Abstract:
A hydrogen generating vessel wherein a reduction plate generates hydrogen by electrolysis of sea water. The hydrogen generating vessel operates at deep ocean levels to provide unexpected advantages. The operating depth is not limited because the hydrogen generating vessel includes openings at or near the bottom, and no pressure differential exists across the vessel walls. Pressure inside and outside are the same, and are determined by the depth at which the hydrogen generating vessel is installed. Electrolysis, collection, and temporary storage take place in the same container. Since the hydrogen pressure is the same as the water pressure at the same depth, the hydrogen is pumped by simply opening a release valve. Operation within recommended guidelines provides a self-cleaning mechanism.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation-in-Part of application Ser. No. 12/381,936, entitled DEEP WATER GENERATION OF COMPRESSED HYDROGEN, which was filed on Mar. 18, 2009 by John E. Menear and is currently pending. Application Ser. No. 12/381,936 is herein incorporated by reference in its entirety. This application further claims priority to: U.S. provisional application No. 61/215,197 entitled MINIMUM VESSEL SIZE FOR DEEP WATER GENERATION OF COMPRESSED HYDROGEN, filed by John E. Menear on Apr. 30, 2009, and U.S. provisional application No. 61/271,332 entitled “CLEAN REDUCTION PLATE FOR DEEP WATER HYDROGEN GENERATION USING HIGH CURRENTS AND ELECTRODE MATERIALS THAT LIMIT BUILDUP” filed by John E. Menear on Jul. 20, 2009. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
       [0002]    Not Applicable 
       REFERENCE TO A MICROFICHE APPENDIX 
       [0003]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    This invention relates to renewable energy, and particularly extraction of hydrogen from flowing conductive water with a predictable flow direction or from an ocean current. The hydrogen is produced from water by electrolysis, and the energy required for electrolysis is derived from the kinetic energy of the flowing water or ocean current. 
         [0006]    2. Description of Related Art 
         [0007]    It is widely accepted that renewable energy sources are needed to supplement or replace fossil fuels. Air quality, global temperature concerns, oil shortages, political concerns, as well as economics combine to make fossil fuels less attractive. 
         [0008]    Hydrogen is the ideal renewable energy source. One major advantage is that hydrogen is portable. For example, hydrogen fueled cars already exist. 
         [0009]    From an environmental viewpoint, hydrogen produced by electrolysis of electrically conductive water has little impact. Hydrogen combustion recreates the water from which the hydrogen was extracted. 
         [0010]    In a large circular view, (1) water in the ocean is converted to hydrogen, (2) the hydrogen is burned to create energy, and burning creates water vapor, (3) water vapor mixes with the atmosphere, and eventually falls as rain, (4) water from the rain enters streams, and (5) the streams return to the ocean. From a chemistry viewpoint, the initial state and the final states are the same. 
         [0011]    From an energetic viewpoint, energy from an ocean current (or other flowing current) is stored as chemical energy, and released by combustion to accomplish useful work. Energy is conserved. 
         [0012]    Many renewable energy efforts have focused on solar and wind. This is appropriate. But both solar and wind are best applied to electrical power generation that is used at fixed locations (home, business, etc) or is added into a power grid. 
         [0013]    Hydrogen can be used for automobiles, eliminating the need for batteries and recharging. That is, hydrogen is a mobile fuel, and can replace gasoline. 
         [0014]    Hydrogen is environmentally preferred over batteries because the batteries are typically charged with electricity generated from fossil fuel. So, carbon dioxide still accrues with battery use. 
         [0015]    Most of today&#39;s commercial hydrogen is derived from fragmenting hydrocarbons, and hence, is tied to fossil fuels. So, even today&#39;s hydrogen cars indirectly depend on fossil fuel, and carbon dioxide still accrues. A source of hydrogen that is not based on fossil fuel adds to the appeal of hydrogen cars. 
         [0016]    Electrolysis of water to produce hydrogen is known in the prior art. Also, the use of ocean currents for electrolysis of water has been described. 
         [0017]    But prior art references to ocean currents have failed to enable a practical method or apparatus for hydrogen production. Normally, prior art embodiments are directed toward generating electricity, and hydrogen production is included as a secondary application. As a consequence hydrogen production ideas are overly complex, expensive to build, or cannot be scaled up to produce commercially useful quantities. 
         [0018]    In short, the desirability of creating hydrogen from ocean currents (or other flowing water sources) has been recognized since the 1980s. But the practical apparatus and method remained unsolved prior to this instant invention. 
         [0019]    There are six problems with prior art proposals to create hydrogen from ocean currents. 
         [0020]    The first problem of the prior art involves electrolysis current requirements. Practical electrolysis requires large current and energy input. It requires 2 Faradays of charge to create one gram-molecular-weight (one mole) of diatomic hydrogen gas. That one gram-molecular-weight equals 2 grams of hydrogen or roughly 22.4 liters (calculated as an ideal gas). 
         [0021]    One Faraday of charge is 96,485 coulombs. It is equivalent to 1 ampere for 96,485 seconds. 
         [0022]    The bottom line is that prior art proposals can be used to generate hydrogen by electrolysis, but the quantities produced are small and cannot be scaled up. 
         [0023]    The second problem of the prior art is collection. If dedicated (and separate) collection vessels are needed to store uncompressed hydrogen after generation, system complexity and cost become prohibitive. Costs are particularly high when those separate collection vessels are positioned at sea level, where small amounts of hydrogen occupy large volumes. Pressurized vessels (relative to atmospheric pressure at sea level) must be sealed, which drives costs upward. 
         [0024]    Floating collection pods are examples of impractical hydrogen collection vessels. Each expensive pod holds very little hydrogen. 
         [0025]    The third problem of the prior art is compression of hydrogen gas. At sea level, hydrogen is produced at 1 atmosphere, and is uncompressed. Compression at the time of generation would minimize hydrogen volume. 
         [0026]    Two (2) grams of hydrogen occupy roughly 22.4 liters at standard temperature and pressure (ideal gas calculation). Without compression at the time of generation, overly large (impractical) generation, collection and storage vessels are needed. A separate apparatus for compression becomes necessary if hydrogen is produced at one atmosphere of pressure. Since volume is inversely proportional to pressure, generation, collection and storage at 8-10 atmospheres would be highly advantageous. The fixed production costs are reduced at 8-10 atmospheres. 
         [0027]    The fourth problem of the prior art is hydrogen transport. Ultimately, hydrogen from the ocean-based generating station has to be transported to a distribution (or purification) terminal. This terminal may be land-based, or the terminal could be an off-shore production ship. Using hydrogen pressure to move hydrogen through piping by expansion (without requiring a separate pump) should be available as a transportation method to either a ship or land-based terminal. 
         [0028]    A fifth problem of the prior art involves operating personnel. On-site operators are expensive. In a preferred generating station, operating personnel are only required for periodic maintenance. Unattended operation is desirable. To accomplish this, generation equipment should be uncomplicated, reliable, and based on scientific principles as opposed to complex electrical controls. The prior art does not reduce maintenance through simplicity. Microprocessor technology is often substituted for scientific fundamentals. 
         [0029]    A sixth problem of the prior art is that safety of marine life is not prioritized. For example, if a high-speed flow-through rotary turbine is utilized (assuming useful hydrogen production quantities were possible), marine life could become trapped, hurt, or killed. 
         [0030]    A slow-moving turbine/propeller combination might be used, but energy capture from the ocean current is low. As a consequence, hundreds of turbines would be needed, and produced hydrogen would be expensive. 
         [0031]    There is a need for an apparatus and associated method that extracts hydrogen from deep level seawater using ocean currents for power. Some embodiments should be capable of producing more than 1 billion standard cubic feet of hydrogen per year. With these volumes, the market for hydrogen fueled cars is supported. 
         [0032]    The invention should overcome the six above-cited problems. 
         [0033]    Throughout this disclosure, hydrogen production quantities are recited in liters or cubic feet, regardless of the actual hydrogen pressure. Yet the volume occupied by a gas varies inversely with pressure and varies directly with Kelvin temperature. By definition in this disclosure, produced hydrogen volumes will always mean standard liters or standard cubic feet, unless specifically stated otherwise. Standard liters or standard cubic feet represent the volume that the hydrogen gas would occupy if that hydrogen were an ideal gas at 1 atmosphere and 25 degrees centigrade. 
       BRIEF SUMMARY OF THE INVENTION 
       [0034]    The core of this instant invention is a hydrogen generating vessel that operates at deep ocean levels. The pressure of the ocean is used to (1) generate hydrogen in a pre-compressed volume, (2) collect and temporarily store the hydrogen in a pre-compressed volume, and (3) pump hydrogen. Specifically, the hydrogen generating vessel is designed for repetitive filling and removal, as opposed to continuous flow-through operation. The presence of a release valve distinguishes repetitive filling and removal from continuous flow-through. 
         [0035]    To accomplish these goals effectively, a minimum size hydrogen generating vessel, a minimum installation depth, a minimum size reduction plate, and water exchange openings are required. Each requirement is established to achieve the desired overall utility. 
         [0036]    Specifically, the internal volume of the hydrogen generating vessel must be 42 cubic feet or greater with openings in the bottom volumetric half that allow water to enter and exit. Openings in the bottom volumetric half allow ocean pressure to compress the hydrogen gas. The minimum forty-two cubic feet size allows a self-pumping feature. 
         [0037]    This hydrogen generating vessel must be installed deep enough to generate and collect hydrogen gas with at least two atmospheres (or greater) of pressure. This corresponds to a depth of nominally 10 meters below the ocean surface. If 90% of the upper volumetric half of the hydrogen generating vessel is disposed 10 meters (or more) below the ocean surface, this requirement of two atmospheres is considered met. 
         [0038]    Since the instant invention is targeted for commercial utility, the reduction plate has an area of at least 4 square feet. The minimum four square feet is derived from a balance between minimum production output and maximum current flux through the reduction plate. 
         [0039]    Ocean water is not clean, and the invention incorporates design features and guidelines to maintain a clean electrolysis (reduction) electrode. Included are (1) seawater level oscillations inside the hydrogen generating vessel, (2) sufficient hydrogen generation to provide turbulence at the reduction plate surface, and (3) materials of construction to reject attachment of living organisms. 
         [0040]    Seawater level changes inside the hydrogen generating vessel arise from the basic operating principle, and are a natural advantage of this invention. Seawater levels lower when generated hydrogen displaces the seawater downward. When hydrogen gas is removed, seawater levels rise. 
         [0041]    A hydrogen generation quantity of at least 1 liter (at standard temperature and pressure) per minute per square foot of electrolysis plate area is recommended to maintain a clean electrolysis (reduction) plate. 
         [0042]    Using construction materials that reject attachment of living organisms (for example, barnacles or tubeworms) is also recommended. 
         [0043]    To be commercially practical, the hydrogen generating vessel is powered by an apparatus that converts kinetic energy of an ocean current to electrical energy. The apparatus described produces considerably more energy than prior art mechanisms, providing that an average-sized current-catcher has an area of nine square feet or more. 
         [0044]    A hydrogen generating station (hydrogen generating vessel, power generator, and associated components) operates unmanned for extended periods of time. This means that hydrogen costs are (1) modest fixed structural expenses, (2) and periodic maintenance costs. This leads to a very low production cost. 
         [0045]    Objects of the invention include: 
         [0000]    a. capture kinetic energy of an ocean current and convert it into current and voltage with electrical generators,
 
b. harness a sufficiently large current and energy source to generate commercially significant hydrogen quantities,
 
c. direct the current and voltage to a negative electrolysis (reduction) plate that is housed within a hydrogen generating vessel,
 
d. build a production facility wherein separate collection and storage vessels are not necessary,
 
e. submerge the hydrogen generating vessel under the ocean surface during operation such that hydrogen is produced at a pressure of 2 atmospheres or greater,
 
f. produce hydrogen in a pre-compressed state, so that production vessels can be smaller than needed for production at 1 atmosphere,
 
g. use hydrogen pressure within a hydrogen generating vessel (based on installation depth) to pump hydrogen or through piping to land based terminals or alternate locations,
 
h. collect and store initial quantities of hydrogen inside the hydrogen generating vessel,
 
i. design a partially self-cleaning hydrogen production station that largely operates unattended, except for periodic maintenance, and
 
j. respect marine life.
 
         [0046]    A central (and required) feature of this instant invention is that hydrogen generation occurs below the ocean surface, where hydrogen is generated under pressure. This feature employs two basic scientific principles to novel advantage. The first principle is that ocean pressure increases as depth increases. The second is that pressure inside a hydrogen generating vessel is the same as pressure outside the hydrogen generating vessel when inside water and outside water are not separated. 
         [0047]    The invented hydrogen generating vessel has openings which allow the surrounding ocean water (or other flowing water) to move in and out. Because a pressure drop does not exist across the walls of the hollow container (part of the hydrogen generating vessel), the cost and complexity is minimal. Inexpensive materials and unsophisticated designs suffice. 
         [0048]    The advantages of deep level hydrogen generation are simplicity, fewer vessels, reduced construction costs, and minimal maintenance. Production is accomplished with fewer (and smaller) structural components than otherwise needed. Fewer components mean less fixed cost and less maintenance. 
         [0049]    Electronic control circuits, microprocessors, or printed circuit boards are optional. The instant invention works without them. In the hostile ocean environment, omitting electronic controls yields a more rugged system. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0050]      FIG. 1  shows a basic hydrogen generating station. In a large scale system, multiple basic hydrogen generating stations may be combined. As shown, this generating station captures kinetic energy for flowing water at three depth levels. A hollow container surrounding the negative electrolysis plate is not shown in this view. 
           [0051]      FIG. 2  shows the top view of a rotating disk with current catchers. Note that the current catchers capture kinetic energy from the ocean current when they travel with the direction of the current. The current catchers fold into the rotating disk when traveling against the current. 
           [0052]      FIG. 3A  shows a deep level hydrogen generating vessel as part of a hydrogen generating station. A deep level hydrogen generating vessel is a combination of a hollow container with openings at the bottom portion, a reduction plate for electrolysis, a conductive wire that originates at a generator and connects to the reduction plate, a release valve, and a means (not shown) for holding the hydrogen generating vessel under water. 
           [0053]      FIG. 3B  describes the upper volumetric half and the bottom volumetric half of a hydrogen generating vessel. 
           [0054]      FIG. 3C  shows why the minimum volume of an invented hydrogen generating vessel is at least 42 cubic feet. 
           [0055]      FIG. 4  shows an atmospheric hydrogen generating station. A separate pumping mechanism moves hydrogen at a pressure of one atmosphere for storage, purification, or compression. 
           [0056]      FIG. 5  shows a torque canceling embodiment that captures the energy of the ocean current with two oppositely rotating disks. This arrangement has the advantage of canceled torque such that the overall structure has minimal tendency to rotate. A figure-eight belt and two-level gear combine the energy generated by the two rotating disks. 
           [0057]      FIG. 6  shows a support frame that holds the system components together. The support frame is stationary, and the ocean current flows through it. 
           [0058]      FIG. 7  describes the pressure advantage of deep level hydrogen generation. 
           [0059]      FIG. 8  shows that a separate pumping mechanism isn&#39;t required for deep level hydrogen generation. Instead, compressed hydrogen moves by expansion when a valve is opened. Excess water removal is another unexpected advantage. 
           [0060]      FIG. 9  shows the use of one or more anchors to hold a hollow container in place at deep levels. 
           [0061]      FIG. 10  shows cables attached to ocean floor rock with secure connectors to hold the hydrogen generating vessel in place. 
           [0062]      FIG. 11  shows a hollow hydrogen generating vessel held at its predetermined depth by a spacing beam. 
           [0063]      FIG. 12  diagrams the self-cleaning capability that arises from hydrogen generation at a rate of at least 1 liter of hydrogen per minute per square foot of reduction plate. 
           [0064]      FIG. 13  diagrams the self-cleaning capability that arises from water expulsion as hydrogen is generated inside the hydrogen generating vessel. 
           [0065]      FIG. 14  diagrams the self-cleaning capability that arises from water intake when hydrogen is removed from the hydrogen generating vessel. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0066]    Ocean currents move massive volumes of water continuously, and their global routes are known. The quantity of water in motion is so large that worldwide temperatures are affected by the currents. 
         [0067]    Some ocean currents have a velocity between 2-6 meters/second. Water is heavy (1000 kilograms per cubic meter), and the kinetic energy of the moving water represents a large untapped energy source. The destructive power of a tsunami testifies to the kinetic energy of moving water. 
         [0068]    A unique situation exists with hydrogen generation from ocean currents. The moving water that supplies the energy for electrolysis is also the reactant for hydrogen production. No additional raw materials need to be transported to the generation site. 
         [0069]    There is a compelling environmental-economic-political argument to utilize this worldwide resource. With a readily available hydrogen source, market acceptance of hydrogen cars will be facilitated. 
         [0070]    The volume of the earth&#39;s oceans is roughly 10,000,000 times larger than the volume of the earth&#39;s oil reserves. Far more energy is available from the oceans than from oil fields. With the current invention, the cost per Joule of hydrogen energy is lower than the cost of equivalent oil energy. 
         [0071]    Following is an estimated cost calculation for hydrogen energy with the instant invention. It is provided only as an index to the economic viability of the instant invention. The inventive principle is not limited by these cost calculations, and it is understood that costs for a generation station will vary widely based on details (total output, location, details of construction, construction contractor costs, efficiencies, modifications, etc.) 
         [0072]    In this calculation, a one-time structural investment is amortized across 25 years. Hence, a $10,000,000 structural cost contributes $400,000 per year. Periodic maintenance is projected at $600,000 per year. Estimating a hydrogen output of 1 billion cubic feet of hydrogen (at standard temperature and pressure) per year, the cost per cubic foot is estimated at 0.1 cent. 
         [0073]    One gallon of gasoline can be replaced with 360 standard cubic feet of hydrogen. Based on 0.1 cent per cubic foot, that one gallon of gasoline can be replaced with 36 cents of raw produced hydrogen. Doubling the raw hydrogen cost (to account for further purification and transportation) leads to 72 cents. 
         [0074]    In short, 72 cents of hydrogen replaces 1 gallon of gasoline. If gasoline prices increase to $7.20 per gallon, the consumer would save 90% by switching to a liquid hydrogen vehicle. Hence, the switch to hydrogen is driven entirely by the free market. Environmental benefits are a bonus. 
         [0075]    A low energy cost structure lays the foundation to solve several recognized economic-environmental-political problems simultaneously. For example, if hydrogen production from this invention were developed on a large scale, hydrogen-fueled cars become practical. In turn, (a) the auto industry could reinvent itself with a very profitable hydrogen business model, (b) trade imbalances from oil imports would drop as hydrogen replaces gasoline, and (c) carbon dioxide emission would drop. 
         [0076]    An unexpected self-cleaning advantage occurs when hydrogen is generated at a rate of 1 liter per minute per square foot of reduction plate. Because hydrogen is moving away from the reduction plate at a rate of roughly 1 liter/minute-square foot, surrounding ocean water moves toward the reduction plate at the same rate. Momentum of the incoming water creates a scrubbing action near the plate surface. 
         [0077]    Within a practical range, higher hydrogen generation per square foot creates even better scrubbing since hydrogen moves away from the reduction plate at higher linear velocity. But there is an upper limit to the hydrogen generation per square foot due to current flux at the reduction plate and to liquid/solid contact, and a minimum 4-square-foot reduction plate is proposed. 
         [0078]    In all embodiments, electrolysis is performed more than 10 meters below the surface of the ocean, where ocean pressure is nominally two atmospheres. Deeper levels (deeper than 10 meters) are even better since compression and pumping capability are both improved. Higher pressure inherently exists at deeper levels, and using the available higher pressure is a logical choice. 
         [0079]      FIG. 1  shows a basic hydrogen production station  1 . It includes one or more rotating disks  2  that rotate due to current catchers  3 . Open current catchers  3  are held open by restraints  4  that hold the current catchers  3  open only in one direction. When the restraints  4  are on the downstream side of the current catchers  3 , the current catchers open, and are pushed by the ocean current  5 . When the restraints  4  are on the upstream side of the current-catchers, the current catchers fold. Current catchers are not pushed by the ocean current  5  when they are folded. The result is a counter-clockwise rotation  6  when viewed from the top. Note that the ocean current  5  itself opens and folds the current catchers. No complex mechanism is needed. At the start of energy capture, the ocean current  5  pushes the current catcher  3  open. At the end of energy capture, the ocean current  5  folds the current catcher  3 . 
         [0080]    The restraints  4  shown in  FIG. 1  are implemented as structural blocks with sufficient rigidity and size to stabilize the open current-catchers  3 . The restraints  4  operate in conjunction with the moveable joints  7  that join the current-catchers  3  to the rotating disks  2 . Note that forces on the restraint  4  can be very large. If an open current-catcher  3  has an area of 100 square meters, and the ocean current is flowing at 5 meters/second, the mass of water pushing the open current-catcher  3  is roughly 500,000 kilograms per second. Furthermore, the forces behind an open current-catcher  3  (as shown) exert a mechanical advantage relative to the restraint  4  due to a greater distance from the rotating shaft  11 . 
         [0081]    In practical applications, the current-catchers have a large cross sectional area. The proposed cross sectional area of an average current catcher at a hydrogen generating station is at least 9 square meters. Forces pushing the current catchers are roughly proportional to the cross sectional area. (Force is the product of flowing water pressure and area.) 
         [0082]    The current-catchers move at ocean current velocity. Hence, marine life is not threatened because they are drifting at the same velocity. High torque allows a high gear ratio. The generator  12  rotates quickly, even though the current-catchers  3  move slowly. 
         [0083]    The current catchers  3 , restraints  4 , and moveable joints  7  shown in  FIG. 1  may be replaced with more complex mechanisms if desired without affecting the inventive concept. Greater complexity may be useful to control opening and folding times, or to increase structural strength. As shown, the rotating shaft  11  is vertical rather than horizontal. This has the advantage that the current-catchers remain supported by the weight of water displaced at all times. But other orientations may be functional. 
         [0084]    Rotating disks  2  drive the rotating shaft  11  which turns the generator  12 . Voltage and electrical current from the generator  12  are connected to the reduction plate  9  and the oxidation plate  10  through conductive wires  8 . Hydrogen gas is created by reduction of hydrogen in water. This is the significant reaction. 
         [0085]    Simultaneously, oxidation of dissolved organics or anions occurs at the oxidation plate  10 . The species which is oxidized is not the significant reaction for this instant application. 
         [0086]    As shown in  FIG. 1 , the generator  12  is rectified. Rectification is useful so that oxygen doesn&#39;t mix with the produced hydrogen. However, rectification isn&#39;t always required. Alternating current has application to electrolysis of water. 
         [0087]    A hollow container, which surrounds the reduction plate  9 , is not shown in  FIG. 1 . 
         [0088]    The conductive wires  8  (and connectors  8 A) are thoroughly insulated and water-proofed to prevent electrolysis from occurring along the conductive wires  8  themselves and to prevent power losses due to shorting. 
         [0089]    Connectors  8 A to the electrolysis plates are also sealed. Without connector sealing, ocean pressure at the connectors  8 A (that are disposed deep within the ocean) would push sea water upward through the insulated conductive wires  8  toward the ocean surface (where the generator is attached). 
         [0090]    It should be noted that the apparatus in  FIG. 1  does not generate electricity with the intention of connecting to an electrical grid. So, filtering, noise control, amplitude control, or synchronizing to a 60 hertz grid is not required. Costs are reduced by omitting them. The generator&#39;s  12  output requirement is production of high current above the ocean water electrolysis voltage threshold. 
         [0091]      FIG. 2  shows a top view of a rotating disk  2  that is rotating in the counter-clockwise direction  6 . The open current catchers  3  are held open by the restraints  4 , capture energy from the ocean current  5 , and force rotation in the counter-clockwise direction  6 . The folded current catchers  3  assume a low profile as they move into the ocean current. In this way, the folded current catchers  3  contribute minimal counter-productive drag as they move toward the re-opening position. 
         [0092]    As drawn in  FIG. 2 , the current catchers  3  have a curvature that approximates the outer circumference of the rotating disk  2 . A curvature isn&#39;t required, but curvature has advantages for both the open and folded current catcher  3  orientations. The folded current catchers  3  lie very close to the rotating disk  2 , and offer minimal resistance to the ocean current  5 . The open current catchers  3  effectively capture the ocean current  5 . 
         [0093]      FIG. 2  shows that the restraints  4  provide a force against the current catchers  3  when they are downstream of the open current catchers  3 , but not when they are upstream of the folded current catchers  3 . Opening and folding occur around the moveable joints  7 , such as hinges, axial rods, ball-and-sockets. There are many options for a moveable joint  7 . 
         [0094]      FIG. 3A  shows a hydrogen generating vessel  13  that is submerged. The hydrogen generating vessel  13  includes a reduction plate  9  that is immersed in seawater  14 . The hollow container  13 A has openings  15  in the bottom volumetric half. The entire bottom may be open. Hydrogen gas collects at the non-porous top. Because the hydrogen generating vessel  13  is located below the ocean surface  14 A, the pressure of generated hydrogen is determined by the depth pressure of the ocean. 
         [0095]      FIG. 3B  divides a hydrogen generating vessel  31 B into an upper volumetric half  32 B and a bottom volumetric half  33 B. Regardless of shape, an upper volumetric half (that 50% closest to the ocean surface) and a bottom volumetric half (that 50% closest to the ocean floor) are inherent. The terms “upper volumetric half” and “bottom volumetric half” are employed in the claims. 
         [0096]      FIG. 3C  is a table that shows why the minimum volume of an invented hydrogen generating vessel is 42 cubic feet. At various ocean depths, the minimum volume of compressed hydrogen gas pump needed to drive itself (by expansion) through a pipe is calculated. The two key considerations are (1) that the minimum length of pipe must be at least equal to the installation depth, and (2) the volume of pressurized hydrogen must expand to at least fill the pipe volume when the pressure is lowered to one atmosphere. 
         [0097]    The calculations in  FIG. 3C  quickly converged on 21 cubic feet of hydrogen gas as the installation depth increased. Since the upper volumetric half of the hydrogen generating vessel is predominantly used for gas collection and storage, the 21 cubic feet was assigned to the upper volumetric half. The bottom volumetric half must also be 21 cubic feet, leading to a total minimum volume of 42 cubic feet. 
         [0098]      FIG. 4  shows a prior art atmospheric hydrogen generation station  41  with the hydrogen generating vessel  43  (and hollow container  43 A) at or above the ocean surface  14 A. Because the hydrogen is generated at roughly 1 atmosphere, it is not compressed. Very little hydrogen can be generated before hydrogen must be transferred out of the hydrogen generating vessel  43 . In addition, a separate pumping mechanism  44  is used to perform the transfer. Separate storage modules  18 , pre-compression modules  16 , and pre-purification modules  17  are necessary and costly. 
         [0099]    Separate pumping mechanisms  44 , separate storage modules  18 , pre-compression modules  16 , and pre-purification modules  17  are not needed with deep level hydrogen generation. That is, deep level generation significantly reduces the cost of construction and the complexity of operation. 
         [0100]      FIG. 7  shows generation of hydrogen more than 40 meters below the ocean surface. A reference scale on the right side of  FIG. 7  is incorporated to show ocean pressure versus depth. As a rule of thumb, pressure increases 1 atmosphere with each 10 meters of depth. As indicated by a dashed line, hydrogen is generated where ocean pressure is 5.3 atmospheres. As an added consideration, the temperature of the ocean at 40 meters will normally be lower than the temperature at the surface. Both factors (higher pressure and lower temperature) decrease the volume of one gram-molecular-weight of hydrogen, relative to 25 degrees C. and 1 atmosphere of pressure. Pressure is the primary compressing factor. 
         [0101]    At 5.3 atmospheres, roughly 5.3 times more hydrogen molecules can accumulate (relative to one atmosphere) before the hydrogen has to be moved elsewhere. Hence, the hydrogen generating vessel  73  also acts as an intermediate storage container, leading to a more efficient (less complex) production flow. 
         [0102]    In  FIG. 7 , the conductive wire  8  attaches to the reduction plate  79  through the bottom of the hollow hydrogen generating container  73 A. Bottom entry isn&#39;t required, but it is convenient because the bottom portion of the hollow hydrogen generating container  73 A is porous. 
         [0103]    At 100 meters below the ocean surface, the compression factor for generated hydrogen is roughly eleven. The size of the overall production station is significantly reduced, and the fixed cost of the station is dramatically reduced (compared to atmospheric production). 
         [0104]    The walls of the hollow container  73 A can be conductive or static dissipative to assure that static charges do not accumulate. This may not be necessary because the ocean itself is conductive. But it serves as an additional preventative safety feature. 
         [0105]      FIG. 8  shows a deep level hydrogen generating vessel  83  that is producing hydrogen at 8.5 atmospheres. The hollow hydrogen generating container  83 A that defines the shape of the hydrogen generating vessel  83  is a domed cylinder. A conductive wire is not shown in this figure. As always, the bottom volumetric half is porous so that ocean water flows in and out. The upper volumetric half is non-porous to prevent hydrogen escape. 
         [0106]    A release valve  84  at the top of the hydrogen generating vessel  83  eliminates the need for a separate pumping mechanism. Because the hydrogen is pressurized, relative to a land terminal at 1 atmosphere, opening the release valve  84  moves the hydrogen to the land terminal. No separate pumping mechanism is needed. 
         [0107]    As the hydrogen moves through the piping  85  it moves upward (the land terminal is higher than the hydrogen generating vessel  83 ). An opportunity to remove entrained seawater exists by ensuring that some of the nearby piping  85  is positioned higher than the release valve. Twists, turns  86 , rough spots, screens, or packing material  87  above the release valve  84  serve as locations for water coalescence. In addition, expansion cools and further aids in removing some of the entrained water. Agglomerated water moves backward (downward) in the piping  85 . 
         [0108]    As shown, removed water (plus dissolved salt) returns to the hydrogen generating vessel  83 , and, hence, back into the ocean. No separate drain is needed. This serves as a pre-purification bonus that arises from considerate design. Transporting partially dries the hydrogen without extra effort or expense. Hence, final purification is simplified and less costly. 
         [0109]    In this  FIG. 8  embodiment, the shape of the hollow container  83 A is cylindrical with a domed top. However, shape is not critical as long as hydrogen can accumulate without escape in the upper volumetric half, and the release valve  84  is above the bulk of collected hydrogen. 
         [0110]    In this embodiment, there is an orifice in the side of the hydrogen generating vessel  83  that allows line-of-sight movement of aqueous ions between the electrolysis plate(s), which is located outside for safety reasons. This is useful for high generation rates because aqueous ion flow between reduction and oxidation plates  90  is unobstructed. This improves performance. 
         [0111]    An optional level sensor  88  is shown in  FIG. 8 . In some embodiments, the sensor  88  automatically activates the release valve  84 . In other embodiments, the release valve can be activated remotely. Wireless communication may be used to control the release valve. Or, the level sensor  88  and release valve  84  may be mechanically linked, and require no electronics. 
         [0112]      FIG. 5  shows a torque canceling system  50 . This is useful to prevent a tendency for the entire structure to rotate. Two rotating disks  2  are combined to cancel torque forces. Note that the two rotating shafts  51  are rotating in opposite directions so that angular momentum is roughly equal and opposite. A figure-eight belt  55  and dual-level gear  54  add the rotational energy of the two rotating shafts  51 , and sum the energy to the generator  52 . 
         [0113]    It is understood that more than one generator  52  may be used, and remain within the inventive concept. For large current-catchers  3 , multiple generators may be employed to convert the large amount of kinetic energy of the ocean current  5  to electrical energy. Only one generator  52  in  FIG. 5  is drawn for purposes of explaining the concept. 
         [0114]    As drawn, the generator(s)  52  is positioned near the ocean surface. This is convenient from a maintenance perspective, but isn&#39;t required. Regardless of depth, the generator  52  will be exposed to hostile conditions, and a protective enclosure is appropriate. 
         [0115]    The restraints  4  are placed to open and fold the current-catchers  3  in opposite directions, and, hence, cause rotation in opposite directions. 
         [0116]      FIG. 6  shows a support frame  60  that contains and stabilizes the components. Ocean current  5  flows through the porous walls  61 . A skeletal frame has advantages in stormy seas since a skeletal frame allows turbulence and large waves to pass through without bending, twisting, damaging or upsetting the hydrogen generating station. 
         [0117]    The invented deep level hydrogen generation operates with minimal human interaction. Unless maintenance is required, human presence is not needed. 
         [0118]    The following energy estimates are included only as an aid to understanding the invention and positioning its importance. The estimates are not intended as specifications or requirements or invention limitations. 
         [0119]    Refer back to  FIG. 1 . Consider an open current catcher  3  whose area is 100 square meters that captures the kinetic energy of an ocean current  5  moving at five meters per second. The available kinetic energy per second is approximately ½ mV 2 , which is theoretically 6.3 million joules per current catcher per second (or 6.3 million Watts per current catcher). 
         [0120]    Scaling up, six current catchers  3  acting together create 38 million Watts. 
         [0121]    Since the electrolysis of water (in concentrated electrolyte) begins at 1.2 volts, 38 million Watts can theoretically supply current to multiple electrolysis plates at up to 32 million amps (32 million coulombs per second). 
         [0122]    193,000 amps (two Faradays per second) will produce (at full efficiency) 1 gram-molecular-weight or 22.4 liters of diatomic hydrogen per second. By proportion, 32 million amps will produce 166 gram-molecular-weights or 3714 liters or 131 cubic feet of hydrogen per second (ideal gas at standard temperature and pressure). 
         [0123]    At continuous generation, this equates to more than four billion cubic feet per year. 
         [0124]    Employing 100 to 1000 hydrogen generating systems in the oceans makes hydrogen cars feasible worldwide. 
         [0125]    Performing electrolysis at deep ocean levels simplifies the overall process, but requires structural means for holding hydrogen generating vessels at predetermined depths. Hydrogen gas weighs less than the seawater that it displaces. As hydrogen gas collects inside a hydrogen generating vessel, the hydrogen generating vessel becomes more buoyant. This has to be countered with a downward force. 
         [0126]    It is also important to keep the top of the hydrogen generating vessels facing upward (toward the ocean surface) or hydrogen could be lost. This upward orientation is partially self-adjusting since the less dense hydrogen gas (relative to water) will seek the highest level. 
         [0127]      FIG. 9  shows the use of one or more anchors  91  to hold a hydrogen generating vessel  93  in place. The weight of the anchor  91  is sufficient to overcome the upward buoyancy due to the hydrogen collected. In this embodiment, multiple anchors are used to further assure that the hydrogen generating vessel  93  maintains an upward orientation (top facing the surface). 
         [0128]    In an effort to minimize the weight of the anchor  91 , hydrogen may be transported from the hydrogen generating vessel  93  before large hydrogen quantities accumulate. That is, a release valve  94  can be activated more often. 
         [0129]    The weight of the hydrogen generating vessel  93  itself acts as an anchor. Heavy metal hollow containers  93 A are possible, but from a cost viewpoint may not be the best choice. Wall strength is not a primary concern. So, thin wall construction is a reasonable option. 
         [0130]      FIG. 10  shows cables  101  connected to the ocean floor  102  or to a heavy object on the ocean floor with secure attachments  104  that hold the hydrogen generating vessel  103  in place. 
         [0131]      FIG. 11  shows a hydrogen generating vessel  113  held at its predetermined depth by a spacing beam  111  positioned between the support frame  110  and the hollow container  113 A. The cross-sectional shape of the spacing beam  111  is not important. For example, it could be linear, triangular, rectangular, square, polygon, elliptical, or equivalent. 
         [0132]    The use of anchors, cables, and spacing beams does not comprise a comprehensive list of ways to hold a hydrogen generating vessel in place at a predetermined depth. They are examples only. Other equivalent methods are useful. 
         [0133]    Much of the above discussion has focused on ocean currents. However, rivers, streams, and fast tidal flows can also apply this invention. For example, the San Francisco bay has deep channels and fast flows. 
         [0134]    Ocean water is not clean. If the reduction plate becomes dirty, the efficiency of hydrogen production could suffer. To maintain efficiency, average hydrogen generation of at least 1 liter per minute per square foot at the reduction plate is suggested. At this generation rate, hydrogen is generated quickly, and provides a scrubbing action at the reduction plate surface. 
         [0135]      FIG. 12  shows how the minimum hydrogen generation rate of 1 liter per minute per square foot at the reduction plate creates a self-cleaning turbulence. The generating surface  121  of the reduction plate  129  releases hydrogen gas bubbles  123 . The hydrogen gas bubbles  123  move away from the reduction plate along an upward-and-outward gas direction line  124 . As the hydrogen bubble leaves the generating surface  121 , ocean water  122  moves toward the generating surface  121  along water direction line  126 . The net result is turbulence  125 , which functions to scrub the generating surface  121 . 
         [0136]    Note that the hydrogen flow is away from the reduction plate surface at roughly 0.4 inches per minute. This further creates a barrier for solid contaminants that might otherwise contact the reduction plate. 
         [0137]    The minimum hydrogen generation rate of 1 liter per minute per square foot (at standard temperature and pressure) at the reduction plate suffices to provide scrubbing at a wide range of ocean depths. With shallow installations, the molar volume of hydrogen is large, and the pressure (force per unit area) of the displacing water is low. At very deep ocean levels, the molar volume of hydrogen is reduced, but the pressure of the displacing water is high. Either situation works. 
         [0138]    Self-cleaning is augmented by continual changes of water inside the hydrogen generating vessel.  FIG. 13  shows that ocean water  132  inside the hydrogen generating vessel  131  moves along the exit direction  133  during hydrogen generation. Ocean water (that previously filled the hydrogen generating vessel  131 ) moves relative to the stationary reduction plate  139 , and returns to the ocean. Contaminants (from any source) inside the hydrogen generating vessel  131  are carried back into the ocean. Contaminants include those released by the scrubbing action of hydrogen generation. 
         [0139]      FIG. 14  describes water movement when the hydrogen inside the hydrogen generating vessel  141  is transferred elsewhere. Ocean water  142  enters from the bottom of the hydrogen generating vessel  141 , and moves past the reduction plate  149  along filling direction  143 . 
         [0140]    The in-and-out water movement shown in  FIG. 13  and  FIG. 14  constitutes a pumping action. Contaminants and dirt do not concentrate inside the hydrogen generating vessel. 
         [0141]    Further self-cleaning is available through selection of reduction plate materials. Low concentrations of copper ions, silver ions, or tin ions near the reduction plate reduce the tendency for barnacles or tube worms to attach to the reduction plate (or other surfaces). The reduction plate may be metallic copper, tin or silver, or the reduction plate may be alloys of copper, tin or silver. Films or hydrolysable polymers may also be used, providing that they can accommodate high current flux. Other metallic ions (beyond copper, tin or silver) may be useful. 
         [0142]    The combination of (a) scrubbing via turbulence and (b) frequent water exchange and (c) copper/tin/silver materials selection increases the mean time period between maintenance visits. 
         [0143]    Although four square feet has previously been cited as the minimum acceptable reduction plate size, much larger reduction plate areas are needed for high quantity hydrogen production. 
         [0144]    Very large hydrogen generating vessels with large reduction plates are indicated. At a hydrogen generation rate of 1 liter per minute per square foot of reduction plate, it requires 53898 square feet of reduction plate to realize 1 billion cubic feet of hydrogen per year. At a hydrogen generation rate of 10 liters per minute per square foot of reduction plate, it requires 5389.8 square feet of reduction plate to realize 1 billion cubic feet of hydrogen per year.