Airbus is now betting heavily on hydrogen as a fuel of the future. It has just unveiled early plans for three "ZEROe" airliners, each using liquid hydrogen to take the place of today's hydrocarbon-based jet-fuel compounds.
"It is really our intent in 15 years to have an entry into service of a hydrogen-powered airliner," says Amanda Simpson, vice president for research and technology at Airbus Americas. Hydrogen, she says, "has the most energy per unit mass of...well, anything. And because it burns with oxygen to [yield] water, it is entirely environmentally friendly."
But is a hydrogen future realistic for commercial aviation? Is it practical from an engineering, environmental, or economic standpoint? Certainly, people at Airbus say they need to decarbonize, and research on battery technology for electric planes has been disappointing. Meanwhile, China, currently the world's largest producer of carbon dioxide, pledged last month to become carbon neutral by 2060. And 175 countries have signed on to the 2015 Paris agreement to fight global warming.
(Score: -1, Offtopic) by Anonymous Coward on Thursday October 15 2020, @06:29AM
yeah! we did it!
(Score: -1, Offtopic) by Anonymous Coward on Thursday October 15 2020, @06:39AM (1 child)
No.
(Score: 0) by Anonymous Coward on Thursday October 15 2020, @06:42AM
yes
(Score: 1) by nostyle on Thursday October 15 2020, @07:06AM
Oh the humanity!
(Score: 3, Insightful) by dltaylor on Thursday October 15 2020, @08:52AM (13 children)
Modern Jet fuel is basically heavy hydrocarbons. Yes, they will burn but it takes significant energy to ignite. So, there are sealed fuel tanks on commercial airliners, AFAICT. Liquid hydrogen is both cryogenic and, often, under significant pressure. If you factor in the mass of the containment vessels and supporting equipment, does hydrogen REALLY have the most energy per unit mass?
Comparing the hydrogen and gasoline big BMWs does not support the idea.
(Score: 2, Interesting) by Anonymous Coward on Thursday October 15 2020, @09:29AM (10 children)
I think that would be part of the experiment here. Keep in mind that hydrogen for cars is NOT the same as for planes.
Planes are fueled immediately before they take off and are nearly empty at landing. In comparison, cars are fueled when empty with purpose of retaining that fuel over indefinite amount of time - days, weeks. Plane fuel tanks are more in line with rocket tanks than cars when it comes to duration of storage.
Also, planes fly at altitude where temperatures outside are in the -40 degree range, which makes it slightly better for keeping cryo fuels liquid and not require venting.
Planes are inspected and maintained at regular intervals. Cars are not. Safety considerations are completely different in a car for this very reason.
And finally, if you compare storage vessel weights like the space shuttle tanks, they hold a multiple of their weight in fuel. So in theory, this is more than doable. In practice, they need to find out.
(Score: 3, Interesting) by c0lo on Thursday October 15 2020, @10:07AM (7 children)
You have some good points, and there are some devils in the details, devils that that will need to be worked out.
The rocket stores the LH for some short hours at best. A transoceanic flight will need to keep it for so 10-12h (at the current flight speeds).
The temperature at the flight altitude is lower, but the pressure differential is higher.
That dam'd hydrogen has the bad habit of embrittleing metals [wikipedia.org] - may need to think of a "swap the bottles" rather "fill'er up" solution. Ummm... a "standard LH bottle for all the plane manufacturers or GTFU from my airport", whoever steps first into H-powered flight has an advantage?
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by Muad'Dave on Thursday October 15 2020, @11:42AM
In-flight pressure and venting concerns will have to do the differential equation dance between fuel consumption and boil-off. As fuel is used, there's less liquid to boil off to create vapor, etc.
(Score: 2) by quietus on Thursday October 15 2020, @11:55AM (3 children)
As to the embrittleing metals meme: there's literally hundreds of kilometers of existing hydrogen-carrying pipelines in the Netherlands, Belgium, France and Germany ... dating back to the 60s. If there are enough leaks in that network to make it not cost-effective, they should have detected them by now, no?
They're planning [fluxys.com] to extend that network to 3,600km by 2030, by the way, and 23,000km by 2040, mainly by converting existing natural gas pipelines, at an estimated cost of €27 to €64 billion.
(Score: 3, Informative) by c0lo on Thursday October 15 2020, @12:05PM (1 child)
Regular steel [wikipedia.org] pipes at 210-220 bars.
Dig up your physics books and compute the volume of hydrogen at that pressure required for 10h flight.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by quietus on Thursday October 15 2020, @04:02PM
Uh-uh, I was specifically reacting to the embrittleing metals part in your post, which always seems to come up when discussing hydrogen as an energy source.
Me thinks that Airbus does have at least a couple of people who know how to build more than a paper aircraft; what makes you doubt they've done their calculations vis-a-vis current A320 fuel storage volume?
Or, put differently, what pressure should be needed for hydrogen fuel tanks with the same volume, and what effects would this have on container embrittlement? Figures and references, please, if you're going to make strong statements.
(Score: 3, Informative) by PinkyGigglebrain on Thursday October 15 2020, @05:58PM
Here is some more ammo for your point
https://en.wikipedia.org/wiki/Hydrogen_embrittlement [wikipedia.org]
of particular note in the article is this tid bit:
"In tensile tests carried out on several structural metals under high-pressure molecular hydrogen environment, ..., aluminium (including alloys), ... are not susceptible to hydrogen embrittlement along with a few other metals."
citations in original article.
That said there is also a big difference between a heavy metal pipe sitting on the ground under constant and consistent pressure with minimal vibration and the thin aluminum sheets used in aircraft that are exposed to constant vibration and constant pressure changes while in flight. I know of several air crashes where the root cause was determined to be the aluminum of the plan's structure tearing due to the vibration/pressure changes and a couple of misplaced rivets.
add to that the simple fact that all metals become more brittle under cryogenic temperatures that will be needed to keep the Hydrogen fuel a liquid.
The engineers at Airbus have their work cut out for them overcoming all the potential issues involved.
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 1, Interesting) by Anonymous Coward on Thursday October 15 2020, @02:26PM
> That dam'd hydrogen has the bad habit of embrittleing metals
My bet is on some sort of composite tank, perhaps with a non-metallic lining? Looks like there is some prior art, the Goog turned up this for example, https://www.sciencedirect.com/science/article/pii/S2352179119300109 [sciencedirect.com] "Hydrogen permeation barriers: Basic requirements, materials selection, deposition methods, and quality evaluation"
(Score: 0) by Anonymous Coward on Thursday October 15 2020, @02:30PM
> A transoceanic flight will need to keep it for so 10-12h
Longer flights might be a "stretch goal" for Airbus at this time? If it was me, I'd focus on shorter range flights first, demonstrate the technology on some fixed and popular route(s) where H2 filling equipment can be installed. Intercontinental flights come later.
(Score: 3, Interesting) by legont on Thursday October 15 2020, @01:27PM (1 child)
Do you imply that cars are designed to be safer? Certainly looks so.
If so, you are definitely wrong. A car is way less safe by design than any airplane. For example, each bolt on an airplane is safety wired, including landing gear calipers even though brakes on most general aviation planes are not critical - one just rolls a Piper off the runway on the grass. Car calipers are on two bolts with no extra security whatsoever. Each time I do brakes I have stomach cramps and can't forget it for awhile.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 1, Interesting) by Anonymous Coward on Thursday October 15 2020, @02:40PM
> A car is way less safe by design than any airplane.
Depends on how you look at it. If I go to a local mall full of cars, there are good odds that *all* of them will start right up and be safe to drive. If I go to any airport, there is near zero chance that all the planes are ready for flight, because maintenance is necessary (and ongoing.)
A couple of examples:
Automotive parts are often fatigue tested to higher cycles than aircraft parts, in anticipation of the lack of constant attention/inspection.
Car electrical connectors working in a salt water environment part of the year, often last for 20 years before failure.
Fuselage structure, subject to pressurization cycles every time they go to altitude are known to crack. The cracks are monitored, holes drilled at the ends (to reduce stress concentration). It often takes 20+ years before rust (here in the Great Lakes salt belt) causes structural failures--with next to no ongoing inspection.
(Score: 2) by richtopia on Thursday October 15 2020, @03:47PM (1 child)
I read a book 7 years ago which made the argument for hydrogen fueled airplanes due to the specific energy. The energy density is lower than hydrocarbons, so you would giveup volume for the increased energy per kg. You are correct that the containment vessel reduces the effective specific energy of liquid hydrogen, but the book was arguing it was still somewhere around 10% more efficient (sorry I cannot remember the title for a proper citation).
Typically when I've read into hydrogen the biggest issue is hydrogen embrittlement of steels. You can run hydrogen through most traditional combustion engines with minor tuning, but the steel will become brittle and fail. This is why research into hydrogen powered cars is now exclusively looking at PEM fuel cells; the ICE-hydrogen was dropped from material challenges. If Airbus can work with their engine vendors to build a turbofan which can reliably handle H2 they could have a winning combination. Carbon aside, fuel costs are one of the biggest costs for operating aircraft and H2 could deliver lower operating costs.
(Score: 2) by choose another one on Thursday October 15 2020, @05:09PM
Steel is not widely used on modern large aircraft due to weight. What effect H2 has on the various materials and alloys used in aircraft fuel tanks, piping and the hot sections of engines probably still needs work to determine.
However, due to cryo and pressure requirements, tanks and piping will probably need to be new anyway, engines could be new (almost certainly easier to fit a new engine than new tanks and pipes) but you might manage with just small mods.
(Score: -1, Flamebait) by Anonymous Coward on Thursday October 15 2020, @09:03AM (3 children)
Hydrogen is produced from fossil fuels, but it isn't as easy to work with. There is no environmental benefit to this. It is just for show.
(Score: 0) by Anonymous Coward on Thursday October 15 2020, @09:16AM (2 children)
https://en.wikipedia.org/wiki/Electrolysis_of_water#Efficiency [wikipedia.org]
And this is even without putting a cost on carbon pollution that drive gas completely non-competitive. Hydrogen production through electrolysis will be the defacto-hydrogen production method simply by the nature of wind and solar being intermittent. Would you sell your excess power for $0.02/kWh or rather just let it go to waste instead? exactly.
(Score: 2) by PiMuNu on Thursday October 15 2020, @09:35AM (1 child)
You are also comparing hydrogen with car petrol. I guess aircraft fuel is more expensive per unit energy (smaller volumes, larger production costs).
One could imagine hydrogen production facilities in/near to airports - it only requires electricity and water after all - much reducing transport costs.
(Score: 0) by Anonymous Coward on Thursday October 15 2020, @02:47PM
Perhaps the right place for H2 production facilities is in the oil well fields where significant amounts of unwanted natural gas is just flared off? In some cases it isn't even being flared, putting methane (and similar) directly into the air, much worse greenhouse gas than CO2. So the process would have feed gas for free, at least as long as there are still oil fields.
I knew of one engineering research project to run an IC engine (and electrical generator) on flare gas to make some use of this fuel, but it seems to have failed. I heard that the flare gas is pretty corrosive. Too bad, since the engine would be running near steady state (generating with a grid load), it could have been possible to really clean up the exhaust nicely.
(Score: 3, Interesting) by Anonymous Coward on Thursday October 15 2020, @09:06AM (1 child)
There is nothing else for planes. What do you want? Batteries?
100-265 Wh/kg for battery storage
33000 Wh/kg for hydrogen
so more energy by a factor of 100+. Energy density of kerosene 12000Wh/kg. So yes, you can have turboprop electric with hydrogen cell. You can't have that with a battery as planes are a weight sensitive thing, unlike their ground counterparts. And the reason they are betting on hydrogen and not some biogas is that you can just use the latter in the current engines and no need to innovate much. With hydrogen, you can get long range and need new designs == innovation. The bet is that hydrogen will become much cheaper than any synthesized kerosene-equivalent.
PS. please don't link some battery plane crap here. This is for planes that actually fly medium range or long range. 2000+ km, not the 20 mile city hopper crap
(Score: 2) by c0lo on Thursday October 15 2020, @09:50AM
One can dream, tho'.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by Muad'Dave on Thursday October 15 2020, @11:38AM (1 child)
... by leaving off the air conditioner. They can just pump the cabin air past the fuel tank/lines to get nice cool, crispy air.
(Score: 5, Informative) by deadstick on Thursday October 15 2020, @11:52AM
Yes, through a nice big heavy heat exchanger. That air has to be pressurized to keep you alive, so it comes out of the engine compressors at about 350F. Boyle's Law and all that.
(Score: 3, Interesting) by legont on Thursday October 15 2020, @01:42PM (4 children)
It took decades to even get a certification to use biofuel which is almost the same. https://en.wikipedia.org/wiki/Aviation_biofuel [wikipedia.org]
15 years to hydrogen? Forgetaboutit. Total bull mixed with horse****.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 2) by choose another one on Thursday October 15 2020, @05:15PM (3 children)
Agreed, but it could have been done faster if it was wanted badly enough (read: if it was made a requirement for operation in significant parts of the world).
I still think that the best solution is to invent something (chemical, biological, whatever) to make Jet A1 out of atmospheric CO2. I'm sure some folks already working on that, maybe with interest or backing from Airbus, but by investing in H2 power research as well they are just backing multiple horses, probably not a bad idea.
(Score: 3, Interesting) by deimtee on Thursday October 15 2020, @06:34PM (1 child)
Isn't that just biofuel?
It already exists, and while it is currently more expensive than fossil fuels its price should drop with increasing usage, as opposed to fossil fuels which should become more expensive as they are used up.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by choose another one on Thursday October 15 2020, @09:55PM
Kind of indirectly yes, but... although biofuel is theoretically carbon neutral it is controversial as it has all sorts of non-carbon-neutral environmental issues, because it needs somewhere to actually grow it and if you are destroying other carbon sinks (e.g. forest) in order to do that...
A chemical process (e.g. https://energypost.eu/extract-co2-from-our-air-use-it-to-create-synthetic-fuels/ [energypost.eu] ), or maybe bio using engineered bacteria or algae or similar, has advantages of repeatability / purity, easy to prove the carbon-neutrality, and (the big one) may be possible to do anywhere without using lots of growing land. Deserts for instance, often plenty of unused land there, and plenty of sun for solar power. We could just put large PV solar farms in deserts, unfortunately it isn't very easy or cheap to pipe electricity from deserts to where it's needed, liquid hydrocarbons however we can pipe easily and cheaply from desert lands... we know because it's what we already do.
Bonus is that if we create excess synthetic fuel we may be able to pump it back where the fossil fuels originally came from making the process carbon-negative. Probably better to fix it into rock though (lookup CarbFix).
(Score: 2) by legont on Friday October 16 2020, @01:53AM
There is a little secret here - the world does not matter. For a long time the US took a position that if an airline does not comply with the US regulations, even outside the US, it can't fly to the US. Since the US was the biggest market, the US regulations became de facto the world regulations and local laws do not matter. This is, for example, the reason why I as a private pilot can fly in Europe at night, but Europeans with similar certifications can't.
The way I see this Airbus bull is an attempt to weaken the US hold on regulations. It has nothing to do with the green idea. They are just measuring dicks.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 0) by Anonymous Coward on Thursday October 15 2020, @06:19PM
Acclimatize to the New Normal.
(Score: 0) by Anonymous Coward on Thursday October 15 2020, @07:35PM
i don't see the benefit of using hydrogen except for the "climate saving" part.
one would assume then that a emotional barrier to more useless air travel would be lifted 'cause "hydrogen is green" we can now fly
around all day long without feeling a bit bad.
note: it's gonna take ALOT of solarpanels (or wind) to get "green" hydrogen ...
the only reason to use cryogenic hydrogen would be to cool the engines when traveling a supersonic speeds
thru the friction atmosphere ... to your next martin meeting to discuss the budget requirements for the next phase of research into hydrogen fusion ^_^