Concept of Operations

 

After an extensive comparison of all potential configurations available, the 64 barge configuration shown below proved to be the most effective and yielded the highest return on investment.  We also seriously considered a 96 barge configuration in a 6 x 16 arrangement because it offered more interior (productive) barges and offered efficiencies in staffing.  However, after taking into consideration the 1/6th reduction in overall productivity due to the shadowing (dampening) of the wave energy with the six wide configurations, the four wide, 64 barge configuration was selected.  That analysis also verified that the production of gasoline was more profitable and exploited a larger and more mature market than would be the case if methanol were the primary product.  This document outlines the operational characteristics of that configuration.


The barge fleet would be comprised of 64 barges in a 4 x 16 array as depicted in the schematic below.  At opposite corners are the two type 1 delivery barges (blue).  Next to the delivery barges are the two type 3 holding barges (green).  The other four end barges are the type 2 production barges (purple).  The fourteen rows in between the two ends would be comprised of four wide type 4 worker barges (white).







The two type 1 barges would be double hulled, since they would be the only barges to transport the gasoline cargo.  They would also have crew quarters, and the navigation & communications equipment.  In addition to generating electricity, these barges would be used for dynamic positioning, to supervise the fleet, and to ferry the gasoline cargo to shore.   The double-hull acts as below deck tankage for fresh water, as well as fulfilling current shipping safety requirements.  Propulsion for the type 1 barges would be provided by two 1,500 kW articulating thrusters.  Unlike the other powered barges at both ends of the fleet, the type 1 barges would have a 3,000 kW diesel generator to provide electricity to the two thrusters when the type 1 barge was making a delivery to port. A total of $3,480,000 has been budgeted for each type 1 barge.  Of that total, $2,310,000 is for the double hull barge; $400,000 is for the propulsion system; $470,000 is for tanks, crew quarters & controls; $260,000 is for the hydraulic & electrical system; and $40,000 is for the pumping equipment. 


The drawing below shows a type 1 delivery barge.  All of the barges in the fleet are built on the same 50’x 200’x 13’ dimensions used by McDonough Marine for one of their standard ocean going barges.  All of the other barges look basically the same without all of the components shown on the type 1 barge below:




















After the type 1 barge has discharged its 450,000 gallons of gasoline, from its three 150,000 gallon above deck tanks, its below deck tank would be filled with 625,000 gallons of fresh water to be transported back to the fleet.  The fresh water in the below deck tank also acts as a ballast and the weight of the barge is maintained by replacing the gasoline cargo discharged at port from its above deck tanks with fresh water into its below deck tank.  When attached to the fleet this balance is maintained by pumping the below deck fresh water into the type 2  and type 3 barges to compensate for the increasing gasoline cargo in its above deck tanks.


The type 1 barge also has an automated system on its bow and starboard side for docking with the two barges which it connects to at the corner of the fleet.  The type 1 barges are powered by two outboard electrical engines which operate on power from the fleet’s central power bus while they are attached to the fleet for repositioning, and powered by diesel driven generators when traveling to and from port.  Each type 1 barge has a four-person crew.  An additional two crew members are assigned to each end of the fleet to supervise general maintenance and maintain the production equipment on the barges at their end of the fleet.  These mechanics stay with the fleet at all times and are quartered in the two-person crew quarters aboard the type 3 holding barge.


There are two type 2 production barges located at each end of the fleet.  Each of these barges has dual electrical engines just like the ones on the type 1 barges, however, these engines do not have gasoline powered generators, since they always remain with the fleet.  The four type 2 barges produce electrical power, as do all of the other barges in the fleet.  However, these barges draw power from the central electrical bus and use that power to produce liquid methanol.  Although the production barges are single hulled they use their single hull as a below deck tank to store water for the production of hydrogen and methanol.  This fresh water comes from the shore aboard the type 1 barges and also from the reclamation of water from the methanol and gasoline production process.  The production equipment aboard each of the four type 2 barges is designed to be able to handle the production of methanol from the electricity generated by sixteen barges.  A total of $4,072,000 is budgeted for each of the four type 2 barges.  Of that amount, $1,732,000 is for the single hull barge; $200,000 is for the propulsion system; $260,000 is for hydraulic & electrical equipment; $40,000 is for pumping equipment; $1,440,000 is for electrolyzing equipment & caustic air scrubbers; and $400,000 is for the catalytic converters.


Since the type 2 barges draw electricity from the central power bus, they maximize the efficiency of the overall system, drawing power from those barges producing the most current and sharing it among the four production barges.  Centralizing the production function insures that maximum capacity is available at all times.  Centralization also reduces capital costs and makes supervision and maintenance of the production equipment much more efficient.  Having the power for dynamic positioning and crew requirements drawn directly from the power bus also increases efficiency and reduces the need to convert this electricity to methanol.  Once the methanol is produced aboard the type 2 barges it is pumped directly to the type 3 barge at the same end of the fleet, where it is converted into gasoline and temporarily stored.


There are two type 3 holding barges, they are located between the type 1 delivery barge and the type 2 production barges at each end of the fleet.  Like the type 2 barges, the type 3 barges have duel electrical engines which are powered from the central power bus.  They also have single hulls and use that hull to store fresh water to be used for methanol production aboard the type 2 barges.  The type 3 barge has one 150,000 gallon, above deck  storage tank to store gasoline when the type 1 barge is away making a delivery to port.  It is also aboard the type 3 barge that the liquid methanol produced on the type 2 barges is converted to gasoline by an on-board catalytic dehydrator.  The type 3 barge also has crew quarters for the two mechanics who stay on-board at that end of the fleet while the type 1 barge is away.  A total of $2,532,000 has been budgeted for each of the type 3 barges.  Of that amount, $1,732,000 is for the single hull barge, $200,000 is for the two electrical engines, $200,000 is for the above deck storage tank & mechanics crew quarters, $260,000 is for the hydraulic & electrical equipment, and $140,000 is for the catalytic dehydrator & pumping equipment.


The remaining fifty-six barges are type 4 worker barges.  These barges have only the hydraulic connectors and generators aboard to feed generated electricity into the central power bus.  These barges do not have any liquid aboard, although the single hulls of the end units could be used for below deck storage for fresh water.  The ten thousand square foot decks of each type 4 barge could also be used for collection of fresh water when it was raining.  Two of the outside end units of the 4 x 14 array of type 4 barges would require mating couplers to facilitate the automatic docking of the type 1 barges.  The remainder of the type 4 barges would have simplified coupling equipment, since they would only be uncoupled for repair or reconfiguration.  A total of $1,992,000 has been budgeted for each of the type 4 barges.  Of this amount, $1,732,000 is for the single hull barge and $260,000 is for the hydraulic & electrical equipment.  The price of the single hull barge is estimated to be 75% of the cost estimated by the marine engineering firm of Glosten & Associates for a double hull barge.


The engines aboard all of the end vessels, as well as the central stiffness controls, are controlled from the bridge of the designated type 1 barge.  Most of the time that control shifts from one end of the fleet to the other on a scheduled basis.  When one of the type 1 barges is away from the fleet, the other controls all these functions.


The barge fleet would be positioned, repositioned, and rotated by the four powered barges at each end of the fleet.  All major movements would be made with all eight of the powered barges in place. Since the delivery of gasoline would be alternated between the type 1 barges the one making the delivery would only be absent from the fleet for a few days.  Most of time, both  type 1 barges would be in place.  Given the production and storage capacity of the barges, only 15 deliveries would be required per year.  These deliveries would be staggered so that only one type 1 delivery barge would be absent form the fleet at any one time.  Water reclaimed by the dehydration of the methanol into gasoline aboard the type 3 barges would be pumped back into the below deck storage tanks on the type 2 barges.  The catalytic dehydrators aboard the type 3 barges would be rated to handle the maximum volume of methanol from the type 2 barges, which is estimated to be 30 gallons per minute.


For a more technical description of the mechanical, chemical, and electrical aspects of our Orca Wave Energy System visit the Technical Summary section on this site.