It's got some 290 ships, thousands of aircraft and probably tens of thousands of small boats

and launches. And apart from a few nuclear powered carriers and submarines, all need

fuel - either from a fleet of 15 so-called oilers or fuel ships, or from bases dotted

around the world.

But the Navy has just announced a technology which is pretty much the holy grail for any

global taskforce. It's managed to perfect the creation of fuel, which is something they

need, from seawater. Which is something they have no shortage of at all.

What's even better from a military perspective is that it doesn't require any modification

of the ships engines - you aren't getting a liquid hydrogen fuel out of the mix that

needs a fuel cell to operate, you're getting a highly efficient hydrocarbon based fuel,

like gasoline, that can power both ships and aircraft.

Although so far the only plane it's powered is this model one at the US Naval Research

Laboratory. Small steps though eh?

Here's the science bit - saltwater is passed through an electrically charged cell, which

causes the seawater to swap hydrogen ions produced at the anode with sodium ions. At

the Cathode, the water is reduced to hydrogen gas and sodium hydroxide. The end result is

CO2 gas and hydrogen, which are then passed through a heated chamber with an iron catalyst

in it, which causes them to combine into long chained hydrocarbons - that is, fuel - and

methane gas, which can be siphoned off and used elsewhere. The fuel is then refined into

jet fuel if needed in another nickel-based catalyst.

It's predicted to cost around $3-$6 a gallon to produce, that's about as much as fuel costs

at the pump in the US right now, and whilst installing distillation equipment on hundreds

of US ships might be expensive, the savings from not having to operate the oiler fleet

or get fuel to bases around the world, or from fluctuating prices, will likely run into

the billions every year.

So what's the downside? Well it's not the most eco friendly solution. Methane is a useful

fuel but a potent greenhouse gas if it's not completely burnt, and even if it is burnt,

the whole lot will produce CO2 just like burning any other liquid or gas fuel does.

But that's not a new problem, nor is saving the environment the navy's task. They prefer

to save people from it. Or sometimes destroy it with bombs. At any rate, there are an estimated

80-100,000 ships in the world, and over quarter of a million planes. So the Navy's emissions

are a bit of a drop in the ocean, pardon the pun.

The military is already working with a number of partners on commercialising the tech, and

it's estimated it'll be finding it's way onto US warships within

a decade.