We think gas is expensive, because we have to put a few gallons in our car every once in a while. If you’re the U.S. Navy operating the world’s largest marine fleet, you might have a different idea about what "expensive" means.
Refueling America’s naval fleet is a massive undertaking. Fifteen replenishment oilers roam the world’s oceans, transporting jet fuel to Navy vessels, each of which burns 600 million gallons of fuel every year.
Now the Navy is testing ways to turn seawater into fuel on the high seas. Scientists at the U.S. Naval Research Laboratory report they have developed a process that splits water into its component hydrogen and oxygen molecules, converting them into jet fuel through a gas-to-liquids process.
The basic principle of a sea-based synthetic fuel is simple: "CO2 + H2 = Jet Fuel." Achieving that little feat of chemistry and physics is not trivial, however, and the Navy is still refining the technique on a "carbon capture skid," a three-chambered electrochemical acidification cell that uses electricity to grab carbon atoms from dissolved CO2 gas and (bi)carbonate in seawater.
"With such a process, the Navy could avoid the uncertainties inherent in procuring fuel from foreign sources and/or maintaining long supply lines," said research chemist Heather Willauer in a release from the Navy.
As the Navy works to meet its target of sourcing 50% of its fuels from alternative means by 2020, it’s going to need every drop of energy it can get that doesn’t come from oil. So how much will it cost? Initial studies suggest refining a seawater-derived jet fuel is feasible for $3 to $6 per gallon, but it gets a lot cheaper when you realize don’t have to transport your fuel anywhere, because you’re floating in it.