Abstract:
This invention is directed to an integrated onboard hydrogen (H 2 ) production and utilization system for all watercraft, which yields environmentally benign vessel power production without new infrastructure requirements. Water (H 2 O) is supplied to a vessel, whether ashore, docked or underway, and is systematically converted into hydrogen and oxygen. The energy required for this process may be provided by any renewable or non-renewable source. The H 2  produced is either utilized at once or stored. Energy is released from the H 2  by one or more power plants.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on U.S. application Ser. No. 60/226,367, filed Aug. 18, 2000, the disclosure of which is incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the production and use of hydrogen onboard a marine vessel and, more particularly, to systems and methods to convert water supplied to a vessel into hydrogen (H 2 ) for later use as an energy carrier for vessel power or propulsion. 
     BACKGROUND OF THE INVENTION 
     Presently, the vast majority of marine vessels use onboard fossil fuel engines, such as diesel, fuel oil or gasoline for power and propulsion. These onboard fossil fuel propulsive systems and electrical generators are large sources of both air and water pollution. Existing fossil fuel technologies also generate noise pollution, vibrations and foul smells. Further, fuel quality and bacterial growth are problems for users of diesel and fuel oils, while explosions from trapped vapors concern operators of gasoline systems. 
     A need has arisen, therefore, for the development of alternative fuels which reduce or eliminate some of the problems associated with fossil-fuel technologies. There exist known technologies for reducing pollution, vibration and noise in land based vehicles, such as the use of gasoline or diesel-electric hybrid power systems, battery and fuel cell electric drives, metal hydride storage technologies, compressed natural gas, methanol, and hydrogen burning internal combustion engines. For example, a gas-hybrid system, in which H 2  is added to the fuel/air intake system or combustion chamber of a fossil fuel engine prior to combustion, can reduce polluting emissions. It is also known that a fuel cell power system consuming H 2  stored in a metal hydride tank can provide safe (relative to fire and explosion hazards), ecologically “clean” power. 
     However, while many developments in the “alternative” fuels industry are aimed at land based transportation systems, which reduce or eliminate some of the above referenced problems in land vehicles, these same technologies and systems show great promise for adaptation to the marine environment. For example, it is known that the most energy efficient, vibration free and quiet method of propelling a large marine vessel is via an electric motor. One additional advantage of some electric motors is that they may also be used as a generator to produce electrical energy. For example, on some gas turbine powered aircraft the starter motor reverts to a generator once the gas turbine engine has started. 
     For all of these systems, however, the single most significant obstacle facing implementation, with the exception of the gasoline-fueled hybrid, is the absence of a national retail “alternative” fueling infrastructure. Developing such an infrastructure would require a multi-billion dollar, decade-long commitment, and even with the advent of gasoline-fueled hybrids, the danger posed by explosion of vapors and the non-renewable nature of gasoline result in a less than optimum long term solution. 
     Thus, a further need has developed for a system which would reduce the polluting effects of fossil-fuel engines in maritime vessels, while also eliminating the need for a new refueling infrastructure. While presently it is known to desalinate and otherwise purify ocean or fresh water through reverse osmosis, for example, and to generate H 2  from that water by electrolysis, i.e., with electrical energy, and while it is also known that the most cost-effective and environmentally benign method of electrolysis uses electricity from renewable sources, such as solar (photo voltaic or PV), wind and water drag electricity generators; and while it is also known that electrical energy suitable for use in onboard electrolysis is also available from engine and auxiliary and shore power sources, these technologies have never been assembled onboard a marine vessel in such a way as to provide a ready source of energy for electrical power or propulsion without the need for the creation of a new external infrastructure. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention is directed to a system and method for producing and utilizing H 2  entirely onboard marine vessels eliminating the need for new refueling infrastructure. 
     In one embodiment, the system utilizes the H 2  produced by the invention as an energy carrier for propulsion and non-propulsion power requirements. In this system, H 2 O is obtained from the sea or other water source and then conducted to an onboard water purification device. The purified H 2 O is then converted via any efficient H 2 O to H 2  conversion device into hydrogen (H 2 ) and oxygen. The gaseous H 2  produced is either used directly by the onboard power plant(s) or stored. 
     In another embodiment, a method is provided so that the system may use electricity for H 2 O to H 2  conversion and other invention processes (e.g., water purification) from multiple renewable and non-renewable sources. 
     In another embodiment of the invention, the system eliminates the trapped vapor explosion danger of gasoline fueled power and propulsion systems by using solid state metal hydride tanking technologies for H 2  storage whenever possible. 
     In another illustrative embodiment of the present invention a system is provided to improve the efficiency of the system by recycling fuel cell waste heat and condensation of steam exhaust for re-use by the electrolysis components. 
     In yet another embodiment the invention is directed to a method for the production and utilization of H 2  onboard a marine vessel utilizing the systems described above. 
     Preferred examples of certain advantageous embodiments of the processes in accordance with the present invention are set forth in the accompanying illustrations and tables together with preferred embodiments of the specific elements of this invention required to properly carry out this invention. 
     In the illustrations and tables and in the following text describing the process and embodiments, the elements of the apparatus and the general features of the procedures are shown and described in relatively simplified and generally symbolic manner. Appropriate structural details and parameters for actual operation are available and known to those skilled in the art with respect to the conventional aspects of the process. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a process flow chart of the principal process methods and steps according to one embodiment of the invention. 
     FIG. 2 is a process flow chart of the principal process methods and steps according to another illustrative embodiment of the invention in which the primary means of H 2  energy conversion is provided by one or more fuel cells. 
     FIG. 3 is a process flow chart of the principal process methods and steps according to another illustrative embodiment of the invention in which H 2  energy conversion is provided by a H 2  consuming internal combustion engine which powers an electrical generator. 
     FIG. 4 is a process flow chart of the principal process methods and steps according to another illustrative embodiment of the invention in which H 2  energy conversion is provided by a H 2  consuming internal combustion engine which powers a mechanical means of power transmission to one or more propulsive systems. 
     FIG. 5 is a process flow chart of the principal process methods and steps according to another illustrative embodiment of the invention in which propulsive power is produced by a fossil fuel consuming internal combustion engine in which H 2  is added into the fuel/air intake system or combustion chamber prior to combustion. 
     FIG. 6 is a process flow chart of the principal process methods and steps according to another illustrative embodiment of the invention in which the primary means of H 2  energy conversion for non-propulsive power is provided by one or more fuel cells. 
     FIG. 7 is a process flow chart of the principal process methods and steps according to another illustrative embodiment of the invention in which the primary means of H 2  energy conversion for non-propulsive power is provided by a H 2  consuming internal combustion engine which powers an electrical generator. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to a system and method for the production and utilization of hydrogen gas (H 2 ) on-board a marine vessel. 
     One embodiment of the hydrogen production and utilization system  10  of the present invention is shown in FIG.  1 . Water is obtained from a water source  12 , e.g., sea, river, lake, estuary, municipal supply etc. Intake of water into the system may be accomplished via any standard method, such as, for example, via a standard seacock, hose attachment or other opening. In one embodiment the water supply is in fluid communication with a pre-filter  14  which filters the water, i.e., strains the water to remove debris. 
     The source water is then conducted to an additional onboard water purification device  16 , commonly called a “watermaker,” which is in fluid communication with the water supply  12 . The water purification device  16  further treats the water and then conducts the water to the water-to-hydrogen conversion device  18 . The amount of supplementary treatment is variable and based on specifications provided by the manufacturer of the water-to-hydrogen conversion device  18 . Some supplementary water treatments may include, for example, desalinization, demineralization, and/or deionization. Any suitable water purification device  16  may be utilized in the system, such as, for example, reverse osmosis, submerged tube, multiple effect, two stage and multi stage, and vacuum vapor compression types. The resulting water is referred to hereafter as “product water,” which is stored in a product water tank  20  in fluid communication with the water purification device  16 . Alternatively, pre-filtered and purified water could be introduced directly into the product water storage tank  20  through an external valve  15 . 
     The product water then passes into a water-to-hydrogen conversion device  18  and is converted via any efficient H 2 O-to-H 2  conversion technology into hydrogen and oxygen (O 2 ). Any suitable H 2 O to H 2  conversion technology may be utilized in the present system as a conversion device  18 , such as, for example, an electrolyzer (alkaline, polymer membrane, steam {using solid oxide electrolytes}, or any other method), a multiphoton photoelectrochemical device, a multiple-band-gap photoelectrochemical cell, or a photoelectrolysis device. A system may have one or more of the above devices and systems may include a mix of these technologies. 
     The gaseous H 2  produced by the conversion device  18  is either directly utilized by the onboard power plant(s)  22 , which is/are adapted to permit the H 2  gas to flow therein, or the H 2  gas is stored in a tank  24  for later use by the power plant(s)  22 , where the tank  24  is in fluid communication with the conversion device  18  and the power plant  22 . The H 2  can be either directly stored in the tank  24 , or it can be compressed by a compressor (not shown) and stored, or compressed, liquified via a liquification system (not shown), and stored as liquid hydrogen (LH 2 ) or “slush” in the onboard tank  24 . Storage tanks used may include any suitable technology, such as, for example, metal hydride tank technology, composite tank technology, vacuum insulated composite tank technology, carbon nanotubes, or any other efficient H 2 , LH 2 , or “slush” storage technology. Alternatively hydrogen gas could be introduced directly into the hydrogen storage tank  24  from an external source through a valve (not shown). 
     The oxygen produced during the H 2 O-to-H 2  conversion can be vented into the atmosphere or stored in an oxygen storage tank  26 . The stored oxygen can then be consumed to enhance the performance of the power plant(s)  22  or utilized for any other suitable purpose. The O 2  can be either directly stored in the tank  26 , or it can be compressed by a compressor (not shown) and stored, or compressed, liquified by a liquification system (not shown), and stored as liquid oxygen (LO 2 ) in the onboard tank  26 . Alternatively oxygen gas could be introduced directly into the oxygen storage tank  26  from an external source through a valve (not shown). 
     The electrical components of the system  10 , such as the water purification device  16  and the conversion device  18 , used in the H 2 O-to-H 2  conversion steps may be powered by one or more electrical source supplies  28  via a power distribution device  30 . The electrical source supply  28  can comprise any suitable technology, including, one or more of the following devices: solar electric systems (Photo Voltaic); solar furnace steam generators; wind generators; water drag generators (hydroelectric); human-powered generators (e.g., attached to an “exercycle”); electrical power from the vessel&#39;s main or auxiliary engines; nuclear power generators; or onshore electrical power (shore power or utility provided shore power). Conventional renewable energy sources, such as those listed above, generally generate low-voltage DC current. This power may not be directly suitable for use via the other components of the system, such as, for example, the conversion device  18  or the purification device  16 . In such cases a power conditioner (not shown) may be installed between the power source  28  and the distribution device  30 , between the distribution device  30  and at least one power utilizing component or may be included as an integral part of either the power source  28  or distribution device  30 . Any power conditioning device suitable for conditioning the power generated by the power source  28  for use by the other power consuming components of the system may be utilized, such as, for example, a step-up transformer and an AC inverter. 
     The energy supplied via the power plant(s)  22  and the electrical source supply  28  may be utilized immediately, either directly or after appropriate conditioning, or can be stored in an energy storage device  32  in electrical communication with the power distribution device  30 . The energy storage device  32  can utilize any known energy storage technology, such as, for example, commercially available deep-cycle marine batteries or other efficient electrical storage devices. There may be one or more of these energy storage devices  32 , or any other electrical energy storage technology in any embodiment of the invention. The energy storage device  32  can be utilized for buffer storage of electrical energy from the electrical source supply  28  and the energy stored therein may be used to provide power to the invention components (e.g., the water purification device  16  and the conversion device  18 ) and on-demand power for propulsion or other requirements via the power distribution device  30 . 
     The hydrogen produced in the conversion device  18  either directly or via a hydrogen storage device  24  passes into the power plant(s)  22  where it is suitably consumed and converted in utilizable energy. Any power plant  22  may be utilized which is capable of converting the energy potential of H 2  into mechanical or electrical energy for propulsion and or non-propulsion utilization onboard a marine vessel. Hydrogen use may include the addition of H 2  to the fuel/air intake system of any fossil fuel or alternative fuel power plant  22 , such as, gasoline, diesel, compressed natural gas, methanol, ethanol, etc. to improve performance and reduce undesirable emissions. 
     The power plants  22  contemplated for use under this invention include, but are not limited to: electrical power plants, such as a fuel cell or any direct or alternating current electrical motor whose power is provided by electricity created by a hydrogen consuming fuel cell; mechanical power plants, such as hydrogen or fossil fuel consuming or burning (“powered”) internal combustion piston engine, hydrogen or fossil fuel powered lean-burn spark-ignited engine, hydrogen or fossil fuel powered steam piston engine, hydrogen or fossil fuel powered steam turbine engine, hydrogen or fossil fuel powered gas (jet) turbine engine, hydrogen or fossil fuel powered rotary engine, and any other hydrogen or fossil fuel powered mechanical engines not listed; electrical/mechanical “hybrid” power plants, such as direct or alternating current electrical motors whose electricity is provided by a generator powered in turn by a hydrogen or fossil fuel consuming or burning mechanical power plant such as any of the ones listed above. 
     Propulsive power is provided to propellers, water-jets, inboard/outboard transmissive drives, or any other water propelling system  34 . There may be no propulsion system (as on a barge), or one or more such propulsion system in any example of the invention. These propulsive systems  34  can derive propulsive power from any of the power plants  22  described above. For example, electrical power plants  22  will derive propulsive power from the direct conversion of H 2  by a fuel cell into electricity which in turn will power an electric propulsive system  34  (e.g., electrical motor). The available electrical energy may be fed directly to the electrical propulsive system  34  from the power plant  22  via the power distribution device  30  or may be fed to the propulsive system  34  from a energy storage device  32  such as a battery or set of batteries via the power distribution device  30 . 
     Mechanical power plants  22  will either directly drive propulsive systems  34  or by way of transmissions (not shown). The power will come from conversion of fuel energy into mechanical energy and then into propulsive energy. 
     Electrical/mechanical (hybrid) power plants  22  derive propulsive power from the conversion of H 2  into mechanical energy by a “mechanical” power plant  22  which consumes H 2 . This power plant in turn will drive a generator (not shown) creating either alternating current or direct current electrical energy which in turn is consumed by an electric propulsive system  34  (e.g., electrical motor) via the power distribution device  30  to move the vessel. 
     Schematics of several alternative embodiments of the above inventive system and method are depicted in FIGS. 2 to  7 . 
     FIG. 2 shows a schematic representation of an alternative embodiment of the system and method of arrangement as described above in a typical sail or power vessel whose primary means of H 2  energy conversion is provided by one or more fuel cell power plants  22  in electrical communication with the power distribution device  30 . In this alternative embodiment, waste heat and water vapor exhausting from the fuel cell power plant(s)  22  are recycled via a heat exchanger  36  to reduce the energy required to produce additional product water and or heat other shipboard water (shower, sink, etc.) or for any other purpose requiring heat including, but not limited to, heating and ventilation, metal hydride H 2  storage tank(s) disassociation or steam needed for steam electrolysis. 
     Any fuel cell power plant  22  configuration may feature a “closed H 2 O loop” system, as shown in FIG. 2, in which the fuel cell “exhaust” (steam H 2 O vapor) is re-condensed into product H 2 O for the H 2 O-to-H 2  conversion device  18  and waste heat is captured in a heat exchanger  36  for useful work. In this closed loop system, product H 2 O is converted into H 2  and O 2  in the conversion device  18 , the H 2  is then either stored in a hydrogen storage device  24  and consumed by the fuel cell power plant  22  or directly consumed by the fuel cell power plant  22 . During consumption by the fuel cell power plant  22 , the H 2  is combined with O 2  to make H 2 O vapor in the form of steam. This steam is then condensed into liquid H 2 O in the heat exchanger  36  and the process is begun again. 
     FIG. 3 shows a schematic representation of the invention components and method of arrangement in a typical sail or power vessel whose primary means of H 2  energy conversion is provided by a H 2  consuming internal combustion engine power plant  22  which powers an electrical generator  38  in electrical communication with the power distribution device  30 . This configuration also illustrates a fuel cell power plant  22   a  in use as an auxiliary source of ship power for non-propulsive requirements in electrical communication with the power distribution device  30  and a heat exchanger  36  to provide a “closed H 2 O loop” system. 
     FIG. 4 shows a schematic representation of the invention components and method of arrangement in a typical sail or power vessel whose primary means of H 2  energy conversion is provided by a H 2  consuming internal combustion engine power plant  22  which powers an alternator  39  in electrical communication with the power distribution device  30  and a mechanical means of power transmission to one or more propulsive systems  34 . This configuration also illustrates a fuel cell power plant  22   a  in use as an auxiliary source of ship power for non-propulsive requirements in electrical communication with the power distribution device  30  and a heat exchanger  36  to provide a “closed H 2 O loop” system. 
     FIG. 5 shows a schematic representation of the invention components and method of arrangement in a typical sail or power vessel whose primary means of power to the propulsive system  34  is produced by a fossil fuel consuming internal combustion engine power plant  22  in mechanical communication with the propulsive system  34 . The fossil fuel is supplied by a separate fuel tank  40  in fluid communication with the internal combustion engine power plant  22 . The internal combustion engine power plant also powers an alternator  39  in electrical communication with the power distribution device  30 . This embodiment reduces the polluting emissions from the internal combustion engine power plant  22  by the addition of H 2  into the fuel/air intake system or combustion chamber of the power plant  22  prior to combustion. The power plant  22  fuel/air intake system and mechanical power transmission system are not a part of the present invention and thus omitted for clarity. This configuration also illustrates a fuel cell power plant  22   a  in use as an auxiliary source of ship power for non-propulsive requirements in electrical communication with the power distribution device  30  and a heat exchanger  36  to provide a “closed H 2 O loop” system. 
     FIG. 6 shows a schematic representation of the invention components and method of arrangement in a typical sail or power vessel whose primary means of H 2  energy conversion for non-propulsive power is provided by one or more fuel cell power plant(s)  22  in electrical communication with the power distribution device  30 . 
     FIG. 7 shows a schematic representation of the invention components and method of arrangement in a typical sail or power vessel whose primary means of H 2  energy conversion for non-propulsive power is provided by a H 2  consuming internal combustion engine power plant  22  which powers an electrical generator  38  in electrical communication with the power distribution device  30 . 
     While any of the above embodiments might be utilized in the present invention, a preferred embodiment is based on the embodiment shown in FIG. 2, in which a fuel cell power plant  22  is utilized, in a sailing vessel, with several modifications. Metal hydride hydrogen storage tank(s)  24  would be used to store the H 2  thus reducing tank storage volume and the need for a compressor. The electrical source supply  28  would comprise a mixture of on-board water drag, solar power and wind power generators. Preferably, this vessel would also feature a “dual mode” electrolysis H 2 O-to-H 2  conversion device  18  to allow for efficient low power conversion (while underway) and high power conversion (when connected to shore power) operation. 
     Most current water drag generators are single purpose stand alone systems. The go water drag generators utilized in the electrical source supply  28  of the preferred embodiment, would preferably use electric motors in the dual role of propulsive power source and water drag generator. This reduces the total number of components onboard, increases the electrical output of the water drag generator, simplifies operation and reduces system cost. However, the invention also anticipates some applications where single purpose water drag generators are the preferred configuration and anticipates the optimization and improvement of such single purpose components. 
     The photo voltaic (PV) solar panels of the electrical source supply  28  of the preferred embodiment, can either be “built in” to marine vessels or added as “after market” items mounted in the “least inconvenient” manner. For example, PV systems can be mounted along the hull, masts, windows or portholes, superstructure, deck, and, even in “hard sails” and incorporated into sail cloth. These marine “solar arrays” could also be constructed in a manner similar to those on spacecraft. Most preferably, the current embodiment would make extensive use of “built in” solar power. In this example, photo voltaic materials would be installed along the hull, on the mast, on deck, and built into the sails. 
     The wind generators of the electrical power supply source  28  would mount on mizzen masts if available. If not, to increase their output, telescoping poles would mount on the vessel&#39;s after rails. These poles would extend upward and aft exposing the wind generators to the greater amounts of potential wind energy available with increasing height above the water and clear of the ship&#39;s rigging by means of their rearward orientation. 
     The data in Table 1 reflects the operating characteristics of a re-fit 30′ long sailboat using H 2  compressed to 5000 psi and commercially available non-optimized components. It is assumed by this example that the original configuration offered an internal combustion engine of approximately 25 horsepower mounted internally to the hull. Fuel tank capacity is limited in this example to the volumetric equivalent of 100 gallons. It is assumed that a 20 kW fuel cell is onboard. Fuel cell efficiency is conservatively estimated at 50% when it may be much higher. 
     If the vessel were a new build, even using compressed H 2 , one could store more than the 100 gallons illustrated herein and increase the useful range. 
     By changing the storage technology to metal hydrides, current metal hydride tank technology would reduce the required volume for the same amount of H 2  by weight by 50%. Using metal hydride tanks would also reduce the energy required to compress the H 2 . This would reduced the kW of energy per hour of production from the illustrated figure of 7.5 kW to approximately 2-3 kW per hour of electrolysis. However, using a metal hydride tank technology would increase system weight and complexity since a source of heat energy is required by metal hydrides to disassociate hydrogen for use. The use of metal hydrides may also require a small tank of compressed H 2  for immediate fuel cell or other power plant use. 
     
       
         
               
             
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Operational Parameters for 30′ Sailboat 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Amount of Product Water Consumed 
               
               
                   
                 456.00 L 
               
               
                   
                 Hours of RO Watermaker Operation to Purify Water 
               
               
                   
                 35.43 hrs. 
               
               
                   
                 RO Watermaker Energy Use 
               
               
                   
                 3.40 kW 
               
               
                   
                 Rate of H 2  Production/hour 
               
               
                   
                 40 Standard Cubic Feet 
               
               
                   
                 Time to Fill Tank 
               
               
                   
                 114 hrs. 
               
               
                   
                 Energy Required to Fill Tank 
               
               
                   
                 852 kW @ 7.5 kW/hr 
               
               
                   
                 Fuel Cell Power Conversion of Stored H 2   
               
               
                   
                 193 kW 
               
               
                   
                 Running Time Provided by Stored H 2   
               
               
                   
                 10 hrs @ 18.64 kW/hr usage 
               
               
                   
                 Speed Through Water @ Maximum Load 
               
               
                   
                 5.5 knots 
               
               
                   
                 Range Provided by Stored H 2  @ Maximum Load 
               
               
                   
                 57 nautical miles 
               
               
                   
                   
               
             
          
         
       
     
     In an additional preferred embodiment, a power boat or ship would be based on the embodiment illustrated in FIG. 2, utilizing a fuel cell power plant  22 , with several modifications. Metal hydride hydrogen storage tank(s)  24  would be used to store the H 2  thus reducing tank storage volume and the need for a compressor. Instead of a single purpose motor and separate water drag generator for use as an electrical supply source  28 , as previously mentioned, a dual use motor/water drag generator electrical supply source  28  would be employed. The preferred embodiment would also make extensive use of “built in” solar power and wind power electrical supply sources  28 . Photo voltaic materials would be installed along the hull, on the superstructure, on the mast(s), on deck, and covering windows or portholes with transparent PV film materials. The wind generators would mount on radar masts if available, and possibly embedded in the superstructure for efficient high speed use. This vessel would also feature a “dual mode” H 2 O-to-H 2  conversion device  18  to allow for efficient low power conversion (while underway) and high power conversion (when connected to shore power) operation. 
     The data in Table 2 reflects the operating characteristics of a new build, 30′ long, hydrodynamically efficient, high speed powerboat using H 2  compressed to 5000 psi and commercially available non-optimized components. It is assumed by this example that a fossil fueled version would require 550 horsepower mounted internally to the hull. Fuel tank capacity is limited in this example to the volumetric equivalent of 1,250 gallons. It is assumed that a 410 kW fuel cell is onboard. Fuel cell efficiency is conservatively estimated at 50% when it may be much higher. 
     By changing the storage technology to metal hydrides, current metal hydride tank technology would reduce the required volume for the same amount of H 2  by weight by 50%. Using metal hydride tanks would also reduce the energy required to compress the H 2  this would reduced the kW of energy per hour of production from the illustrated figure of 30 kW to approximately 8-12 kW per hour of electrolysis. However, as discussed previously, using a metal hydride tank technology would increase system weight and complexity by requiring an additional source of heat energy and potentially a small tank of compressed H 2  for immediate use. 
     It is expected that this invention will also be used as a source of non-propulsion power both in conjunction with its use for propulsive power and alone as a Ship Service Generator (SSG) supplying the needs of traditional “Hotel Loads” and other onboard power requirements. 
     
       
         
               
             
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Operational Parameters for 30′ Powerboat 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Amount of Product Water Consumed 
               
               
                   
                 1,420 L 
               
               
                   
                 Hours of RO Watermaker Operation to Purify Water 
               
               
                   
                 110 hrs. 
               
               
                   
                 RO Watermaker Energy Use 
               
               
                   
                 10.59 kW 
               
               
                   
                 Rate of H 2  Production/hour 
               
               
                   
                 160 Standard Cubic Feet 
               
               
                   
                 Time to Fill Tank 
               
               
                   
                 355 hrs. 
               
               
                   
                 Energy Required to Fill Tank 
               
               
                   
                 10,654 kW @ 7.5 kW/hr 
               
               
                   
                 Fuel Cell Power Conversion of Stored H 2   
               
               
                   
                 2,415 kW 
               
               
                   
                 Running Time Provided by Stored H 2   
               
               
                   
                 6 hrs @ 410 kW/hr usage 
               
               
                   
                 Speed Through Water @ Maximum Load 
               
               
                   
                 35 knots 
               
               
                   
                 Range Provided by Stored H 2  @ Maximum Load 
               
               
                   
                 206 nautical miles 
               
               
                   
                   
               
             
          
         
       
     
     The data in Table 3 reflects the operating characteristics of a Ship Service Generator system sized for a 30′ long boat using H 2  compressed to 5000 psi and commercially available non-optimized components. It is assumed by this example that a 2 kW capacity for non-propulsion use is adequate. Fuel tank capacity is limited in this example to the volumetric equivalent of 20 gallons. It is assumed that a 20 kW fuel cell is onboard. Fuel cell efficiency is conservatively estimated at 70%. 
     
       
         
               
             
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                 Operation Parameters for SSG on 30′ Boat 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Amount of Product Water Consumed 
               
               
                   
                 92 L 
               
               
                   
                 Hours of RO Watermaker Operation to Purify Water 
               
               
                   
                 7.15 hrs. 
               
               
                   
                 RO Watermaker Energy Use 
               
               
                   
                 0.69 kW 
               
               
                   
                 Hydrogen (H 2 ) Tank Size 
               
               
                   
                 20 gal 
               
               
                   
                 Capacity @ 5,000 psi. 
               
               
                   
                 25,754 L 
               
               
                   
                 Rate of H 2  Production/hour 
               
               
                   
                 1132 L 
               
               
                   
                 Time to Fill Tank 
               
               
                   
                 23 hrs. 
               
               
                   
                 Energy Required to Fill Tank 
               
               
                   
                 170 kW @ 7.5 kW/hr 
               
               
                   
                 Fuel Cell Power Conversion of Stored H 2   
               
               
                   
                 54 kwh 
               
               
                   
                 Running Time Provided by Stored H 2   
               
               
                   
                 27 hrs @ 2 kwh/hr usage 
               
               
                   
                   
               
             
          
         
       
     
     As discussed above, using metal hydride tanks would also reduce the energy required to compress the H 2  this would reduced the kW of energy per hour of production from the illustrated figure of 7.5 kW to approximately 2-3 kW per hour of electrolysis. However, as discussed previously, using a metal hydride tank technology would increase system weight and complexity by requiring an additional source of heat energy and potentially a small tank of compressed H 2  for immediate use. 
     An illustrative example of the average non-propulsive energy usage and production for a 30′ sailboat at anchor and underway is shown in Table 4, below. It will be realized that these values are only meant to be a rough calculation for a standard vessel containing the equipment listed and is not meant to confine the scope of the current invention in anyway. One skilled in the art would be able to calculate a similar power usage chart for any vessel using the method shown. 
     
       
         
               
             
               
               
               
               
             
               
               
               
               
             
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
             
             
               
                 Schedule of Power Consumption and Onboard Production 
               
               
                 for a 30′ Sailboat 
               
               
                 Onboard Power Consumption 
               
             
          
           
               
                   
                 Current in 
                 Hours of 
                 Total Amp 
               
               
                 Equipment 
                 Amps 
                 use/day 
                 Hrs./Day 
               
               
                   
               
               
                 Anchor light 
                 1 
                 10 
                 10 
               
               
                 Tri-color masthead 
                 1.5 
                 10 
                 15 
               
               
                 Running lights 
                 2 
                 10 
                 20 
               
               
                 Bilge pump 
                 5 
                 0.25 
                 1.25 
               
               
                 VHF - receive 
                 0.5 
                 1 
                 0.5 
               
               
                 VHF - transmit 
                 4.5 
                 0.07 
                 0.315 
               
               
                 Loran C 
                 1.5 
                 3 
                 4.5 
               
               
                 Radar 
                 12 
                 2 
                 24 
               
               
                 SSB radio - receive 
                 0.1 
                 4 
                 0.4 
               
               
                 SSB radio - transmit 
                 12 
                 0.07 
                 0.84 
               
               
                 Depth sounder 
                 0.4 
                 1.5 
                 0.6 
               
               
                 Autopilot 
                 1 
                 24 
                 24 
               
               
                 Anchor windlass 
                 20 
                 0.06 
                 1.2 
               
               
                 Cabin light 15 w 
                 1.25 
                 5 
                 6.25 
               
               
                 Cabin light 25 w 
                 2.1 
                 3 
                 6.3 
               
               
                 Marine stereo 
                 2.5 
                 2 
                 5 
               
               
                 Pressure water 
                 2.8 
                 0.34 
                 0.952 
               
               
                 Electric refrigerator 
                 6 
                 12 
                 72 
               
               
                 Microwave* 
                 50 
                 0.3 
                 15 
               
               
                 Coffee maker* 
                 42 
                 0.04 
                 1.68 
               
               
                 Hair dryer 750 w* 
                 63 
                 0.04 
                 2.52 
               
               
                 Blender* 
                 63 
                 0.01 
                 0.63 
               
               
                 Food processor* 
                 34 
                 0.02 
                 0.68 
               
               
                 Color TV (9″)* 
                 5 
                 2 
                 10 
               
               
                 Color TV (19″)* 
                 8.25 
                 2 
                 16.5 
               
               
                 VCR* 
                 1.75 
                 2 
                 3.5 
               
               
                 ¼″ drill* 
                 12 
                 0.1 
                 1.2 
               
               
                 750 CFM fan* 
                 1.1 
                 3 
                 3.3 
               
               
                 PC computer* 
                 5.8 
                 1 
                 5.8 
               
               
                 Watermaker 
                 8 
                 3 
                 24 
               
               
                 Electrolyser 7.5 kW 
                 500 
                 24 
                 12000 
               
               
                 (May require an AC inverter) 
               
               
                   
               
             
          
           
               
                   
                 Total Energy Use/day: 
                  12,277.9 Amp Hrs. 
                 147.3 kWH 
               
               
                   
                 Electrolyser Power Use: 
                 12,000.00 Amp Hrs. 
                 144.0 kWH 
               
               
                   
                 Other Power Use: 
                    277.9 Amp Hrs. 
                  3.3 kWH 
               
               
                   
                   
               
             
          
           
               
                   
                 Onboard Power Production 
                 Onboard Power Production 
               
               
                   
                 Anchored 
                 Underway 
               
               
                   
                   
               
             
          
           
               
                 Solar Panels 
                 1.2 kWH 
                 Solar Panels 
                 1.2 kWH 
               
               
                 (4 × 120 W) 
                   
                 (4 × 120 W) 
               
               
                 Wind Power 
                 2.8 kWH 
                 Wind Power 
                 1.4 kWH 
               
               
                 (2 × 7.6 A @ 15 knots) 
                   
                 (2 × 7.6 A @ 15) 
               
               
                 1 A/knot Water Drag 
                   0 kWH 
                 1 A/knot Water Drag 
                 1.8 kWH 
               
               
                 Total Production 
                 4.0 kWH 
                 Total Production 
                 4.0 kWH 
               
               
                 Standard Hotel Load 
                 3.3 kWH 
                 Standard Hotel Load 
                 3.3 kWH 
               
               
                 Excess Production 
                 0.7 kWH 
                 Excess Production 
                 1.1 kWH 
               
               
                   
               
             
          
         
       
     
     For clarity and simplicity the present invention is described in the above example with a proton exchange membrane (PEM) fuel cell in every instance. The invention may make use of any H 2  consuming fuel cell technology. 
     Further, for clarity and simplicity the present invention is described with commercially available water conversion components. It is anticipated by the present invention that water conversion technology will continue to improve and that suppliers will offer technologies optimized for use in the present invention. Specifically, the invention anticipates the advent of highly efficient steam electrolysis water conversion systems and low power electrolysis water conversion systems which are optimized for use with renewable energy supply sources. The invention anticipates that some configurations may use dual mode or more than one conversion device or technology: one for low power and low rates of production, the other for use with shore power and offering higher rates of production. 
     Further yet, for clarity and simplicity the present invention is described with commercially available renewable energy supply sources. However, it is anticipated that significant improvements will be forthcoming in the key renewable electrical production technologies which will improve the practicality, cost effectiveness and total system efficiency of the present invention. 
     For the purposes of clarity, these examples only illustrate hydrogen production with electrical energy provided by utility shore power. A unique feature of this invention is the ability to partially replenish expended H 2  or LH 2  or “slush” supplies while underway. Sailboats or motor-sail boats and sailing ships could produce more “slush,” H 2  or LH 2  than consumed if traveling in sunny and windy conditions. H 2  can also be produced exclusively by using renewable energy systems or in combination with energy provided by these renewable components, which would reduce the cost of such H 2  accordingly. This is accomplished by operation of the conversion equipment while at anchor or while tied to a dock (with or without shore power) using the power supplied by the electrical supply source(s). It should also be noted that the actual range of any vessel equipped with the present invention would be extended to the extent that the renewable electrical supply source while underway provides for the non-propulsion requirements of the vessel avoiding the consumption of H 2  for that purpose. 
     The examples set out in this application are merely illustrative, other uses will become obvious to one of skill in the art after reviewing this disclosure. This system may be utilized on any potential maritime vessel including: government vessels, such as military watercraft, submarines, oceanic research vessels, law enforcement vessels, search &amp; rescue vessels, harbor pilot ships, environmental clean-up boats/ships, etc.; commercial vessels, such as passenger transports, water bus/tax, cruise ships, ferries, charter boats, scenic vessels, party boats, scuba-diving boats, cargo transports, container ships, coastal freighters, auto carriers, oil and other bulk carriers, tugs, oil rig work/support boats, fishing vessels and support (processing and factory) ships, etc.; recreational boats, such as power boats 15 feet and greater, small watercraft less than 15 feet (JetSkis, SeaDoo, etc.), sail boats, etc.; and all other sea, lake and river marine vehicles. 
     The elements of the apparatus and the general features of the components are shown and described in relatively simplified and generally symbolic manner. Appropriate structural details and parameters for actual operation are available and known to those skilled in the art with respect to the conventional aspects of the process.