Navy May Have Figured Out a Way to Make Fuel from Seawater

Navy May Have Figured Out a Way to Make Fuel from Seawater April 10, 2014

This would be epoch-making, if true. It could mean the elimination of a potentially civilization-destroying problem: the eventual depletion of our hydrocarbon-based fuels.

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  • Paul Druce

    Instead we get civilization destroying releases of carbon dioxide, brilliant!

  • Elmwood

    If it sounds too good to be true it probably is. How exactly do you separate out hydrogen and oxygen from H2O without electrolysis–which requires an energy source?

    • kenofken

      The Navy has plenty of electricity on aircraft carriers. A few hundred megawatts. From what I can tell browsing patents and the news, I think the second half of the process is nothing new, in concept at least. I think they’re using the Fischer Tropsch process, which is what the Nazis used to make synthetic gasoline from coal gas during the war. With the right temperature and catalysts, you cook carbon monoxide and hydrogen into liquid petroleum-like fuels.

      I think the new breakthrough comes in the efficiency with which they’re able to capture CO2 from the water. Instead of just bubbling out the dissolved gas, it sounds like they’re able to free the carbon tied up in carbonic acid/bicarbonate forms using some fancy sort of membrane and electricity. They may have found a neat new catalyst for Fischer-Tropsch conversion as well.

      In the end, I think there’s no free energy. This method is attractive because it offers fuel on demand, and the product is cleaner in some ways than petroleum – no sulfur or wacky aromatic compounds that come with crude oil. You also don’t have to drill for your carbons source. You’re sailing on it 24/7, and at least a good portion of that carbon is stuff we already have put into the atmosphere, not net new carbon dredged up from past epochs.

      Still, research on catalysts and new systems is all upside. It has a potential hydrogen side breakthrough. Electrolysis sucks. Plants, however, have been splitting water very efficiently for billions of years and they’re making some progress in figuring out how they do that on the nano scale and toying with ways to build artificial photosynthetic membranes.

      • Elmwood

        Didn’t think there was enough CO2 dissolved in seawater to make it worth while, but hey, with 400 ppm of CO2 in the atmosphere, maybe not. Either way, this seems to have a potential niche application for the Navy, maybe some other small scale uses, but not a new way to create a energy source for next to nothing. I know there has always been talk of gas to liquids technology being used on the North Slope of Alaska, but so far nobody is using this on a large commercial scale at least up here.

        It seems this fuel they produce is mixed with diesel or JP8 for combustion. I don’t think they would use this stuff in its pure form. Cool technology nonetheless, thanks for the insight.

  • kenofken

    I think for the forseeable future, the real breakthrough has less to do with freeing the world from fossil fuels and more to do with enhancing the military’s operating flexibility. It might free the navy from the instabilities of foreign suppliers or the need to stop at ports in hostile regions, but there’s still a net energy problem as far as I can tell.

    From the little I’ve read on it so far, the process runs, at the high end, at 60% efficiency, at least where CO2 conversion to liquid fuel is concerned. That means you essentially have to burn 10 barrels of oil to produce 6. There’s also an energy cost to extract the CO2 from the water, although it looks like a decent efficiency at that end. If you happen to have a great big nuclear reactor as you do on aircraft carriers, the tradeoff makes sense. You get a nice unlimited on-site fuel refinery for your aircraft and a conversion process that’s less than break-even where energy is concerned, but which has a not-too-bad greenhouse gas footprint, because nukes are clean (that way).

    It’s an entirely different matter to scale up to the equivalent of the 32 billion barrels of oil the world uses each year, to say nothing of the natural gas and the heinously dirty hydrocarbon sources we’d like to phase out – coal, tar sands etc. Unless we pull off a massive conversion to wind, solar and nuclear, we’ll end up burning fossil fuel to produce less seawater hydrocarbon fuel.

    There’s also another consideration when we thing about mining the oceans on a vast scale for hydrogen and CO2: the gas and bicarbonate and carbonate ions being stripped and re-balanced in this process control the pH of the oceans and the viability of the entire food chain from phytoplankton down to shellfish etc. which depend on these things. There is also a big interaction between atmospheric CO2 and how the oceans can act as a “sink” to sequester some of that out of the atmosphere. I don’t pretend to know enough oceanography to understand all the implications of it, but it’s clear that scaling up the Navy’s new tech that large would take our tinkering with the planet’s climate engines to a whole new level of interesting.

    For all those caveat’s I still think it’s a damn interesting development, and on some scale it may well help stabilize world oil markets and deflate some of the regional conflicts caused by the massive geographical balance between supply and demand.

  • Paul

    If I understand the article correctly, they are talking about extracting hydrogen from sea water, and then burning that hydrogen as fuel. Of course you can do that, and there is nothing radically new or innovative about this process.

    But the problem is that the energy you obtain by burning the hydrogen will always be less than the energy that was expended in making the hydrogen. So this is just a method of converting energy from one form to another — perhaps burning oil or running a nuclear reactor in order to generate hydrogen, and then burning the hydrogen at a later time. But again, you won’t get any more energy out at the end than you put in at the beginning.

    • kenofken

      I think the breakthrough isn’t so much on the hydrogen side as it is carbon, and the ability to build your own kerosene/jet type fuel on the fly using nothing but seawater as your raw materials source. Being able to do that on a shipboard environment and at a cost more or less comparable to petroleum is pretty cool, if what they say is true and not heavy on sci-fi optimism about scaling and engineering problems yet to be solved. Of course U.S. military economics is different from what the rest of us have to live with. Electrolysis is cheap if you happen to be sitting on a nuclear core that just happens to be burning for other purposes regardless.

  • Dan Berger

    As several people have pointed out below, this only works if you have an unlimited source of free, clean energy — because all this does is convert energy from one form to another. But if you had an unlimited source of free, clean energy, you wouldn’t need to use it to make hydrocarbon fuel (well, I take that back, liquid fuels have a much higher energy density than batteries or fuel cell/hydrogen, and energy density is important for small, self-contained vehicles).

  • MarylandBill

    The two articles I have read so far are very confusing. They are written as if they are talking about fuel for the ships, but as others have pointed out, you would need plenty of energy to produce the fuel. But if you have that energy say via a nuclear reactor, then you don’t need the fuel. I suppose it might make sense to add a ship to a task force that is nuclear powered whose job is to produce fuel for the rest of the task force. It would also make sense on an aircraft carrier where the ships nuclear reactors can produce fuel for the aircraft flying from its flight deck.

    • falstaff77

      Exactly. This *might* make sense if the task force nuclear carrier is turned into a fuel depot/factory, or an additional nuclear fuel factory is added, but that seems an odd use of that very expensive at-sea nuclear power. I’ll wager they’ll save money by simply making more nuclear warships.

  • The innovation here is not chemical but economic. Converting gas to liquids was solved 90 years ago in theory. Doing it cheaply enough to supplant drilled petroleum has been the problem for decades.