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    The Navy Wants to Make Jet Fuel Out of Seawater

    Written by

    Adam Estes

    The U.S. Navy wasn’t kidding when they said they wanted to transition their fleet over to a more sustainable fuel model. The announcement came earlier this summer when top brass finally came to the realization that it didn’t make great sense to continue to depend on oil to power our warships when the majority of the world’s oil comes from the very countries we may go to war with. Plus, it’s good for the environment and stuff, so that can’t hurt. The only problem is, it’s wicked expensive.

    Earlier this summer, the Navy embarked upon its first large-scale demo of replacing its regular gas with biofuel. The idea was to fill up the ships with eco-friendly biofuel, run some exercises and see how the ships perform. Everything went just fine — until the bill came. In the Pacific, the demo’s price tag was upwards of $12 million, which broke down to about $27 per gallon for the biofuel, a significant amount more than the $3.50 per gallon they paid for the regular stuff. So with Congress and Department of Defense budget watchers on their back, the Navy went back to the drawing board and came up with a pretty fascinating plan. Since all these Navy ships are just floating on seawater all the time, why not just come up with a way to turn that into jet fuel?

    Believe it or not, the Navy did just that. The mad scientists at the U.S. Naval Research Laboratory are currently perfecting a process whereby they can extract the carbon dioxide from seawater and produce pure hydrogen. Then, using something called an electrochemical acidification cell, they’re able to convert the carbon dioxide and hydrogen into hydrocarbons that can be used for jet fuel. That’s a pretty simplified version of the process, actually, but we’ll turn to the folks at NRL to explain the details:

    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.

    If all goes as planned, this process would effectively bring down the price of fuel. The Navy estimates that, with a little bit of work, they can get their seawater fuel down into the $3 to $6 per gallon range. However, as Treehugger points out, the resultant fuel isn’t really any more environmentally friendly than old stuff when it burns, as it’s still the same blend of hydrocarbons as jet fuel. It would, however, cut down on the energy used to transport the fuel out to sea, if indeed they manufactured the seawater fuel close on site. It also wouldn’t need to be pulled out of the ground, refined, and stored for shipping like oil.

    So the Navy’s not necessarily going to save the planet with their fancy new fuel process, but it does help. And they’ll certainly wow the socks off the enemy when they’re busy trying to find a gas station, and we’re just turning the ocean into jet fuel. Kind of like this guy.

    Image via Flickr