That is exactly why its such a big deal. Current jet fuel costs over $8/gal delivered. It costs so much because even if it comes out of the refinery at San Diego at $2/gal it has to be loaded into an oiler [1] and then driven out to sea where the carrier task group is.
If you're on a nuclear powered aircraft carrier you have plenty of electricity so this is a pretty huge win.
Of course an alternative way to make this feasible for the fleet would be to build a nuclear powered oiler. It could process seawater into jet fuel as it cruised along with the fleet and transfer fuel as needed, but to this day fuel transfer at sea is one of the more dangerous things they do.
Jet Fuel (Kerosene) closed at $3.135/gallon today[1]. And that doesn't include the cost of transporting it from the Gulf Coast to where your Navy needs it.
In 2009, chemists working for the U.S. Navy investigated a modified Fischer–Tropsch process for generating fuels. When hydrogen was combined with the carbon dioxide over a cobalt-based catalyst, the reaction produced mostly methane gas. However, the use of an iron-based catalyst reduced methane production to 30 per cent with the rest being predominantly short-chain, unsaturated hydrocarbons [27] The introduction of ceria to the catalyst's support, functioning as a reverse water gas shift catalyst, furthermore increased the yield of the reaction. [28]. The short chain hydrocarbons were successfully upgraded to liquid fuels over solid acid catalysts, such as zeolites.
[A patent application and a more in-detail research paper describing the process(es) is referenced there.]
Overall this looks very interesting as a military application (independence from other sources, logistics).
You will find more articles from 2009+ on this topic by searching for "Fischer-Tropsch seawater".
This is why electric vehicles won't work. I'll copy in most of a comment I made a few days back.
Let's say tomorrow some grad student gets fusion going at a very low price. The best way to use this to power cars would be to use it to create a fuel with a high energy density. If you had 'free energy' you'd extract C02 from the atmosphere and turn it into a hydrocarbon.
the key quote is:
"The ones that are technically trained get it right away: hydrocarbons, which we burned today have the greatest energy density possible of all fuels. Things that have carbon in them. Will people fly airplanes? Usually people say yes for the same reasons. Well, how are you going to make the airplanes fly? Battery. Batteries are pretty heavy. Oh--you can't have airplanes unless you have hydrocarbon fuels. You could in theory do it with hydrogen, but it's highly dangerous, noxious fuel. Quantum-mechanically, we know the energy content of those fuels is optimal. There will never be anything that beats them."
A massive breakthrough in energy density for batteries might be possible but it's unlikely. Huge resources have been put into improving batteries and while they have improved it's not been enough to get near the energy density of hydrocarbons.
Electrolysing water to make H2 and extracting CO2 from the environment, and then synthesizing hydrocarbons from them, is extremely energy inefficient.
Sure, theoretically, it can be done, and maybe one day it could even be done efficiently. But Tesla is making battery-electric cars that work today.
The military does not care about efficiency because they have nuclear reactors on their ships and their goal is to not to have to transport liquid fuel.
Lithium-air batteries (an immature technology, certainly) have an energy per gram 3.5 times less than gasoline's. But electric motors are about 3.5 times more efficient than internal combustion engines. And the technology to produce synthetic fuels from CO2 is pretty much as far from mass scale as lithium-air batteries.
I agree that we will need carbon-based fuels for jet engines, but as for cars, the physics and economics are by no means as favorable as you represent.
"Let's say tomorrow some grad student gets fusion going at a very low price. The best way to use this to power cars would be to use it to create a fuel with a high energy density."
That is incorrect. If the fusion source is compact, and can produce a lot of instantaneous electrical power, and is quick to throttle up and down, then a "Back to the Future"-style Mr. Fusion would be the best way to power cars.
Energy density isn't the only factor. There's also a question of infrastructure. Electrical distribution has few moving parts, while extracting C02 from the atmosphere to make fuel and distributing the fuel has many more mechanical parts. A fusion plant which could produce 50 kW, weighed 2 tons, and could be installed in the back yard of a home would mean that a house could be off the grid and still have power left over to charge the car, while using intermediate hydrocarbon storage would mean trips to fill the car, or heating oil, or cooking gas.
So while I completely agree that airplanes will not be powered by batteries, I don't think that energy density is the only factor to consider in the economics equation.
Your argument is only balanced on that one premise of Fusion or free energy, both of which are still vaporware and will be for decades if not centuries to come. Have you considered that maybe electric cars will fill the gap between now and then if ever? And you consider free energy a possibility but advancement in battery technology too far fetched. I don't agree at all.
Energy density is a critical issue for aircraft because lift/drag ratios are capped at around 15 to 30. For every 15-30 N of fuel weight, you must supply at least 1 N of additional thrust (which translates to power, once you multiply by speed).
Cars, on the other hand, experience a combination of aerodynamic and powertrain drag and rolling resistance, of which only (mostly?) the rolling resistance depends on mass. The typical coefficient of rolling resistance is about 10x better than the typical L/D ratio for aircraft (if I believe Wikipedia). Hence, road vehicles are 10x less sensitive to energy density than aircraft.
So a statement that electric vehicles won't work is nonsense, without considering how sensitive the different vehicles are to fuel mass.
Most people miss the difference between hydrocarbon fuels as energy source* and as energy carrier. If you make HC fuels from atmospheric or oceanic carbon, you have a nice closed cycle.
(*) Technically fossilised solar energy of course.
Very good point. But it doesn't make Tesla cars a folly so much as put a strong constraint on their long term economic viability: the invention of fusion power or some other method of making energy abundant turned to making hydrocarbons effectively renewable. But that could be decades away, timeline of practical viability is effectively unknown. Considering how speculative this notion of really cheap energy is (for now), I still think Tesla is a good bet. On the event of the floor dropping off the prices in energy markets, there will be few that are dependent on large energy barriers to entry that will emerge unscathed.
It is also effectively win-win. If such a thing becomes possible the costs in much of production will cut very drastically and the potential of things now open would be just incredible. So much of expense is due to energy constraints.
Electric engines run at 92% efficiency. Car engines run at ~15%. So energy density need not reach equivalence.
That physicist is wrong too (Nobel prizes don't mean you aren't wrong - it just means people listen to you more) - jet engines on planes require oxygen to work - hence capped at ~10 km altitude with massive drag causing ineffecient travel.
10 years till battery tech reaches complete parity for lowest denominator cars, and 7 years before we start to see hyper sonic electric passenger jets being tested way up in the upper atmosphere (no oxygen needed, go as high and fast as you want - London - LA in a few hours - space views - cheap power).
When energy is cheap, plentiful and clean things like this are possible. If only we built more nuclear power plants and solar power farms. Turning coal into jet fuel isn't a great idea :)
One of the main endurance (and damage control) problems for a nuclear carrier is the huge amount of jet fuel used by the air wing, so this would be a huge deal. After jet fuel, they just need to underway replenish armaments and food, both of which are easier than fuel (food isn't dangerous, and most missions don't expend weapons now, so the total volume is lower than for fuel).
Once again, military research might lead the way. Note, if they invest into this, it's _not_ because of reduced price, increased efficiency or reduced greenhouse effects, but because of an _strategic_ advantage against "the enemy".
Personally, I read about similar methods, for synthesizing carbon based fuels, many times before. Most of them were private founded but rather small scale. I can't judge if there was a significant science or engineering breakthrough. So, I suspect the only thing that might have changed, is that a clever guy convinced the military this would be a huge strategic advantage.
The ironic thing is, the US could instead focus on producing all their fuel at home to end the dependency on oil from the middle east. Then, they would have an even bigger strategic advantage and wouldn't need as much military investment.
Anyway, we might end up with synthetic carbon based fuel with all its advantages - and probably the military can keep their carriers.
Can someone who knows about this stuff comment on whether the energy required to extract the H2 from the water, is more than the energy contained in the chemical bonds of the H2 itself?
(assume both sides of the comparison contain equal number of molecules)
I suspect it is.. otherwise they are potentially sitting on a much more important innovation, than mere jet fuel.
Consider it from the perspective of the conservation of energy:
2H2 + O2 = 2H2O + energy
The energy is on the right because the reaction is exothermic.
The opposite reaction must be endothermic and must have the same amount of energy on the left:
2H2O + energy = 2H2 + O2
Otherwise, energy isn't conserved.
Because nothing is 100% efficient, there's also energy lost to inefficiencies. So the answer to your question is that yes, you need more energy to make the second reaction happen than is stored in the chemical bond.
Isn't this also heavily destructive to our ecosystem because they use the carbon trapped in the water and release it into our atmosphere? Didn't we want more trapped carbon than less?
I don't get why everyone finds this great since it takes a very long time for carbon in the atmosphere to get trapped in seawater.
CO2 in atmosphere -> CO2 in water -> Ocean acidification[1] -> Change in ocean ecosystem
The oceans absorb OC2 from the atmosphere, which you could argue is good, but it is not without consequences. Putting CO2 in the water moves the problem from having it in the atmosphere elsewhere, but it's still a problem. In some ways then, this can be seen as a good thing, because it is undoing the effects that increased CO2 in the atmosphere has on the oceans. Obviously though, I doubt that its effects would be at all noticeable.
The wiki article already linked has a chapter called 'Possible Impact'.
France could certainly use this technology. With their abundance of unused nuclear power and access to the sea, this could bridge the gap between hydrocarbon powered and electric vehicles.
jws|13 years ago
initial studies predict that jet fuel from seawater would cost in the range of $3 to $6 per gallon to produce
ChuckMcM|13 years ago
If you're on a nuclear powered aircraft carrier you have plenty of electricity so this is a pretty huge win.
Of course an alternative way to make this feasible for the fleet would be to build a nuclear powered oiler. It could process seawater into jet fuel as it cruised along with the fleet and transfer fuel as needed, but to this day fuel transfer at sea is one of the more dangerous things they do.
[1] http://en.wikipedia.org/wiki/Replenishment_oiler
Sukotto|13 years ago
Jet Fuel (Kerosene) closed at $3.135/gallon today[1]. And that doesn't include the cost of transporting it from the Gulf Coast to where your Navy needs it.
[1] Sep 28, 2012: http://www.eia.gov/dnav/pet/pet_pri_spt_s1_d.htm
fpp|13 years ago
From Wikipedia on Fischer-Tropsch: ( http://en.wikipedia.org/wiki/Fischer–Tropsch_process )
Carbon dioxide reuse
In 2009, chemists working for the U.S. Navy investigated a modified Fischer–Tropsch process for generating fuels. When hydrogen was combined with the carbon dioxide over a cobalt-based catalyst, the reaction produced mostly methane gas. However, the use of an iron-based catalyst reduced methane production to 30 per cent with the rest being predominantly short-chain, unsaturated hydrocarbons [27] The introduction of ceria to the catalyst's support, functioning as a reverse water gas shift catalyst, furthermore increased the yield of the reaction. [28]. The short chain hydrocarbons were successfully upgraded to liquid fuels over solid acid catalysts, such as zeolites.
[A patent application and a more in-detail research paper describing the process(es) is referenced there.]
Overall this looks very interesting as a military application (independence from other sources, logistics).
You will find more articles from 2009+ on this topic by searching for "Fischer-Tropsch seawater".
sien|13 years ago
This is why electric vehicles won't work. I'll copy in most of a comment I made a few days back.
Let's say tomorrow some grad student gets fusion going at a very low price. The best way to use this to power cars would be to use it to create a fuel with a high energy density. If you had 'free energy' you'd extract C02 from the atmosphere and turn it into a hydrocarbon.
For more info look at:
http://en.wikipedia.org/wiki/Energy_density
and this interview with Nobel Prize winning Physicist Robert Laughlin
http://www.econtalk.org/archives/2010/08/laughlin_on_the.htm....
the key quote is: "The ones that are technically trained get it right away: hydrocarbons, which we burned today have the greatest energy density possible of all fuels. Things that have carbon in them. Will people fly airplanes? Usually people say yes for the same reasons. Well, how are you going to make the airplanes fly? Battery. Batteries are pretty heavy. Oh--you can't have airplanes unless you have hydrocarbon fuels. You could in theory do it with hydrogen, but it's highly dangerous, noxious fuel. Quantum-mechanically, we know the energy content of those fuels is optimal. There will never be anything that beats them." A massive breakthrough in energy density for batteries might be possible but it's unlikely. Huge resources have been put into improving batteries and while they have improved it's not been enough to get near the energy density of hydrocarbons.
ta12121|13 years ago
Electrolysing water to make H2 and extracting CO2 from the environment, and then synthesizing hydrocarbons from them, is extremely energy inefficient.
Sure, theoretically, it can be done, and maybe one day it could even be done efficiently. But Tesla is making battery-electric cars that work today.
The military does not care about efficiency because they have nuclear reactors on their ships and their goal is to not to have to transport liquid fuel.
comicjk|13 years ago
I agree that we will need carbon-based fuels for jet engines, but as for cars, the physics and economics are by no means as favorable as you represent.
dalke|13 years ago
That is incorrect. If the fusion source is compact, and can produce a lot of instantaneous electrical power, and is quick to throttle up and down, then a "Back to the Future"-style Mr. Fusion would be the best way to power cars.
Energy density isn't the only factor. There's also a question of infrastructure. Electrical distribution has few moving parts, while extracting C02 from the atmosphere to make fuel and distributing the fuel has many more mechanical parts. A fusion plant which could produce 50 kW, weighed 2 tons, and could be installed in the back yard of a home would mean that a house could be off the grid and still have power left over to charge the car, while using intermediate hydrocarbon storage would mean trips to fill the car, or heating oil, or cooking gas.
So while I completely agree that airplanes will not be powered by batteries, I don't think that energy density is the only factor to consider in the economics equation.
lumberjack|13 years ago
pigboy|13 years ago
Cars, on the other hand, experience a combination of aerodynamic and powertrain drag and rolling resistance, of which only (mostly?) the rolling resistance depends on mass. The typical coefficient of rolling resistance is about 10x better than the typical L/D ratio for aircraft (if I believe Wikipedia). Hence, road vehicles are 10x less sensitive to energy density than aircraft.
So a statement that electric vehicles won't work is nonsense, without considering how sensitive the different vehicles are to fuel mass.
Mvandenbergh|13 years ago
(*) Technically fossilised solar energy of course.
Dn_Ab|13 years ago
It is also effectively win-win. If such a thing becomes possible the costs in much of production will cut very drastically and the potential of things now open would be just incredible. So much of expense is due to energy constraints.
confluence|13 years ago
Electric engines run at 92% efficiency. Car engines run at ~15%. So energy density need not reach equivalence.
That physicist is wrong too (Nobel prizes don't mean you aren't wrong - it just means people listen to you more) - jet engines on planes require oxygen to work - hence capped at ~10 km altitude with massive drag causing ineffecient travel.
10 years till battery tech reaches complete parity for lowest denominator cars, and 7 years before we start to see hyper sonic electric passenger jets being tested way up in the upper atmosphere (no oxygen needed, go as high and fast as you want - London - LA in a few hours - space views - cheap power).
spullara|13 years ago
ryanwaggoner|13 years ago
rdl|13 years ago
FrojoS|13 years ago
Personally, I read about similar methods, for synthesizing carbon based fuels, many times before. Most of them were private founded but rather small scale. I can't judge if there was a significant science or engineering breakthrough. So, I suspect the only thing that might have changed, is that a clever guy convinced the military this would be a huge strategic advantage.
The ironic thing is, the US could instead focus on producing all their fuel at home to end the dependency on oil from the middle east. Then, they would have an even bigger strategic advantage and wouldn't need as much military investment. Anyway, we might end up with synthetic carbon based fuel with all its advantages - and probably the military can keep their carriers.
1rae|13 years ago
wamatt|13 years ago
Can someone who knows about this stuff comment on whether the energy required to extract the H2 from the water, is more than the energy contained in the chemical bonds of the H2 itself? (assume both sides of the comparison contain equal number of molecules)
I suspect it is.. otherwise they are potentially sitting on a much more important innovation, than mere jet fuel.
jordanb|13 years ago
2H2 + O2 = 2H2O + energy
The energy is on the right because the reaction is exothermic.
The opposite reaction must be endothermic and must have the same amount of energy on the left:
2H2O + energy = 2H2 + O2
Otherwise, energy isn't conserved.
Because nothing is 100% efficient, there's also energy lost to inefficiencies. So the answer to your question is that yes, you need more energy to make the second reaction happen than is stored in the chemical bond.
Roritharr|13 years ago
I don't get why everyone finds this great since it takes a very long time for carbon in the atmosphere to get trapped in seawater.
zmmz|13 years ago
CO2 in atmosphere -> CO2 in water -> Ocean acidification[1] -> Change in ocean ecosystem
The oceans absorb OC2 from the atmosphere, which you could argue is good, but it is not without consequences. Putting CO2 in the water moves the problem from having it in the atmosphere elsewhere, but it's still a problem. In some ways then, this can be seen as a good thing, because it is undoing the effects that increased CO2 in the atmosphere has on the oceans. Obviously though, I doubt that its effects would be at all noticeable.
The wiki article already linked has a chapter called 'Possible Impact'.
1: http://en.wikipedia.org/wiki/Ocean_acidification
jimworm|13 years ago
gunn|13 years ago
landryraccoon|13 years ago
unknown|13 years ago
[deleted]
bluestix|13 years ago
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