How the navy will turn seawater into fuel
Photo: U.S. Navy
— By Janet Fang on April 10, 2014, 9:05 PM PST
Can a nuclear reactor produce enough pressured steam from salt water to put a steam motor to work efficiently?
Electric motors are the answer but most people do not know that their use in things like torpedoes and submarines are the mostclosely guarded secret of the worlds naviesabove everything else.
The energy must be supplied by electrolysis of seawater, from a nuclear reactor in one ship to make hydrocarbon fuel to burn in other ship's engines.
No free lunch. Where does the energy come from to extract hydrogen from sea water? It's not photosynthesis, not fusion and not fossil fuel so it must be
This technology has a revolutionary application on land and that is if you can convert CO2 to fuels, you could capture CO2 from coal plants, put it through the same chemical process as used by the Navy and add to the power output of the coal plant, while eliminating CO2 pollution. FuelCell Energy Inc is working on a similar idea, where they separate CO2 emissions from coal plants and feed it through to their fuel cells for power generation.
I do not see how the energy to power the process could ever be substantially less than the energy created to make this worth doing.
As stated by others here, 1,000 gallons of diesel will get you 920 gallons of clean fuel, would be a pointless endeavor.
Now if they were going to deploy this on nuclear powered ships designed to sail with a fleet to produce fuel for the fleet, different story.
There's Good news and Bad news! I am excited about the fuel alternative, but the process has been in existence for too long or the results to be so miniscule. Producing fresh water and energy from sea water is not new. Producing thorium power from sea water is the future. Too many scientists and physicists know this.... the government still hasn't read the memo?
I can sorta see the sense for needing a reliable source of liquid
fuels on (nuclear-powered*) aircraft carriers - but surely there must be
dozens of better ways of recovering HCs and upgrading them to fuels. ... How about all those defecating seamen for a start! ... Food waste... CO2 in engine exhaust ... blah blah blah
* why, nowhere in the article do the words 'electricity' or 'nuclear' even appear? - Shoddy.
Will taking CO2 out of sea water cause kelp and other seaweeds to die??? Remember that CO2 is a fertilizer and plants need it to grow.
No mention of where the energy comes from to make the fuel...
It does say 92% efficiency, so 1,000 gallons of diesel will get you 920 gallons of clean fuel (in the perfect diesel to clean fuel process). Or, it's electricity? If so, nuclear sourced electricity requires about 3x the thermal (just as coal, etc, due to the confines of thermodynamics). Perhaps the 92% is from thermal reactions which would make the nuclear FAR more efficient!
This, then would be a model for the world. Develop whatever best and safest nuclear (such as the molten salt reactor or fast reactor) and make clean liquid fuels from CO2 and H2O in the oceans.
This 92%, however, sounds to good to be true. Even at a lower efficiency, nuclear must be the clean energy source which powers planetary civilizations (wind and solar are too intermittent and diffuse to power such large ships).
If this worked it'd put most of the petrochemical industry out of business overnight and largely solve global carbon emission problems.
These molecules (H20 and C02) are tightly bound in a low energy state. It takes net energy input to separate/rearrange them into a combustable form. Where is that energy going to come from in a ship at sea?
Let me see it currently cost $3.50 to $4.00 per gallon for fuel and the navy or author says the Navy wants to be in the $3.00 to $6.00 per gallon range. It is O.K. if we are at the $3.00 range, but anything over $4.00 seems a loss for the taxpayers. Am I missing something here????
And no mention of the long term effect of extracting/burning - or possibly dissolving it back into seawater....
You forgot to mention that this requires power, ie a nuclear reactor.
You need electricity to get hydrogen from seawater.
"I do not see how the energy to power the process could ever be substantially less than the energy created to make this worth doing."
It doesn't work that way. Sum of inputs (life cycle) where work is done is always > sum of outputs. This is conservation of energy and matter and simple thermodynamics, otherwise we would have a 'perpetual motion machine'.
Government PR would have science-illiterate Americans believe they are going to get a free lunch. If it wasn't so sickening it would be funny.
@Big Foot John Not a problem. It will just reduce the acidification that has been occurring because of burning fossil fuels. There is no chance we will reduce the CO2 in sea waters below what is was 100 years ago when all those seaweeds were doing just fine.
@UNCLE STOAT Or, it could help the coal industry. By capturing CO2 and feeding the gas through a chemical reagent to produce heat/power you could add the system to a coal plant, capture the carbon and produce additional power from it. This would be a net add, while conventional pollution control reduces power output. You would also reduce or eliminate a green house gas source. Much depends on cost and efficiency.
@Uncle Stoat Nuclear.
Actually I hear the cost is closer to $50-$60 a gallon when you add the cost of shipping it out to the ships. The airforce cost is $3-$4 a gallon on the ground, but $20 a gallon if you hook up to a tanker aircraft. You alway have to add the cost of logistics.
Actually I hear the total cost for shipping fuel to tje ships is $50 to $60 a gallon. Just like the airforce buys and fuels its jets at $3-4 a gallon, getting fuel from a tanker aircraft cost $20 a gallon. Always have to count the cost of logistics
@geofer50 It's not all about cost; it's about availability and redundancy. $4-per-gallon fuel doesn't do you any good if you are thousands of miles away from a friendly port.
@geofer50 it's not that they want to be in that range it's what it cost to produce the fuel.
but if you take into account that it's eliminate the need for stops to refuel, transprtation the fule to the ship
need to stock up on fuel and other storage costs ,other extra costs
it might still be cheaper over all. but given the fact that you need to produce electricity to make this work, I repeat again why not just
go all electric all together?
it might not be the same as on land, where it have been prooven that electric motors are more efficient compaired to ICE so I am not sure
@ma4cma4c well frankly if you need electicity to get this working than why not just convert the boat to electric power all together?
the tech exists today, there are many nuc powered submarines in service today.
As much as I like transparency in government, nuclear is one of those issues that's far out of reach of the average voter's level of understanding. They don't even realize the 3 main accidents they're aware of are 3 different types of reactors.
Excactly; three different types of reactors. None of them is reliable, despite their differences. Understanding nuclear energy is easy, it's just that very few care to delve into it. It's so much easier to just watch gameshows and eat garbage. And IF something happens that You don't understand, You can always sue. It's the american way.
Back to the topic: CO2 is already burnt carbon. And extracting hydrogen is nothing new, as has already been stated. So where is the invention? And why not drive these ships directly with nuclear power? Because even the military knows how dangerous nuclear power is.