Fuel cells may have lost some steam of late here in the automotive realm, but they're still going strong at 30,000 feet. Over in Hamburg, Germany, the Antares DLR-H2 has become the first piloted aircraft capable of taking off using only power from fuel cells, which means that it flies with absolutely no carbon emissions. The craft is based on the Antares 20E glider, which boasts a wingspan of just over 65 feet and has a cruising range of 466 miles over five hours. Currently, the propulsion system permits maximum flying speeds of around 105mph, but we're certain those behind the creation are gunning for more. As for its future? It'll be stationed at Lufthansa Technik in Hamburg where it'll act a "flying test platform" for the next three years, and afterwards, we fully expect to see this thing fetch a pretty penny on eBay. Action-packed video is after the break.
Actually, Boeing used a combination of battery and fuel-cell power for take-off and ascending whereas this aircraft used ONLY fuel-cell power the entire time.
Fuel cells are only zero-emissions if the hydrogen is produced from renewable energy. Most hydrogen today is produced by reforming natural gas or other fuels that absolutely has emission.
Making no judgement on the viability of fuel cells or other technologies, it is important to realize when technologies are 'zero-emissions' and when they are quasi-zero-emissions.
You are completely correct. However, it is still important for these first steps so that they become more mainstream and cleaner, no-emission sources of hydrogen become economical (such as electrolysis of water with electricity produces from non-carbon emitting sources).
Also, hydrogen from gasified fossil fuels used to power fuel cells is still WAY more efficient than the direct burning of the same fossil fuels, so it is a step in the right direction.
No, fuel-cells do not store any energy. They simply convert a fuel (in this case, hydrogen gas) to usable energy (in this case, torque). The energy is stored in the FUEL, the fuel cell is simply the transforming component.
"Making no judgment on the viability of fuel cells"
I will. Aircraft and spacecraft are the only areas where I think fuel cells make any kind of sense. Firstly, electrolysis of water is inefficient, only about half the electricity actually produces usable fuel, the other half is waste heat. Then you need to compress it, (more energy) ending up with only about 40% to 45% efficiency to generate the H2 from H2O, never mind that most H2 comes from natural gas... then the efficiency of fuel cell systems to drive motors is only about 50%. So the total efficiency from production to kinetic is somewhere around 22.5% (50% of 45%). This does not factor in the efficiency of producing and delivering the electricity used for electrolysis. For planes this makes sense because batteries are too heavy.
Contrast that with charging LiIon batteries, which is 90%+ efficient, then the efficiency of a battery driven motor is around 85%. Of your original energy investment you get about 75% efficiency (85% of 90%).
@schmitty - you're right technically, but wrong practically. The point Nelson was trying to make is that hydrogen itself is not in practice a fuel, but a means of energy (usually electricity) storage. This is because rather than hydrogen materialising from thin air or spouting out of the ground or whatever, it has to be produced - usually by a process that uses electricity. Then a fuel cell converts hydrogen back to electricity again, with some proportion of losses. In other words, for practical purposes, hydrogen fuel has the same effect as a rechargeable battery - energy storage.
It's an interesting type of energy storage technology though because of the high energy density etc.
And the Antares is meant only as a test platform to save costs for including fuel cells into airliners. Doing every test in a live Airbus is costing a lot. Getting the security clearing alone is costly enough.
Fuel cells in Airliners have certain features: - the Airliner could drive on the ground on its own - when you have a power loss the blue system would be powered by the fuel cell instead of an emergency flap out power generating turbine. Has the advantage that at low speed you still have the full power - you can use it to flood the tanks with Nitrogenium during a rapid emergency descend to prevent the inflooding air creating an explosive mixture with the kerosine.
Fuel-cells are still a premature battery technology, and thats what they are... in the respect that there are no lakes of hydrogen lying about, so while it may be abundant you aren't going to find it anywhere in the planet not bonded to something else. So currently you are either using electrolysis to extract hydrogen and then further power to compress and transport it, or you're extracting it from natural gas which while more efficient clearly doesn't represent a fuel source but an energy transport.
And SURPRISE, NIMH and nano-tech lithium batteries are simply more efficient batteries when it comes to transporting that energy (currently around 90% plant to output efficiency which is amazing compared to about 25% for fuel-cells to date). So, people, lets leave fuel cells where they belong, IN THE LAB, and lets get more viable technology out there in the field such as NIMH and Lithium powered aircraft. By being many times more efficient, its greener, and its output on release is also 0% pollution and the batteries themselves now have very long lifespans and the nickel recovered from the recycling process (the only real toxic/bad part) more than pays for the recycling process making it a viable "lets get this ball rolling" answer for today, not tomorrow!!! =)
Ummmm.....no..... Fuel-cells have are a MUCH better technology for portable power than any battery on the large scale. Filling up a tank of hydrogen (in the future hopefully mostly obtained through electrolysis of water with clean energy from hydro/wind/solar/thermal/etc electricity) in 1 minute is a hell of a lot faster and just as equally efficient (electricity transported from generating plant to transforming stations to your house/charging station to your battery loses just as much and sometimes more, depending on how far it travels, energy than conversion of energy to hydrogen storage and back).
My point is, for large-scale, portable power supplies, fuel-cells are far superior to any current or near-future battery tech.
Energy transported from a power plant to the point of use for either electrolysis or charging a battery is going the be the same so is not relevant.
Electrolysis to H2 to fuel cell to kinetic is only 20% to 25% efficient. Charging a LiIon battery to drive a motor is overall about 70% to 75% efficient.
With today's technology batteries are about 3 time as efficient as fuel cells.
H2 has a much higher energy density that LiIon batteries, but the volume required is quite large, even if you liquefy the H2 (which takes a fair amount of energy BTW), so there is a practical limit to how much you can take with you.
The only advantage H2 has over batteries as a storage medium is density, which makes a lot of difference in an aircraft, where safety and range are more important than efficiency, and weight is a critical factor. In an automobile however, IMO fuel cells make no sense when compared to even current battery technology.
I disagree. Large hydrogen production plants would almost definitely be located at or extremely near the point of electricity generation. The loss of energy transporting hydrogen gas via pipeline is negligible whereas the loss of electrical potential over hundreds or thousands of kilometers (this distance will increase as we transport more and more renewable energy from areas with the best wind/hydro/solar resources to areas of high demand).
It basically comes down to storage. Massive quantities of hydrogen gas can be stored extremely easily and relatively cheaply, and the same cannot be said about electricity which, except for very small scale, cannot be stored in adequate amounts.
The one most crucial factor in a plane is weight. And Lithium Ion Batteries Are after all heavy. just take out your laptop battery and you'll be astonished how much lighter your laptop got. What theyre testing here is not only the possibility of fuel cells in a plane but also the possibility of H2 driven planes. After all it IS possible to build a H2 turbine, and H2-driven rockets are nothing new either.
The one crucial thing is: how do you store the H2 safely in a plane. and from there on you can think about all the possibilities. I think this project will give us a lot of insight how H2 could be stored on a plane safely.
The best bet so far for aircraft storage of hydrogen is as a supercooled liquid. This way it takes up little room, is no more 'unsafe' than current jet fuel storage.
Another benefit of this storage method is that it can be used to create liquid nitrogen before it is combusted, which can then be circulated around the wings/body of the aircraft to reduce drag, thus increasing speed and/or fuel efficiency even further.
actually I was considering the possibility that one day maybe liquid hydrogen might replace kerosine (i hope i spelled it right, im no native speaker).
the liquid nitrogen method is also very interesting.. it's a russian invention if im not mistaken: the "shkval" torpedo. it uses supercavity effects to reduce the drag in water. this might of course be applied also to planes, by creating a "bubble" of a gas with lower density than air around the plane so you could reduce the drag coefficient. I'm not sure though if the effect has such an impact on efficiency that it's worth the trouble to implement. but of course further research is needed to be certain about such effects.
and yeah, it's good to see some mature discussions on engadget, lately the average age of the readers seems to have dropped to under-14, considering all those "FIRST !!!!" comments and whining about "oh, the apple product is the better one", etc. (Im not attacking apple fanboys here, so please dont start a war now)
As a glider pilot myself, I think I should clarify a few points here -- though I think this is great news.
Primarily: "cruising range of 466 miles over five hours"
The Antares 20E uses an electric motor for launch, climbs up to about 5,000', and then shuts down the engine and folds up the propeller in to the body of the aircraft. Then, using just gravitational potential energy, flies across the countryside until it's low, then it opens up the propeller and climbs back up to 5,000' or so and repeats.
This is referred to as "Sawtooth Operation." The Antaries 20E has a glide ratio of 56:1, which means that as it descends from 5,000 to 1,000ft while travelling 224,000ft forward -- about 56km or 42 miles. So, this means that 466 miles over 5 hours means 11 climbs, which take about 3 minutes each. So, the motor can run for about 35-40 minutes per flight.
Next up: "propulsion system permits maximum flying speeds of around 105mph but we're certain those behind the creation are gunning for more"
Well, for the design of the aircraft, that's the optimized climbing speed. That glide ratio of 56:1 I mentionned above is the peak of efficiency, and it's at about 75mph. The aircraft can fly at up to 180mph, but then it's gliding distance performance drops off significantly: http://www.lange-aviation.com/htm/english/products/antares_20e/technical_data.html
So, this "flying speed" of 105mph (92 kts) is the speed it flies during climb, then it drops to 75mph for descent while the engine is stowed in order to get that 466-mile range they spoke of earlier.
I can say with certainty that this aircraft cannot fly 466 miles at 105mph at a constant altitude.
As for the "gunning for more" comment -- again, it has nothing to do with the fuel cells, it's just that 105mph is the most efficient climbing speed, and certainly not the most efficient cross-country cruising speed. Since this fuel cell can only run the aircraft for about half an hour, their primary goal will be to extend that running time long before they consider putting this energy system in to a "faster" aircraft.
A fuel cell is simply a container for fuel!! My Cessna 172 has a fuel cell... It drive me crazy when people refer to hydrogen based engines as "fuel cells".
"Ummmm.....no..... Fuel-cells have are a MUCH better technology for portable power than any battery on the large scale. Filling up a tank of hydrogen (in the future hopefully mostly obtained through electrolysis of water with clean energy from hydro/wind/solar/thermal/etc electricity) in 1 minute is a hell of a lot faster and just as equally efficient (electricity transported from generating plant to transforming stations to your house/charging station to your battery loses just as much and sometimes more, depending on how far it travels, energy than conversion of energy to hydrogen storage and back).
My point is, for large-scale, portable power supplies, fuel-cells are far superior to any current or near-future battery tech."
See, its this kind of ignorance that I'm talking about. Its one thing to be wrong, its another to be so confident about a fallacy, and I blame the media and politicians for this. The above poster for example completely disregarded the comment about efficiency, and makes up his own. Lets look at actual facts here... the efficiency of obtaining hydrogen through electrolysis (the easiest and also least efficient prospect) is in the range of 25-40%. Hydrogen has extremely low energy density, so it has to be compressed to be viable, and anyone with an air-compressor knows how much power that involves. I won't even delve into the ridiculousness of claiming that it is less expensive and energy efficient to transport liquid hydrogen in trucks compared to the electrical grid that is already in place. The neurons should start firing and you'd figure out pretty quickly that its at the very least no less expensive than transporting gasoline, and maybe, just maybe, a little more pricey considering the 10K PSI pressure and temperature sensitivity of the medium.
Do everyone a favor and lookup the actual EROEI on hydrogen fuel cell technology right now and compare that to a NIMH or A123 lithium battery, and before you come back and say something silly like "well, just build ten times more nuclear plants", look into the actual cost and time involved in building one.
A hydrogen economy is a possible FUTURE technology, but it sucks ass right now and does not belong outside the lab. NIMH and nano lithium battery technology is a right now viable technology, and it'd be nice if the mainstream media and politicians acknowledged this. The potential benefit of a hydrogen economy is that, as a liquid, it'd be very quick to fill a vehicle. But battery technology isn't at a standstill either (far from it), and rapid-charge batteries and cheap super capacitors are on the horizon.
The best bet so far for aircraft storage of hydrogen is as a supercooled liquid. This way it takes up little room, is no more 'unsafe' than current jet fuel storage.
Another benefit of this storage method is that it can be used to create liquid nitrogen before it is combusted, which can then be circulated around the wings/body of the aircraft to reduce drag, thus increasing speed and/or fuel efficiency even further.
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posted Jul 9th 2009 8:57AM
FIRRRRRRRRRRSSSSSTTTTT
he said "poopy".
Actually Boeing was first over a year ago to fly a completely fuel cell powered aircraft:
http://www.boeing.com/news/releases/2008/q2/080403a_nr.html
They also have flown a fuel cell powered helicopter, but that is designed for military applications.
Actually, Boeing used a combination of battery and fuel-cell power for take-off and ascending whereas this aircraft used ONLY fuel-cell power the entire time.
Fuel cells are not necessarily zero-emission!
Fuel cells are only zero-emissions if the hydrogen is produced from renewable energy. Most hydrogen today is produced by reforming natural gas or other fuels that absolutely has emission.
Making no judgement on the viability of fuel cells or other technologies, it is important to realize when technologies are 'zero-emissions' and when they are quasi-zero-emissions.
You are completely correct. However, it is still important for these first steps so that they become more mainstream and cleaner, no-emission sources of hydrogen become economical (such as electrolysis of water with electricity produces from non-carbon emitting sources).
Also, hydrogen from gasified fossil fuels used to power fuel cells is still WAY more efficient than the direct burning of the same fossil fuels, so it is a step in the right direction.
I'm beginning to think that most people view fuel cells as an energy source. The reality is that it's an energy STORAGE system.
You have to do something to get the energy into it -- That's the hydrogen.
@ Nelson,
No, fuel-cells do not store any energy. They simply convert a fuel (in this case, hydrogen gas) to usable energy (in this case, torque). The energy is stored in the FUEL, the fuel cell is simply the transforming component.
"Making no judgment on the viability of fuel cells"
I will. Aircraft and spacecraft are the only areas where I think fuel cells make any kind of sense. Firstly, electrolysis of water is inefficient, only about half the electricity actually produces usable fuel, the other half is waste heat. Then you need to compress it, (more energy) ending up with only about 40% to 45% efficiency to generate the H2 from H2O, never mind that most H2 comes from natural gas... then the efficiency of fuel cell systems to drive motors is only about 50%. So the total efficiency from production to kinetic is somewhere around 22.5% (50% of 45%). This does not factor in the efficiency of producing and delivering the electricity used for electrolysis. For planes this makes sense because batteries are too heavy.
Contrast that with charging LiIon batteries, which is 90%+ efficient, then the efficiency of a battery driven motor is around 85%. Of your original energy investment you get about 75% efficiency (85% of 90%).
@schmitty - you're right technically, but wrong practically. The point Nelson was trying to make is that hydrogen itself is not in practice a fuel, but a means of energy (usually electricity) storage. This is because rather than hydrogen materialising from thin air or spouting out of the ground or whatever, it has to be produced - usually by a process that uses electricity. Then a fuel cell converts hydrogen back to electricity again, with some proportion of losses. In other words, for practical purposes, hydrogen fuel has the same effect as a rechargeable battery - energy storage.
It's an interesting type of energy storage technology though because of the high energy density etc.
The Boing one was a hybrid system.
And the Antares is meant only as a test platform to save costs for including fuel cells into airliners.
Doing every test in a live Airbus is costing a lot. Getting the security clearing alone is costly enough.
Fuel cells in Airliners have certain features:
- the Airliner could drive on the ground on its own
- when you have a power loss the blue system would be powered by the fuel cell instead of an emergency flap out power generating turbine. Has the advantage that at low speed you still have the full power
- you can use it to flood the tanks with Nitrogenium during a rapid emergency descend to prevent the inflooding air creating an explosive mixture with the kerosine.
Wow, that's crazy. I had no idea the Auto-Tune people made airplanes.
Fuel-cells are still a premature battery technology, and thats what they are... in the respect that there are no lakes of hydrogen lying about, so while it may be abundant you aren't going to find it anywhere in the planet not bonded to something else. So currently you are either using electrolysis to extract hydrogen and then further power to compress and transport it, or you're extracting it from natural gas which while more efficient clearly doesn't represent a fuel source but an energy transport.
And SURPRISE, NIMH and nano-tech lithium batteries are simply more efficient batteries when it comes to transporting that energy (currently around 90% plant to output efficiency which is amazing compared to about 25% for fuel-cells to date). So, people, lets leave fuel cells where they belong, IN THE LAB, and lets get more viable technology out there in the field such as NIMH and Lithium powered aircraft. By being many times more efficient, its greener, and its output on release is also 0% pollution and the batteries themselves now have very long lifespans and the nickel recovered from the recycling process (the only real toxic/bad part) more than pays for the recycling process making it a viable "lets get this ball rolling" answer for today, not tomorrow!!! =)
Ummmm.....no..... Fuel-cells have are a MUCH better technology for portable power than any battery on the large scale. Filling up a tank of hydrogen (in the future hopefully mostly obtained through electrolysis of water with clean energy from hydro/wind/solar/thermal/etc electricity) in 1 minute is a hell of a lot faster and just as equally efficient (electricity transported from generating plant to transforming stations to your house/charging station to your battery loses just as much and sometimes more, depending on how far it travels, energy than conversion of energy to hydrogen storage and back).
My point is, for large-scale, portable power supplies, fuel-cells are far superior to any current or near-future battery tech.
Energy transported from a power plant to the point of use for either electrolysis or charging a battery is going the be the same so is not relevant.
Electrolysis to H2 to fuel cell to kinetic is only 20% to 25% efficient. Charging a LiIon battery to drive a motor is overall about 70% to 75% efficient.
With today's technology batteries are about 3 time as efficient as fuel cells.
H2 has a much higher energy density that LiIon batteries, but the volume required is quite large, even if you liquefy the H2 (which takes a fair amount of energy BTW), so there is a practical limit to how much you can take with you.
The only advantage H2 has over batteries as a storage medium is density, which makes a lot of difference in an aircraft, where safety and range are more important than efficiency, and weight is a critical factor. In an automobile however, IMO fuel cells make no sense when compared to even current battery technology.
@Craig,
I disagree. Large hydrogen production plants would almost definitely be located at or extremely near the point of electricity generation. The loss of energy transporting hydrogen gas via pipeline is negligible whereas the loss of electrical potential over hundreds or thousands of kilometers (this distance will increase as we transport more and more renewable energy from areas with the best wind/hydro/solar resources to areas of high demand).
It basically comes down to storage. Massive quantities of hydrogen gas can be stored extremely easily and relatively cheaply, and the same cannot be said about electricity which, except for very small scale, cannot be stored in adequate amounts.
On a side note, it's nice to see mature, constructive conversing on Engadget...seems to be getting more rare by the day! :-)
I second Craig.
The one most crucial factor in a plane is weight. And Lithium Ion Batteries Are after all heavy. just take out your laptop battery and you'll be astonished how much lighter your laptop got.
What theyre testing here is not only the possibility of fuel cells in a plane but also the possibility of H2 driven planes. After all it IS possible to build a H2 turbine, and H2-driven rockets are nothing new either.
The one crucial thing is: how do you store the H2 safely in a plane. and from there on you can think about all the possibilities. I think this project will give us a lot of insight how H2 could be stored on a plane safely.
@bonevbs
The best bet so far for aircraft storage of hydrogen is as a supercooled liquid. This way it takes up little room, is no more 'unsafe' than current jet fuel storage.
Another benefit of this storage method is that it can be used to create liquid nitrogen before it is combusted, which can then be circulated around the wings/body of the aircraft to reduce drag, thus increasing speed and/or fuel efficiency even further.
@schmitty
actually I was considering the possibility that one day maybe liquid hydrogen might replace kerosine (i hope i spelled it right, im no native speaker).
the liquid nitrogen method is also very interesting.. it's a russian invention if im not mistaken: the "shkval" torpedo. it uses supercavity effects to reduce the drag in water. this might of course be applied also to planes, by creating a "bubble" of a gas with lower density than air around the plane so you could reduce the drag coefficient. I'm not sure though if the effect has such an impact on efficiency that it's worth the trouble to implement. but of course further research is needed to be certain about such effects.
and yeah, it's good to see some mature discussions on engadget, lately the average age of the readers seems to have dropped to under-14, considering all those "FIRST !!!!" comments and whining about "oh, the apple product is the better one", etc. (Im not attacking apple fanboys here, so please dont start a war now)
As a glider pilot myself, I think I should clarify a few points here -- though I think this is great news.
Primarily: "cruising range of 466 miles over five hours"
The Antares 20E uses an electric motor for launch, climbs up to about 5,000', and then shuts down the engine and folds up the propeller in to the body of the aircraft. Then, using just gravitational potential energy, flies across the countryside until it's low, then it opens up the propeller and climbs back up to 5,000' or so and repeats.
This is referred to as "Sawtooth Operation." The Antaries 20E has a glide ratio of 56:1, which means that as it descends from 5,000 to 1,000ft while travelling 224,000ft forward -- about 56km or 42 miles. So, this means that 466 miles over 5 hours means 11 climbs, which take about 3 minutes each. So, the motor can run for about 35-40 minutes per flight.
Next up: "propulsion system permits maximum flying speeds of around 105mph but we're certain those behind the creation are gunning for more"
Well, for the design of the aircraft, that's the optimized climbing speed. That glide ratio of 56:1 I mentionned above is the peak of efficiency, and it's at about 75mph. The aircraft can fly at up to 180mph, but then it's gliding distance performance drops off significantly: http://www.lange-aviation.com/htm/english/products/antares_20e/technical_data.html
So, this "flying speed" of 105mph (92 kts) is the speed it flies during climb, then it drops to 75mph for descent while the engine is stowed in order to get that 466-mile range they spoke of earlier.
I can say with certainty that this aircraft cannot fly 466 miles at 105mph at a constant altitude.
As for the "gunning for more" comment -- again, it has nothing to do with the fuel cells, it's just that 105mph is the most efficient climbing speed, and certainly not the most efficient cross-country cruising speed. Since this fuel cell can only run the aircraft for about half an hour, their primary goal will be to extend that running time long before they consider putting this energy system in to a "faster" aircraft.
ze germans are coming!
A fuel cell is simply a container for fuel!! My Cessna 172 has a fuel cell... It drive me crazy when people refer to hydrogen based engines as "fuel cells".
I don't know if I want to fly across the ocean on a cloudy day in one of these.
"Ummmm.....no..... Fuel-cells have are a MUCH better technology for portable power than any battery on the large scale. Filling up a tank of hydrogen (in the future hopefully mostly obtained through electrolysis of water with clean energy from hydro/wind/solar/thermal/etc electricity) in 1 minute is a hell of a lot faster and just as equally efficient (electricity transported from generating plant to transforming stations to your house/charging station to your battery loses just as much and sometimes more, depending on how far it travels, energy than conversion of energy to hydrogen storage and back).
My point is, for large-scale, portable power supplies, fuel-cells are far superior to any current or near-future battery tech."
See, its this kind of ignorance that I'm talking about. Its one thing to be wrong, its another to be so confident about a fallacy, and I blame the media and politicians for this. The above poster for example completely disregarded the comment about efficiency, and makes up his own. Lets look at actual facts here... the efficiency of obtaining hydrogen through electrolysis (the easiest and also least efficient prospect) is in the range of 25-40%. Hydrogen has extremely low energy density, so it has to be compressed to be viable, and anyone with an air-compressor knows how much power that involves. I won't even delve into the ridiculousness of claiming that it is less expensive and energy efficient to transport liquid hydrogen in trucks compared to the electrical grid that is already in place. The neurons should start firing and you'd figure out pretty quickly that its at the very least no less expensive than transporting gasoline, and maybe, just maybe, a little more pricey considering the 10K PSI pressure and temperature sensitivity of the medium.
Do everyone a favor and lookup the actual EROEI on hydrogen fuel cell technology right now and compare that to a NIMH or A123 lithium battery, and before you come back and say something silly like "well, just build ten times more nuclear plants", look into the actual cost and time involved in building one.
A hydrogen economy is a possible FUTURE technology, but it sucks ass right now and does not belong outside the lab. NIMH and nano lithium battery technology is a right now viable technology, and it'd be nice if the mainstream media and politicians acknowledged this. The potential benefit of a hydrogen economy is that, as a liquid, it'd be very quick to fill a vehicle. But battery technology isn't at a standstill either (far from it), and rapid-charge batteries and cheap super capacitors are on the horizon.
Comments like these are why I read Engadget's comments section, keep up the good work.
WRONG!
http://www.youtube.com/watch?v=s4NSUA-soKs
Haha....I doubt you were being serious, but that 'aircraft', while cool, is neither piloted or capable of taking off under its own power.
@bonevbs
The best bet so far for aircraft storage of hydrogen is as a supercooled liquid. This way it takes up little room, is no more 'unsafe' than current jet fuel storage.
Another benefit of this storage method is that it can be used to create liquid nitrogen before it is combusted, which can then be circulated around the wings/body of the aircraft to reduce drag, thus increasing speed and/or fuel efficiency even further.