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Turning the oceans into jetfuel

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  • Turning the oceans into jetfuel

    The US Navy has a problem. Its ships often stay at sea for months on end far away from home. To keep its fleet of ships, boats and aircraft running, a fleet of 15 oil tankers roams the globe acting like floating gas stations. According to the Naval Research Laboratory (NRL) nearly 600 million gallons (2,700 million litres) of fuel were delivered to Navy vessels in 2011.

    Moving those tanks of oil is an expensive business and that is even before the cost of the oil itself is factored in. Over recent years, the price of oil has fluctuated wildly, but has generally been on an upward trend. Throw in the fact that many of the large oil-producing nations are generally situated in volatile regions of the world, and you begin to understand why the Navy is interested in cutting its dependence on oil.

    One of the most interesting lines it is pursuing is a plan to generate jet fuel from a source that is abundance wherever the fleet is: seawater.

    Jet fuel, along with all other common fuels, is a hydrocarbon. As the name suggests, these are chains of hydrogen and carbon atoms. In theory if you can combine those two elements in the correct way you can produce a fuel. It turns out that seawater is a good source of both ingredients – it contains hydrogen in the H20, and a lot of dissolved carbon dioxide (CO2). It also has the advantage of occurring in abundance - and for the Navy - close to the action.

    “The ocean contains about 100mg per litre of CO2,” explains the NRL’s Dr Heather Willauer. “It’s about 140 times more concentrated in sea water than it is in the air.”

    Dr Willauer has developed a machine to grab those raw ingredients directly from sea. “We have an electrochemical unit. We feed it seawater, we acidify the seawater, and what comes out of the cell is oxygen, CO2, and hydrogen,” she says.

    The oxygen is released, and the other two gasses are combined to make a liquid fuel.

    “You take those components (CO2 and hydrogen), and use a catalytic process, for a gas to liquid type reaction,” she adds. The basics are similar to the descriptions of a process for converting water and air into petrol, that grabbed headlines last week.

    If both sound too good to be true, then you would be right. There is a catch. According to the first law of thermodynamics, nothing comes for free. To get useful energy out, you need to put useful energy in to the system. It is like combustion in reverse. Energy is needed to break the water and the carbon dioxide down into constituent parts and then more energy – and time – is needed to form the hydrocarbon.

    “We do have to have a power source to supply the electricity for the electrochemical process,” admits Dr Willauer. That could come from solar or – more likely - the nuclear reactors already onboard many ships.

    The system would also only have marginal environmental benefits. It would reduce the burden of moving fuel around, but that may be offset by the production process. And, in the end, it would still produce traditional fuel with its associated emissions when burnt. For the Navy, this is more about convenience.

    ‘Chicken power’

    At the moment a 1.5mx1.5m (5ftx5ft) prototype is installed onshore at an NRL engineering facility in Key West, Florida. It has been using seawater from the Gulf of Mexico to test the conversion process and is now focused on optimising the technology and scaling it up. They are also beginning to think about the engineering challenges of putting a system to sea.

    “Because we are developing technologies to potentially be used by the Navy, that goes into the technology when we develop it,” says Dr Willauer. “We want to make sure it has as small a footprint, and a small a size as possible, and keep those constraints in mind.”

    The team is also willing to stick its neck out and predict a cost for jet fuel produced by the process of $3 to $6 per gallon.

    If they were able to keep to that cost – and there are plenty of people who think that the real cost would be much higher – it would give it the edge over another fuel the Navy is currently experimenting with.

    Earlier this summer, the Navy ran its first large-scale exercise fuelled by a $12m blend of biofuels produced from everything from chicken bones to algae. The Pacific demonstration was part of a project known as Great Green Fleet. During the manoeuvres, F/A-18 Super Hornets and other aircraft screamed off the flight deck of the USS Nimitz over the Pacific Ocean powered by conventional jet fuel mixed with the biofuels. Two destroyers and a cruiser also ploughed the oceans fuelled by a similar mix.

    All went well with the exercise, until the costs came in. The biofuel mix cost around $26 per gallon ($6 per litre), significantly more than the $3.50 per gallon ($1 per litre) paid for regular fuel. Critics pointed out that the Navy’s job was defending the US, not helping the emerging biofuel industry bring down its costs, a point that has been compounded by looming defence cuts. For now, the Navy is continuing with its vision and has reiterated its commitment to have half of its fleet powered by alternative energy sources by 2020.

    But don’t expect that fleet to be accompanied by refueling ships, sucking in seawater. That research is far behind the biofuel work. It will take six to eight years for the NRL to fully develop the seawater idea, depending on funding. And then it will take many more years to build working systems. By then, the Great Green Fleet may have already sailed.

    BBC - Future - Science & Environment - Turning the oceans into jetfuel

  • #2
    It's interesting, but there's nothing particularly exotic about the concept. The problem will forever be the enormous amount of energy needed to create the fuel, and the only real solution would be a large, floating nuclear reactor. Solar would probably require a supertanker-sized field of cells to get a trickle of fuel flowing.

    In theory, you don't need the liquid fuel except for the jets. You could simply crack water into hydrogen and oxygen, and use those gases to fire the steam boilers of a traditional ship. But liquids are far more storable and transferable.


    • #3
      The back end of this electric powered process (see below) is similar to Fischer-Tropsch conversion of coal to fuel oil, and the processing plants used for Fischer-Tropsch conversion were not small. I have to think an apparatus capable of providing an adequate supply of fuel oil for ships in a CSG and JP5 for the aircraft would also not be very small.

      The Ford class does have a large capacity nuclear-electric power plant. But CVNs are narrowly focused on aviation. The Ford class doesn't have big islands for big radar, and likewise doesn't have big guns or a large array of VLS. Other ships in the CSG provide the capabilities not provided in the CVN. I don't think they would trade away some aviation capacity on a CVN to gain a JP5 / fuel oil synthesizer with a large volume space claim.

      They do want big radar in the CSG, and are looking at putting 12-foot to 14-foor AMDR on a future flight of A-B DDGs. Radar sensitivity is proportional to the cube of the aperture size, 3x increase in aperture is 27x increase in sensitivity. AMDR could scale up to 36-foot aperture, but they don't have a big hull available in the CSG to support that, and are not going to put big radar on the CVN.

      If shipboard fuel oil synthesis proves viable, I think that processing plant would be a capability provided by another ship in the CSG, with the CVN remaining focused on aviation. That ship could not only provide JP5 to the CVN for aviation, but also could serve as an oiler for the other ships in the CSG. If it is going to be a large ship with a nuclear electric plant for propulsion and for synthesizing fuel oil, it could be made large enough to also carry big radar (36-foot aperture AMDR), a large quantity of missiles in VLS, lasers (see below), rail guns, etc. To me that points toward a very large CGN oriented toward operating in CSGs, much larger than past CGNs.

      Fueling the Fleet, Navy Looks to the Seas

      09/24/2012 --- Refueling U.S. Navy vessels, at sea and underway, is a costly endeavor in terms of logistics, time, fiscal constraints and threats to national security and sailors at sea.

      In Fiscal Year 2011, the U.S. Navy Military Sea Lift Command, the primary supplier of fuel and oil to the U.S. Navy fleet, delivered nearly 600 million gallons of fuel to Navy vessels underway, operating 15 fleet replenishment oilers around the globe.

      From Seawater to CO2

      Scientists at the U.S. Naval Research Laboratory are developing a process to extract carbon dioxide (CO2) and produce hydrogen gas (H2) from seawater, subsequently catalytically converting the CO2 and H2 into jet fuel by a gas-to-liquids process.

      "The potential payoff is the ability to produce JP-5 fuel stock at sea reducing the logistics tail on fuel delivery with no environmental burden and increasing the Navy's energy security and independence," says research chemist, Dr. Heather Willauer.

      NRL has successfully developed and demonstrated technologies for the recovery of CO2 and the production of H2 from seawater using an electrochemical acidification cell, and the conversion of CO2 and H2 to hydrocarbons (organic compounds consisting of hydrogen and carbon) that can be used to produce jet fuel.

      Electrochemical Acidification Carbon Capture Skid. The acidification cell was mounted onto a portable skid along with a reverse osmosis unit, power supply, pump, carbon dioxide recovery system, and hydrogen stripper to form a carbon capture system [dimensions of 63" x 36" x 60"].

      "The reduction and hydrogenation of CO2 to form hydrocarbons is accomplished using a catalyst that is similar to those used for Fischer-Tropsch reduction and hydrogenation of carbon monoxide," adds Willauer. "By modifying the surface composition of iron catalysts in fixed-bed reactors, NRL has successfully improved CO2 conversion efficiencies up to 60 percent."

      A Renewable Resource

      CO2 is an abundant carbon (C) resource in the air and in seawater, with the concentration in the ocean about 140 times greater than that in air. Two to three percent of the CO2 in seawater is dissolved CO2 gas in the form of carbonic acid, one percent is carbonate, and the remaining 96 to 97 percent is bound in bicarbonate. If processes are developed to take advantage of the higher weight per volume concentration of CO2 in seawater, coupled with more efficient catalysts for the heterogeneous catalysis of CO2 and H2, a viable sea-based synthetic fuel process can be envisioned. "With such a process, the Navy could avoid the uncertainties inherent in procuring fuel from foreign sources and/or maintaining long supply lines," Willauer said.

      NRL has made significant advances developing carbon capture technologies in the laboratory. In the summer of 2009 a standard commercially available chlorine dioxide cell and an electro-deionization cell were modified to function as electrochemical acidification cells. Using the novel cells both dissolved and bound CO2 were recovered from seawater by re-equilibrating carbonate and bicarbonate to CO2 gas at a seawater pH below 6. In addition to CO2, the cells produced H2 at the cathode as a by-product.

      These completed studies assessed the effects of the acidification cell configuration, seawater composition, flow rate, and current on seawater pH levels. The data were used to determine the feasibility of this approach for efficiently extracting large quantities of CO2 from seawater. From these feasibility studies NRL successfully scaled-up and integrated the carbon capture technology into an independent skid to process larger volumes of seawater and evaluate the overall system design and efficiencies.

      The major component of the carbon capture skid is a three-chambered electrochemical acidification cell. This cell uses small quantities of electricity to exchange hydrogen ions produced at the anode with sodium ions in the seawater stream. As a result, the seawater is acidified. At the cathode, water is reduced to H2 gas and sodium hydroxide (NaOH) is formed. This basic solution may be re-combined with the acidified seawater to return the seawater to its original pH with no additional chemicals. Current and continuing research using this carbon capture skid demonstrates the continuous efficient production of H2 and the recovery of up to 92 percent of CO2 from seawater.

      Located at NRL's Center for Corrosion Science & Engineering facility, Key West, Fla., (NRLKW) the carbon capture skid has been tested using seawater from the Gulf of Mexico to simulate conditions that will be encountered in an actual open ocean process for capturing CO2 from seawater and producing H2 gas. Currently NRL is working on process optimization and scale-up. Once these are completed, initial studies predict that jet fuel from seawater would cost in the range of $3 to $6 per gallon to produce.

      How it Works: CO2 + H2 = Jet Fuel

      NRL has developed a two-step process in the laboratory to convert the CO2 and H2 gathered from the seawater to liquid hydrocarbons. In the first step, an iron-based catalyst has been developed that can achieve CO2 conversion levels up to 60 percent and decrease unwanted methane production from 97 percent to 25 percent in favor of longer-chain unsaturated hydrocarbons (olefins).

      In the second step these olefins can be oligomerized (a chemical process that converts monomers, molecules of low molecular weight, to a compound of higher molecular weight by a finite degree of polymerization) into a liquid containing hydrocarbon molecules in the carbon C9-C16 range, suitable for conversion to jet fuel by a nickel-supported catalyst reaction.

      Navy’s Top Geek Says Laser Arsenal Is Just Two Years Away

      October 22, 2012 --- Never mind looming defense cuts or residual technical challenges. The Navy’s chief futurist is pushing up the anticipated date for when sailors can expect to use laser weapons on the decks of their ships, and raising expectations for robotic submarines.

      “On directed energy” — the term for the Navy’s laser cannons, “I’d say two years,” Rear Adm. Matthew Klunder, the chief of the Office of Naval Research, told Danger Room in a Monday interview. The previous estimate, which came from Klunder’s laser technicians earlier this year, was that it will take four years at the earliest for a laser gun to come aboard.

      “We’re well past physics,” Klunder said, echoing a mantra for the Office of Naval Research’s laser specialists. Now, the questions surrounding a weapon once thought to be purely science fiction sound almost pedestrian. “We’re just going through the integration efforts,” Klunder continued. “Hopefully, that tells you we’re well mature, and we’re ready to put these on naval ships.”

      Klunder isn’t worried about the ships generating sufficient energy to fill the laser gun’s magazine, which has been an engineering concern of the Navy’s for years. “I’ve got the power,” said Klunder, who spoke during the Office of Naval Research’s biennial science and technology conference. “I just need to know on this ship, this particular naval vessel, what are the power requirements, and how do I integrate that directed energy system or railgun system.”

      That’s a relief for the Navy. It means that the Navy’s future ships probably won’t have to make captains choose between maneuvering their ships and firing their laser weapons out of fear they’d overload their power supplies.

      But shipboard testing is underway. Klunder wouldn’t elaborate, but he said that there have been “very successful” tests placing laser weapons on board a ship. That’s not to say the first order of business for naval laser weaponry will be all that taxing: In their early stages, Pentagon officials talk about using lasers to shoot down drones or enable better sensing. Klunder alluded to recent tests in which the Navy’s lasers brought drones down, although he declined to elaborate.
      Last edited by JRT; 26 Oct 12,, 02:52.


      • #4
        Here is the laser mounted on USS Dewey a few months back
        Attached Files


        • #5
          James Bond.......

          Originally posted by Gun Grape View Post
          Here is the laser mounted on USS Dewey a few months back
          Now this advancement in military arms will be even more marketable when it hits the domestic market.
          Imagine the mid night commericlas on the Home shoping network! ;)

          Homedefense, eliminate stray cats, a can opener.... all in one handy dandy self contained unit and for the low low cost of 12-installments...... Hope it comes with a solar powered attachment as the brown outs on both coasts will increase no doubt when the need comes to recharge these devices.


          • #6
            Now the increased energy generating and distributing capabilities of the new Ford-class aircraft carriers makes sense; it's not just for the EMALS, it's for this thing, too. I noticed they have a couple of 1MW generators sitting next to it, that gives you an idea of how much power it needs.
            "There is never enough time to do or say all the things that we would wish. The thing is to try to do as much as you can in the time that you have. Remember Scrooge, time is short, and suddenly, you're not there any more." -Ghost of Christmas Present, Scrooge


            • #7
              Originally posted by Stitch View Post
              Now the increased energy generating and distributing capabilities of the new Ford-class aircraft carriers makes sense; it's not just for the EMALS, it's for this thing, too. I noticed they have a couple of 1MW generators sitting next to it, that gives you an idea of how much power it needs.
              The relatively new battery-capacitor hybrids have come a long way, likewise the recent advances in graphene ultracapacitor technology. These are already mature enough for use in applications that could be useful for boosting local power supply capacity, reducing load crests on the ship's power system.

              IEEE Spectrum 2008 article on battery-capacitor hybrids

              IEEE Spectrum 2010 article on graphene ultracapacitors

              Axion Power's PbC battery-capacitor hybrid looks like a good product (link to tech overview), and their packaged Power Cube looks interesting for inland stationary applications, but would need major redesign for shipboard applications (shock qualification, corrosion resistance, LSZH wiring, etc.).

              Check out the related tech-marketing videos:

              Last edited by JRT; 27 Oct 12,, 04:13.


              • #8
                Originally posted by Chogy View Post
                It's interesting, but there's nothing particularly exotic about the concept. The problem will forever be the enormous amount of energy needed to create the fuel, and the only real solution would be a large, floating nuclear reactor. Solar would probably require a supertanker-sized field of cells to get a trickle of fuel flowing. In theory, you don't need the liquid fuel except for the jets. You could simply crack water into hydrogen and oxygen, and use those gases to fire the steam boilers of a traditional ship. But liquids are far more storable and transferable.
                On the subject of fuel oil from sea water... I ran a Google search on Dr. Heather D. Willauer to see if she has written anything recently on this area of study, and found the following, which I suspect some here might find very interesting.

                Since discussion here on this subject has been sparse, and also since new info trickles out over spans of many months, it seemed reasoable to dredge up this old thread to give this recent info some useful context, directly related to Chogy's comments above.

                The info quoted below is excerpted from the more detailed information available in the full paper at the hypertext link included below.

                Naval Research Laboratory
                Washington, DC 20375-5320

                An Economic Basis for Littoral Land-Based Production of Low Carbon Fuel from Renewable Electrical Energy and Seawater for Naval Use: Diego Garcia Evaluation

                HEATHER D. WILLAUER
                Materials Science and Technology Division

                DENNIS R. HARDY
                Nova Research Inc., Alexandria, Virginia

                FREDERICK W. WILLIAMS
                Navy Technology Center for Safety and Survivability Chemistry Division

                FELICE DIMASCIO
                Office of Naval Research, Arlington, Virginia

                EXECUTIVE SUMMARY

                NRL was challenged to determine the maximum size and configuration of a fuel producing process on the remote island of Diego Garcia using electricity from renewable sources such as wind and solar. Data from renewable site assessments of Diego Garcia conducted by NREL and NAVFAC have been used in this report to support an economic basis for the littoral production of low carbon fuel from carbon dioxide (CO2) and hydrogen (H2) in seawater.

                NRL has estimated that 320 MW of electricity is needed to produce the 47 million gallons of fuel delivered annually to Diego Garcia. Using published capital cost estimates and a range of solar and wind renewable electrical energy scenarios, costs ranging between $3.76 and $5.12 per gallon are calculated for producing 129,000 gallons per day of fuel. It is possible to supply up to 100% of the fuel now imported to the tiny foot-print of Diego Garcia. Current real total costs of this imported fuel is about $6.60/gallon. This provides policy analysts with a reasonable economic rationale and justification for planning and designing a new littoral energy conversion process to provide low carbon jet and diesel fuel for naval operations at sea.

                A graphic depiction illustrates how a fuel process could be configured on the island of Diego Garcia. This remote base represents the most difficult challenge for using wind and PV arrays due to its extremely small land area (10 square miles, of which only about 6 square miles is actually available) and Class II wind classification. Larger area potential sites of strategic naval importance such as Guam, Cuba, Djibouti, and Hawaii could be constructed at lower capital costs and therefore achieving lower per gallon prices than Diego Garcia.

                1.0 BACKGROUND

                SECNAV has set forth Navy goals for alternative energy use which require that 50 percent of DON energy requirements at sea and on shore be derived from alternative (non-petroleum) sources by 2020 [1]. The five ambitious energy goals involve energy efficient acquisition, sailing the “Great Green Fleet” by 2016, reducing non-tactical petroleum use by 50% by 2015, increasing alternative energy ashore, and increasing alternative energy so that by 2020, 50% of total navy energy consumption will come from alternative sources. These goals seek to enhance combat capabilities and to provide greater energy security [1].

                In pursuit of these ambitious energy goals, the US Navy has enlisted the National Renewable Energy Laboratory’s (NREL) technical assistance in the evaluation of 22 Navy installations. One of these installations is located on the remote island of Diego Garcia [2]. The Naval Support Facility Diego Garcia is one of the most strategically important U.S. military installations. Located over 2,750 miles south of Iraq and Afghanistan, the base has served as a critical refueling station during the Persian Gulf War, Operation Desert Fox, and the Afghanistan war. Due to its location in the middle of the Indian Ocean, the base relies solely on petroleum based resources to provide power and electricity to the island [3]. In addition the base relies on petroleum based resources to support all naval operations in, around, and from the installation. The island’s potential renewable resources, extremely small land mass, and its importance in US military operations provides one of the most challenging cases for assessing how these resources could be exploited and used to ensure its maximum energy security and strategic importance for the US Navy.

                2.0 INTRODUCTION

                NRL was tasked by the Congressional Research Service (CRS) to determine the size, estimated cost, and configuration of a fuel producing process on the remote island of Diego Garcia using electricity from renewable sources such as wind and solar. In November of 2013, NREL performed a net-zero renewable energy site assessment of Diego Garcia and initially estimated the potential amount of wind and solar power that could be generated on site to be used to supply electricity to the island [4]. “Net Zero Energy” means that the renewable energy produced on-site over the period of a given year is equal to the installation’s energy demand [5]. The island’s average annual electrical production is ~10 MW that is supplied by roughly 20 MW to 25 MW of diesel generators [6]. The prior year NRL published a cost/benefit and energy balance analysis that addresses the critical scientific and technical challenges that impact the economic feasibility of producing jet fuel at sea using CO2 and H2[7]. These data have been used as a starting point by NRL to conduct a reasonable economic analysis to support the rational and justification of planning and designing a new future littoral renewable energy conversion process that provides low carbon jet and diesel fuel for all naval operations at Diego Garcia, including the use of the synthetic hydrocarbon fuel to power the island’s electrical grid.

                3.0 RESULTS AND DISCUSSION

                3.1 Photovoltaic Renewable Generation On Diego Garcia

                Figure 1 is a picture of the island and Table 1 provides the island dimensions relative to the large lagoon it encompasses. In the image, 10 square miles of land (27 km2) surround a 57 square mile (147 km2) lagoon [8]. With respect to solar feasibility, NREL used a Preliminary Technical Assessment (PTA) that had already been conducted and published for official use only by NAVFAC in 2011 [6]. The photovoltaic arrays renewable energy estimates are based on the use of roughly 1% of the island’s total (~0.27 km2) dry land area, and this only includes the land that bounds the western side of the lagoon. This side of the island is the one that is occupied by military operations and is home to the island’s power stations and the 2.3 to 2.6 mile long airstrip (Figure 2) [8-9]. Ideally the alternative renewable sources should be located as close to the grid they support. Therefore, it is this land that was used in NAVAC’s initial assessment for the locations of photovoltaic arrays on Diego Garcia [6].

                The total amount of power that could be provided by PV in the 1% of land was reported to be between 15 to 30 MW. NAVFAC reported that additional 3 to 5 MW could be achieved with PV locations on top of selective installations on the island. During NREL’s site assessment, they determined that approximately ~2 MW would be the upper limit before serious grid integration measures would be required. The proposed NRL process would use the 15 to 30 MW of solar power to produce liquid hydrocarbon fuel as a drop in replacement for traditional petroleum based JP5 that is currently being used for the power stations. This novel way of storing renewable energy as a liquid hydrocarbon would avoid the need for serious modifications and power integration to the current infrastructure on Diego Garcia.

                Sources indicate that 20-25 MW is the average rated size of the JP5 fueled power stations supplying electricity to Diego Garcia [6]. Since this power originates from petroleum based resources, an estimated average of 5.6 million gallons of fuel must be delivered annually to Diego Garcia just to operate the power plants. In FY2014, this Fully Burdened Cost of Fuel (FBCF) is estimated at $37 million dollars.

                The FBCF is defined and explained as follows. The Defense Logistics Agency/Energy (DLA/E) reported a fuel price-per-gallon of $3.64 (JP-5) and $3.61 (F-76) in FY2014 [10]. This price does not include the additional costs of logistical storage and delivery of the fuel to naval operational vessels at sea and strategic installations such as Diego Garcia. The Fully Burdened Cost of Fuel (FBCF) is defined as the standard price per gallon diesel or jet paid by the DOD plus the logistical cost to procure, store, and deliver the fuel at sea. The most recent detailed justified FBCF can be found in the 2008 report by the Defense Science Board [11]. The report establishes an FBCF of $4.00/gallon for FY2005. Using data from previous reports ($1.56/gallon procured price) a burden cost of $2.44/gallon was established. This burden cost of fuel can be adjusted for the last 9 years using standard inflation calculators to arrive at an FY2014 value of $2.97/gallon. This gives a FBCF price for FY2014 of $6.61 JP-5 and $6.58 F-76.

                Table 2 shows that the 5.6 million gallons of fuel annually to support the power facilities at Diego Garcia is only a fraction (~12%) of the total amount of the 47 million gallons of fuel delivered to the installation a year (129,000 gallons/day) [12]. The other 88% is used to support Naval operations in, around, and from the installation.

                NAVFAC and NREL estimate that 15 to 30 MW of power can be produced using photovoltaic renewable generation on 1% of the island [6]. Based on former analysis by the Naval Research Laboratory, 15 to 30 MW of electricity can produce 6,000 gallons/day to 12,000 gallons/day of fuel using CO2and H2feedstock from seawater [7]. Based on the numbers provided by NAVFAC and further supported by NREL’s net-zero renewable energy site assessment, a scenario can be envisioned where an additional 9% to 19% of the land or enclosed water of the island could be used to generate electricity from photovoltaic renewable generation. This would result in the ability to produce from 150 MW to 600 MW of electricity. This electricity would be enough to support the production of 60,000 to 243,000 gallons of fuel per day from CO2and H2 in seawater. However only 320 MW of electricity is needed to support production of the 129,000 gal/day that is used on average at Diego Garcia.

                The derivation of solar power generation from photovoltaic systems in a particular geographical location is dependent on a rather large number of variables (solar cell material, altitude, irradiance, ability to track the sun, etc.) that change the overall efficiencies of the systems [6,13]. Therefore it is only reasonable to ascertain a large range of power production for a given amount of area as proposed by NAVFAC for Diego Garcia (15 MW to 30 MW) and verified by NREL. Indeed the difference between the minimum and maximum power production proposed was based on the lowest efficiency solar panels versus the highest efficiency in industry. This large range in power production will greatly impact the footprint and cost, therefore final economic analysis for implementing a photovoltaic system capable of supplying 320 MW of electricity for the production of 129,000 gal/day of fuel needed at Diego Garcia.

                NRL uses the solar irradiance for the area around Diego Garcia as a minimum of 5.0 kWh/m2/day [14-15]. Dividing this number by 24 hours in a day gives a power rating 0.208 kW/m2 at 100% efficiency of the PV array. Typically PV arrays are approximately 16% to 25% efficient. To derive the lower value for NREL (15 MW on ~1% of Diego Garcia land area), we need to assume 26% efficiency of the solar panels.

                Since 320 MW of power is needed to produce all the fuel at Diego Garcia, a ratio is used to derive the size of PV arrays as follows:

                15_MW / 275,017_m^2 = 320_MW / x

                x = 5,867,000_m^2 = 5.87_km^2, or

                x = 63_million_ft^2 = 2.27_miles^2

                This means we need approximately 5.87_km^2 of arrays that would take up 21.7% of the land mass on Diego Garcia. The cost of the arrays at $4.80/watt installed is $1.54 billion. Table 3 provides the cost breakdown of the various major components (solar PV arrays, the carbon/hydrogen production units, and the FT units) of the littoral land-based solar powered fuel process. These values are used in the estimated capital analysis of the process in Table 4. The total cost to produce 47,085,000 gallons a fuel a year would be $2,090,000,000. The operation and maintenance costs at 5% a year would be $104,500,000 at an expected lifetime of at least 25 years. The capital cost amortized over this 25 year period would be $83,600,000, for a final estimated fuel cost of $3.99/gallon.

                While it may be feasible to utilize approximately 22% of the island for solar arrays, it is not necessarily a practical solution with respect to preserving and maintaining the island’s ecology. Reports indicate that the eastern half of the island is a restricted zone that remains much as it was in the late 1800s and early 1900s (Figure 2) [8]. Visitors can obtain a pass to tour the remains of what was once a coconut plantation located on the East side of the island at East Point. As a result of limited land availability for this assessment, NRL has spent time investigating the use of Diego Garcia’s 57 square mile lagoon (147 km2) that could be home to floating structures such as barges or modular floats made from high density polymer HDP (Jet Dock and Versa Dock). These floats could support the entire solar PV array process and occupy only 4% to 6% of the lagoon depending on configuration with a minimum impact of the ecology of the lagoon and land. Interestingly enough these materials have a similar life expectancy to that of the PV arrays (~25 years). An additional row in Table 3 accommodates the capital costs associated with the HPD floats. Individual quotes from both companies indicate the cost will be roughly $100/m2 and that as the size increases the overall cost per/m2will be expected to decrease. In this analysis we used the worst case scenario of $100/m2. When this cost is accounted for in the second column in Table 4, the cost of the fuel increases from an estimated $3.99/gallon to $5.11/gallon.

                3.2 Wind Renewable Generation On Diego Garcia

                Since the island is situated 7 degrees south of the equator, its average yearly wind speed is 12.5 miles per hour [16]. This is just barely high enough to receive a Class II wind classification (200 W/m2) as shown in Table 5 [17]. NREL’s PTA team met with environmental and planning personnel to determine suitable locations for wind turbines. The locations were determined to be feasible for both 275 kW and 1 MW turbines [18]. While NREL is still in their preliminary state of determining the feasibility of wind vs PV, they have found that wind is more cost effective by a factor of 2 over PV and that wind is much easier to integrate into the electrical grid then PV [4].

                NREL also proposed that the wind farm should be located at the south-eastern part of the island just after the u-bend in the island between the T-site and GEODSS Gate (Figures 1 and 2) [18]. The estimated NREL power from wind generation is between 15 to 19 MW. NREL is in the process of collecting on-site wind data using a Triton Sodar unit. This is far short of the 320 MW of electricity needed for fuel production on the island [18].

                To achieve any significant wind power generation above 19 MW, NRL investigated the use of the commercial Vestas V164 wind turbines [19]. Each wind turbine has the maximum nameplate output of 8 MW. Given the class II winds, the maximum per Vectra generator on the island is 2.1 MW. These wind generators have rotor diameters of 164 meters and swept areas of 21,000 m2and are located on towers of about 100 m in height and about 50% conversion efficiency. Given the size of the generators, it is envisioned that they would be configured in a single row, 2 per kilometer (2 per 0.6 miles = 2 per 3000 feet), beginning approximately 2 to 3 kilometers south of the airstrip. Thus it is only possible to efficiently position up to 26 windmills for a total of 52 MW of electricity before the restricted area is reached.

                Since the capital cost of the wind turbines is half that of the solar PV per Watt ($2.40/watt), the total cost installed would be approximately $125 million dollars [4]. A 2011 wind energy report from NREL estimates that a 200 MW land based wind turbine project containing 133 wind turbines each rated at a capacity of 1.5 MW would cost $419,000,000 or $2.10/watt [20]. Another more recent 2013 estimate from NREL suggests it would cost $2.64/watt [21]. Therefore NRL’s costs in Table 4 assume a worst case scenario for the inclusion of wind turbines in the renewable energy matrix on Diego Garcia. Table 4 column 3 shows the estimated capital cost of the fuel after replacing 52 MW of the solar panels with windmills and leaving the entire solar array on land. This would reduce the size of the arrays from 5.87 km2to 4.9 km2. The capital cost of the arrays on land would be reduced from $1.5 billion to $1.3 billion. The cost of the fuel would be reduced from $3.99/gallon to $3.76/gallon. If the arrays remained in the water the price of fuel would increase to $4.70/gallon. From these estimates it can be determined that the cheapest price per gallon of fuel would be obtained by maximizing the use of wind turbines and PV on the available island.

                In this assessment, the possibility of putting wind turbines offshore was not consider due to the cost estimates that suggest that it is 2 times more expensive (~$5.60/watt) than land [21] and in some instances may be up to 3 times more expensive. These costs will most certainly be increased by the number of wind turbines that will be needed because Diego Garcia has wind speeds that are just high enough to receive a Class II wind classification (Table 5). This could also perhaps be the most ecologically problematic approach to renewable energy on Diego Garcia, as the turbines must be installed by pile driving them into the seabed.

                3.3 Estimated Size of the Fuel Process on Diego Garcia

                It is estimated that 573,000 m3/day of CO2and 1400 m3/day H2is needed for a synthetic hydrocarbon fuel process to produce 129,000 gal/day of jet fuel on Diego Garcia. Anticipated future large scale NRL carbon capture modules (18 gpm seawater) have been conceptually designed, scaled up, and configured on the basis of current NRL small carbon capture prototypes (process 0.5 gpm of seawater). The conceptual module design along with the pumps and the infrastructure needed to move the water were used to estimate the total square footage needed for the carbon capture process on Diego Garcia. NRL estimates the total size of the carbon capture process would be 285,000 ft2and the total volume would be 5,000,000 ft3. To take into consideration the fuel process, an additional 570,000 ft2is needed at a volume of 17,000,000 ft3. The entire process would take 855,000 ft2or 0.08 km2and a total volume of 22,000,000 ft3. The significant increase in volume of the whole process is due to the height needed for the modular chemical reactors.

                Approximately 0.3% of the land mass of Diego Garcia is needed to fit the entire carbon capture and fuel production part of the process. The modular nature of the chemical reactors and carbon capture modules mean that the square footage of the process could easily be configured to fit on the island near the south power plant or on the eastern side of the island near the transmitter site as shown in Figure 2. Figure 3 is a graphic depiction that illustrates how NRL would envision the entire fuel process configured on the island of Diego Garcia for to make the 129,000 gal/day needed for operations.

                4.0 CONCLUSIONS

                This analysis focuses on determining the size, cost, and configuration of a low carbon fuel producing process on the remote island of Diego Garcia. The amount of fuel (nearly 8% of all Navy operational fuel at sea) that is delivered and utilized on this island along with the extremely small land area, and potential environmental restrictions represent just a few of the many challenges of taking advantage of the renewable energy on the island for producing drop in low carbon fuel. This analysis provides a variety of scenarios that show it is possible to supply up to 100% of all the power and energy needs of Naval Support Facility Diego Garcia without importing any fuel for the foreseeable future. Furthermore, it is shown that through various potential combinations of renewable energy including land based wind, land based PV arrays, and floating PV arrays that this can be done with favorable economics for the Navy when compared to current FY14 FBCF. Finally, it is obvious that on all other potential land based littoral sites that the cost of siting, building, operating, and resulting cost/gallon of final fuel produced will be much lower than projected for Diego Garcia as an actual fuel producing site due to the fact that much higher proportions of wind energy can be utilized on the much larger land footprints

                5.0 RECOMMENDATIONS

                NREL and NAVFAC estimate that 15 to 30 MW of electricity, could be produced from PV on 1% of the island without restriction. NRL would instead propose to use this electricity as a first step toward demonstrating the feasibility of a fuel process on the island. The 30 MW of PV could be used to produce up to 12,000 gallons/day of the 15,000 gallons/day currently imported to supply power to Diego Garcia. This novel approach to storing renewable energy as a high energy density low carbon fuel would eliminate the costs associated with all the modifications needed to integrate any renewable energy into the existing grid on Diego Garcia. This type of demonstration would provide future policy makers with many more choices as to the future of naval energy resources.

                6.0 REFERENCES

                1. Department of the Navy’s Energy Program for Security and Independence., 2010. Available at:< df>, last accessed October 2014. 2. NREL Helps the Navy with Renewable Energy Site Assessment at Indian Ocean Base., 2013. Available at:<>, last accessed December 2014. 3. Bélanger, P.; Arroyo, A. S., “Logistics Islands. The Global Supply Archipelago and Topologics of Defense.” Features, Prism 3, NO. 4. Available at:>, last accessed December 2014. 4. Long, B. Navy Net-Zero Energy Initiative, Diego Garcia Site Visit, November 8-14th2013. NAVFAC EXWC. 5. Callahan, M.; Anderson, K.; Booth, S.; Katz, J.; Tetreault, T. “Lessons Learned from Net Zero Energy Assessments and Renewable Energy Projects at Military Installations.” NREL/TP-7A40-54598, September 2011. National Renewable Energy Laboratory, Golden Colorado 80401. 6. Solar Feasibility Study and Preliminary Technical Assessment, Navy Support Facility Diego Garcia September 20, 2011. NAVAC Pacific Utilities & Energy Management, PW6, Pearl Harbor, HI. 7. Willauer, H.D., Hardy, D.R., Schultz, K.R., Williams, F.W., 2012b. The feasibility and current estimated capital costs of producing jet fuel at sea using carbon dioxide and hydrogen. J. Renewable and Sustainable Energy-AIP American Institute of Physics, 4. art. no. 033111-13. 8. Diego Garcia. Available at:<>, last accessed December 2014. 9. Diego Garcia NSF, World Aero Data. Available at:<>, last accessed December 2014. 10. Defense Logistics Agency Energy, 2013. Available at: <>, last accessed September 2014. 11. Office of the Under Secretary of Defense For Acquisition, 2008. Report of the Defense Science Board Task Force on DOD Energy Strategy, More Fight-Less Fuel, Technology, and Logistics. Washington DC. 12. Personal Communication, NAVSUP Energy, GLS C70. 13. Solar Power (Technology and Economics). Available at: <>, last accessed December 2014. 14. Renné, D.; George, R.; Marion, B.; Heimiller, D; Gueymard, C. “Solar Resources Assessment for Sir Lanka and Maldives.” NREL/TP-710-3464, August 2003. National Renewable Energy National Renewable Energy Laboratory, Golden Colorado 80401. 15. Global Mean Solar Irradiance, 3TIER by Vaisala. Available at:>, last accessed December 2014. 16. Average Weather For Diego Garcia, British Indian Ocean Territory. Available at: <>, last accessed December 2014. 17. Classes of wind power density. Available at: <>, last accessed December 2014. 18. Navy Net Zero/Energy Security Assessment for Diego Garcia (DG), Site Assessment November 8th-14th2013, NREL. 19. Vestas V164. Available at: <>, last accessed December 2014. 20. Tegen, S.; Lantz, E.; Hand, M.; Maples, B.; Smith, A.; Schwabe, P. “2011 Cost of Wind Energy Review,” NREL Technical Report NREL/TP-5000-56266 March 2013. 21. Distributed Generation Renewable Energy Estimate of Costs, 2013 August, NREL. Available at:<>, last accessed December 2014.
                Last edited by JRT; 18 Jul 16,, 18:22.


                • #9
                  I ran a search on YouTube to see if there was anything posted regarding efforts by NRL's Dr. Heather D. Willauer on this topic. Looks like they have been making some steady progress. I am appending this older thread to keep the info bundled together.

                  Brief interview circa 2018:

                  Webinar circa 2017
                  (older, but includes better tech content):


                  • #10
                    Originally posted by labroots

                    Converting seawater into fuel requires a special catalyst

                    by Kathryn DeMuth Sullivan
                    17 July 2020

                    In new research published in Energy & Environmental Science, chemical engineers from the University of Rochester, the Naval Research Laboratory, the University of Pittsburgh, and OxEon Energy detail the most recent update in the mission to generate fuel from seawater.

                    The research elaborates on a particular step in the conversion process, during which carbon dioxide is converted into monoxide. The new findings highlight the use of a potassium-promoted molybdenum carbide catalyst to complete this step.

                    "This is the first demonstration that this type of molybdenum carbide catalyst can be used on an industrial scale," says Marc Porosoff, assistant professor of chemical engineering at Rochester.

                    The Navy has invested in this process ever since 2014 when it was first suggested by a Naval Research Laboratory team led by Heather Willauer. Converting seawater into fuel would eliminate the need for oil and would allow for continuous operation.

                    The potassium-modified molybdenum carbide catalyst solves several problems that this project has been facing. First, it uses low-cost components necessary to first convert carbon dioxide into carbon monoxide via the reverse water-gas shift (RWGS) reaction. Second, it does not show any signs of deactivation under reaction conditions, as previous catalysts have.

                    Porosoff adds that the potassium acts to decrease the energy barrier related to the RWGS reaction, while the gamma-alumina makes sure the molybdenum carbide catalyst particles stay separated, which maximizes the surface area of the chemical reaction.

                    All in all, write the authors of the study, “experiments across the molecular, laboratory and pilot scales demonstrate that K-Mo2C/γ-Al2O3 is an economically-viable RWGS catalyst with promising future applications in the US Naval Research Laboratory's seawater-to-fuel process, downstream methanol synthesis and FT.”



                    Originally posted by University_of_Rochester_press_release

                    This low-cost catalyst helps turn seawater into fuel at scale

                    July 15, 2020
                    A replenishment oiler, left, refuels a naval ship at sea. The Porosoff research group at the University of Rochester has demonstrated that a potassium-promoted molybdenum carbide catalyst can help the US Navy achieve its goal of converting seawater to fuel, effectively eliminating the need for traditional refueling operations. (Getty Images photo)

                    For the first time, Rochester chemical engineers have demonstrated a ‘potassium-promoted’ catalyst’s potential for use on an industrial scale.

                    Now, the Navy’s quest to power its ships by converting seawater into fuel is nearer fruition.

                    This reactor at OxEon Energy was used to validate the effectiveness of the potassium-promoted molybdenum carbide catalyst on an industrial scale. (OxEon Energy photo)

                    University of Rochester chemical engineers—in collaboration with researchers at the Naval Research Laboratory, the University of Pittsburgh, and OxEon Energy—have demonstrated that a potassium-promoted molybdenum carbide catalyst efficiently and reliably converts carbon dioxide to carbon monoxide, a critical step in turning seawater into fuel.

                    “This is the first demonstration that this type of molybdenum carbide catalyst can be used on an industrial scale,” says Marc Porosoff, assistant professor in the Department of Chemical Engineering at Rochester. In a paper in the journal Energy & Environmental Science, the researchers describe an exhaustive series of experiments they conducted at molecular, laboratory, and pilot scales to document the catalyst’s suitability for scale-up.

                    If navy ships could create their own fuel from the seawater they travel through, they could remain in continuous operation. Other than a few nuclear-powered aircraft carriers and submarines, most navy ships must periodically align themselves alongside tanker ships to replenish their fuel oil, which can be difficult in rough weather. The project could also provide fuel for fighter jets on the nuclear-powered carriers.

                    In 2014, a Naval Research Laboratory team led by Heather Willauer announced it had used a catalytic converter to extract carbon dioxide and hydrogen from seawater and then converted the gases into liquid hydrocarbons at a 92 percent efficiency rate.

                    Since then, the focus has been on increasing the efficiency of the process and scaling it up to produce fuel in sufficient quantities.

                    A key step in the seawater-to-fuel conversion process

                    The carbon dioxide extracted from seawater is extremely difficult to convert directly into liquid hydrocarbons. So, it is necessary to first convert carbon dioxide into carbon monoxide via the reverse water-gas shift (RWGS) reaction. The carbon monoxide can then be converted into liquid hydrocarbons via Fischer-Tropsch synthesis.

                    Madeline Vonglis ’20, who interned with the Porosoff research group last summer, conducted many of the laboratory-scale experiments to characterize the potassium-promoted molybdenum carbide catalyst, and is second author on the Energy & Environmental Science paper. She’ll begin her PhD in chemical engineering this fall at Pennsylvania State University. (University of Rochester photo / J. Adam Fenster)

                    Typically, catalysts for RWGS contain expensive precious metals and deactivate rapidly under reaction conditions. However, the potassium-modified molybdenum carbide catalyst is synthesized from low-cost components and did not show any signs of deactivation during continuous operation of the 10-day pilot-scale study. That’s why this demonstration of the molybdenum carbide catalyst is important.

                    Porosoff, who first began working on the project while serving as a postdoctoral research associate with Willauer’s team, discovered that adding potassium to a molybdenum carbide catalyst supported on a surface of gamma alumina could serve as a low-cost, stable, and highly selective catalyst for converting carbon dioxide into carbon monoxide during RWGS.

                    The potassium lowers the energy barrier associated with the RWGS reaction, while the gamma alumina—marked with grooves and pores, much like a sponge—helps ensure that the molybdenum carbide catalyst particles remain dispersed, maximizing the surface area available for reaction, Porosoff says.

                    To determine whether potassium-promoted molybdenum carbide might also be useful for capturing and converting carbon dioxide from power plants, the research group will conduct further experiments to test the catalyst’s stability when exposed to common contaminants found in flue gas such as mercury, sulfur, cadmium, and chlorine.

                    Rochester coauthors include lead author Mitchell Juneau, a PhD student in the Porosoff research group, and Madeline Vonglis ’20, a former undergraduate researcher.

                    An Office of Naval Research award supported this project.

                    Last edited by JRT; 14 Dec 20,, 18:20.