Thing I don’t get is people believing that hydrogen is going to be a useful automotive fuel. Are they all oil company shills?
Hydrogen is an objectively terrible fuel for pretty much any use with the possible exception of aviation.
It has abysmal energy density for a given volume, even if you liquify it (compare Falcon heavy to Delta IV heavy: similar lift capacities but the latter is fucking enormous because hydrogen takes up stupid amounts of space and the former runs on kerosene).
It doesn’t stay where you put it, ever. It’s literally impossible to keep hydrogen in a container. A hydrogen molecule is so small that it will fuck off through the gaps in soils iron. You cannot store it long term.
To get ANY kind of sensible energy density from it, you have to liquify it (where it’s still shit compared to pretty much any other energy source in the same volume), and that’s cold. Seriously, seriously, mind bendingly cold. It makes liquid nitrogen look like lava.
Oil companies like it because atom for atom, crude oil is mostly hydrogen. Go figure.
But it’s an objectively dreadful fuel. Stop trying to make hydrogen a thing. It’s never going to be (again, planes maybe excepted).
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Mark vW
in reply to Sarah Brown • • •Sarah Brown
in reply to Mark vW • •Sarah Brown
in reply to Sarah Brown • •Mark vW
in reply to Sarah Brown • • •Sarah Brown
in reply to Mark vW • •@Mark vW Water is what you get when you burn hydrogen.
So your “catalyst” is gonna need to procure energy to crack it, so you can then use (40% of) it to produce propulsion in an internal combustion engine.
The second law of thermodynamics wants a word.
Sarah Brown
in reply to Sarah Brown • •Mark vW
in reply to Sarah Brown • • •Sarah Brown
in reply to Mark vW • •David Blue ※
in reply to Sarah Brown • • •Clara Listensprechen {in stickershock}
in reply to Sarah Brown • • •Sarah Brown
in reply to Clara Listensprechen {in stickershock} • •@Clara Listensprechen {in stickershock} that’s why it’s maybe got future in aviation where the weight of batteries is their Achilles’ heel.
But if you aren’t flying, then batteries are superior to hydrogen in every way.
Particularly when you start asking awkward questions like, “where did this hydrogen come from?”
Clara Listensprechen {in stickershock}
in reply to Sarah Brown • • •Sarah Brown
in reply to Clara Listensprechen {in stickershock} • •@Clara Listensprechen {in stickershock} can’t use hydrazine as a fuel on Earth because it’s like, lethally poisonous.
It’s what satellites use in their manoeuvring engines (with nitric acid as an oxidiser) though.
Sarah Brown
Unknown parent • •@Alex Holst there isn’t going to be progress because it’s fucking stupid.
Gonna explain why I think aviation is an exception. Planes NEED to get off of kerosene. It’s filthy.
Planes are about, first and foremost, weight. Batteries are no good. They are heavy and they stay heavy even when flat. A plane that’s burned all its jet fuel is a light glider. A plane full of flat batteries is a flying brick.
So the fact that you’re chucking out the back is a benefit. Planes also have a lot of empty space inside the fuselage so the fact that hydrogen has shite energy density by VOLUME is not so important as it having pretty good energy density by MASS.
And finally, they fly from airport to airport quickly. Airports have economies of scale to handle large quantities of the stuff in deep cryo and the planes are not sitting around fuelled up for days on end, so the fact that it fucks off by itself doesn’t matter so much.
But for
... show more@Alex Holst there isn’t going to be progress because it’s fucking stupid.
Gonna explain why I think aviation is an exception. Planes NEED to get off of kerosene. It’s filthy.
Planes are about, first and foremost, weight. Batteries are no good. They are heavy and they stay heavy even when flat. A plane that’s burned all its jet fuel is a light glider. A plane full of flat batteries is a flying brick.
So the fact that you’re chucking out the back is a benefit. Planes also have a lot of empty space inside the fuselage so the fact that hydrogen has shite energy density by VOLUME is not so important as it having pretty good energy density by MASS.
And finally, they fly from airport to airport quickly. Airports have economies of scale to handle large quantities of the stuff in deep cryo and the planes are not sitting around fuelled up for days on end, so the fact that it fucks off by itself doesn’t matter so much.
But for automotive and domestic use? Forget it. Batteries are objectively superior for automotive and always will be. For domestic use, you have to change all your appliances anyway because if you try using hydrogen in methane burning appliances they fucking explode.
And air source heat pumps are about 3x more efficient at producing hot water even in cold climates.
And cooking over a naked flame is filthy and inefficient. We are not fucking Bronze Age cave dwellers and induction hobs are a thing.
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Clara Listensprechen {in stickershock}
in reply to Sarah Brown • • •Sarah Brown
in reply to Clara Listensprechen {in stickershock} • •@Clara Listensprechen {in stickershock} It's used in deep space rocketry because it's a storable. You can coast for years and then when you need to light your engines, it will still be there.
"Ignition" by John Clark is a useful read on this.
Don't use it on Earth. It's repulsive stuff.
Katie Fenn
in reply to Sarah Brown • • •I found this episode of Real Engineering to be pretty inspiring.
Rethinking the air liner using the latest composite materials and advances in aeronautics could transform the internal volume for hydrogen too.
I only wish we had the Boeing that designed the 777, and not the mess that designed the 737 MAX.
youtu.be/59A8-rKRs-0?si=Yuq_r1…
The Plane That Will Change Travel Forever
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Sarah Brown
in reply to Katie Fenn • •Katie Fenn
in reply to Sarah Brown • • •They could, but I’m sure they’ll find a way to wring the joy out of it somehow.
Maybe we’ll enjoy a brief renaissance like the dawn of the 747 era, where they had no idea what to do with all the new space before realising “let’s shoehorn more bodies in here”.
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Mackaj
in reply to marlies :tblverified: • • •@marlies
I like systemd.
(ducks)
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Unknown parent • •@Andrew Hickey “but you can get it on a large scale by cracking seawater”
Yeah. You can do a lot of things, but no fucker is going to.
TeflonTrout
in reply to Sarah Brown • • •TANSTAAFL is a real bitch!
About aviation though: Hydrogen is a shit fuel source for flight for all the reasons it blows everywhere else- especially energy density by volume and weight.
Free space in aircraft is actually incredibly limited, and hydrogen containers are both fuck-off heavy and very constrained in shape. Wing fuel tanks work fine for liquids, but pressure vessels won't fit well between the rigid structures of wings and fuselages.
1/2
TeflonTrout
in reply to TeflonTrout • • •You are 100% correct about the issue of dead battery weight, hydrogen tanks have the same problem to a lesser extent, but lack the flexibility batteries have in form factor-you can wedge those bastards in all sorts of convenient places.
As for gliding? Well, most powered aircraft, particularly all jets that I know of, are *terrible* gliders. The aerodynamic rules that make them efficient at high speed also dictate that they float like rocks, so that's not a major consideration. 2/2
TeflonTrout
in reply to TeflonTrout • • •tl:dr, Batteries aren't currently feasible for flight, but hydrogen has all the drawbacks of batteries plus all the drawbacks of being an awkward and specialized material to handle.
Source: I was an Army Aviation Operations Specialist for 14 years. Def not a pilot, but aviation is Mah Jam
Sarah Brown
in reply to TeflonTrout • •TeflonTrout
in reply to Sarah Brown • • •Tim is wearing a mask 🌈
in reply to Sarah Brown • • •Historical note on domestic cooking in the UK: before gas from the North Sea oil fields became popular, "town gas" was piped around, composed of hydrogen and carbon monoxide.
Jono Ferguson
in reply to Sarah Brown • • •I'm open to there being uses for it, but I'm not seeing any in conventional land transport.
Trains maybe? ( no I haven't thought this through, and am likely in the pocket of big electron)
Kincaid
in reply to Jono Ferguson • • •Sarah Brown
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Jono Ferguson
in reply to Sarah Brown • • •@kincaid
look, it was late and I did say I didn't put any thought into it.
I was thinking of the ass end of Australia, but you are, rather cruelly using my own argument against me that electrons are easier to move than explody gas
I'll go back to my previous position of "I'm open to ideas, but cant' think of any" and this time not offer half ass, clearly not thought through ones 😀
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Jan Adriaenssens
in reply to Sarah Brown • • •Kincaid
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in reply to Jan Adriaenssens • •Hen Gymro Heb Wlad
in reply to Sarah Brown • • •Sarah Brown
in reply to Hen Gymro Heb Wlad • •Sarah Brown
in reply to Sarah Brown • •@Hen Gymro Heb Wlad hindenburg (Dirigible hydrogen fire): 97 people on board. 35 of them died.
TWA800 (Boeing 747-100 kerosene explosion): 230 people on board. 230 died.
Hen Gymro Heb Wlad
in reply to Sarah Brown • • •Ed Davies
in reply to Sarah Brown • • •99% agree with you - hydrogen for any consumer application is stupid - electricity (via batteries were required) will always make more efficient use assuming the bulk of our energy is coming from renewable electricity in some form or other.
No opinion one way or the other on hydrogen in aviation. Maybe alcohol or ammonia? Dunno.
Hydrogen for grid-scale semi-interseasonal energy storage does seem to make some sense to me, though. L²/L³ is on your side if you're storing enough of the stuff. OK, the round-trip efficiency isn't great but I don't really see any other way of storing multiple TWh over weeks or months.
The Dutch government seems to have big plans in that direction. They must make at least a bit of sense, even if they're over-affected by the proximity of Shell or whoever.
A reminder for me to re-read Chris Goodall's The Switch, I think.
Sarah Brown
in reply to Ed Davies • •Sarah Brown
Unknown parent • •@argv minus one Ok, so when referring to hydrogen as a fuel, I’m talking about burning it.
Fusion is a different beast, and nearly all hydrogen on the planet is useless for it because any feasible design we can build or envisage uses deuterium and tritium. The former it extracts from seawater. The latter it breeds by bombarding lithium with neutrons.
Anyway, different issue. I do happen to think that trying to build fusion reactors is largely pointless too, but for entirely different reasons: the economics will never compete with a shitlaod of solar panels and a big-ass battery.
spmatich :blobcoffee:
Unknown parent • • •Matthew Malthouse
in reply to Sarah Brown • • •Even some of the high temperature industries that 5 years ago I was guessing would want hydrogen have tuned to electricity. There have been electric furnaces for steel recycling for years and recently smelting furnaces have gone into production.
Michael Liebreich's hydrogen ladder makes a nice graphic and even that keeps shifting (away from widespread hydrogen use) and is now on version 5.
Clara Listensprechen {in stickershock}
in reply to Sarah Brown • • •Sarah Brown
Unknown parent • •Sarah Brown
Unknown parent • •@argv minus one That upper limit is orders of magnitude more than humankind's entire energy use of all forms put together.
We don't need fusion power on earth, and probably never will, and of the people experimenting with it, the only ones making significant process are just using as a cover for thermonuclear weapons research (National Ignition Facility).
Sarah Brown
Unknown parent • •@argv minus one I mean, the following text literally appears verbatim on their website. It's not like they're trying to hide it.
Sarah Brown
Unknown parent • •Sarah Brown
Unknown parent • •@argv minus one Their bombs are old as fuck.
And they aren’t allowed to set them off by treaty.
So they do this instead. Even if they don’t know why, it keeps the talent trained, I guess.