- cross-posted to:
- tech@kbin.social
- cross-posted to:
- tech@kbin.social
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You’d need huge cryogenic tanks due to the volume density of hydrogen over kerosene. Good for rockets that you can jettison tanks from, but less so for planes. I just don’t see it ever being practical for aviation over just creating our own hydrocarbons out of something else. Either catalyst based or otherwise. That’s potentially carbon neutral as well.
Edit: my comment, but with numbers https://pubs.aip.org/physicstoday/article/74/9/11/928294/Hydrogen-as-an-aviation-fuel
Even if it takes more space, there are still benefits over biofuels.
The hydrogen can be created using electricity. Currently it is not very efficient, but only uses electricity and water. Electricity can come from de carbonated (/low carbon) sources.
And a fuel cell will use that hydrogen to generate electricity by combining the hydrogen into water with outside oxygen.
For the biofuel, it’s a big climate hoax. The issue with bio fuels, is that the energy required to produce them is huge. It required bacteria producing carbon emissions, and the fuel also produced carbon emissions. Whatever entered that plan, will get out, and even more because of the transformation. (i don’t remember which video from Undecided with Matt Ferell was about biofuels). Tho maybe it could be used for something. To get slightly less carbon emissions than with normal fuel.
There may also be a solution with batteries. However the energy density for them is lower compared to hydrogen. Tho, there may be some battery innovation I saw passing by which could be pretty interesting.
CO2 to syngas to hydrocarbon fuels is probably a better carbon zero process, considering we will need to do a ton of cdr anyway…although doubt energetics and economics would be great. Hydrogen, just like biofuels today are anything but carbon neutral, and efficient electrolysis might never happen. Hydrogen production will also face water shortage issues and in general electrolysis requires pretty low tds water which is not trivial to source…not sure what’s best way to get carbon zero airplanes honestly…
If we’re able to make hydrocarbon-synthesis from CO2 efficient… we’re still going to need to source the hydrogen somewhere.
But if we do that using electrolysis (with renewables), and are able to create more energy efficient CO2 capturing processes, I could see synthetic hydrocarbons as a viable fuel option in the future. The thing is: They’re stupidly good at being stable, energy dense, energy carriers. We also have a lot of infrastructure in place to handle hydrocarbons already.
In principle, synthetic hydrocarbons could be part of a zero-emission cycle, where we capture CO2 and electrolyse hydrogen with renewable energy, and use the hydrocarbons as an energy carrier. But if we go that way, we’re definitely going to have to research efficient hydrogen production, and probably storage as well.
i think the important thing to consider is that not EVERYTHING has to emit no carbon… it’s perfectly acceptable (IMO) to make air travel carbon neutral by eg carbon capture, etc… sometimes it’s just not efficient to either carry around carbon neutral but not dense fuel, or capture and carry your waste with you
it’s shit that carbon offset programs have been hijacked :(
This seems to be a key point ppl miss. There is still quiet a big question if cdr and storage can be net negative…for example one place we want to store co2 is in saline basins, but this will require disposal and treatment of the brines removed from the basin…which might emit might end up emmiting as much co2 as ends up being stored in the saline basin. There is a paper on this issue…
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There was an article around here about Germany ditching hydrogen for their trains, which, if justifiable, seems damning for anything in the air.
As someone from Germany that’s the first time in reading that it was ever a thing for trains
Pretty much all our rails have electric lines on top and most trains are working electrically already
I really don’t see a point to waste hydrogen on cars or trains where pure electricity is working fine
Planes seems to be the main target that absolutely will never work electrically so it needs hydrogen - there even was an article about a ship running on batteries a couple of days ago
The thing with trains is twofold: First of all, it’s relatively easy to ensure that a train is more or less always hooked up to the grid (lines over the tracks). That means it can charge almost constantly, and doesn’t need a large battery.
The second thing is that the energy required to run a train scales very slowly with mass, because there is almost no rolling resistance (steel wheels on steel tracks have that advantage). That means you can increase the base weight of the train a bit without worrying about increased energy consumption.
Hydrogen can compete in applications where you need large amounts of energy, that needs to be transported, and where you don’t have regular access to the grid. Prime examples could be long-distance shipping, flight, and long-distance trucking through areas with little or no electric infrastructure (e.g. rural Australia).
It’s no more of a problem than dealing with LPG, surely? Pressurise it for storage.
The difference is the ‘L’ in LPG. It turns liquid at a relatively low pressure and takes up much less space then. Hydrogen does not do that, so it has to be stored at a much, much higher pressure. For example, a medical oxygen bottle or a scuba tank has around 200 atm of pressure. For cars, hydrogen is usually stored at 700 atm. And the pressure inside an LPG tank is around 8 atm at room temperature.
You can’t keep liquid hydrogen by pressure alone and even as a liquid it’s volume density it’s very low compared to other liquids.
I think it is, not sure but it requres bigger pressure and hidrogen is smallest atom that escapes even from high presure tanks.
Germany just announced they will discontinue their hydrogen-powered train service in favor of a battery-based solution due to the higher running cost.
Hydrogen may be an alternative, but it has yet to make continuous, solid financial sense for any type of transport.
If weight isn’t an issue, then it makes sense to use a system that only costs a fraction of a hydrogen-powered setup.
Trains don’t need to fly. Just pack them full of batteries or - arguably even better - just electrify the line wherever possible.
That’s just not an option for planes, so hydrogen remains a potentially viable approach.
That’s actually because trains can get away with batteries. Batteries aren’t a very dense energy storage and you’d never get a commercial plane to be economical with batteries. Similar to how you can have a coal ship or train, but never a commercial plane. Hydrogen is lighter than hydrocarbons by a lot, but volume wise, hydrogen takes up more space. The cryo tanks and fuel cells are heavy.
Hydrogen sounds like a great idea for decarbonization until you get around to asking, “wait, where do we get the hydrogen from?” and realize that it’s incredibly energy intensive and the most popular process releases a lot of CO2 directly.
Hydrogen is an energy storage, like a battery, so of course it requires a lot of energy to produce, that’s the energy that you get back when consuming it (minus inefficiency losses of course).
The advantage of hydrogen over fossil fuels is that it can be produced from renewable energy, while fossil fuels cannot.
There’s a comment on another post with this article doing the math on this, and it seems like the net emissions (when you account for efficiencies) actually favour steam-reforming + fuel cells.
Last time I checked, CO2 released at that altitude has 3x the effect on radiative forcing, so it’s good that we’re not dumping it up there. I know water is also a greenhouse gas, but I expect the residence time to be substantially lower than for CO2. So it would be a net positive as long as we’re emitting on the ground the same amount of CO2 as emitted up there (we’re probably emitting more, but probably not 3x more and it would be easier to capture at the exhaust than from up there)
PS: more on radiative forcing factors here https://sustainable.stanford.edu/sites/g/files/sbiybj26701/files/media/file/s3-radiative-forcing-rfi-memo_public.pdf
No… No, it isn’t… But you can imagine what it would be like if it was, right?
This is the best summary I could come up with:
A complete hydrogen fuel cell powertrain assembly occupied the pride of place in the pavilion of Beyond Aero at the recently concluded Paris Air Show.
That a fuel cell system was the Toulouse-based startup’s centerpiece at the biennial aero event is an indication of the steps being taken by a range of companies, from startups to multinational corporations, toward realizing the goal of using hydrogen as fuel in the aviation sector.
Even though in its current form, it serves only ultralight aviation, the successful test of the powertrain is a crucial step in our technical development path for designing and building a business aircraft,” Beyond Aero co-founder Hugo Tarlé told Ars Technica.
“The CS23 is a EASA (European Union Aviation Safety Agency) certification for small aircraft with a low Maximum Take-off Weight.
Speaking about the design challenges, Tarlé said mastering the characteristics of hydrogen and oxygen inside the fuel cell was a critical task.
Mastering the complexity of the cooling system is therefore critical,” he said, adding Beyond Aero has patented a solution in this regard.
I’m a bot and I’m open source!
Imagine the explosion upon impact. 🤣
Leaking hydrogen into the upper atmosphere sounds like a bad idea. It extends the life of methane, making the green house problem worse. I really hope that they reduce the leaking issue to a minimum.
Isn’t it flammable? I’d think leaks would have to be zero for even more basic reasons.
Yes, it’s very flammable. But it’s also very light. Lighter than Oxygen. And the molecules are small which means most air tight applications don’t work well. Even the tanks they make now still has this issue where hydrogen molecules can escape through the barriers over time.
But the short term profits!!!
