
Airbus eyes hydrogen power for airliner in next decade - prostoalex
https://www.ainonline.com/aviation-news/air-transport/2020-07-21/airbus-eyes-hydrogen-power-airliner-next-decade
======
walrus01
For reference from the UAV industry. The very best lithium ion batteries are
about 250Wh/kg but limited in the instantaneous amperage they can put out.
High amperage capable batteries are more like 170Wh/kg.

UAV compressed hydrogen tank systems with fuel cells in the 800-1600W range,
the full system with tank, fuel cell and a small buffer battery works out to
between 800-1200Wh/kg depending on size. Some guys in south Korea recently
hovered a large hexacopter for 10.5 hours. The systems I've seen are typically
configured for an output voltage equivalent to the float voltage of a 12S
lipo.

Diesel fuel, jet a, avgas and other fuels are a whole magnitude more dense in
Wh/kg stored than the above-mentioned hydrogen system.

~~~
5ersi
Actually liquid H2 has energy density of 39 kWh/kg, where common CH fuels are
around 12-13 kWh/kg. So about 3x more energy per kg then conventional fuels.

~~~
jcranmer
Note that H₂ boils around 20-30K (depending on pressure). Once you take into
account the weight of the insulated tanks, liquid H₂ is going to have much
worse energy density.

~~~
gsnedders
Liquid storage I believe typically gets up to about 20wt%, so you're talking
around 7.8kWh/kg. Compressed storage is around 6–10wt%, so up to 3.9kWh/kg.

------
korantu
If my understanding is correct, the goal is to reduce aviation effect on
climate change.

There is an ongoing project [1] by US NAVY to turn seawater into jet fuel.
This way we would not need to burn fossil fuels and would not need to throw
away much of existing aviation technology.

[1] [https://www.eurekalert.org/pub_releases/2020-07/uor-
lch07152...](https://www.eurekalert.org/pub_releases/2020-07/uor-
lch071520.php)

~~~
gus_massa
Note that this convert

H2O, CO2, energy -> fuel

Water is free [1], Carbon Dioxide is free [2]. Energy is never free.

You need some big solar panels or a nuclear reactor to get the energy. (Can
you put a wind turbine in a ship?) (The usual trick of burning fuel to produce
energy is not a good idea here.) So this kind of process should not be
interpreted as "water -> fuel" but like "energy -> fuel".

It can be useful to store energy for a while, or producing fuel using a
nuclear reactor in the carrier and using the fuel in the planes. (I'm not sure
that this is economical or tactically a good idea.)

If the idea is to produce the fuel on land, it is much more efficient to sell
the energy and buy fuel. The energy you sell will cause a electric plant that
use carbon to close and the net effect will be bigger reduction of the CO2
level.

From the article:

> _Laboratory team led by Heather Willauer announced it had used a catalytic
> converter to extract carbon dioxide and hydrogen from seawater and then
> converted the gases into liquid hydrocarbons at a 92 percent efficiency
> rate._

I really doubt this. Organic reactions have a horrible low efficiency,
specially the ones that create complex molecules using simple ones. (Perhaps
the 92% efficiency is counting how many of the CO2 are converted, but the most
important part of this reaction is the energy. If it convert the 92% of the
CO2, but it stores only the 1% of the energy, it is very wasteful.)

[1] Processing water to avoid the problems with salt and tartar may be a big
problem, so it may not be so easy.

[2] But the concentration is usually low, that is generally bad for fast and
efficient reactions.

~~~
jjoonathan
In terms of energy, it's not a contest and it's not a hangup. Carriers are
already powered by nuclear reactors. They have about 1500MW of steam power
available as a matter of course. Compare to 25MW if you paved the flight
surfaces with solar panels and parked it at the equator on a sunny day with
perfectly calm seas and measured at noon. Unlike solar in this example, the
nuclear design is not bumping up against physical constraints and could be
scaled up quite dramatically if there was a compelling reason to do so. Fuel
production would be a compelling reason.

The chemistry and chemical engineering problems you point out are the major
hangups.

------
alkonaut
Hydrogen is expensive to produce, cumbersome and dangerous to store and
handle. How will that be competitive with traditional jet fuel?

Jet fuel is safe to handle, the infrastructure is there, it doesn’t go all
Hindenburg in a crash, and it doesn’t require new engines.

What we need in the next decade is a better jet fuel.

If commercial flights all used 50/50 renewable fuel that would cut greenhouse
emissions in half. Providing that much biofuel without disrupting food
production or fresh water supply will require a moonshot effort but it still
seems like a simple obstacle compared to replacing fleets with electric or
hydrogen powered aircraft.

~~~
jacquesm
Also, Hydrogen isn't a fuel, it is a storage medium, a battery if you will.

~~~
masklinn
That could eventually be true, but currently under 5% of hydrogen is produced
by electrolysis _or_ biomass gasification, the rest is all processing of
fossil fuels.

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ncmncm
Hydrogen's energy-density makes it by far the best possible fuel for aviation.
Improvements in aerogel manufacturing are making liquid-hydrogen tanks a
practical prospect. LH2 is not mass-dense enough to fit in the wing tanks of
existing airframes, but at least the LH2 tanks won't need to be pressure
vessels.

Production of LH2 from cheap solar- and wind-generated electric power and
water, right at the airport, will make aviation the most practical place to
start using hydrogen as a fuel. Maybe auxiliary LOX tankage could help reach
cruise altitude more quickly, or enable flying higher, so as not to waste the
oxygen by-product.

~~~
HPsquared
Hydrogen only has a high energy density by weight, but by volume it's actually
quite low compared to other liquid fuels. Then you have all the problems with
handling liquid hydrogen, insulation needed, all sorts of additional functions
are required of the storage system compared to jet fuel. For example, icing
would probably be a problem if the wing tanks are full of liquid hydrogen!

~~~
dieortin
Considering the freezing point of hydrogen is −259.14 °C, I doubt it would be
a problem.

~~~
regularfry
Ice on the outside isn't a problem for the hydrogen. It's the other way round.
The weight calculations have to include enough insulation on the tanks to
prevent rain from freezing to the wings.

------
Havoc
That would be good. I'd love to travel more without feeling guilty about the
env impact

~~~
akkawwakka
I feel more guilty about our usage of non-renewable, GHG-generating power
sources like coal or natural gas power plants, and about driving around in my
car (even though it’s electric).

Aviation accounts for just 2% of CO2 emissions. While it’s good that Airbus is
considering alternative, greener fuels, because aviation will continue to
grow, there are larger determinants of GHG emissions and warming.

Also, how you even certify use of hydrogen on an aircraft will be a challenge.
The current design for fuel has been well-understood for seventy-five years
now, and like the rest of aviation some improvements have unfortunately but
unavoidably come from tragedy (see TWA 800). You can throw a match into Jet-A
and it won’t catch fire. Throw a match into a flask of hydrogen and you have a
fire or explosion.

~~~
coeneedell
I've noticed that a lot of the discussion around environmentalism is focused
as if the bad decision-making is happening at the consumer level. The
pervasive belief that A: electric cars directly reduce your personal carbon
footprint (they do, but the substantiality of that depends on where you live)
and B: travel is a major drain on the environment are very suspicious to me.
These are pervasive beliefs among environmentalists. Meanwhile very little
attention is paid to corporate and nation level changes. The best thing you
can do for the environment is vote. This feels counterproductive but it's
entirely true.

In addition, it seems to me that the discussion around nation level changes
has become focused on a developed nations vs developing nations issue, when in
reality it's all of our issues.

~~~
politelemon
I do agree, and take it a bit further: I feel that one of the greatest modern
tricks that have been played on us is to shift attention away from the actual
culprits and make us believe that it is us, at the lowest levels, who need to
make the changes and fix the environment. Things like flight shaming and
straws stand out as prominent examples and this could very well be due to the
tangibility of the actions. When they avoid a flight and take public
transport, or use a metal straw, they can feel like they are doing something.
But the impact is miniscule compared to what they could be doing which is
enacting a policy change at higher levels, changes which will have an impact
for years to come.

This 'attention shift', it's similar to the way the plastic/oil industry
successfully instilled recycling as a way to get us thinking we're doing
something useful, while the larger goal was to keep plastic bans at bay [1]

This trick plays itself out in other spheres; recently in the UK we would have
people "clapping for the NHS". They would stand outside their doors and clap
or bang pots/pans together. Very few of us wrote to our MPs asking for better
working conditions and better pay. Anyway, just last week, our government
voted against protecting the NHS from a post-Brexit trade deal.

1: [https://www.npr.org/2020/03/31/822597631/plastic-wars-
three-...](https://www.npr.org/2020/03/31/822597631/plastic-wars-three-
takeaways-from-the-fight-over-the-future-of-plastics?t=1595756112035)

~~~
WalterBright
The most efficient solution is ridiculously simple - put a tax on the emission
of pollution. Couple it with a corresponding tax reduction on productive
behavior.

This is based on the blindingly obvious maxim that if you want more of
something, subsidize it. If you want less, tax it.

And by taxing pollution instead of regulating it, you generate revenue for the
government.

~~~
PaulHoule
In the us people riot if police kill an unarmed black.

People in the us accept that the price of fuel goes up and down but they are
the only ones. In other countries people riot when the cost of fuel goes up.

Many people have a lot of fear that tradable emission permits are an Enron-
style scam that will suck money out of our pockets into somebody's pocket who
will recycle 1% of profits back to politicians to maintain their privilege.

What we need to is either ban certain uses of fossil fuels or introduce an
energy source that is so superior that people don't want to use fossil fuels.
The latter is hard but doesn't violate the laws of physics, but any other kind
of Collective action on climate violates the laws of social physics which are
absolute for N > 10^9.

~~~
lcam84
return the money from these tariffs to everyone through a unconditional income

~~~
PaulHoule
Definitely if you did a carbon tax it could be made revenue neutral by either
paying it back to people and cut other taxes.

~~~
lcam84
The protests happen in part because the demonstrators do not trust the
government to spend the money well. They are afraid that they will distribute
it to the "usual few" or "subsidize the lazy ones". Distributing the tariffs
equitably among the population would take that stigma away. This would
encourage those tariffs that are so necessary for us to comply with the Paris
agreement.

------
socialdemocrat
Stupid choice. Combine electrolyzed hydrogen with CO2 Instead to produce
methane. A safer and easier fuel to handle and use. SpaceX is already
developing their rockets to use it.

Hydrogen is too much of a trouble fuel with no infrastructure in place to
handle.

The problem is of course where to get the CO2 from. It should be gotten from
some kind of carbon capture setup. Ideally from biomass power plants.

~~~
otterley
Methane is a greenhouse gas[1] - much more potent than CO2, in fact. The
objective is to be environmentally friendly as well as economical and safe.

[1] [https://www.edf.org/climate/methane-other-important-
greenhou...](https://www.edf.org/climate/methane-other-important-greenhouse-
gas)

~~~
Ericson2314
As long as your fuel tank doesn't like it's fine. Burnt methane is back to
CO2.

What this whole thread boils down to is we need a huge amount of nuclear
power, after which rather than worrying about all 3 of "safe", "dense",
"efficient", we can just worry about the first 2.

Seriously, if it takes 1000x the energy from nuclear power to fix enough C02
to make conventional jet fuel from the air, that is _fine_. That's something
we can optimize on a leisurely basis when we are not worrying about global
warming.

------
Gwypaas
I always wonder if hydrogen is a side-step without any real practical use or
will somehow create a niche where the high-density requirements of long range
travel are needed. I.e. airplanes and cargo ships.

Hydrogen is awful to store and has no existing infrastructure around it, and
you only get efficiency gains if you use fuel cells, otherwise it's back to
Carnot's law.

Compare this to synthetic biofuels. They are already the market, as an example
I can go fill up my diesel car right now with it, certified to work by the
manufacturer, and can be transported and used by existing infrastructure.

Why isn't this talked about more? Are the land usage requirements making it
unfeasible for a global switchover in the aviation and maritime industries
requiring converting CO2 from the air making it much more expensive? Or is it
simply not flashy enough?

~~~
m4rtink
I'm not sure hydrogen can be really said to be high density - at least as
rocket popelant it is notoriously low density, even in liquid form.

~~~
WJW
Compared to battery packs (the main competitor for "green" vehicles) it has a
very high energy density.

~~~
masklinn
It has a higher energy density but not "very high".

Lithium-ion tops out around 2.4 MJ/L, LOH 8~10. Maybe one order of magnitude
difference when you use less dense li-ion. Plus that energy density of LOH
doesn't take in account the absolute hell that it is to keep stored. Fossil
fuels are in the mid-30s by comparison.

What LOH does have compared to batteries and even fossil fuels is very high
_specific energy_ (energy per kg), it's about triple fossil fuels and a good 2
orders of magnitude better than li-ion. That's why it's been used a lot in
rocketry, where mass is a much bigger concern than volume.

------
credit_guy
This is nonsense. If they want to be net zero emissions, they can use
synthetic jet fuel produced from sea water. The US Navy has studied the topic
and concluded they can produce such fuel at a cost of $3-6 per gallon [1].

[1][https://www.zmescience.com/research/us-navy-synthetic-jet-
fu...](https://www.zmescience.com/research/us-navy-synthetic-jet-fuel-
seawater-0423432/)

~~~
Hypx
Synfuels are made using H2 and CO2. In practice, they're just H2 with more
steps. So while you can use them, it ends up being a trade-off between cost
and how much you really need synfuels.

~~~
credit_guy
Yes, but synfuels are a drop in replacement of the current fuels, and they are
net zero emissions. Hydrogen is nasty. Really, really nasty: in liquid form it
can only be stored at impossibly low temperatures, it has a very low density
(about 13 times less dense than water), it leaks easily, it creates frost
(remember the o-rings from the doomed space shuttle). Building a new airplane
is difficult enough, building that burns hydrogen instead of regular jet fuel
is an enormous engineering challenge. The chance of us ever seeing a hydrogen-
based airplane is exactly zero.

~~~
Hypx
Synfuels are not a drop-in replacement. Jet-A has exacting standards, and it
would be a serious chemistry challenge for synfuels to match Jet-A exactly.
Most likely it would be possible but very costly.

Most of that stuff is engineering superstition at this point. Most problems
regarding hydrogen were solved decades ago. BMW actually made a LH2 powered
car and had no big problems (except limited range).

Frankly, you're just incredibly out of touch. We already are seeing H2 powered
planes now, and a commercial jetliner powered by H2 should happen by 2030 or
so. This very thread is about Airbus planning on building one.

------
kemiller
It really seems like synthetic fuels using water and co2 and excess solar
energy as inputs Is probably the best bet ultimately.

~~~
jacknews
butanol was being highlighted a few years ago. I don't know it's still a good
choice, or some problems were discovered.

------
stormdennis
Evokes the Hindenburg disaster for me though I presume that this would be no
more of a fire risk than today's aircraft fuel.

~~~
layoutIfNeeded
You can drop a match in jar of jet fuel and it will go out. Don’t try the same
with hydrogen.

[https://youtu.be/7nL10C7FSbE](https://youtu.be/7nL10C7FSbE)

~~~
WalterBright
There are many aviation disasters caused directly or indirectly by the fuel
catching fire.

Such as the horrific SST crash.

The idea that jet fuel is somehow safe is just a terrible misjudgment of the
situation. What we have learned over time is how to handle it safely - but it
is NEVER safe and it DOES burn. Another way to set it merrily burning is to
scrape an airliner along the runway, or have the airliner hit any sort of
obstacle, or for the fuel to leak onto hot engine parts, and on and on.

~~~
masklinn
> The idea that jet fuel is somehow safe is just a terrible misjudgment of the
> situation.

Surely if that's your benchmark then nothing is safe (with enough effort, few
things don't burn), and the point is really rather the _safety margin_ , which
is significantly larger for fossil fuels than for LOH, therefore making them
much safer than LOH? There's a reason why we prefer dynamite to liquid
nitroglycerin, even though both do, in fact, explode.

~~~
WalterBright
A lot of aviation accidents result in devastating fire. A fire in the air can
destroy the airplane in a minute or two. If there's a ground accident, there's
a darn good reason why the FAA requires evacuations within 90 seconds or
something like that. Fire is the reason.

As I said, jet fuel is NOT safe. What we do is try to safely handle it.

For example, nobody in the industry is going to allow a lit cigarette anywhere
near an airplane.

We have a lot of experience with jet fuel fires and have learned how they
burn, how they start, how to fight them, and how to prevent them. We have very
little experience with hydrogen fires. They may be worse, they may be better.
We don't know.

------
joyj2nd
Old news. Germans did this before.
[https://www.history.com/.image/c_limit%2Ccs_srgb%2Cq_auto:go...](https://www.history.com/.image/c_limit%2Ccs_srgb%2Cq_auto:good%2Cw_686/MTU3ODc4NjAzMjQ3ODU1MzI3/image-
placeholder-title.webp)

------
fnord77
in general, biofuels are not the greatest, but it might be the best solution
for aviation.

The US military has already proven a jet aircraft can be run on biofuels.

~~~
otterley
Combustion of biofuels still produces CO2, which is one of the outputs these
projects are trying to eliminate.

~~~
aunty_helen
The concept of biofuels is a closed carbon cycle (more closed but not ideal).
Plants with the aid of the sun scrub CO2 from the atmosphere, you make the
plants into biofuel and then burn that back into CO2 in the atmosphere.

As opposed to digging it out of the ground where it's happy staying outside of
our environmental system.

------
jacquesm
There is no way you'd get me on a hydrogen powered aircraft. Hydrogen is a
tricky substance to handle at the best of times, it explodes with the least
provocation and has a lot of effect on the materials that package it. By then
I hope my flying days are over but just in case they aren't that is something
that would have an immediate impact on my decision to travel or not.

~~~
darkerside
I assume this is fear of a Hindenburg type incident? I would assume that these
aircraft would be carrying much less hydrogen, since it's used only for
propulsion, not as a lighter than air filling. But, that's only speculation.
Anybody have facts to inform this?

~~~
jacquesm
Here is an example:

[https://electrek.co/2019/06/11/hydrogen-station-explodes-
toy...](https://electrek.co/2019/06/11/hydrogen-station-explodes-toyota-halts-
sales-fuel-cell-cars/)

Hydrogen needs to be treated with the proper respect at all times when it
isn't safely bound to something else. It really doesn't take much to set it
off. That the Hindenburg ever got off the ground is what is impressive about
it, the amount of care that went into ensuring that a static charge could
never reach the reservoir must have been massive.

Hydrogen plants have exploded in the past as well. Given aircrafts' tendency
to build up static charges and to be hit by lightning I would not bet on that
particular technology to work out.

The Hindenburg was - and that a pretty weird thing to write - about as good as
it gets for an accident like that. Only about 1/3rd of the people on board
died and it happened during a time when the aircraft was already fairly low
(during the last stage of mooring). Had this happened at altitude likely all
hands would have been lost.

~~~
darkerside
The article ends by pointing out the author has no data on whether hydrogen
cars are more dangerous than others. Nobody would argue hydrogen can't be
dangerous. The question is, is it more dangerous than jet fuel?

~~~
jacquesm
Jet fuel is closer to diesel than to gasoline the activation energy for jet
fuel is _much_ higher than for hydrogen, its molecules are larger so it can be
contained safer and with less chance of leaks. So the answer is yes, it very
likely is much more dangerous than jet fuel.

------
Kuinox
In my city there is a bus using a hydrogen fuel cell. I noticed it produced
interference in my bluetooth headset with noise reduction (I can hear the
engine in my headset), i'm curious if it will interfer with plane sensors.

~~~
_fizz_buzz_
This is maybe an inverter. But definitely not the fuel cell itself. The fuel
cell will produce pure DC current which won't interfere with anything.
However, e.g. a DC/DC inverter that steps up the voltage might not be well
shielded.

------
holoduke
just curious, but what about nuclear powered planes. didn't the us and Russia
had operational planes back in the 70s?

~~~
jeffreyrogers
I know there were some test engines, but none every flew to my knowledge. The
problem is they spit out radioactive matter over everything they fly over and
expose the occupants to a lot of radiation (since you can only contain the
radiation so much when you have weight limits to make). They are badass
though.

------
LargoLasskhyfv
[1]
[https://duckduckgo.com/?t=ffsb&q=slush+hydrogen](https://duckduckgo.com/?t=ffsb&q=slush+hydrogen)

------
Simulacra
Ok..but.. what about kaboom?

------
dfilppi
Oh the humanity

------
baybal2
> energy can be carried onboard through fuel cells to drive gas turbines

I don't think the author has a slimmest idea how gas turbines, and fuel cells
work

