the underwater turbine 100 to sink to a lower depth. The pump 135 can also be selectively operated to expel water OW from the hollow shell of the upper pontoon 110 to decrease the weight of the upper pontoon 110 (e.g., increase the buoyancy of the upper pontoon 110). Advantageously, this reduces the weight of the underwater turbine 100 (e.g., increases the buoyancy of the underwater turbine 100) and allows the turbine to rise to shallower depths. In some embodiments, the upper pontoon 110 can have a cover 29 (see FIG. 3C). Advantageously, this allows a user to access the pump 135 for maintenance, repair, replacement, or the like.

[0055] Although not shown, operation of pump 135 can be controlled by an electronic controller (e.g., using one or more processors) based on input (e.g., instructions, commands) from a user, for example, to raise or lower underwater turbine 100. In another implementation, operation of pump 135 can be automatically controlled by an electronic controller (e.g., using one or more processors) based at least in part on data from sensors in underwater turbine 100 (e.g., gyroscopes or tilt sensors that sense the tilt of underwater turbine 100, velocity or flow sensors that measure the speed of underwater ocean currents, sensors that sense one or more parameters of the operation of components within underwater turbine 100). For example, if a sensor senses that the velocity of the underwater stream is too high, the controller can operate pump 135 to lower underwater turbine 100 to a lower depth in the ocean where the velocity of the underwater stream may be slower. Alternatively, if the sensed velocity of the underwater stream is too low, the controller can operate pump 135 to raise underwater turbine 100 to a shallower depth where the underwater stream velocity is higher. In another example, if a sensor detects a fault in a component of the underwater turbine 100, requiring maintenance, or if scheduled maintenance is required, the controller may operate the pump 135 to raise the underwater turbine 100 to the ocean surface.

[0056] 2 , one advantage of the underwater turbine 100 is that the upper pontoon 110 automatically applies a counter torque or counter moment C M (e.g., in a counterclockwise direction in FIG. 2 ) to the underwater turbine 100 that balances the torque or moment M (e.g., in a clockwise direction in FIG. 2 ) applied to the underwater turbine 100 by the rotation of the propeller assembly 140 (e.g., due to forces applied to the propeller assembly 140 by the underwater stream S). The underwater turbine 100 can reach an equilibrium orientation in which the counter moment C M balances the moment M, and this equilibrium orientation can be angled away from the vertical axis Y by an angle α. Furthermore, the counter torque or counter moment C M applied by the upper pontoon 110 is self-adjusting such that the angle α can change depending on the amount of torque applied by the rotation of the propeller assembly 140 (e.g., due to changes in rotational speed caused by changes in the velocity of the underwater stream S). Thus, the upper pontoons 110 facilitate (e.g., assist) in maintaining the underwater turbine 100 in a balanced orientation during operation and inhibit (e.g., prevent) roll motion of the lower pontoons 120 about the X-axis (see FIG. 1A ). Furthermore, the automatic counter-torque or counter-moment applied by the upper pontoons 110 to counteract the torque or moment applied by the rotation of the propeller assembly 140 allows the underwater turbine 100 to have only one propeller assembly 140 (e.g., the system does not need to have a second propeller assembly 140 rotating in the opposite direction to counteract the torque or moment applied by the first propeller assembly 140), thus advantageously simplifying the system and reducing the costs of manufacturing, maintaining, and operating the underwater turbine 100.

[0057] 3-3B show cross-sectional views of the lower pontoon 120 of the underwater turbine 100 and a propeller assembly 140 having one or more (e.g., a plurality, three) blades 145 rotatably coupled to the lower pontoon 120. The blades 145 can advantageously be made of a cost-effective material with improved corrosion resistance. In one implementation, the blades 145 can be made of a cast aluminum alloy material (e.g., A380 alloy). In another embodiment, the blades 145 can be made of fiber-reinforced concrete. The blades 145 rotate about the axis of the lower pontoon 120 by forces exerted by the underwater stream on the propeller assembly 140. During operation, the rotation of the propeller assembly 140 (e.g., caused by the underwater stream S) rotates the shaft 156, which rotates one portion of the generator 150 (e.g., the armature, rotor) relative to another portion of the generator 150 (e.g., the stator) to generate electricity. In some implementations, the underwater turbine 100 generates between 50 and 100 kW of power. In one implementation, the generator (e.g., the electric motor-generator 150) can include a variable frequency drive that allows it to operate at different speeds. Although not shown, one or more power cables can be connected to the generator 150 through which generated electricity is transmitted from the underwater turbine 100, as described further below.

[0058] The underwater turbine 100 also includes three compartments within the lower pontoon 120: a first compartment 152A, a second compartment 152B, and a third compartment 152C. The first compartment 152A and the third compartment 152C may be filled with air, thereby providing an amount of buoyancy to the lower pontoon 120 (e.g., independent of the buoyancy applied to the upper pontoon 110). Additionally, the first compartment 152A and the third compartment 152C may be maintained at atmospheric pressure within the shell of the lower pontoon 120 and remain dry (e.g., seawater does not enter the first compartment 152A and the third compartment 152C). In one implementation, the first compartment 152A is sealed (e.g., waterproof) from the second compartment 152B, and the third compartment 152C is sealed (e.g., waterproof) from the second compartment 152B. The first section 152A may include an electric motor 154 (and optionally a gearbox) coupled to bearings 151 (see FIG. 3A) and a generator 150 that may be operably connected to a shaft 156, where the shaft 156 is coupled to the propeller assembly 140.

[0059] The first compartment 152A can be connected to a humidity chamber 158 (see FIG. 3A). As water enters the humidity chamber 158 through a seal on the lower pontoon 120, the water is pumped out of the humidity chamber 158, blocking (e.g., preventing) seawater from entering the first compartment 152A. The second compartment 152B can include a pitch control mechanism 170 (see FIG. 3A) operable to maintain the lower pontoon 120 in alignment with the underwater stream S (e.g., to maintain the lower pontoon 120 in a horizontal orientation along the X-axis, as shown in FIG. 1A). The operation of the pitch control mechanism 170 is described below. The third compartment 152C can include a pump (e.g., hydraulic and / or electric) capable of maintaining the chamber at ambient air pressure (e.g., atmospheric pressure). In one implementation, the propeller assembly 140 is spaced from the end of the lower pontoon 120, where water entering the first compartment 152A can be pumped out of the first compartment 152A. In some implementations, the lower pontoon 120 can have one or more covers (see FIGS. 3 and 3C) 159, 159A, 159B with gaskets 155. Advantageously, this allows a user to access components within the compartment (e.g., via openings O1 in a pontoon, such as the lower pontoon 120) to, for example, repair or replace a compartment or component within the lower pontoon 120.

[0060] 4-4B show the lower pontoon 120 of the underwater turbine 100, having a pitch control mechanism 170 operable to maintain the lower pontoon 120 in alignment with the underwater stream S (e.g., maintain the lower pontoon 120 in a horizontal orientation X) and to inhibit (e.g., prevent, correct, compensate for) pitch motion of the lower pontoon 120. The pitch control mechanism 170 is spaced from the end of the lower pontoon 120 and is aligned with a centerline of the lower pontoon 120 that extends through the center of the propeller assembly 140 and the midline of the pylon structure 130, as described further below.

[0061] The pitch control mechanism 170 may include a hinge 183, a rigid plate 182, a piston 184 (e.g., a piston-cylinder assembly), and a cable 180. The cable 180 may be connected to a mooring weight (e.g., mooring weight A in FIG. 9A ) located on the seabed and may include a first portion coupled to the rigid plate 182 and a second portion coupled to the mooring weight. In one example, the mooring weight may be a concrete block fixed to the seabed. In another example, the mooring weight may be an anchor. In another example, the mooring weight may be a movable weight (e.g., a rake) that moves along the seabed, allowing the underwater turbine 100 to move (e.g., not be moored to a single location).

[0062] The cables 180 can be coupled to the rigid plate 182 through openings O on the rigid plate 182 such that the connected cables 180 at openings O are centered on the midline of the lower pontoon 120, the midline of the pylon structure 130, and the midline of the propeller assembly 140 (e.g., the intersection of lines F1 and F2 in FIG. 1A ). The rigid plate 182 can be connected to a hinge 183 that is operably coupled to a portion of the shell of the lower pontoon 120 (e.g., within the second section 152B). Thus, as the orientation of the rigid plate 182 changes (e.g., to maintain the lower pontoon 120 in a horizontal position aligned with the underwater stream S), the rigid plate 182 rotates about the hinge 183 (e.g., toward the forward end of the lower pontoon 120 or toward the aft end of the lower pontoon 120). The pitch control mechanism 170 can adjust the orientation of the rigid plate 182 via a piston 184 operably connected to the rigid plate 182. In one example, the piston extends (relative to the cylinder it moves in) to pivot the rigid plate 182 in one direction (e.g., toward the aft end of the lower pontoon 120). In another example, the piston retracts (relative to the cylinder it moves in) to pivot the rigid plate 182 in another (opposite) direction (e.g., toward the forward end of the lower pontoon 120). The pitch control mechanism 170 operates to maintain the orientation of the lower pontoon 120 aligned with the direction of the underwater stream S by pivoting the rigid plate 182 to offset or correct the pitch of the underwater turbine 100. (E.g., caused by the velocity of the underwater current S, the force F1 through the pylon structure 130, the force F2 from the underwater stream S, and the force from the cable 180 are not centered relative to the lower pontoon 120.) Advantageously, the shape of the rigid plate 182 is such that it can withstand the forces of the cable 180, piston 184, and hinge 183 without breaking.Additionally, the rigid plate 182 has a thin profile in one direction but a wide profile in a second direction, advantageously allowing the rigid plate 182 to pivot about the axis of the hinge 183 but inhibiting (e.g., preventing) the rigid plate 182 from pivoting laterally (e.g., pivoting across the width of the lower pontoon 120). In one implementation, the piston 184 (e.g., a piston-cylinder assembly) can be a hydraulically actuated piston. In one implementation, the piston 184 (e.g., a piston-cylinder assembly) can be a pneumatically actuated piston. However, the piston 184 can be replaced with any suitable linear actuator (e.g., a lead screw assembly) operable to change the angular orientation of the rigid plate 182 to offset or compensate for the pitch of the underwater turbine 100 and thereby maintain the orientation of the lower pontoon 120 aligned with the direction of the underwater stream S.

[0063] The piston 184 or linear actuator may be operated by an electronic controller (e.g., having one or more processors). In one implementation, the pitch control mechanism 170 is operated via the electronic controller based on user input. In another implementation, the pitch control mechanism 170 is automatically controlled by the electronic controller (e.g., using one or more processors) based at least in part on data from sensors on the underwater turbine 100 (e.g., gyroscopes or tilt sensors that sense the tilt or pitch of the underwater turbine 100). For example, if the sensors sense that the underwater turbine is experiencing a pitch relative to the horizontal (e.g., the X-axis in FIG. 1A ), the controller may automatically operate the pitch control mechanism 170 to offset the pitch and bring the underwater turbine 100 into alignment with the underwater stream S.

[0064] Another advantage of the underwater turbine 100 is that the upper pontoon 110 is buoyant and applies a vertical (e.g., Y-direction) upward force F1 (e.g., buoyancy) to the pylon structure 130 and the lower pontoon 120. The lower pontoon 120 is attached to a cable 180, which in turn is attached to a mooring weight that applies a force (e.g., tension) to the lower pontoon 120 and the pylon structure 130 in an opposite direction (e.g., downward Y) to the upper pontoon 110. Thus, the pylon structure 130 is maintained under tension by the buoyancy and tension from the upper pontoon 110 and the lower pontoon 120, respectively. Because the pylon structure 130 is fabricated from at least two thin sheets of metal 133A, 133B, maintaining the pylon structure 130 under tension is advantageous and facilitates maintaining the underwater turbine 100 in an equilibrium orientation during operation. Furthermore, because the pylon structure 130 is maintained under tension, the pylon structure 130 does not buckle, allowing the pylon structure 130 to be a thin metal sheet. Furthermore, because the pylon structure 130 is maintained under tension, the torque T or moment M applied to the underwater turbine 100 by the rotation of the propeller assembly 140 is transmitted through the pylon structure 130 (e.g., two thin hydrodynamic metal sheets 133A, 133B) to the upper pontoon 110, which automatically balances the force with a counter torque or counter moment C M (see FIG. 2 ). Thus, the underwater turbine 100 can reach an equilibrium orientation.

[0065] The underwater turbine 100 can be maintained at least 50 m below the sea surface (e.g., to avoid interference with any vessels moving above the turbine), even when the cable 180 is oriented vertically. Advantageously, the depth of the underwater turbine 100 can be varied as described above. For example, the underwater turbine 100 can be raised to sea level SL (e.g., for maintenance). In another example, the depth of the underwater turbine 100 can be varied to expose it to different current velocities.

[0066] 5-6 illustrate an underwater turbine 100′ for use in generating electricity from an ocean stream (e.g., the Gulf Stream off the coast of Florida). Some of the features of system 100′ are similar to those of system 100 of FIGS. 1-4B. Accordingly, the reference numbers used to designate various components of system 100′ are identical to the reference numbers used to identify corresponding components of system 100 of FIGS. 1-4B, except that a "'" is added to the end of the numeric identifier. Accordingly, it will be understood that the structure and description of various features of system 100 in FIGS. 1-4B, and how they operate and are controlled, also apply to corresponding features of system 100′ in FIGS. 5-6, except as noted below.

[0067] The underwater turbine 100' includes an upper pontoon 110' and a lower pontoon 120' interconnected by a pylon structure 130'. The upper pontoon 110', the lower pontoon 120', and the pylon structure 130' have rounded edges (e.g., the upper pontoon 110' and the lower pontoon 120' have circular cross sections) to advantageously reduce drag on the turbine 100'. The pylon structure 130' may be a unitary structure (e.g., a single piece) and may include a pair of lower legs 132A', 132B' separated by an opening 132C' and a pair of upper legs 131A', 131B' separated by an opening 131C', which allows water to pass therethrough (e.g., to reduce the effect of cross-current forces, such as those in FIG. 1 , acting on the turbine 100). Additionally, the pylon structure 130' can act as a fin to block (e.g., prevent) yaw motion of the underwater turbine 100', keeping the underwater turbine 100' aligned with the current S. Advantageously, the upper pontoon 110' is buoyant, and the upper pontoon 110' provides at least 50% (e.g., 60%, 70%, 100%) of the buoyancy of the underwater turbine 100', exerting a buoyancy force F1 (see FIG. 7 ) on the underwater turbine 100'. In one implementation, the upper pontoon 110' is hollow and can be filled with air. In another embodiment, the upper pontoon 110' can include a foam material.

[0068] The upper pontoon 110' and the lower pontoon 120' may have the same shape or profile (e.g., transverse or cross-sectional shape, substantially the same length, same outer diameter), which may advantageously reduce manufacturing costs (e.g., using a single mold to fabricate the upper pontoon 110' and the lower pontoon 120'). Additionally, by having the same shape or profile, the upper pontoon 110' and the lower pontoon 120' may experience substantially the same amount of drag (e.g., the same drag force) from the stream S (e.g., an underwater marine stream).

[0069] 5-6 , the underwater turbine 100′ includes a propeller assembly 140′ having one or more (e.g., many, a plurality, three) blades 145′ rotatably coupled to the lower pontoon 120′. The blades 145′ are urged to rotate about an axis X of the lower pontoon 120′ by a force F2 (see FIG. 1A ) exerted by an underwater stream S (e.g., an underwater ocean stream) on the propeller assembly 140′. Similar to the underwater turbine 100, one advantage of the underwater turbine 100′ is that the upper pontoon 110′ automatically applies a counter-torque or counter-moment to the underwater turbine 100′ (as shown in FIG. 2 ) that balances the torque or moment applied to the underwater turbine 100′ by the rotation of the propeller assembly 140′, resulting in the underwater turbine 100′ reaching an equilibrium orientation during operation.

[0070] 7-8 show another example of an underwater turbine 100″, including a pylon structure 130″ including first and second spaced apart legs 132A″ and 132B″ extending between and interconnecting an upper pontoon 110″ and a lower pontoon 120″, and an opening 132C″ defined between the first and second legs 132A″ and 132B″ (e.g., along their entire lengths) that allows water to pass therethrough (e.g., to reduce the effect of cross-current forces acting on the turbine 100″, such as within the page of FIG. 1 ). Some of the features of the system 100″ are similar to those of the system 100 of FIGS. 1-4B or the system 100′ of FIGS. 5-6 . Accordingly, the reference numbers used to designate the various components of system 100'' are identical to the reference numbers used to identify the corresponding components of system 100 of FIGS. 1-4B, except that a "'" is added to the end of the numeric identifier. Accordingly, it will be understood that the structure and description of the various features of system 100, and how they operate and are controlled, in system 100' of FIGS. 1-4B and 5-6 also apply to the corresponding features of system 100'' of FIGS. 7-8, except as noted below.

[0071] Pylon structure 130'' (e.g., first leg 132A'' and second leg 132B'') can act as fins to block (e.g., prevent) yaw motion of underwater turbine 100'' and maintain underwater turbine 100'' aligned with underwater stream S. Underwater turbine 100'' includes a shaft 152'' in first section 152A'' that couples to a propeller assembly 140'' at one end and to a generator (e.g., electric motor-generator) 150'' in second section 150A''. During operation, rotation of propeller assembly 140'' (e.g., caused by underwater stream S) rotates shaft 152'', which rotates one portion of generator 150'' (e.g., armature, rotor) relative to another portion of generator 150'' (e.g., stator) to generate electricity. In some implementations, underwater turbine 100'' generates between 50 and 100 kW of power. The generator (e.g., electric motor-generator) 150'' may include a variable frequency drive that allows it to operate at different speeds. Although not shown, one or more power cables may be connected to the generator 150'' through which generated electricity is transmitted from the underwater turbine 100'', as described further below.

[0072] The underwater turbine 100'' also includes an electric motor (and optionally, a gearbox) 154' in the third section 154A'' and a shaft 156'' in the fourth section 156A'' that is rotated by the electric motor 154'. The electric motor 154' can be operated using power generated by the generator 150''. The shaft 156'' couples to a pulley assembly 160'' in the fifth section 160A''. In one implementation, the first section 152A'' is sealed (e.g., waterproof) from the second section 150A'', which is sealed from the fifth section 160A'', which is sealed from the fourth section 156A'', which is sealed from the third section 154A''. The compartments 152A'', 150A'', 160A'', 156A'', 154A'' can be filled with air, which provides an amount of buoyancy to the lower pontoon 120'' (independent of the buoyancy exerted by the upper pontoon 10''). In one implementation, the propeller assembly 140'' is spaced from the end of the lower pontoon 120'' (e.g., by about 10 mm, so that water entering the first compartment 152A'' can be pumped out of the first compartment 152A'').

[0073] The pulley assembly includes a first pulley 161″, a second pulley 162″, a third pulley 163″, and a fourth pulley 164″. A cable 180″ can be connected to tether weight A (see FIG. 9A ) and includes a first portion 180A″ that wraps around at least a portion of the first pulley 161″, continues to wrap around at least a portion of the second pulley 162″, extends to and wraps around at least a portion of the third pulley 163″, and extends to and wraps around at least a portion of the fourth pulley 164″. In some examples, the first portion 180A″ can wrap around the second pulley 162″ and the third pulley 163″ multiple times (e.g., twice) before extending to the fourth pulley 164″. A second portion 180B'' of cable 180'' extends from fourth pulley 164'' to weight assembly 190'' (see FIG. 9B). Cable 180'' can have a diameter of approximately 20 mm in some examples. In some examples, the force acting on cable 180'' (e.g., due to underwater turbine 100' and mooring weight A) can be 10 to 15 tons. While pulley assembly 160'' is shown and described in connection with underwater turbine 100'', those skilled in the art will recognize that pulley assembly 160'' can also be implemented in underwater turbine 100' or underwater turbine 100 (e.g., in place of pitch control mechanism 170 shown in FIGS. 4-4B).

[0074] Referring to FIG. 7 , another advantage of the underwater turbine 100″ is that the upper pontoon 110″ helps maintain the lower pontoon 120″ in a horizontal orientation (e.g., preventing pitching motion of the lower pontoon 120″) and keeps the underwater turbine 100″ aligned (e.g., horizontal) with the underwater stream S. As described above, the upper pontoon 110″ is buoyant and exerts a buoyancy force F1 on the lower pontoon 120″ in a vertical direction (e.g., the Y direction). The underwater stream S exerts a drag force F2 on the lower pontoon 120″ and the propeller assembly 140″ in the X direction. Additionally, the cable 180″ attached to the mooring weight A (e.g., the first portion 180A″ of the cable 180″) exerts a force (e.g., tension) F3 on the lower pontoon 120″ via the first pulley 161″. Advantageously, the buoyancy force F1, the drag force F2, and the cable (tension) force F3 intersect and are centered on the lower pontoon 120'' to counter (e.g., prevent) pitch of the lower pontoon 120'' and maintain the lower pontoon 120'' substantially horizontal. In one example, the position of the first pulley 161'' (in a horizontal direction parallel to the axis X of the lower pontoon 120'') can be adjusted (e.g., via a slider, via a lead screw, via a solenoid) to ensure that the forces F1, F2, and F3 are advantageously centered to counter (e.g., prevent) pitch moments on the lower pontoon 120''. In one example, a tilt sensor (e.g., a gyroscope) 157'' can be located on the lower pontoon 120'', and an electronic controller can control a mechanism that adjusts the position of the first pulley 161'' based at least in part on the sensed orientation from the tilt sensor 157'' to center forces F1, F2, and F3 and counteract the pitch moment.

[0075] 9A-9B , the underwater turbine 100′ can be maintained at least 50 m below sea level SL (e.g., to avoid interference with vessel B traveling above the turbine 100′), even when the cable 180′ is oriented vertically. Advantageously, the depth of the underwater turbine 100′ can be varied as described further below. For example, the underwater turbine 100′ can be raised to sea level SL (e.g., for maintenance). In another example, the depth of the underwater turbine 100′ can be varied to expose it to different underwater stream velocities V. While FIGS. 9A-9B are shown and described with respect to the underwater turbine 100′, those skilled in the art will recognize that both the underwater turbine 100 of FIGS. 1-4B and the underwater turbine 100′ of FIGS. 7-8 can be maintained at least 50 m below sea level SL and can utilize the same mooring system and pulley assembly 160′ shown in FIGS. 9A-9B and described below.

[0076] Cable 180′ may be moored to mooring weight A. In one example, mooring weight A may be a concrete block secured to the seabed SB. In another example, mooring weight A may be an anchor. In another example, mooring weight A may be a movable weight (e.g., a rake) that moves along the seabed SB, allowing underwater turbine 100′ to move (e.g., not be moored to a single location).

[0077] Pulley assembly 160' can advantageously be part of or provide a friction winch that frictionally engages (e.g., "grabs onto") cable 180' (e.g., the first portion 180A' of cable 180') to move underwater turbine 100' up and down. For example, when the friction winch is actuated in one direction (e.g., second pulley 162' and third pulley 163' are rotated clockwise in FIG. 8 ), it shortens the first portion 180A' of cable 180' between underwater turbine 100' and mooring weight A, causing underwater turbine 100' to sink to a greater depth. In another example, when the friction winch is actuated in the opposite direction (e.g., second pulley 162′ and third pulley 163′ are rotated counterclockwise in FIG. 8 ), it lengthens first portion 180A′ of cable 180′ between submersible turbine 100′ and mooring weight A, lifting submersible turbine 100′ to a shallower depth or sea level SL. Thus, the friction winch can be operated to lift submersible turbine 100′ to sea level SL for maintenance. In another example, the friction winch is operated to submerge submersible turbine 100′ to a deeper depth, for example, to expose submersible turbine 100′ to an underwater stream S with a lower velocity V, where the velocity V at the shallower depth is much higher (e.g., about 2.1 m / s) than the speed for which submersible turbine 100′ is designed (e.g., 1.5 m / s). Advantageously, operating the friction winch in this manner eliminates the need for a large spool for winding cable, as opposed to operating a conventional spool for winding cable.

[0078] 9A-9B, the second portion 180B' of the cable 180' extending from the fourth pulley 164' is advantageously connected to a weight assembly 190' to inhibit (e.g., prevent) the second portion 180B' of the cable 180' from hanging freely and potentially contacting the propeller assembly 140'. The weight assembly 190' may include a weight W and a shaft 191' connected to the weight W and extending to a primary roller 192'. The weight assembly 190' may also include secondary rollers 193', 194' such that the first portion 180A' of the cable 180' extends between the primary roller 192' and secondary rollers 193', 194'. The weight assembly 190' has a connector 195' to which the second portion 180B' of the cable 180' connects (e.g., removably couples).

[0079] 10A-14D illustrate an underwater turbine 100''' (system) for use in generating electricity from an underwater ocean stream (e.g., the Gulf Stream off the coast of Florida). Some of the features of the underwater turbine 100''' are similar to those of the underwater turbine 100 of FIGS. 1-4B, the underwater turbine 100' of FIGS. 5-6, and the underwater turbine 100'' of FIGS. 7-8. Accordingly, the reference numbers used to designate various components of the underwater turbine 100''' are identical to the reference numbers used to identify corresponding components of the underwater turbine 100 of FIGS. 1-4B, the underwater turbine 100' of FIGS. 5-6, and the underwater turbine 100'' of FIGS. 7-8, except that a "'''" is added to the end of the numeric identifier. Accordingly, it will be understood that the structure and description of various features of the underwater turbines 100, 100', and 100'', and how they operate and are controlled, also apply to corresponding features of the underwater turbine 100''', except as noted below.

[0080] The underwater turbine 100''' includes an upper pontoon 110''' and a lower pontoon 120''' interconnected by a pylon structure 130''', and a propeller assembly 140''' having multiple (e.g., three) blades 145''' attached to the lower pontoon 120'''. The upper pontoon 110''', the lower pontoon 120''', and the pylon structure 130''' are aligned on intersecting axes (e.g., an axis or plane intersecting each of the upper pontoon 110''', the lower pontoon 120''', and the pylon structure 130'''). The blades 145''' rotate about the axis of the lower pontoon 120''' by forces exerted by the underwater stream S (e.g., an underwater ocean stream) on the propeller assembly 140'''. The upper pontoons 110''' and the lower pontoons 120''' have rounded edges (e.g., the upper pontoons 110''' and the lower pontoons 120''' have circular cross sections) to advantageously reduce drag on the system 100'''. The upper pontoons 110''' and the lower pontoons 120''' may also be made of the same material. The blades 145''' may also be made of the same material as the upper pontoons 110''' and the lower pontoons 120'''. For example, in one implementation, the upper pontoons 110''', the lower pontoons 120''', and the blades 145''' may be made of concrete. Advantageously, making the blades 145''' from concrete allows the blades to withstand greater underwater compressive forces. Furthermore, in one example, the upper pontoons 110''' may be spaced apart from the lower pontoons 120''' by approximately 10 meters. In one example, the upper pontoons 110''' and the lower pontoons 120''' can have an outer diameter of approximately 1 meter. In one example, the blades 145''' can have a radius or length of 7 to 8 meters (e.g., measured from the hub of the propeller assembly 140'''). Additionally, in some examples, the blades 145''' are foldable (see FIGS. 14A-14D, discussed below), advantageously facilitating transportation of the underwater turbine 100'''.Advantageously, the size of the underwater turbine 100'' avoids the development of substantial (e.g., high) velocity gradients across the underwater turbine 100'', improving the stability of the underwater turbine 100'' in the ocean. The size of the underwater turbine 100''' also reduces the amount of stress or load placed on the propeller assembly 140''' during operation.

[0081] 10A-10B, pylon structure 130''' may include connection plates 137A''', 137B''', 137C''', 137D''' (e.g., sheet metal plates, etc.) arranged in an X-shape or a triangular configuration to connect upper pontoon 110''' to lower pontoon 120''''. For example, connection plates 137A'''' and 137B'' are connected to upper pontoon 110'' at a first upper end (e.g., via fasteners 134'''', similar to fasteners 134 in FIGS. 1C-1D), and connection plates 137A'''' and 137B'' are coupled to pins 138''' in a triangular configuration at a second lower end. Additionally, connection plates 137C''' and 137D''' are connected at first upper ends to pin 138''', and connection plates 137C'''' and 137D'''' are connected at second lower ends in a triangular configuration (e.g., via fasteners 134'''', similar to fasteners 134 in FIGS. 1C-1D) to lower pontoon 120'''. Connection plates 137A'', 137B'', 137C'', and 137D''' can rotate about pin 138'''. Connection plates 137A''' and 137B'''' can be supported by interconnection plate 139A''', and connection plates 137C'''' and 137D'' can be supported by interconnection plate 139B''''. Advantageously, interconnecting plates 139A''' and 139B''' and their ability to rotate about pin 138''' inhibit (e.g., prevent) connecting plates 137A''', 137B''', 137C''', and 137D''' from buckling under load. Furthermore, connecting plates 137A''', 137B''', 137C''', and 137D''' are thin, e.g., 2 mm to 5 mm thick, which can facilitate or improve the hydrodynamics of underwater turbine 100'''. Submersible turbine 100''' is buoyant, and upper pontoon 110''' provides at least 50% (e.g., 60%, 70%, 100%) of the buoyancy of underwater turbine 100''', exerting a buoyancy force B (see FIG. 11B) on underwater turbine 100'''.Advantageously, pylon structure 130''' allows water to pass through openings between connecting plates 137A''' and 137B'' and connecting plates 137C'''' and 137D'' (e.g., reducing the effect of ocean current forces acting on underwater turbine 100''').

[0082] 11A-11C, one advantage of the underwater turbine 100''' is that the upper pontoon 110''' automatically applies a counter torque CT or counter moment (e.g., in the counterclockwise direction in FIG. 11B ) to the underwater turbine 100''' that balances the torque T or moment M (e.g., in the clockwise direction in FIG. 11B ) applied to the underwater turbine 100''' by the rotation of the propeller assembly 140''' (e.g., due to forces applied to the propeller assembly 140''' by the underwater stream). The weight (e.g., weight Wup) of the upper pontoon 110''' is exerted in the opposite Y direction (e.g., the negative Y direction) equal to the buoyancy force B (e.g., the positive Y direction). The lower pontoon 120''' has a weight (e.g., weight Wlp) that acts in the same direction (e.g., the positive Y direction) as the weight Wup of the upper pontoon 110'''. The underwater turbine 100''' can reach an equilibrium orientation where the counter torque CT balances the torque T, causing the pylon structure 130''' to tilt at an angle φ away from the vertical axis Y. Furthermore, the counter torque CT or counter moment applied by the upper pontoon 110''' is self-adjusting such that the angle φ can change depending on the amount of torque T applied by the rotation of the propeller assembly 140''' (e.g., due to a change in rotational speed caused by a change in the velocity of the underwater stream S). For example, the greater the torque T that the rotation of the propeller assembly 140''' applies to the lower pontoon 120''', the greater the counter torque CT applied by the upper pontoon 110''' to achieve equilibrium, and the greater the angle φ at which the pylon structure 130''' extends relative to the vertical. Similarly, the smaller the torque T that rotation of the propeller assembly 140''' applies to the lower pontoon 120''', the smaller the counter torque CT applied by the upper pontoon 110''' to achieve equilibrium, and the smaller the angle φ at which the pylon structure 130''' extends relative to the vertical. Thus, the upper pontoon 110''' facilitates (e.g., assists) in maintaining the underwater turbine 100''' in a equilibrium orientation during operation and inhibits roll motion of the lower pontoon 120''' about the X-axis (see FIG. 10B).Furthermore, the automatic counter-torque CT or counter-moment applied by the upper pontoon 110''' to counter the torque T or moment applied by the rotation of the propeller assembly 140''', advantageously allows the underwater turbine 100''' to have only one propeller assembly 140''' (e.g., the system does not need to have a second propeller assembly 140 rotating in the opposite direction to counter the torque or moment applied by the first propeller assembly 140), thus advantageously simplifying the system and reducing the costs of manufacturing, maintaining, and operating the underwater turbine 100'''.

[0083] Another advantage of the underwater turbine 100''' is that the upper pontoon 110''' is buoyant and applies a vertical (e.g., negative Y) upward force B (e.g., buoyancy) to the pylon structure 130''' and the lower pontoon 120'''. The lower pontoon 120''' is attached to cables 180''', which in turn are attached to mooring weights that apply a force F T (e.g., tension) to the lower pontoon 120''' and pylon structure 130''' in the opposite direction (e.g., downward or in the positive Y direction) of the upper pontoon 110'''. Thus, the pylon structure 130''' is maintained under tension by the buoyancy force B and tension force F T from the upper pontoon 110''' and lower pontoon 120''', respectively. Furthermore, because pylon structure 130''' is triangular in shape and connecting plates 137A''', 137B''' are connected to connecting plates 137A''', 137B''' with rotating pins 138''', pins 138''' can transfer loads (e.g., buoyancy B, tension F T) by axial loading along connecting plates 137A''', 137B''', 137C''', 137D'''. Furthermore, pylon structure 130''' being under tension is advantageous and facilitates maintaining underwater turbine 100''' in an equilibrium orientation during operation. Furthermore, because pins 138''' are rotatable, pylon structure 130''' does not buckle, which allows pylon structure 130''' to be made of a thin sheet of metal (e.g., steel, aluminum, etc.). Furthermore, because the pylon structure 130''' is maintained under tension, any torque T applied to the underwater turbine 100''' by the rotation of the propeller assembly 140''' is transmitted through the pylon structure 130''' (e.g., sheets of thin hydrodynamic metal connecting plates 137A''', 137B''', 137C''', 137D''') to the upper pontoons 110''', which automatically balance the force with a counter torque. Thus, the underwater turbine 100''' can reach an equilibrium orientation.Advantageously, due to the pylon structure 130''' (e.g., the triangular formation of the pylon structure 130'''), the bending moment acting on the underwater turbine 100''' is minimized and the tension force FT and buoyancy force B forces are optimized in the load direction (e.g., the Y direction).

[0084] FIG. 12 illustrates an upper pontoon 110''', which has a first chamber 153A''' (e.g., a forward water chamber) and a second chamber 153B''' (e.g., a dry chamber). The first chamber 153A''' can be hollow at ambient pressure (e.g., atmospheric pressure) and can be operably connected to a well pump 135'''. The well pump 135''' can selectively operate to supply water OW into the first chamber 153A''' to increase the weight of the upper pontoon 110''' (e.g., to reduce the buoyancy of the underwater turbine). Additionally, the well pump 135''' can exhaust water OW from the first chamber 153A''' to reduce the weight of the upper pontoon 110''' (e.g., to increase the buoyancy of the underwater turbine). Thus, the upper pontoon 110'" has variable buoyancy, which allows the submersible turbine 100'" to be raised to shallower depths or the surface (e.g., raised to the top of the ocean), or submerged to lower depths or submerged. Advantageously, the variable buoyancy of the upper pontoon 110'" minimizes stress on the submersible turbine 100'" and propeller assembly 140'" because the submersible turbine 100'" can avoid high ocean currents by altering the buoyancy of the upper pontoon 110'" (e.g., by filling the upper pontoon 110'" with water to lower the submersible turbine 100'" or by draining water from within the upper pontoon 110'" to increase its buoyancy and raise the submersible turbine 100'". Furthermore, by having the upper pontoons 110''' with variable buoyancy, advanced blade pitch control in the propeller assembly 140''' may be unnecessary because the buoyancy of the upper pontoons 110''' (e.g., by increasing or decreasing buoyancy to raise or lower the underwater turbine 100'') may allow the underwater turbine 100''' to avoid high ocean currents. In other words, blade pitch control may be eliminated by the propeller assembly 140''''.Furthermore, the well pump 135''' can quickly inject (e.g., fill) the first chamber 153A''' of the upper pontoon 110''' to change (e.g., reduce) the buoyancy of the upper pontoon 110''', thereby allowing the underwater turbine 100''' to quickly sink and avoid strong ocean currents.

[0085] With continued reference to FIG. 12 , the well pump 135′″ can be operatively connected to a magnetic coupler 142′″ and an electric motor 141′″. The magnetic coupler 142′″ and the electric motor are located within the second chamber 153B′″ and maintained dry (e.g., within a dry chamber). Operation of the well pump 135′″ can be automatically controlled by an electronic controller (not shown) coupled to the electric motor 141′″ that controls operation of the well pump 135′″ via the magnetic coupler 142′″ based, at least in part, on sensors in the submersible turbine (e.g., a gyroscope or tilt sensor detecting tilt of the submersible turbine 100′″, a velocity or flow sensor measuring the velocity of underwater currents, or a sensor detecting one or more parameters of operation of components within the submersible turbine 100′″). Advantageously, the ability to supply water OW to the first chamber 153A′″ using the pump can alter the center of buoyancy of the submersible turbine 100′″. Altering the center of buoyancy enables active pitch control of the upper pontoon 110′″. For example, changing the center of buoyancy can maintain the upper pontoon 110''' with the underwater stream S (e.g., maintain the upper pontoon 110''' in a horizontal orientation X) and counteract (e.g., prevent, correct, compensate for) pitch movement of the upper pontoon 110'''. Because the flow S is non-uniform along the upper pontoon 110''' and the submersible turbine 100''', actively adjusting the pitch allows the submersible turbine 100''' to maintain a desired position (e.g., keep the upper pontoon 110''' aligned with the direction of the flow S).

[0086] Although not shown in FIG. 12 , the upper pontoon 110′″ may also include a third chamber (e.g., an aft water chamber) and a fourth chamber (e.g., an aft dry chamber) at the opposite end of the upper pontoon 110′″ (e.g., opposite chambers 153A′″ and 153B′″ shown in FIG. 12 ). The third chamber may be hollow at ambient pressure (e.g., atmospheric pressure) and operably connected to an additional well pump (not shown). The additional well pump may be selectively operable to supply water OW to the third chamber, in addition to the first chamber 153A′″ connected to the well pump 135′″, to increase the weight of the upper pontoon 110′″ (e.g., to reduce the buoyancy of the underwater turbine). The additional well pump may also exhaust water OW from the third chamber to reduce the weight of the upper pontoon 110′″. For example, when the first chamber 153A''' and the third chamber are both supplied (e.g., filled) with water from their respective well pumps (e.g., well pump 135'''), the weight of the upper pontoon 110''' increases to lower the submersible turbine 100''' in the ocean. Furthermore, when water is expelled from the first chamber 153A''' and the third chamber, the weight of the pontoon 110''' decreases, exerting a greater buoyant force B on the submersible turbine 100''', allowing the submersible turbine 100''' to rise in the ocean. Furthermore, when the first chamber 153A''' is filled and the third chamber is drained (e.g., no longer filled), the front of the upper pontoon 110''' becomes heavier than the rear, causing the pitch of the upper pontoon 110''' relative to the horizontal (e.g., X-axis, vertical axis) to be negative (e.g., the upper pontoon 110''' tilts downward so that the front of the upper pontoon 110''' is lower than the rear). In another example, when the first chamber 153A''' is unfilled (e.g., drained) and the third chamber is filled, the rear of the upper pontoon 110''' becomes heavier than the front, causing the pitch of the upper pontoon 110''' relative to the horizontal (e.g., X-axis, vertical axis) to be positive (e.g., the upper pontoon 110''' tilts upward so that the front of the upper pontoon 110''' is higher than the rear).Advantageously, by having an upper pontoon 110''' having a first chamber 153A''' and a third chamber coupled to a well pump (e.g., well pump 135'''), the underwater turbine 100''' has pitch control via the upper pontoon 110''', which can be actuated to control or maintain the alignment of the underwater turbine 100''' with the underwater stream S (e.g., by counteracting pitch forces exerted on the underwater turbine 100''').

[0087] The submersible turbine 100'" can also be controlled based on the velocity of the underwater stream S or based on a forecast (e.g., prediction) of the velocity of the underwater stream S. For example, the submersible turbine 100'" can be raised or lowered in the ocean to an ideal operating environment, which can be an underwater stream S having an ocean current between 1.25 m / s and 1.5 m / s, e.g., 1.35 m / s. When the submersible turbine 100'" needs to be raised or lowered in the ocean to find the ideal underwater current S, one or more of the well pumps (e.g., well pump 135'") can fill or empty the upper pontoon 110'" to change the weight (e.g., Wup) and buoyancy B of the upper pontoon 110'". Advantageously, a predictive model or predictive controller (e.g., a predictive AI controller) can determine and / or predict an optimal ocean current speed (e.g., 1.35 m / s) based on underwater current streaming data at past and / or current times. For example, the underwater current streaming data can be sent to a predictive model (e.g., a predictive artificial intelligence model), and the predictive AI model can predict future underwater stream speeds of underwater stream S at any ocean depth. For example, the predictive AI model can predict the ocean current profile of underwater stream S at a depth of 100 m 45 minutes into the future. Thus, based on the prediction of the underwater stream speed, a predictive controller (e.g., a predictive AI controller) driven by the predictive AI model can adjust the buoyancy of upper pontoon 110''' of underwater turbine 100''' to raise or lower underwater turbine 100''' to a desired depth for optimal performance of underwater turbine 100'''. The predictive controller may be operably coupled to one or more well pumps (e.g., well pump 135''') to (e.g., automatically) vary the depth of the submersible turbine 100''' (e.g., by increasing or decreasing the buoyancy B) taking into account the expected velocity of the underwater stream S.Advantageously, raising and lowering the underwater turbine 100'" based on a predictive controller can maximize the capacity factor (e.g., the electrical energy output of the underwater turbine 100'") and minimize stress on the underwater turbine 100'". The underwater turbine 100'" can also have a digital twin (e.g., a virtual representation of the underwater turbine 100'") driven by an AI or deep learning model to remotely monitor the structural integrity of the underwater turbine 100'" (e.g., monitor the structural integrity of one or more of the lower pontoon 120'", the pylon structure 130'", the propeller assembly 140'", and the upper pontoon 110'", such as by monitoring stress loads on these components), optimize parameters of the underwater turbine 100'", and improve the efficiency of the blades 145'". For example, the AI-driven digital twin may enable optimization of the blades 145''' by determining the optimal chord and pitch angle distribution of the blades 145''' based on ocean conditions and loads on the underwater turbine 100'''. Additionally, the AI-driven digital twin may optimize the efficiency of the underwater turbine 100''' by determining the optimal buoyancy B of the upper pontoon 110''', determining the optimal length of the blades 145''', and determining the optimal or ideal current speed of the underwater stream S at a particular depth. After determining the optimal conditions for the underwater turbine 100''', using the AI-driven digital twin, new operating conditions for the underwater turbine 100''' (e.g., buoyancy B of the upper pontoon 110''') can be achieved. The AI-driven digital twin may also determine the maximum allowable deflection range and minimum and maximum stress loads that can be exerted on the blades 145''' for a particular underwater current S and depth, thereby improving the lifespan (e.g., lifespan) of the blades 145''' and the underwater turbine 100'''. Those skilled in the art will recognize that the above-described controllers (e.g., AI controllers, AI digital twins) may also be applied to the underwater turbine 100 of Figures 1-4B, the underwater turbine 100' of Figures 5-6, and the underwater turbine 100'' of Figures 7-8.

[0088] 13A and 13B show components within the lower pontoon 120''' of the underwater turbine 100''' connected to the propeller assembly 140''', with the outer housing of the lower pontoon 120''' removed for purposes of showing the components. The underwater turbine 100'' includes a first section 152A''', a second section 152B''', and a third section 152C'''. The first section 152A''' includes a shaft 156''' coupled to bearings 151'''', a generator 150''' (e.g., an electric motor-generator), and an electric motor 154''''. The generator 150''' (e.g., an electric motor-generator) may include a variable frequency drive that allows it to operate at different speeds. Although not shown, one or more power cables may be connected to the generator 150''' through which generated electricity is transmitted from the underwater turbine 100'''. The electric motor 154''' may be operated using the power generated by the generator 150'''. During operation, rotation of the propeller assembly 140''' (e.g., caused by the current S) rotates the shaft 156''', which rotates one portion of the generator 150'' (e.g., the armature, rotor) relative to another portion of the generator 150'' (e.g., the stator) to generate electricity. The first compartment 152A''' and the third compartment 152C''' can be filled with air, thereby providing an amount of buoyancy to the lower pontoon 120'''. Alternatively, the first compartment 152A''' and the third compartment 152C''' can be filled with oil (e.g., biodegradable oil). Components within the first compartment 152A''' (e.g., bearings 151''', generator 150''' and electric motor 154''') can operate effectively within the oil-filled first compartment 152A'''.

[0089] 13A and 13B, first compartment 152A''' is spaced apart and separated from second compartment 152B''' by membrane 167''' (e.g., a rubber membrane, one or more membranes). Third compartment 152C''' is spaced apart and separated from second compartment 152B''' by another membrane 167''' (e.g., a rubber membrane). Membrane 167''' is configured to prevent leakage of oil from first compartment 152A''' into second compartment 152B''' and from third compartment 152C''' to second compartment 152B'''. Advantageously, rubber membrane 167''' can equalize pressure in first compartment 152A''' and third compartment 152C''' to ensure little or no leakage of oil (e.g., biodegradable oil) from first compartment 152A''' and third compartment 152C'''. Additionally, wells can be positioned throughout the first compartment 152A''', the second compartment 152B''', and the third compartment 152C''' to effectively utilize the space within each chamber (e.g., to maintain pressure). The third compartment 152C''' can include multiple weights 198''' to modify the weight (e.g., weight Wlp) of the lower pontoon 120'''.

[0090] The pitch control mechanism 170''' of the underwater turbine 100''' (which may, for example, include a well pump 135''' operably connected to the magnetic coupler 142''' and electric motor 141''' in the upper pontoon 110''' as described above) may include a hinge 183''', a rigid plate 182''', and a cable 180'''. The cable 180''' may be connected to a mooring weight (e.g., mooring weight A in FIG. 9A ) located on the seabed and may include a first portion coupled to the rigid plate 182''' and a second portion coupled to the mooring weight. The cable 180''' may be coupled to the rigid plate 182''' through an opening in the rigid plate 182''' such that the connected cable 180''' at the opening is centered on the midline of the lower pontoon 120''', the midline of the pylon structure 130''', and the midline of the propeller assembly 140'''. The rigid plate 182''' can be connected to a hinge 183''' that is operably coupled to a portion of the shell of the lower pontoon 120''' (e.g., at the second section 152B'''). Thus, as the orientation of the rigid plate 182''' changes (e.g., maintaining the lower pontoon 120 in a horizontal position aligned with the underwater stream S), the rigid plate 182''' rotates about the hinge 183''' (e.g., rotates toward the forward end of the lower pontoon 120''' or rotates toward the aft end of the lower pontoon 120'''). Furthermore, the rigid plate 182''' has a thin profile in one direction but a wide profile in a second direction, advantageously allowing the rigid plate 182''' to pivot about the axis of the hinge 183''' but inhibiting (e.g., preventing) the rigid plate 182''' from pivoting laterally (e.g., pivoting across the width of the lower pontoon 120'''). In one implementation, the pitch control mechanism 170''' can include a piston (eg, piston 184 in FIGS. 3 and 4) that actuates the orientation of the rigid plate 182'''.In another implementation, no piston is provided and rotation of the rigid plate 182''' about the axis of the hinge 183''' is passive (e.g., not actuated, and pitch control is affected by the well pump 135''' operably connected to the magnetic coupler 142''' and electric motor 141''' in the upper pontoon 110''' as described above).

[0091] 14A-14D show the underwater turbine 100'" with the blades 145'" folded into a storage container or compartment C (e.g., a storage and / or shipping container during transport of the underwater turbine 100'" to a deployment location). Advantageously, having the blades 145'" foldable allows for efficient deployment and delivery of the underwater turbine system 100'" by reducing the number of large components. Furthermore, reducing the number of large parts allows more underwater turbines 100'" to fit within the container C on a ship, thereby reducing shipping and deployment costs. The blades 145'" can be folded about hinges 144'" from a folded (e.g., closed) position (see FIG. 14C) to a deployed (e.g., extended) position (see FIG. 14D). When blade 145'" is rotated about hinge 144'" from the folded position to the deployed position, tube connector 146'" coupled to the bottom or proximal end of blade 145'" rotates approximately 90 degrees about hinge 144'". When tube connector 146'" is fully extended and rotated from a horizontal position (e.g., 90 degrees) to a vertical position (e.g., 0 degrees) to deploy (e.g., extend) blade 145'", tube connector 146'" becomes concentric and / or coaxial with tube channel 147'". Once blade 145'" is rotated 90 degrees about hinge 144", and tube connector 146'" becomes concentric and / or coaxial with tube channel 147'", tube connector 146'" and hinge 144" can retract into tube channel 147'" to lower blade 145'" and secure it to propeller assembly 140'" in the deployed position. Additionally, blade 145''' has a second connector 148''' located at the bottom or proximal region of blade 145''' (and spaced from tube connector 146''') that extends into second channel 149''' to secure blade 145''' to propeller assembly 140''' in a deployed (e.g., extended) position.Additionally, to rotate blade 145''' from the deployed position to the folded position, hinge 144''' and tube connector 146''' protrude (e.g., extend) from tube channel 147''', and second connector 148''' protrudes (e.g., extend) from second channel 149'''. When hinge 144''', tube connector 146''', and second connector 148''' are all disengaged from (e.g., extend from) their respective channels (e.g., tube channel 147''', second channel 149'''), tube connector 146''' can be rotated about hinge 144''' from a vertical (e.g., 0 degree) deployed position to a horizontal (e.g., 90 degree) position to move blade 145''' to the folded position.

[0092] FIG. 15 schematically illustrates the use of an underwater turbine 100′ to generate electrical power, which is transmitted from the underwater turbine 100′ to an electrical grid via one or more power cables PL. For simplicity, some features (e.g., cable 80′, mooring weight A) have been omitted. The power cables PL can travel along the seabed SB until they reach a land-based power transmission station PT, which transmits the generated electricity to the electrical grid. While FIG. 15 is illustrated and described with reference to an underwater turbine 100′, those skilled in the art will recognize that the underwater turbines 100 of FIGS. 1-4B, the systems 100″ of FIGS. 7-8, and the systems 100′″ of FIGS. 10A-14D also operate to generate electrical power and transmit it to a power transmission station PT via the power cables PL.

[0093] FIG. 16 illustrates schematically the use of an underwater turbine 100′ to produce hydrogen via an electrolyzer system ES. For simplicity, some features (e.g., cable 80′, mooring weight A) have been omitted. Power generated by the underwater turbine 100′ is transmitted to the electrolyzer system ES via one or more cables C. Although not shown, once hydrogen is produced by the electrolyzer, the hydrogen is stored in tanks for subsequent transport. While the illustrated embodiment shows the electrolyzer system underwater, those skilled in the art will recognize that the electrolyzer system may be on land G, with cables C extending from the underwater turbine 100′ (e.g., along the seabed SB) to an electrolyzer system located on land G. Although Figure 16 is illustrated and described with respect to an underwater turbine 100'', those skilled in the art will recognize that the underwater turbines 100 of Figures 1-4B, the systems 100'' of Figures 7-8 and the systems 100''' of Figures 10A-14D may also be operated to generate electricity used to operate the electrolyzer unit ES, as described above, to produce hydrogen that may be stored and / or transported.

[0094] 17A-17D schematically illustrate the use of underwater turbines 100'" to generate electricity within a modular farm MF. The modular farm MF consists of multiple underwater turbines 100'" arranged in pods, each coupled to a mooring weight A via a cable 180'" (e.g., an electrical cable). For example, the modular farm MF may include a pod of approximately 20 underwater turbines 100'", each coupled to a mooring weight A (see FIG. 17A). Each of the mooring weights A may be coupled to a cable PC (e.g., a 100 kW electrical cable at 3 kV), which may be the same cable (e.g., cable 180'") connected to the underwater turbines 100'". The cable PC is connected to a subsea junction box J. The subsea junction box J may also be connected to a static collector cable CC (e.g., a 6 MW static collector cable). Advantageously, the arrangement of 20 underwater turbines 100''' in a pod of the modular farm MF shown in FIG. 17A can generate 2 MW of power (e.g., each underwater turbine 100''' can generate 100 kW of power). During operation, rotation of the propeller assemblies of the underwater turbines 100''' generates electricity (via their respective generators) and transmits it via cables 180''' and cables PC to the subsea junction box J. Power from the pod can then be transmitted from the subsea junction box J by static collector cables CC (as described below).

[0095] Advantageously, the modular farm MF is scalable. For example, the modular farm MF can have multiple pods of submersible turbines 100''' arranged in clusters CL (e.g., 24 pods in one cluster CL, with each pod having 20 submersible turbines 1000''') and generate 48 MW of power (e.g., 24 pods x 2 MW / pod = 48 MW, see FIG. 17B). The clusters CL can be arranged in rows (e.g., six clusters CL per row, for a total of four rows). Each row of clusters CL is parallel to one another and can be arranged in a grid. The rows of clusters CL can be connected to another, larger subsea junction box SJ via static connector cables CC. The larger subsea junction box SJ can be coupled to an aggregator cable AC. The aggregator cable AC can deliver the 48 MW of power generated by the clusters CL of the pods of the modular farm MF to a substation SS (see FIG. 17C). In one example, the clusters of pods CL of the modular farm MF can be sectioned to generate more energy / electricity. For example, as shown in FIG. 17C, there can be six sections of clusters of pods CL in the modular farm MF, each generating 48 MW of power for a total of 288 MW (e.g., 6 x 48 MW). The sections of the clusters of pods CL of the submersible turbine 100''' can be arranged in rows (e.g., three rows of sections with two sections per row) as shown in FIG. 17C, all of which are connected (via respective aggregator cables AC) to a substation SS. Furthermore, the substation SS can be connected to a shore connector SCC via a shore cable SC (e.g., to transmit power to the onshore grid). Advantageously, multiple sections of the clusters of pods CL of the submersible turbine 100''' can be arranged in rows in the farm (e.g., five sections of clusters CL) to generate 1.44 GW of power that is transmitted to the shore connector SCC (see FIG. 17D).Although Figures 17A-17D are shown and described with reference to an underwater turbine 100'', those skilled in the art will recognize that the underwater turbine 100 of Figures 1-4B, the underwater turbine 100' of Figures 5-6, and the system 100'' of Figures 7-8 can also be operated to generate electrical power.

[0096] Advantageously, operation of the underwater turbines 100, 100', 100", and 100'" allows for continuous power generation from a given renewable source (e.g., an ocean stream) with a high capacity factor (e.g., 70%, 80%). While a single underwater turbine 100, 100', 100", and 100'" has been described, those skilled in the art will recognize that multiple underwater turbines 100, 100', 100", and 100'" can be operated simultaneously to generate power from an underwater ocean stream (e.g., the Gulf Stream off the coast of Florida), and 1 MW of power can be generated by multiple such underwater turbines 100 (e.g., 10 underwater turbines 100 each generating 100 kW of power).

[0097] Additional Embodiments In embodiments of the present disclosure, the underwater turbine and method of operation thereof, and / or system for generating electricity from underwater ocean streams may comply with any of the following items. (Item 1) 1. An underwater turbine system for generating electricity from an underwater marine stream, the system comprising: an upper pontoon; a lower pontoon; a pylon structure extending between and interconnecting the upper pontoon and the lower pontoon; and a single propeller assembly having a plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from the underwater marine stream flowing along the lower pontoon and past the single propeller assembly, wherein the upper pontoon exerts a vertical buoyancy force on the lower pontoon, and rotation of the single propeller assembly generates electricity via a generator in the lower pontoon, the upper pontoon is configured to automatically generate a counter moment opposite to a moment generated by rotation of the single propeller assembly to prevent roll motion of the underwater turbine about an axis of the lower pontoon, and the system is configured to facilitate alignment of the lower pontoon with the underwater marine stream flowing along the lower pontoon and past the single propeller assembly. (Item 2) Item 1. The system of item 1, wherein the upper pontoons have the same shape and profile as the lower pontoons. (Item 3) 3. The system of claim 2, wherein the upper pontoon and the lower pontoon have substantially the same length and outer diameter. (Item 4) 4. The system of claim 1, wherein the pylon structure is configured to provide a fin to prevent yaw motion of the underwater turbine and to facilitate alignment of the lower pontoon with an underwater stream flowing past the single propeller assembly along the lower pontoon. (Item 5) 5. The system of claim 1, wherein the lower pontoon comprises a shaft operably coupled to the single propeller assembly and a generator, wherein rotation of the single propeller assembly by the underwater ocean stream rotates the shaft, thereby rotating a rotor relative to a stator of the generator to generate electricity. (Item 6) Item 6. The system of item 5, wherein the lower pontoon further comprises an electric motor coupled to a shaft, the shaft coupled to a friction winch assembly. (Item 7) 7. The system of claim 6, wherein the friction winch assembly comprises a plurality of pulleys around which a cable is at least partially wound, and the friction winch assembly is operable to shorten or lengthen the length of the cable between the underwater turbine and a mooring weight to vertically lower or raise the underwater turbine. (Item 8) Item 8. The system of item 7, wherein the cable extends to a mooring weight configured to anchor the underwater turbine to the seabed. (Item 9) 9. The system of any one of items 1 to 8, wherein the pylon structure includes two spaced apart legs extending between and interconnecting the upper pontoon and the lower pontoon. (Item 10) The system according to any one of items 1 to 8, wherein the pylon structure includes a plurality of connection plates extending between and interconnecting the upper pontoon and the lower pontoon, and the plurality of connection plates are arranged in an X-shape or a triangular shape around a rotation pin. (Item 11) Item 11. The system of item 10, wherein the rotation pin is configured to axially transfer the vertical buoyancy force from the upper pontoon through the plurality of connecting plates. (Item 12) 12. The system of any one of items 1 to 11, wherein the upper pontoon houses a water pump operable to supply water into and expel water from the upper pontoon to vary the vertical buoyancy force exerted by the upper pontoon and raise or lower the underwater turbine. (Item 13) Item 13. The system of item 12, wherein the upper pontoon includes a first chamber and a second chamber, the first chamber operably connected to the water pump to supply water to the first chamber and discharge water from the first chamber, and the second chamber operably connected to a second water pump operable to supply water to the second chamber and discharge water from the second chamber, and wherein filling the first chamber or the second chamber with water changes the center of buoyancy acting on the upper pontoon of the underwater turbine system, thereby controlling the pitch of the underwater turbine system. (Item 14) 14. The system of any one of items 1 to 13, wherein the pylon structure includes a plurality of sheet metal plates extending between and interconnecting the upper pontoon and the lower pontoon. (Item 15) 15. The system of any one of items 1 to 14, further comprising a rigid plate pivotally coupled to the lower pontoon about a pivot axis perpendicular to a longitudinal axis of the lower pontoon, the rigid plate configured to couple to a cable connected to a mooring weight, the rotational direction of the rigid plate being adjustable to align the lower pontoon with a direction of the underwater ocean stream, and the rigid plate being pivotable to align an intersection between the cable and the rigid plate with the longitudinal axis of the lower pontoon and a vertical axis of the pylon structure. (Item 16) Item 16. The system of item 15, further comprising a piston operable to pivot the rigid plate about the pivot axis to counteract pitch forces exerted on the lower pontoon. (Item 17) 17. The system of any one of items 1 to 16, further comprising a shaft coupled to the single propeller assembly and an electric motor-generator and an electric motor, all of which are housed within a chamber of the lower pontoon. (Item 18) Item 18. The system of item 17, wherein the chamber is filled with air. (Item 19) Item 18. The system of item 17, wherein the chamber is filled with a biodegradable oil. (Item 20) 20. The system of any one of items 1-19, further comprising a predictive artificial intelligence controller operable to adjust the vertical buoyancy force exerted on the lower pontoon to align the lower pontoon with a desired underwater stream depth. (Item 21) 21. The system of any one of items 1-20, further comprising an artificial intelligence digital twin configured to provide remote structural monitoring of one or more of the lower pontoon, the pylon structure, the propeller assembly, and the upper pontoon. (Item 22) 1. An underwater turbine system for generating electricity from an underwater ocean stream, the system comprising: an upper pontoon; a lower pontoon; a pylon structure extending between and interconnecting the upper pontoon and the lower pontoon; a single propeller assembly having a plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from the underwater ocean stream flowing along the lower pontoon and past the propeller assembly; a pulley on the lower pontoon; and a cable extending between the single propeller assembly and a mooring weight configured to be placed on the seabed, wherein a buoyancy force exerted by the upper pontoon on the lower pontoon, a drag force exerted by the stream on the lower pontoon and the propeller assembly, and tension exerted by the cable are configured to intersect at a center of the lower pontoon to prevent pitch of the lower pontoon and to facilitate alignment of the lower pontoon with the underwater stream flowing along the lower pontoon and past the propeller assembly. (Item 23) 23. The system of claim 22, wherein the upper pontoons have the same shape and profile as the lower pontoons. (Item 24) Item 24. The system of item 23, wherein the upper pontoon and the lower pontoon have substantially the same length and outer diameter. (Item 25) 25. The system of any one of items 22 to 24, wherein the pylon structure is configured to provide a fin to prevent yaw motion of the underwater turbine and to facilitate alignment of the lower pontoon with an underwater stream flowing along the lower pontoon and past the propeller assembly. (Item 26) 26. The system of any one of items 22-25, wherein the lower pontoon comprises a shaft operably coupled to the propeller assembly and a generator, and rotation of the propeller assembly by the stream rotates the shaft, thereby rotating a rotor relative to a stator of the generator to generate electricity. (Item 27) 27. The system of claim 26, wherein the lower pontoon further comprises an electric motor coupled to a shaft, the shaft coupled to a friction winch assembly. (Item 28) 28. The system of claim 27, wherein the friction winch assembly comprises a plurality of pulleys around which the cable is at least partially wound, and the friction winch assembly is operable to shorten or lengthen the length of the cable between the underwater turbine and the mooring weight to vertically lower or raise the underwater turbine. (Item 29) 29. The system of any one of items 22 to 28, wherein the pylon structure includes two spaced apart legs extending between and interconnecting the upper pontoon and the lower pontoon. (Item 30) 1. An underwater turbine system for generating electricity from an underwater ocean stream, the system comprising: an upper pontoon; a lower pontoon; a pylon structure extending between and interconnecting the upper pontoon and the lower pontoon; a single propeller assembly having a plurality of blades, the plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from the underwater ocean stream flowing along the lower pontoon and past the propeller assembly; and a cable extending between a pulley on the lower pontoon and a mooring weight configured to be positioned on the seabed, the pulley being positioned in a forward direction. and a cable that is laterally adjustable in a direction parallel to the axis of the lower pontoon, wherein the buoyancy force exerted on the lower pontoon by the upper pontoon, the drag force exerted on the lower pontoon and the propeller assembly by the stream, and the tension applied to the pulley by the cable are configured to intersect at a central position of the lower pontoon to prevent pitch of the lower pontoon and facilitate alignment of the lower pontoon with the underwater stream flowing along the lower pontoon and past the propeller assembly, and the position of the pulley is adjustable to maintain the intersection of the forces at the central position. (Item 31) Item 31. The system of item 30, wherein the upper pontoons have the same shape and profile as the lower pontoons. (Item 32) Item 32. The system of item 31, wherein the upper pontoon and the lower pontoon have substantially the same length and outer diameter. (Item 33) 33. The system of any one of items 30-32, wherein the pylon structure is configured to provide a fin to prevent yaw motion of the underwater turbine and to facilitate alignment of the lower pontoon with an underwater stream flowing along the lower pontoon and past the propeller assembly. (Item 34) 34. The system of any one of items 30 to 33, wherein the lower pontoon comprises a shaft operably coupled to the propeller assembly and a generator, and rotation of the propeller assembly by the stream rotates the shaft, thereby rotating a rotor relative to a stator of the generator to generate electricity. (Item 35) 35. The system of any one of items 30 to 34, wherein the lower pontoon further comprises an electric motor coupled to a shaft, the shaft being coupled to a friction winch assembly. (Item 36) Item 36. The system described in item 35, wherein the friction winch assembly comprises a plurality of pulleys around which the cable is at least partially wound, and the friction winch assembly is operable to shorten or lengthen the length of the cable between the underwater turbine and the mooring weight to vertically lower or raise the underwater turbine. (Item 37) 1. A system for generating electricity from an underwater marine stream, the system comprising: a plurality of underwater turbines, each of which comprises an upper pontoon, a lower pontoon, a pylon structure extending between and interconnecting the upper pontoon and the lower pontoon; and a single propeller assembly having a plurality of blades rotatably coupled to the lower pontoon, the single propeller assembly having a plurality of blades rotatably coupled to the lower pontoon, the single propeller assembly being configured to rotate by force from the underwater marine stream flowing along and past the lower pontoon, the upper pontoon applying a vertical buoyancy force to the lower pontoon, and rotation of the propeller assembly generating electricity via a generator in the lower pontoon. a plurality of underwater turbines, the upper pontoon configured to automatically generate a counter moment opposite to a moment generated by rotation of the propeller assembly to arrest roll motion of the underwater turbine about the axis of the lower pontoon, and configured to facilitate alignment of the lower pontoon with the underwater ocean stream flowing along the lower pontoon and past the propeller assembly; and a junction box operably coupled to each of the plurality of underwater turbines via an electrical cable connecting the junction box to the plurality of underwater turbines, the junction box configured to transmit electricity generated by the plurality of underwater turbines via a current collecting cable. (Item 38) Item 38. The system of item 37, wherein the plurality of underwater turbines are arranged in a plurality of rows. (Item 39) Item 39. The system of item 38, wherein the multiple rows are parallel rows.

[0098] While specific embodiments of the present invention have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the present disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and modifications of the systems and methods described herein may be made without departing from the spirit of the present disclosure. The appended claims and their equivalents are intended to cover such forms or modifications as fall within the scope and spirit of the present disclosure. Accordingly, the scope of the present invention is defined solely by reference to the appended claims.

[0099] It should be understood that features, materials, properties, or groups described in connection with a particular aspect, embodiment, or example are applicable to any other aspect, embodiment, or example described in this section or other sections of this specification, except where incompatible. All features disclosed herein (including the accompanying claims, abstract, and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except combinations in which at least some of such features and / or steps are mutually exclusive. Protection is not limited to the details of such embodiments described above. Protection extends to any novel, or any novel combination of, features disclosed in this specification (including the accompanying claims, abstract, and drawings), or to any novel, or any novel combination of steps of any method or process so disclosed.

[0100] Furthermore, certain features that are described in this disclosure in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, while features may be described above as functioning in a particular combination, one or more features from a claimed combination can, in some cases, be deleted from the combination, and the combination can be claimed as a subcombination or a variation of the subcombination.

[0101] Furthermore, while operations may be depicted in the figures or described in the specification in a particular order, such operations need not be performed in the particular order or sequence shown, nor need all operations be performed, to achieve desirable results. Other operations not shown or described may be incorporated into the example methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between the operations described. Furthermore, in other embodiments, operations may be rearranged or reordered. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the illustrated and / or disclosed processes may differ from those shown in the figures. Depending on the embodiment, certain steps described above may be removed, and other steps may be added. Furthermore, features and attributes of specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which are within the scope of the present disclosure. Also, the separation of various system components in the above-described embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the above-described components and systems may typically be integrated into a single product or packaged into multiple products.

[0102] For purposes of this disclosure, certain aspects, advantages, and novel features have been described herein. Not necessarily all such advantages may be achieved in accordance with a particular embodiment. Thus, for example, one skilled in the art will recognize that the present disclosure may be embodied or practiced in a way that achieves one advantage or group of advantages taught herein, but not necessarily achieves other advantages that may be taught or suggested herein.

[0103] Conditional language such as "can," "can," "could," or "may," unless otherwise specified or interpreted otherwise within the context of use, is generally intended to convey that certain features, elements, and / or steps are included in certain embodiments but not in other embodiments. Thus, such conditional language is generally not intended to suggest that the features, elements, and / or steps are somehow required in one or more embodiments or that one or more embodiments necessarily include logic for determining whether these features, elements, and / or steps are included in or performed in any particular embodiment, with or without user input or prompting.

[0104] Unless otherwise specified, conjunctive language such as "at least one of X, Y, and Z" is understood in the context in which it is generally used to convey that an item, term, etc. can be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that a particular embodiment requires the presence of at least one X, at least one Y, and at least one Z.

[0105] As used herein, language of degree, such as "approximately," "about," "generally," and "substantially," refers to a value, amount, or characteristic that is close to a stated value, amount, or characteristic that still performs a desired function and / or achieves a desired result. For example, the terms "approximately," "about," "generally," and "substantially" can refer to an amount that is within 10% or less, 5% or less, 1% or less, 0.1% or less, and / or 0.01% or less of the stated amount, depending on the desired function or intended result. As another example, in certain embodiments, the terms "generally parallel" and "substantially parallel" refer to a value, amount, or characteristic that is 15 degrees or less, 10 degrees or less, 5 degrees or less, 3 degrees or less, 1 degree or less, or 0.1 degrees or less away from exactly parallel.

[0106] The scope of the present disclosure is not intended to be limited by the specific disclosure of preferred embodiments in this section or elsewhere herein, but may be defined by the claims, as presented in this section or elsewhere herein, or as presented in the future. The language of the claims is to be interpreted broadly based on the language used in the claims, and is not limited to the examples described herein or during the prosecution of this application, which examples are to be construed as non-exclusive.

[0107] Of course, the above description is directed to specific features, aspects, and advantages of the present invention, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Furthermore, the devices described herein need not necessarily include all of the objects, advantages, features, and aspects discussed above. Thus, for example, those skilled in the art will recognize that the present invention may be embodied or implemented in a manner that achieves or optimizes one advantage or group of advantages taught herein without necessarily achieving other objects or advantages taught or suggested herein. Moreover, while numerous variations of the present invention have been shown and described in detail, other modifications and uses that fall within the scope of the present invention will be readily apparent to those skilled in the art based on this specification. It is contemplated that various combinations and subcombinations of these specific features and aspects of the examples may be made and still remain within the scope of the present invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another to form various forms of the discussed devices.

Claims

1. 1. An underwater turbine system for generating electricity from an underwater ocean stream, comprising: The upper pontoon and The lower pontoon and a pylon structure extending between and interconnecting the upper and lower pontoons; a single propeller assembly having a plurality of blades, the plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from an underwater ocean stream flowing along the lower pontoon and past the single propeller assembly; Equipped with The upper pontoon applies vertical buoyancy to the lower pontoon, rotation of the single propeller assembly generates electricity via a generator in the lower pontoon, the upper pontoon is configured to automatically generate a counter moment opposite to the moment generated by the rotation of the single propeller assembly to prevent roll motion of the underwater turbine about the axis of the lower pontoon, and is configured to facilitate alignment of the lower pontoon with the underwater marine stream flowing along the lower pontoon and past the single propeller assembly.

2. The system of claim 1 , wherein the upper pontoons have the same shape and profile as the lower pontoons.

3. The system of claim 2 , wherein the upper pontoon and the lower pontoon have substantially the same length and outer diameter.

4. 2. The system of claim 1, wherein the pylon structure is configured to provide a fin to prevent yaw motion of the underwater turbine and to facilitate alignment of the lower pontoon with an underwater stream flowing along the lower pontoon and past the single propeller assembly.

5. 2. The system of claim 1, wherein the lower pontoon comprises a shaft operatively coupled to the single propeller assembly and a generator, wherein rotation of the single propeller assembly by the underwater ocean stream rotates the shaft, thereby rotating a rotor relative to a stator of the generator to generate electricity.

6. The system of claim 5 , wherein the lower pontoon further comprises an electric motor coupled to a shaft, the shaft coupled to a friction winch assembly.

7. 7. The system of claim 6, wherein the friction winch assembly comprises a plurality of pulleys around which a cable is at least partially wound, the friction winch assembly being operable to shorten or lengthen the length of the cable between the underwater turbine and a mooring weight to vertically lower or raise the underwater turbine.

8. The system of claim 7 , wherein the cable extends to a mooring weight configured to anchor the underwater turbine to the seabed.

9. The system of claim 1 , wherein the pylon structure includes two spaced apart legs extending between and interconnecting the upper and lower pontoons.

10. 2. The system of claim 1, wherein the pylon structure includes a plurality of connecting plates extending between and interconnecting the upper pontoon and the lower pontoon, the plurality of connecting plates being arranged in an X-shape or a triangular shape about a rotation pin.

11. The system of claim 10 , wherein the rotation pin is configured to axially transfer the vertical buoyancy force from the upper pontoon through the plurality of connecting plates.

12. 2. The system of claim 1, wherein the upper pontoon houses a water pump operable to supply water into and expel water from the upper pontoon to vary the vertical buoyancy force exerted by the upper pontoon to raise or lower the underwater turbine.

13. 13. The system of claim 12, wherein the upper pontoon includes a first chamber and a second chamber, the first chamber operably connected to the water pump to supply water to the first chamber and discharge water from the first chamber, and the second chamber operably connected to a second water pump operable to supply water to the second chamber and discharge water from the second chamber, and wherein filling the first chamber or the second chamber with water changes the center of buoyancy acting on the upper pontoon of the underwater turbine system to control the pitch of the underwater turbine system.

14. The system of claim 1 , wherein the pylon structure includes a plurality of sheet metal plates extending between and interconnecting the upper pontoon and the lower pontoon.

15. 2. The system of claim 1, further comprising a rigid plate pivotally coupled to the lower pontoon about a pivot axis perpendicular to a longitudinal axis of the lower pontoon, the rigid plate configured to couple to a cable connected to a mooring weight, the rotational orientation of the rigid plate being adjustable to align the lower pontoon with a direction of the underwater ocean stream, and the rigid plate being pivotable to align an intersection between the cable and the rigid plate with the longitudinal axis of the lower pontoon and a vertical axis of the pylon structure.

16. The system of claim 15 , further comprising a piston operable to pivot the rigid plate about the pivot axis to counteract pitch forces exerted on the lower pontoon.

17. 10. The system of claim 1, further comprising a shaft coupled to the single propeller assembly and an electric motor-generator and an electric motor, all of which are housed within a chamber of the lower pontoon.

18. 20. The system of claim 17, wherein the chamber is filled with air.

19. 20. The system of claim 17, wherein the chamber is filled with a biodegradable oil.

20. 10. The system of claim 1, further comprising a predictive artificial intelligence controller operable to adjust the vertical buoyancy force exerted on the lower pontoon to align the lower pontoon with a desired underwater stream depth.

21. 10. The system of claim 1, further comprising an artificial intelligence digital twin configured to provide remote structural monitoring of one or more of the lower pontoons, the pylon structure, the propeller assembly, and the upper pontoons.

22. 1. An underwater turbine system for generating electricity from an underwater ocean stream, comprising: The upper pontoon and The lower pontoon and a pylon structure extending between and interconnecting the upper and lower pontoons; a single propeller assembly having a plurality of blades, the plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from an underwater ocean stream flowing past the propeller assembly along the lower pontoon; and a cable extending between the pulley of the lower pontoon and a mooring weight configured to be placed on the seabed; Equipped with A system in which the buoyancy force exerted on the lower pontoon by the upper pontoon, the drag force exerted on the lower pontoon and the propeller assembly by the stream, and the tension exerted by the cable are configured to intersect at a center position of the lower pontoon to prevent pitch of the lower pontoon and to facilitate alignment of the lower pontoon with the underwater stream flowing along the lower pontoon and past the propeller assembly.

23. 23. The system of claim 22, wherein the upper pontoons have the same shape and profile as the lower pontoons.

24. 24. The system of claim 23, wherein the upper pontoon and the lower pontoon have substantially the same length and outer diameter.

25. 23. The system of claim 22, wherein the pylon structure is configured to provide a fin to inhibit yaw motion of the underwater turbine and to facilitate alignment of the lower pontoon with an underwater stream flowing along the lower pontoon and past the propeller assembly.

26. 23. The system of claim 22, wherein the lower pontoon comprises a shaft operatively coupled to the propeller assembly and a generator, wherein rotation of the propeller assembly by the stream rotates the shaft, thereby rotating a rotor relative to a stator of the generator to generate electricity.

27. 27. The system of claim 26, wherein the lower pontoon further comprises an electric motor coupled to a shaft, the shaft coupled to a friction winch assembly.

28. 28. The system of claim 27, wherein the friction winch assembly comprises a plurality of pulleys around which the cable is at least partially wound, the friction winch assembly operable to shorten or lengthen the length of the cable between the underwater turbine and the mooring weight to vertically lower or raise the underwater turbine.

29. 23. The system of claim 22, wherein the pylon structure includes two spaced apart legs extending between and interconnecting the upper and lower pontoons.

30. 1. An underwater turbine system for generating electricity from an underwater ocean stream, comprising: The upper pontoon and The lower pontoon and a pylon structure extending between and interconnecting the upper and lower pontoons; a single propeller assembly having a plurality of blades, the plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from an underwater ocean stream flowing past the propeller assembly along the lower pontoon; and a cable extending between a pulley of the lower pontoon and a mooring weight configured to be placed on the seabed, the position of the pulley being laterally adjustable in a direction parallel to the axis of the lower pontoon; and Equipped with A system in which the buoyancy force exerted on the lower pontoon by the upper pontoon, the drag force exerted on the lower pontoon and the propeller assembly by the stream, and the tension exerted on the pulley by the cable are configured to intersect at a central position of the lower pontoon to prevent pitch of the lower pontoon and facilitate alignment of the lower pontoon with the underwater stream flowing along the lower pontoon and past the propeller assembly, and the position of the pulley is adjustable to maintain the intersection of the forces at the central position.

31. 31. The system of claim 30, wherein the upper pontoons have the same shape and profile as the lower pontoons.

32. 32. The system of claim 31, wherein the upper pontoon and the lower pontoon have substantially the same length and outer diameter.

33. 31. The system of claim 30, wherein the pylon structure is configured to provide a fin to inhibit yaw motion of the underwater turbine and to facilitate alignment of the lower pontoon with an underwater stream flowing along the lower pontoon and past the propeller assembly.

34. 31. The system of claim 30, wherein the lower pontoon comprises a shaft operatively coupled to the propeller assembly and a generator, wherein rotation of the propeller assembly by the stream rotates the shaft, thereby rotating a rotor relative to a stator of the generator to generate electricity.

35. 31. The system of claim 30, wherein the lower pontoon further comprises an electric motor coupled to a shaft, the shaft coupled to a friction winch assembly.

36. 36. The system of claim 35, wherein the friction winch assembly comprises a plurality of pulleys around which the cable is at least partially wound, the friction winch assembly operable to shorten or lengthen the length of the cable between the underwater turbine and the mooring weight to vertically lower or raise the underwater turbine.

37. 1. A system for generating electricity from an underwater ocean stream, comprising: a plurality of underwater turbines, each comprising: The upper pontoon and The lower pontoon and a pylon structure extending between and interconnecting the upper and lower pontoons; a single propeller assembly having a plurality of blades, the plurality of blades rotatably coupled to the lower pontoon and configured to rotate due to force from an underwater ocean stream flowing past the propeller assembly along the lower pontoon; and Equipped with a plurality of underwater turbines, the upper pontoons applying vertical buoyancy to the lower pontoons, rotation of the propeller assemblies generating electricity via generators in the lower pontoons, the upper pontoons configured to automatically generate a counter moment opposite to the moment generated by the rotation of the propeller assemblies to prevent roll motion of the underwater turbines about the axes of the lower pontoons, and configured to facilitate alignment of the lower pontoons with the underwater ocean stream flowing along the lower pontoons and past the propeller assemblies; a junction box operably coupled to each of the plurality of underwater turbines via an electrical cable connecting the junction box to the plurality of underwater turbines; Equipped with The system, wherein the junction box is configured to transmit electricity generated by the plurality of underwater turbines via a current collection cable.

38. 38. The system of claim 37, wherein the plurality of underwater turbines are arranged in a plurality of rows.

39. 39. The system of claim 38, wherein the plurality of rows are parallel rows.

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