Abstract:
A system and method for converting energy of a moving fluid into electrical power. In one embodiment, the invention is a system comprising: a) a platform fixedly attached to the earth; b) a blade transport mechanism supported by the platform; c) a plurality of blades operably coupled to the blade transport mechanism and oriented to couple energy from the moving fluid; d) a power train operably coupled to the blade transport mechanism; and e) a generator operably coupled to the power train for producing electric power.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/520,403, filed Jun. 9, 2011, and entitled Method and System for Converting Energy in Flowing Water to Electric Energy, the entire disclosure of which is incorporated herein by reference. 
     
    
       [0002]    Harvesting the energy from existing and renewable sources is a critical endeavor if the world is to reduce or eliminate its dependence on fossil fuels. One of the greatest existing and renewable sources of energy is the energy inherent in large flows of water, e.g., river or sea currents, tidal currents, etc. While a variety of submersible systems have been proposed to convert the energy in flowing water to electric energy, none of the proposed systems have been commercially realized owing to mechanical complexities and/or energy-conversion inefficiencies inherent therein. 
       SUMMARY OF THE INVENTION 
       [0003]    The present method and system can be used for converting the energy in a flowing fluid (such as water) into electric energy. In one embodiment a platform having a top surface and a bottom surface, connected by an edge surface, is aligned with the flow of a fluid, and an assembly of blades harvests the energy in the moving fluid by moving with the fluid. The blades are coupled to a blade transport mechanism which carries the blades and which couples to a power train, which in turn couples to a generator. In one embodiment the blades are attached to a belt mechanism which is slideably located in the platform and moves with the blades. The belt mechanism engages with a power train (which in one embodiment is a series of gears) to rotate a generator to produce electricity. In an alternate embodiment the blades travel on a rail or in a slot (which can be on top of the platform, in the side, or on the bottom) and couple with a power train to rotate the generator. In one embodiment the blades can be made to be variable buoyancy, and as such can be made to be density-neutral to water such that they are effectively weightless in water. This has the advantage of reducing friction and stress within the blade coupling system. In one embodiment air or another gas can be pumped into the blades to make them more buoyant in water. A rail mechanism can be used to support the blades, or a slot can contain a C-clamp which goes over the edge surface. In another embodiment, a slot in the side (edge) of the platform hosts an arm on which the blade is attached. The linear motion of the blades can be converted to rotational motion about a number of axes including a vertical axis or a horizontal axis. 
         [0004]    In one embodiment the blades are density neutral to water and the buoyancy is not varied significantly. Arrayed blades, in which sets of blades, spaced horizontally (in the plane of the platform) or vertically (perpendicular to the plane of the platform) can be used to collect additional power from the moving fluid. The arrayed blades can be made to be variable buoyancy and density neutral to water. 
         [0005]    In one embodiment magnetic levitation (maglev) technology is used to levitate and/or direct/align the blades and to reduce friction. In one embodiment the maglev system can be used in conjunction with linear generators to provide power as well as levitate. 
         [0006]    The platform can be made to be adjustable and can be raised and lowered in the fluid (e.g. from the seabed to the surface) via changes in buoyancy. Directional (e.g. yaw) adjustments can be made through a variety of mechanisms including a bridle and windlass system. An automatic flow sensing system can be used in conjunction with a control system to detect the direction of flow and to cause the system to automatically align with the direction of flow. As such, changes in the direction of tides and currents can be accommodated. 
         [0007]    Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The following detailed description will be better understood when read in conjunction with the appended drawings, in which there is shown one or more of the multiple embodiments of the present disclosure. It should be understood, however, that the various embodiments of the present disclosure are not limited to the precise arrangements and instrumentalities shown in the drawings. 
           [0009]    Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawings, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein: 
           [0010]      FIG. 1  is a plan view of a support plate assembly used in the flowing water power generation system in accordance with an embodiment of the system; 
           [0011]      FIG. 2  is a cross-sectional view of the conductor plate assembly taken along line  2 - 2  in  FIG. 1 ; 
           [0012]      FIG. 3  is a schematic view of a paddle/blade assembly designed to move along the plate assembly and convert water movement into electricity in accordance with an embodiment of the present invention; 
           [0013]      FIG. 4  is a schematic view of a support plate assembly indicating locations thereon where a paddle assembly&#39;s paddle flip control can be activated; 
           [0014]      FIG. 5  is a schematic view of a support plate assembly supported by multiple post assemblies and configured for adjustment in yaw in accordance with another embodiment of the system; 
           [0015]      FIG. 6  is a schematic view of a channeling system disposed upstream and downstream of a support plate assembly in accordance with another embodiment of the system; 
           [0016]      FIG. 7  is a schematic view of an adjustable platform; 
           [0017]      FIG. 8  is a schematic view of another embodiment of the system; 
           [0018]      FIG. 9  is a schematic end cross-sectional view of the embodiment of the system shown in  FIG. 8 ; 
           [0019]      FIGS. 10A and 10B  are cross-sectional views of a maglev embodiment of the system; 
           [0020]      FIGS. 11A and 11B  are views of an embodiment including directional adjustment and in particular yaw adjustment; 
           [0021]      FIGS. 12A and 12B  are schematic views of flows sensors; 
           [0022]      FIGS. 13A and 13B  are schematic views of horizontal and vertical arrays respectively; 
           [0023]      FIG. 14  is a schematic view of a horizontal cross-section of a hollow paddle/blade. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Certain terminology is used herein for convenience only and is not to be taken as a limitation on the embodiments of the present disclosure. In the drawings, the same reference letters are employed for designating the same elements throughout the several figures. 
         [0025]    The present invention is a novel method and system for converting the power inherent in moving or flowing fluids (e.g. water, air) to electricity. The method and system described herein can be adapted to a variety of moving fluid environments such as, but not limited to, rivers, littoral regions subjected to tide-based water movement, areas subject to enhanced water movement due to the presence of man-made structures (e.g., bridge trestles), and man-made flow-directing structures (e.g., spillways, pipes, etc.) as well as terrestrial or offshore wind or water currents and tides. Accordingly, the description that follows will focus on the essential features and operating principles of embodiments of the system, but the system and method are not to be considered limited by size constraints or construction specifics that are subject to change for a particular application. 
         [0026]    For clarity of illustration,  FIGS. 1-3  illustrate the primary sub-assemblies of an embodiment of the flowing fluid power generation system of the present invention. In  FIGS. 1 and 2 , a support plate assembly in accordance with an embodiment of the present invention is shown and is referenced generally by numeral  10 .  FIG. 3  illustrates a paddle/blade assembly  100  in accordance with an embodiment of the present invention that cooperates with fluid movement and support plate assembly  10  to generate electricity. A number of such paddle/blade assemblies  100  will be used with one support plate assembly  10  as will be described further below. For generation of electric energy, it is assumed that both support plate assembly  10  and each provided paddle assembly  100  are submerged within a flow of moving fluid (e.g. water, not shown). 
         [0027]    Referring first to  FIGS. 1 and 2 , support plate assembly  10  includes a main plate  12  and a plate support post  14  coupled thereto at a central portion of main plate  12  by, for example, use of supports  16 . In the illustrated embodiment, plate support post  14  is hollow and fits coaxially over a lower support post  18  affixed to a ground location (e.g., a sea floor  200 ). Lower support post  18  can also be hollow for reasons that will be explained later below. In general, the combination of plate  12 /post  14  is movable up/down relative to (and on) post  18  so that plate  12  can be positioned at a desired depth in its water environment. To facilitate such movement and maintenance of plate  12  at a desired depth, permanent and/or adjustable ballast elements  20  can be coupled to plate  12 . The number, size, and type of ballast elements  20 , and control thereof, are not limitations of the present invention. Since plate  12  in combination with ballast  20  can be the same density as water and can move up and down as needed (e.g., above the water&#39;s surface for maintenance), lower support post  18  will only receive stresses from horizontal forces or yaw. Such forces can be readily handled by an anchoring system (not shown) for post  18 . 
         [0028]    Main plate  12  can be solid but can also have holes therein (not shown) to allow water to flow therethrough without departing from the scope of the present invention. The hole pattern can have the goals of reducing the amount of material needed for plate  12 , lowering the weight of plate  12 , directing flowing water moving past plate  12 , or combining attributes of these goals. The material used for plate  12  should generally be light in weight, strong, electrically insulating, and non-corrosive in water. Plate  12  can also be constructed to have the same density as water in order to facilitate the raising/lowering thereof using ballast  20 . The various parts can be made using materials that have the same density as water thereby making them very light in an underwater environment. Further, the parts could be partially or fully hollow to facilitate the density attribute. Material choices for plate  12  can include plastics, composites, etc. Similar materials can be used for plate support post  14  and support  16 . Lower support post  18  could also make use of the same materials but could also be made from concrete for permanent installations. 
         [0029]    Support plate assembly  10  includes structural elements that allow a number of paddle/blade assemblies  100  to “walk” around a defined “oval” shape on plate  12  where such movement is propelled by flowing fluid. As used herein, the term “oval” includes any shape having opposing longer sides/legs joined by opposing shorter sides/legs with some type of curvature or other connecting shape formed in the shorter sides/legs. For example, an oval can be a racetrack-type of shape, a rectangle with curved corners, two same-length parallel lines connected to one another at their aligned ends by semicircles or other arc shapes, a dog-bone shape, etc. 
         [0030]    Support plate assembly  10  is positioned in its fluid environment such that the long straight sides/legs of the oval shape are aligned with the direction of the flowing fluid. For example, the direction of the flowing fluid in the illustrated embodiment is indicated by arrows  300 . Disposed along the oval shape on plate  12  are a gear track  30  in a groove  32  formed in plate  12 , on elevated rail track  34  (shown as a single solid line in  FIG. 1 ) inside of and concentric with gear track  30 , an elevated rail track  36  (shown as a single solid line in  FIG. 1 ) outside of and concentric with gear track  30 , and an electrical conductor track  38  (shown as a dashed line in  FIG. 1 ) embedded within the electrically insulting material of plate  12 . 
         [0031]    Gear track  30  is analogous to a rack gear laid out in a continuous oval. The radius of curvature of the oval and configuration of the gear teeth (of gear track  30 ) at the oval&#39;s curves can be designed to satisfy the needs of a particular installation without departing from the scope of the present invention. The placement of gear track  30  in groove  32  provides guidance for each paddle assembly&#39;s pinion gear as will be explained later below. Gear track  30  and the walls of groove  32  can be constructed of or coated with low-friction materials to minimize friction losses with each paddle assembly&#39;s pinion gear. 
         [0032]    Elevated rail tracks  34  and  36  provide support and guidance for each paddle assembly  100  propelled around support plate assembly  10  by flawing fluid. While two such elevated rail tracks are shown in the illustrated embodiment, it is to be understood that additional (or fewer) rail tracks could be used without departing from the scope of the present invention. It is to be further understood that other types of paddle assembly support/guidance structures could be employed on and/or in plate  12  without departing from the scope of the present invention. 
         [0033]    As shown in  FIG. 2 , each elevated rail track  34  and  36  includes an elevating structure(s)  34 A and  36 A, respectively, fixedly mounted on plate  12 . For example, elevating structures  34 A and  36 A could be realized by a series of posts distributed about the oval shape defined on plate  12 . Mounted atop elevating structures  34 A and  36 A are housings  34 B and  36 B, respectively, each of which runs continuously around plate  12  in the defined oval shape as best seen in  FIG. 1 . As will be explained further below; housings  34 B and  36 B provide support and guidance for wheels mounted on a rotating axle of each paddle assembly  100 . Materials used for the interior wheel-bearing surfaces of housings  34 B and  36 B can be constructed of or coated with low-friction materials. 
         [0034]    As mentioned above, electrical conductor track  38  is embedded within the electrically insulating material of plate  12 . However, an electrical tap (to be discussed further below) of each paddle/blade assembly  100  needs to make electrical contact with conductor track  38  as each paddle assembly  100  walks around the oval shape defined on support plate assembly  10 . That is, the electrical tap of each paddle/blade assembly  100  transfers the electric power generated by each paddle assembly  100  to conductor track  38 . A surface of conductor track  38  (e.g., a top surface as illustrated) is separated from the water environment (in which assembly  10  is submerged) by a self-sealing membrane assembly  40 . Membrane assembly  40  incorporates a slit  40 A therethrough that is continuous over conductor track  38 . In this way, the electrical tap from each paddle assembly  100  can pass through membrane  40  to contact conductor track  38  as a paddle assembly  100  walks around the oval shape defined on support plate assembly  10 . Membrane  40  can be made from a variety of pliable, self-sealing materials to keep conductor track  38  dry as the electrical tap moves through slit  40 A. 
         [0035]    The electric energy generated by each paddle/blade assembly  100  is transferred to conductor track  38  as described above. One (or more) radial conductor taps (illustrated by dashed line  50  in  FIG. 1 ) transfer the electric energy from conductor track  38  to the hollow regions of posts  14 / 18  where an underwater electrical conductor  52  can carry the electric energy to its next destination (e.g., energy storage facility, energy distribution facility, etc.). 
         [0036]    One paddle/blade assembly  100  in accordance with an embodiment of the present invention will now be described with reference to  FIG. 3  where the portions of support plate assembly  10  interfacing with paddle assembly  100  are also illustrated. As mentioned above, a number of paddle/blade assemblies  100  will be used to convert the energy in flowing water to electric energy. In  FIG. 3 , the flow of fluid is assumed to be into the surface of the paper and perpendicular thereto. All such paddle/blade assemblies  100  are mechanically linked to one another in succession for simultaneous movement around the oval shape defined by support plate  10 . Methods and systems used to link paddle/blade assemblies  100  are not limitations of the present invention. 
         [0037]    Paddle/blade assembly  100  includes a pinion gear  102  coupled to an axle  104  such that rotation of pinion gear  102  causes simultaneous rotation of axle  104  as indicated by rotational arrows  106 . Coupled to axle  104  on one side of pinion gear  102  is a wheel  108  that resides in housing  34 B of elevated rail track  34 . Coupled to axle  104  on the other side of pinion gear  102  is a wheel  110  that resides in housing  36 B of elevated rail track  36 . Wheels  108  and  110  can rotate with axle  104  or independently thereof. 
         [0038]    Axle  104  extends away from wheel  110  to a bearing  112  that couples axle  104  to a paddle axle  114 . Bearing  112  is configured to allow axles  104  and  114  to rotate independently. Axle  114  has a paddle/blade flip control  116  coupled thereto and has a paddle/blade  118  fixedly coupled to the outboard end thereof such that any rotation of paddle axle  114  causes commensurate rotation of paddle/blade  118 . Paddle/blade  118  is any structure having at least one flat and broad face  118 A that develops a substantial force over face  118 A when face  118 A is perpendicular (as shown) to an oncoming flow of water. Paddle/blade  118  is also a thin structure such that minimal forces act thereon when face  118 A is aligned parallel to an oncoming flow of water. That is, when paddle/blade  118  is rotated 90° to its illustrated orientation, minimal force from the flow of fluid acts on paddle/blade  118 . 
         [0039]    Paddle/blade flip control  116  controls the rotational orientation of paddle/blade  118  based upon the direction of the flowing water and the position of paddle assembly  100  on support plate assembly  10 . In general, paddle/blade flip control  116  positions paddle/blade  118  such that face  118 A is (i) perpendicular (as shown) to an oncoming flow of fluid along one long side of the oval shape defined on support plate assembly  10 , or (ii) parallel to an oncoming flow of fluid along the remaining portions of the oval shape defined on support plate assembly  10 . That is, paddle/blade flip control  116  causes paddle/blade axle  114  to rotate 90° (as indicated by rotational arrow  120 ) when paddle/blade  118  must be parallel to the flowing water, and also causes axle  114  to rotate paddle/blade  118  when face  118 A must be perpendicular to the flowing water. 
         [0040]    Paddle/blade flip control  116  can be realized in a variety of ways without departing from the scope of the present invention. For example, paddle/blade flip control  116  could be a mechanical feature (e.g., gear) provided on paddle/blade axle  114  that is designed to cooperate with another mechanical feature (e.g., gear) positioned at specified locations on support plate assembly  10 . Paddle/blade flip control  116  could also be realized by magnetic or electromagnetic features coupled to or incorporated in paddle/blade axle  114  where such features are activated by cooperating features positioned at specified locations on support plate assembly  10 . 
         [0041]    In use, with paddle/blade assembly  100  positioned as shown with an oncoming flow of fluid moving into the paper, forces on paddle/blade  118  cause paddle/blade assembly  100  to walk along support plate assembly  10  as pinion gear  102  rotates and cooperates with gear track  30 . At the same time, wheels  108  and  110  travel in the oval shape defined by housings  34 B and  36 B, respectively. 
         [0042]    Each paddle/blade assembly  100  also includes a generator  122  coupled to axle  104  such that the axle&#39;s rotation (owing to the rotation of pinion gear  102 ) is converted to electricity. While the speed of the flowing fluid, and in particular with respect to water, may be slow (e.g., 2-3 knots for a tidal current), the hydrodynamic force thereof is substantial. Thus, the flow of water will typically produce slow-speed but high-torque rotation of gear  102 /axle  104 . Accordingly, generator  122  is configured to convert such slow-speed, high-torque rotation of axle  104  to electric energy. The electric energy produced by generator  122  is transferred to conductor track  38  using a conducting “pin”  124  that extends through membrane slit  40 A where the “foot”  124 A of pin  124  contacts track  38 . Pin  124 /foot  124 A can be realized by a variety of constructions without departing from the scope of the present invention. Current blocking element(s)  126  (e.g., a diode) electrically prevent the back flow of electric current into generator  122  as paddle assembly  100  moves around support plate assembly  10 . Note that electric energy transfer from generator  122  to track  38  could also be accomplished in other ways such as through the use of a commutator as would be understood in the art. 
         [0043]    As mentioned above, each paddle/blade assembly&#39;s paddle/blade  118  is positioned (by its paddle/blade flip control  116 ) to have its face  118 A either perpendicular or parallel to an oncoming flow of fluid. Such positioning is governed by the direction of the flowing fluid and the position of the paddle/blade assembly on the oval shape defined on support plate assembly  10 . Two flow direction scenarios illustrating this concept are presented schematically in  FIG. 4  where the oval shape defined by the various track elements described above is referenced on support plate assembly  10  simply by a dashed line  11 . For clarity of illustration, no paddle/blade assemblies  100  are shown in  FIG. 4 . Two possible water flow directions are indicated by arrows  300  and  302 . As described above, support plate assembly  10  is positioned such that the two long sides of oval  11  are substantially aligned with flows  300  and  302 . By way of example, flows  300  and  302  could represent incoming and outgoing, respectively, tidal flows. Four locations  11 A- 11 D indicate locations on oval  11  where the above-described paddle/blade flip control  116  of each paddle/blade assembly  100  will be engaged/activated. When flowing water is in the direction of flow  300 , each paddle/blade assembly has its paddle/blade rotated to be perpendicular to flow  300  at location  11 A. In this way, each paddle/blade assembly&#39;s paddle/blade is positioned to maximize the hydrodynamic force acting thereon. When each paddle/blade assembly reaches location  11 B, the corresponding paddle/blade is rotated to be parallel to flow  300  to thereby minimize the hydrodynamic force acting thereon. The parallel position of the paddle/blade is maintained along oval  11  from location  11 B, past locations  11 C and  11 D, and until location  11 A where it is once again rotated to be perpendicular to flow  300 . When the fluid is flowing in the direction of flow  302 , each paddle assembly has its paddle/blade rotated to be perpendicular to flow  302  at location  11 C. Then, when each paddle/blade assembly reaches location  11 D, the corresponding paddle/blade is rotated to be parallel to flow  302 . The parallel position of the paddle/blade is maintained along oval  11  from location  11 D, past locations  11 A and  11 B, and until location  11 C where it is once again rotated to be perpendicular to flow  302 . 
         [0044]    Depending on the size of the support plate assembly, in some instances it is advantageous to support the plate (e.g., plate  12 ) with more than the central post assembly (e.g., posts  14 / 18 ). Further, it may be desirable to provide for directional adjustment (e.g. yaw) of the support plate assembly so that the straight portions of the oval shaped track elements can be aligned with the direction of an oncoming flow of fluid. Accordingly,  FIG. 5  illustrates a schematic plan view of support plate to assembly  10  having additional support post assemblies  60  coupled thereto. Assuming a system (not shown) is provided to adjust support plate assembly  10  in yaw (as indicated by two headed arrows  62 ), support plate assembly  10  can incorporate curved slots  64  to facilitate yaw motion  62 . Note that the amount of curvature in slots  64  has been exaggerated for illustration purposes. 
         [0045]    In order to keep friction at a minimum in the system, a number of low friction materials can be used including low friction polymers such as polytetrafluoroethylene (PTFE, also known as Teflon), Delrin, Vesconite (which performs well even in water), and Near Frictionless Carbon (NFC). These materials can be used to form or coat the gears in the power train, can be coated onto the platform or even form some or all of the platform itself and thus provide low friction guidance/support for the blades in a slot or C-clamp configuration or for a rail system on which the blades travel. In embodiments where a belt are used, high-strength synthetic fibers such as Kevlar can be incorporated into the belt or can be used to form the belt in its entirety. Other low friction materials can be incorporated into the components of the system to minimize friction while maintaining strength. 
         [0046]    The present invention can also be used in conjunction with a fluid channeling system disposed both upstream and downstream the support plate assembly with its paddle assemblies described above. In general, the channeling system directs an oncoming fluid (e.g. water) flow along one long side of the support plate assembly where paddles/blades will be perpendicular thereto while simultaneously impeding the water flow on the other long side of the support plate assembly where paddles/blades will be parallel to the oncoming water flow. An example of such a channeling system is illustrated schematically in  FIG. 6 . Upstream and downstream of support plate assembly  10  are fixed walls  70  and  72  extending away from assembly  10  to define V-shaped channels starting at either end of assembly  10  as shown. Positioned in each such V-channel is a gate  74  coupled to a pivot  76 . The operation and function of gates  74  will be explained for flow  300  flowing in the direction indicated. Gates  74  are configured such that when an oncoming water flow (e.g., flow  300 ) impinges on a gate  74  upstream of assembly  10 , gate  74  pivots at  76  to direct flow  300  towards one long side of assembly  10  while impeding flow  300  along the other long side of assembly  10 . At the same time, gate  74  at the downstream side of support plate assembly  10  is positioned centrally between channel walls  70 / 72  to allow flow  300  to move therethrough. The situation would be reversed if the water flow came from the opposite direction. 
         [0047]    Referring to  FIG. 7 , an embodiment of the system in which support plate assembly  10  is supported by a plate support post  14  moveably engaged in a post  18  is illustrated. In one embodiment post  18  is embedded or otherwise attached to an anchor element  700  (e.g. concrete) within sea floor  200 . In one embodiment the system (including paddle/blade assemblies not shown in  FIG. 7 ) can be raised and lowered along vertical axis  710 . This can be accomplished through the use of ballast elements  20  or through the use of variable buoyancy components. In one embodiment support plate assembly  10  has variable buoyancy elements (e.g. hulls or chambers) which can be filled with gas (e.g. air, nitrogen, helium) or liquid (e.g. water) to vary the buoyancy of the entire platform. In one embodiment the system is operated underwater (e.g. in a river, estuary, or other area with substantial tides or underwater currents) and support plate assembly  10  can be raised to the surface for servicing, repair, inspection, or other activities. The system can also be sunk to allow for complete clearance, or can be placed at an optimum height for collection of tidal power. The variable buoyancy elements can be pumped out or filled with an appropriate density gas or liquid to obtain the desired buoyancy. In one embodiment the system can be made to be water-density neutral and as such will essentially float beneath the surface of the water, thus reducing stress on plate support post  14  and post  18  or on whatever alternate support/anchoring structure is utilized. 
         [0048]    Referring to  FIG. 8 , an embodiment of the system is shown which is based on the use of a belt coupled to a power train which converts the linear motion of the belt to rotational motion which drives a generator to produce electricity. In  FIG. 8  the folding paddle/blade assembly  800  is comprised of outer blade  820  coupled to inner blade  810  via a first hinge  834 . The folding paddle/blade assembly  800  connects to an attachment assembly  830  via a second hinge  832 . In one embodiment an attachment block  835  connects attachment assembly  830  to arm  840 . In another embodiment arm  840  connects directly to attachment assembly  830 . Arm  840  connects to belt  842  which, in one embodiment, has teeth which engage with a series of belt contacting gears  850 . Belt contacting gear  850  interfaces with generator gear  855  to drive a generator. The belt. contacting gear  850  in conjunction with generator gear  855  serves as a power train, although a number of power trains can be used, all based on mechanical mechanisms for the transfer of power and to obtain appropriate rotational speeds for the optimum generation of electricity. As can be understood from  FIG. 8 , fluid flow  300  results in folding paddle/blade assembly  800  opening when moving with fluid flow  300 , and closing (folding over) when traveling against fluid flow  300 . In one embodiment activated stops can be used in first hinge  800  to place outer blade  820  at less than a 90° angle to the direction of fluid flow  300 . For example, an electrically activated solenoid can be used in first hinge  800  to maintain a shape on folding paddle/blade assembly  800  that maximizes the collection of energy from the moving fluid, while allowing the folding paddle/blade assembly  800  to flatten completely as it travels against the current. 
         [0049]    Referring to  FIG. 9 , a cross-sectional end view of the embodiment of  FIG. 8  is shown in which support plate assembly  10  contains a bottom slot  920  and a corresponding upper slot  922 . The slots house a C-clamp assembly  900  which attaches to both arm  840  and attachment assembly  830  (attaching to folding paddle/blade assembly  800  via second hinge  832 ). In this embodiment arm  840  is connected to belt,  842 , which is in turn engaged with belt contacting gear  850 . As previously discussed, belt contacting gear  850  is engaged with generator gear  855  (not shown) which turns generator  910 . In this embodiment generator assembly  860 , in the form of an arch, houses and holds generator  910 . In this embodiment the linear motion of belt  842  (created by the capture of the flowing fluid energy by folding paddle/blade assemblies  800 ) is converted into rotational motion about an axis which is perpendicular to support plate assembly  10 . 
         [0050]    It should be understood that belts, rails, and slots, all of which can be placed either on the top, edges, or bottom of the platform, can be used to both guide the paddles/blades, as well as for coupling the power from the linear motion of the paddles/blades to a power train (which is typically comprised of sets of gears, although other mechanical mechanisms including belts, clutches, drive shafts can be used). The belts, rails and slots which guide the paddles/blades can all be considered to be blade transport mechanisms, although other blade transport mechanisms are possible. 
         [0051]    Referring to  FIGS. 10A and 10B  embodiments utilizing magnetic levitation (maglev) are shown.  FIG. 10  illustrates an embodiment housing C-clamp  900  (bottom portion not illustrated) or a partial C-clamp (having only an upper engaging portion). In this embodiment upper slot  922  houses clamp magnets  1001 ,  1003  and  1011 . Clamp magnets  1001 ,  1003  and  1011  arc of a polarity opposite to their corresponding platform magnets  1000 ,  1003  and  1112  respectively. As will be understood by one of skill in the art, the opposing magnets  1011  and  1012  provide levitation and opposing magnets  1000 - 1001  and  1002 - 1003  provide positioning. This allows for near frictionless motion of C-clamp  900 . Other configurations of magnets can be utilized to reduce or nearly eliminate friction. 
         [0052]      FIG. 10B  illustrates a maglev configuration based on an embedded slot  1060  with a corresponding embedded arm  1020 . Embedded arm  1020  houses magnets  1031 ,  1033 ,  1041  and  1043  for positioning/alignment through interaction with platform magnets  1030 ,  1032 ,  1050  and  1052  respectively. Embedded arm magnet  1022  provides levitation of embedded arm  1020  through interaction with platform magnet  1021 . 
         [0053]    In one embodiment permanent magnets are used for some or all of the magnets illustrated in  FIGS. 10A and 10B . Materials such as Neodymium Iron Boron (NdFeB) can be used, and the magnets can be divided into subassemblies. In one embodiment a Halbach array of permanent magnets that augments the magnetic field on one side of the array while cancelling the field to near zero on the other side is used. In an alternate embodiment some or all of the magnets of  FIGS. 10A and 10B  are electromagnets, in which a current passed through a coil of wire creates a magnetic field. 
         [0054]    As will be discussed, folding paddle/blade assemblies  800  can be made to be variable buoyancy or water-density neutral, thus reducing their effective weight and therefore reducing the effective load and friction between C-clamp  900  and its corresponding slot, or between embedded arm  1020  and embedded slot  1060 . In this embodiment the magnets used to obtain levitation (and for alignment) can be of lesser or very modest strength as compared to magnets which must bear the full weight of the folding paddle/blade assemblies  800 . 
         [0055]    In another embodiment, platform magnets  1000 ,  1002  and  1030 ,  1032 ,  1050  and  1052  are replaced with coils and instead of providing positioning/alignment are used to produce electricity. In this embodiment, the sidewall maglev configuration becomes the generator, thus eliminating the need for a power train and rotating generator. Other configurations of magnets and coils, know to those of skill in the art, can be used to combine the properties of magnetic levitation systems with generators and can result in the elimination of the separate generator. In other embodiments, generator  122  is used in conjunction with the maglev subsystem to provide powered levitation. 
         [0056]      FIGS. 11A and 11B  are views of an embodiment including directional adjustment and in particular yaw adjustment.  FIG. 11A  illustrates an embodiment in which yaw of support plate assembly  10  is adjusted through rotation about a vertical axis  1182 , in order to align horizontal platform axis  1180  with flowing fluid direction  300 .  FIG. 11B  illustrates a bridle and windlass system in which a stern windlass  1120  and bow windlass  1140  are used in conjunction with stern adjustment cable  1100  and bow adjustment cable  1130  (anchored via stern anchor points and bow anchor points  1132  and  1134  respectively) to adjust the yaw of support plate assembly  10 . An advantage of the embodiment of  FIG. 11B  is that both the bow and stern can be adjusted, allowing for better alignment of the system (e.g. horizontal platform axis  1180 ) with flowing fluid direction  300 . Variations on the bridle and windlass system, known to those of skill in the art, can be used to provide yaw alignment of the system. 
         [0057]      FIG. 12A  illustrates a flow direction monitoring system comprised of a flow direction sensor  1200  having a series of directional flow channels  1202 ,  1204 ,  1206 ,  1208  and  1210 . By sensing the amount of fluid passing through the flow channels, flowing fluid direction  300  can be determined. A number of readily available flow sensors, including mechanical, electromechanical, and/or optical sensors can be used in the flow direction sensor. An alternate flow direction measuring system is shown in  FIG. 12B  and is based on the use of a flow sensing blade  1244  which in one embodiment is attached to a front fixed blade  1240  via pivot  1242 . In one embodiment the angle θ  1246  is measured via mechanical, electrical, or optical means and provides an indication as to the correction need to the yaw to align the platform with flowing fluid direction  300 . In this embodiment when θ=approximately 180° the platform is approximately aligned with flowing fluid direction. In an alternate embodiment front fixed blade  1240  is not utilized. In yet another embodiment, the torque of the flow sensing blade  1244  on pivot  1242  is used to determine the flowing fluid direction  300 . 
         [0058]    In the embodiments shown in  FIGS. 12A and 12B  as well as in other embodiments where fluid flow direction  300  is measured, a control system including alignment motors and feedback are used to automatically align the system. As will be understood by one of skill in the art, by measuring the misalignment of the system, adjusting the yaw, and again measuring the direction of flow with respect to the orientation of the system, support plate assembly  10 , and in particular horizontal platform axis  1180  can be made approximately parallel with fluid flow direction  300 . 
         [0059]    Referring to  FIG. 13A  a horizontally arrayed configuration is shown with inner blades  1300  and outer blades  1310 . In this embodiment blades operating at different distances from horizontal platform axis  1180  are utilized to collect more power from the moving fluid. In this embodiment the blades are positioned such that the turbulence or shielding generated from inner blades  1300  is not so great that it prevents additional power from being extracted from outer blades  1310 . As will be understood by one of skill in the art, the blades can be designed and arrayed such that additional power can be extracted over which would be extracted from a single set of blades. 
         [0060]      FIG. 13B  illustrates a vertically arrayed system in which center blades  1342  are used in conjunction with top blades  1340  and bottom blades  1344 . This configuration provides for additional power extraction from the moving fluid. Other configurations of arrayed blades, including combinations of horizontal and vertical arrays of blades, can be used to extract additional power than what would be extracted using a single set of blades. 
         [0061]    Referring to  FIG. 14 , a hollow blade is illustrated in which both outer blade  820  and inner blade  810  are completely or partially hollow and are created using a skin  1400  used in conjunction with supporting members  1410 . In this embodiment the supporting members (typically of a lightweight composite material such as fiber-reinforced polymers, carbon-fiber reinforced plastic, carbon composite) provide structural strength while the skin  1400  (which can be a composite fabric, metal, plastic, Kevlar, or other suitable material) seals the blade clement. In the case of blades used in water, the configuration of  FIG. 14  can be used to make the blade variable buoyancy by pumping in different gases or liquid. In one embodiment, air is pumped into the blade to cause it to float. In this embodiment combination of air and water can be used to make the blade water-density neutral, thus giving it approximately zero effective weight in the water. In other embodiments only one of outer blade  820  or inner blade  810  is made hollow, or compartments are used in the blade. In these embodiments by filling compartments or a single blade with air (or an alternate gas) the entire blade assembly can be made to be water-density neutral or to create buoyancy. 
         [0062]    The advantages of the system and method are numerous. The strong, inherent, and renewable energy associated with flowing water is converted to electric energy by a simple submergible system. The system can be sized and configured for a variety of flowing water environments and a variety of electric energy generation applications. The system is environmentally friendly as it creates no sight pollution and its moving parts move no faster than the ambient flowing water thereby minimally impacting local flora and fauna. 
         [0063]    Although the system has been described relative to several embodiments thereof, there are numerous variations and modifications that will be readily apparent to those skilled in the art in light of the above teachings. For example, the paddle/blade described herein could be realized by a multiple slat design (e.g., pivotable vertical slats, pivotable horizontal slats, two slats hinged along the axis of the paddle axle, etc.). In this embodiment, the slats would rotate to be perpendicular or parallel to the flowing fluid in the same way as the monolithic paddle/blades described earlier herein. If the pivots/hinges provide for this rotation in a passive fashion, the above-described paddle/blade flip control could be omitted. 
         [0064]    Still another embodiment of the system includes the plate and multiple paddles, but not the rack and pinion gear system. In this embodiment, the gears would be replaced with an arm extending down to the plate from the axle/rod that supports the paddle/blade. The end of the arm would terminate in a permanent magnet riding within a groove in the plate. The sides and the bottom of the groove would incorporate conductor strips that alternate in polarity with insulation between them. As the permanent magnet is pushed forward through the groove with the alternating polarities, alternating electricity is generated by induction. The electricity can be tapped directly from each conductor with a wire or other suitable means, which are, in turn, then fastened to a conductive plate that gathers together all of the electricity generated at the individual conductors. This has the advantage of easily insulating the conductive plate and gathering all of the generated electricity. The amount of electricity produced is governed by the velocity of the magnet passing by a set of two conductors. Therefore, the conductors should be small and close together. This can be achieved by making a pre-insulated wire package that can be installed easily at the site. This embodiment could also make use of nano-conductors, which would enable realization of very high velocities due to the narrow width of two conductors. 
         [0065]    The present system and method extracts power from a series of blades which are pushed by a moving fluid in what can be considered to be an endless path. The linear motion of the blades can be converted to rotational motion to drive a generator, or a linear configuration of magnets and coils can be used in a linear generator embodiment. In one embodiment the blades are caused to have a density close to that of water, thus reducing their effective weight and minimizing friction in the blade transport mechanism. 
         [0066]    In an alternate embodiment magnetic levitation (maglev) technology is used (and can be used in conjunction with buoyant blades) to reduce or eliminate friction in the blade transport mechanism. In this embodiment permanent or electromagnets provide levitation and/or guidance for the blades in the blade transport mechanism. In one embodiment the maglev system is used in conjunction with linear generators, thus eliminating the need for a power train. 
         [0067]    While specific embodiments have been described in detail in the foregoing detailed description and illustrated in the accompanying drawings, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure and the broad inventive concepts thereof. It is understood, therefore, that the scope of the present disclosure is not limited to the particular examples and implementations disclosed herein, but is intended to cover modifications within the spirit and scope thereof as defined by the appended claims and any and all equivalents thereof.