Comments
RevolutionaryMove357 t1_iy3vt6c wrote
I thought I read somewhere about solar powered condensers that could pull liquid from the air.
I see it all working well, a greener future.
Kinexity t1_iy4cq3n wrote
The problem is that in places where condensers make enough water are places which doesn't need them.
Franklin_le_Tanklin t1_iy4l3d5 wrote
If they work on tatooine they’ll work here too
[deleted] t1_iy4q8tq wrote
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travellerw t1_iy431ja wrote
Traditional hydrolysis of seawater is a super wasteful process. The water must be desalinated first using reverse osmosis or distillation. Then chemicals (usually potassium hydroxide) can be added back to the water to allow "clean" hydrogen to be generated.
Straight hydrolysis of sea water creates chlorine gas. Not only is chlorine gas highly toxic (used as a chemical agent during WWI and WWII), but very hard on equipment. Not to mention you would have to figure out how to dispose of it. Thus the desalination first.
This makes "green" hydrogen from sea water very costly. You are just better off to use that wind and/or solar energy elsewhere as you get more bang for your buck. It also means that green hydrogen simply cannot compete with natural gas derived hydrogen.
That brings up another topic. Hydrogen from natural gas can also be green. The process strips the hydrogen from the natural gas leaving you with the remaining chemicals (mostly carbon). Those chemicals "could" then be returned back down the well. Of course that also adds costs and no company will do it unless regulation requires it.
dbxp t1_iy4q1g7 wrote
I think ATM the focus should be on electrifying the things we can easily and improving the carbon footprint of the grid. Thing like hydrogen powered ships and planes are very much in the R&D phase. Maybe we can even avoid it by offsetting via reforestation and replacing short haul flights with high speed rail.
ArmagedonOverdrive t1_iy5gjs5 wrote
Toyota is testing hydrogen cars out in California right now. They have set up hydrogen fueling centers at gas stations in the Bay Area.
Old_Dave t1_iy5v4o0 wrote
Honda has been doing that for 20yrs in California.
ArmagedonOverdrive t1_iy69vxs wrote
Really? Hydrogen fuel cells? I had only seen adverts for Toyota!
Old_Dave t1_iy6anqe wrote
Their 1st car was the FCX and then the Clarity. They're building a large hydrogen generator to demonstrate commercial power supply for buildings. It's at their Torrence, CA campus. I think it produces 1MW AC and 1150KW DC
travellerw t1_iy6by7e wrote
Agree %100.. Right now its time to grab the low hanging fruit. When there is none of that left, then we move on to the harder problems. If we could eliminate daily personal travel and home heating energy usage that would be HUGE!
paulmclaughlin t1_iy4t1j7 wrote
Hydrolysis is using water to split something else, you're thinking of electrolysis of water.
travellerw t1_iy6bji2 wrote
Thank you.. Yup brain fart..
Robot9P t1_iy4w0a2 wrote
Could we not use fresh water, currently abundant in the Great Lake and similar areas to avoid the desalination and Clorox problems? And I realize fresh water is not endless and with climate change, reliable. But can it jumpstart or fill a void until the tech matures?
travellerw t1_iy6bhhs wrote
We %100 could.. However, its usually a bad idea to make a basic human resource compete with fuel. This is why fuel from crops is a bad idea.
[deleted] t1_iy5bv5c wrote
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No-Yogurtcloset-400 t1_iy63ro6 wrote
Only 2.5% of water on earth is freshwater. Could be tricky to divert so much of that away from agriculture.
dr_jiang t1_iy5ar4z wrote
Commercial aviation burned 95 billion gallons of jet fuel in 2019. Hydrogen has one fourth the energy density of jet fuel, and takes 2.4 gallons of water per kilogram of hydrogen if we're making it through electrolysis.
There's plenty of water in the Great Lakes (for now: we're currently turning it saline). There's not plenty of spare electricity to power the electrolysis plants, or plenty of spare money to build them, or plenty of hydrogen transport and storage infrastructure to get it from the Great Lakes to everywhere planes need to take off from.
Hydrogen has plenty of use cases where it makes sense, and its weaknesses as a fuel can be mitigated. Aviation is not one of them.
Nyrin t1_iy5gq4n wrote
>Hydrogen has one fourth the energy density of jet fuel
Just to call out: as density decreases, fuel requirement goes up a lot worse than linearly. You have to burn fuel at the beginning of the flight to transport the fuel you'll use for the rest of the flight, and the more fuel you need, the more dire that picture looks.
The exact numbers would depend on a lot of variables (weight and distance chief among them) but most flights, even the smaller and shorter ones that are feasible with hydrogen's energy density, will need way more than four times the fossil fuel amount in hydrogen.
I do think that hydrogen (and even BEV in narrow situations) might have a place in limited aviation scenarios (very short/light flights) but completely agreed that the math just doesn't work for either of these electric modalities to replace fossil fuels in-place for long, heavy flights — and that's not a "point in time, technology will keep getting better" thing.
dr_jiang t1_iy5ip33 wrote
I'd forgotten about the "need gas to haul gas" math. Honestly, I stopped taking hydrogen as aviation fuel seriously when the white papers came in describing the plane passenger economics.
The reference escapes me, but the bottom line was that converting existing airframes to hydrogen meant ripping out 14-20% of seats and paying 60% higher fuel costs. Barring science-fiction level advancements in the underlying technologies, commercial air travel as we know it can't exist in a hydrogen-fueled world.
No industry, no government, and no passenger is going to tolerate that.
[deleted] t1_iy5agi1 wrote
>Hydrogen from natural gas can also be green... Those chemicals "could" then be returned back down the well.
There is currently no way to 100% prevent methane escaping from wells or distribution pipelines. Estimates range from 2%-4% of all natural gas produced leaks into the atmosphere. And fracking has shown us that pumping chemicals back down wells can have very severe consequences. Look at the earthquake data for Oklahoma over the last decade or so.
travellerw t1_iy6cvty wrote
I agree with the leaking, however, there is tons of methane that naturally leaks out from numerous sources in the earths crust. In the grand scheme of things, the leaks would be insignificant "IF" they stopped the general burning of carbon fuels for shipping.
I don't agree with you on putting the chemicals back. Fracking is a completely different process that pumps a hydraulic fluid down the holes . Carbon capture and sequestering from natural gas hydrogen would pump the chemicals back down dead wells. It would not use hydraulic forces to try and create fractures in the crust. Simply put the unwanted chemicals back in a chamber that is now empty.
[deleted] t1_iyahp4i wrote
I think you are confused about what causes earthquakes from fracking. They're not caused by the initial fracturing of the crust, they are caused by wastewater disposal wells, which is exactly the kind of solution you are proposing.
https://www.usgs.gov/faqs/does-fracking-cause-earthquakes
>In Oklahoma, which has the most induced earthquakes in the United States, 2% of earthquakes can be linked to hydraulic fracturing operations. Given the high rate of seismicity in Oklahoma, this means that there are still many earthquakes induced by hydraulic fracturing. The remaining earthquakes are induced by wastewater disposal.
So only 2% of the earthquakes are from the actual fracking, 98% are from wastewater disposal. If waste disposal can trigger that many earthquakes in a relatively inactive zone like Oklahoma, imagine the problems it would cause in a state like California where the majority of the population lives within 30 miles of a fault zone.
tyranicalteabagger t1_iy69d9d wrote
There's a whole nother dimension to this problem also. Compressing the hydrogen to the necessary pressures to get descent energy efficiency uses a ton of energy also. Hydrogen is a really terrible energy storage and transport mechanism.
travellerw t1_iy6df25 wrote
Not to mention hydrogen embrittlement. Hydrogen is a "slippery" molecule and can even escape solid steel pipes. As the molecule passes through the pipe it creates a phenomenon called hydrogen embrittlement. Steel is eventually weakened to the point of failure. This is not only a safety issue, but a maintenance nightmare. Steel pipes need to be replaced a much faster rate when used with Hydrogen. I understand there are coating now to mitigate this problem, but they add cost and complexity.
tyranicalteabagger t1_iy6l0mu wrote
Yeah. That too. Composites mitigate it, but high pressure hydrogen is phenominally dangerous when mistakes or accidents happen. Not even so much fire, but 20000psi suddenly releasing is basically a bomb.
Mrqueue t1_iy52259 wrote
And so is some electricity but we have to take steps in the right direction. It’s very possible to make hydrogen with excess wind or solar energy once we actually fucking invest in green energy
atehrani t1_iy69gsk wrote
I was under the impression that the volumetric density of hydrogen just isn't practical for commercial flight. The tanks would be far too large?
plantman-2000 t1_iy4wm80 wrote
Almost everything even your Tesla is powered by fossil fuels.
MailFucker t1_iy52nz1 wrote
Burning fossils fuels in a power plant is more efficient than burning them in an IC engine.
AzzaClazza t1_iy7yyq1 wrote
That's true for a gas turbine plant, is it true for coal fired?
MailFucker t1_iy86mn4 wrote
The very first result on google says the average coal plant in the US is 33% efficient, while ICE is between 11 and 27%.
For what it’s worth, basically every power plant uses a turbine.
AzzaClazza t1_iy9kwpe wrote
33?, impressive. thanks.
Meatball_pressure t1_iy3eaj1 wrote
And batteries are made of organic fairies? Don’t forget most electric grids in the US are still powered by coal power plants! Id rather bet on hydrogen tech any day and get over this battery obsession!
69tank69 t1_iy3jiwh wrote
It’s not like hydrogen storage requires any precious metals
upvt_cuz_i_like_it t1_iy3jbfb wrote
You sure told him!
AlexB_SSBM t1_iy3r4wi wrote
Dams are often used as giant batteries.
Meatball_pressure t1_iy3s00d wrote
That’s because we have unlimited energy unlike republicans
dont_even_bother_ t1_iy5c5gk wrote
Coal is 20% of the US overall and falling rapidly, so this is just flat out misleading.
My state currently has 0% of electricity produced by coal. At this very moment the CA grid is currently producing approximately 75% of it energy from renewable (63%) and nuclear (8.5%).
Meatball_pressure t1_iy5cq0u wrote
If it helps you sleep at night. Don’t feel guilty driving your obnoxiously fascist Tesla.
dont_even_bother_ t1_iy5cyq1 wrote
I drive a Porsche Cayman S. Nothing in that link disproves what I said, in fact it confirms it.
Meatball_pressure t1_iy5d4k0 wrote
Here’s a list of coal powered plants you can go visit in your overpriced wagon.
https://en.m.wikipedia.org/wiki/List_of_coal-fired_power_stations_in_the_United_States
dont_even_bother_ t1_iy5dywv wrote
Well you must admit, it's a good looking wagon: https://i.imgur.com/ia2gZ2c.jpg
Fiorta t1_iy5vaux wrote
That's looks kinda like the Panamera and not the Cayman.
dont_even_bother_ t1_iy66eg9 wrote
Panamera is 4 door, but the design language is similar. It’s extremely similar to the 991 911, though, even sharing a bunch of parts. It’s also teeny tiny in person. Another angle gives a better idea of the proportions:
Fiorta t1_iy693c6 wrote
Ah shit, I was thinking of the Cayenne SUV lol
[deleted] t1_iy3jo8k wrote
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XonikzD t1_iy3s8q6 wrote
If it's about point of use variables and if all production, transport, and useage "carbon impact" costs were equal, then hydrogen is great for personal transport. Unfortunately, production and transport aren't equal. Applications like jet fuel where hydrogen is part of a controlled reaction for thrust are way different that hydrogen applications in vehicles where hydrogen is part of the electrical discharge process to power electrical batteries that then deliver energy for motors. In the EV Vs Hydrogen dialogues online most people seem to think that hydrogen cars and busses are "burning" hydrogen and that is not the case.
Meatball_pressure t1_iy4epz7 wrote
Elon fanboys got their crotch less panties in a bunch. I said it before and I’ll say it again, fuck EVs. https://www.bloomberg.com/news/articles/2022-10-18/bmw-group-chairman-oliver-zipse-hydrogen-cars-are-still-happening
XonikzD t1_iy4ghoo wrote
I also am not a fan of Elon or his business practises or the mismanagement of EV marketing over the past two decades from him and any of the fanboys on that particular side of the playing field. I also, however, have been around long enough to know that each vehicle and each "fuel source" will have its proponents and its naysayers and eventually everything works out to whatever the easiest possible method is for getting something done with the appropriate tool at hand. I think every single one of these should be developed to their extent and the market should decide which one is the easiest thing to work with for the desired outcome and desired cost.
A40 t1_iy3hf6e wrote
Make hydrogen locomotives a thing. And shipping. And hydrogen made with green energy, not coal/oil.
singulargaysock t1_iy3qhnw wrote
or just electrify and modernize our rail network… y’know… like the rest of the world?
A40 t1_iy3riip wrote
I'm in Canada: it'd take new nuclear power or hydro dams (and there aren't accessible rivers) and two or three third-world strip mines to electrify rail here.
Paris to Berlin: 1054 km
Halifax to Vancouver: 6,150 km
Beenforevertiltoday t1_iy40bqv wrote
Hear me out, just make it a nuclear powered train, fallout meets snowpiercer style.
idigclams t1_iy4cwxw wrote
I’d like a seat toward the front of the train, please.
adamketchum t1_iy4k7m3 wrote
Moscow to Vladivostok: 9,289 km https://en.wikipedia.org/wiki/Trans-Siberian_Railway
Running trains on Hydrogen will also require a lot of new infrastructure, and far more electricity generation such as nuclear, hydro, or whatever since going through electrolysis and fuel cells is much less efficient than using the electricity directly. Something like 30 % efficient I think.
There might be a place for hydrogen trains, for example long distance rural lines with low usage and smaller trains (not good at freight), but it is not an obvious decision and should not have widespread adoption. All of the complicating factors with hydrogen and the greater continuous costs make electrification the best choice in the long run.
lestofante t1_iy7l6hd wrote
When they build that they did not have current technology.
Yes you need special infrastructure, but for a mega project like that would be the small issue.
In the end is a simple "what is cheaper to build and/or maintain", and surely there are cases where the the diesel wins, and could be replaced with hydrogen, if hydrogen cist will be low enough.
Electrification may even be better in the long run, but if the project cost much more and there are no money, a country may decide that something is better than nothing, and electrify on a later time
Formendacil t1_iy4r35p wrote
Yeah, but Sweden has roughly the same amount of railway per capita, and yet it is 84,2 % electrified, more electrified than South Korea and Japan, whereas Canada is 0,2 % electrified, and Sweden and Canada are roughly as wealthy. Australia is also roughly as wealthy, even sparser, culturally closer, and yet it has large, well used electrified commuter rail systems similar to those in Europe and Asia, whereas Canada does not
A40 t1_iy53y9w wrote
Distances are different. Canada is thousands of miles across and very sparsely populated compared to Europe.
Formendacil t1_iy56nm9 wrote
Firstly, countries such as Sweden, Finland and Norway also have low densities, not all of Europe is is the Rhine valley or Southern England. secondly, most Canadians live in a relatively small part of it anyway, meaning that densities are similar to modestly populated parts of Europe in a lot of Ontario and Quebec. Thirdly, Australia has much more electrification and much more well used passenger rail in spite of being even sparser. Sure, the distance between Perth and Sydney is impractical for high frequency rail, but that doesn’t mean that there can’t be climate friendly, efficient transport in the dense areas
A40 t1_iy5eod7 wrote
I was wondering about gas storage cars on the trains, like old-timey coal tenders. Liquid hydrogen tanks?
Formendacil t1_iy5r9zk wrote
I mean, yeah, sure, maybe, but electrification is a proven, efficient technology. It’s just not as impractical as you make it out to be. It’s used in low density and moderate density areas all around the world with no problem
Xe6s2 t1_iy5rghi wrote
Energy efficient small modular magnetic bottles might work better
FalconX88 t1_iy54lrd wrote
Distances in Canada are much longer, and once most of it runs on diesel there's not really a point to electrifying small parts of it since all the equipment is not made for it anyway.
Formendacil t1_iy589nk wrote
I mean, most countries run on a mix of diesel and electric. Japan isn’t all electric. Both Germany and France are only half electrified. Switzerland is basically the only moderately large network which is entirely electrified
FalconX88 t1_iy59dhl wrote
Again, distances. Easy to electrify a large and heavily used part of the network in Germany or France and then use diesel on the lesser used lines where it doesn't make sense to build the infrastructure. Of course you will then operate a mix of diesel, electric, or hybrid.
If you have distances like in Canada it's not easy to electrify a decent percentage of your rail network and then it makes more sense to just stick primarily to diesel.
Formendacil t1_iy5aznb wrote
If you electrify the Windsor-Quebec city corridor along with the GO-trains and Exo trains, that would be a pretty significant electric system. I can say this for sure, if that kind of corridor existed in the Nordic (except for maybe Denmark) it would without a doubt be electrified, Toronto and Montreal are large cities an intermediate distance apart
fasda t1_iy58ahh wrote
And what about the corridor between Toronto and Quebec city? That's only 800 Km and contains a large majority of Canada's population. And only two or three mined worth of copper isn't all that much.
HydrogenPowder t1_iy4kztl wrote
Electrify the SEA
Kinexity t1_iy4cybq wrote
Hydrogen is inefficient, hard to store/transport and requires complex infrastructure. Overhead electric is the best for trains.
A40 t1_iy54f5g wrote
Distances are different. Canada is thousands of miles across and very sparsely populated compared to Europe, for instance.
Overhead electric on 5,000+ km of freight rail? (That's as the crow flies.) Not at all practical.
[deleted] t1_iy5b2ef wrote
How much do you think gas pipelines cost to install and maintain?
A40 t1_iy5ej8z wrote
I was wondering about gas storage cars on the trains, like old-timey coal tenders. Liquid hydrogen tanks?
Vickrin t1_iy59co5 wrote
Do you know how much hydrogen you'd need to travel 5000kms?
Just put up some power lines...WAAAAY more practical.
myflippinggoodness t1_iy5b3py wrote
Can you feed the electrical system directly off the track? Then, any issues that would cause? Also, how's that holding up in Canadian winters?
Gah this seems tricky and costly but mby(?????) A good idea?? Fckn advanced shiprec is.. Advanced 🤦♂️
Vickrin t1_iy5cjcj wrote
Hydrogen is just a poor fuel compared to hydrocarbons.
Hydrogen takes up space and is heavy in the quantities you'd need.
Electricity is great because you don't need to ship it with your goods.
People trying to reinvent the train should just try trains first.
Japan has an amazing train network and yet nobody is copying them.
myflippinggoodness t1_iy5dy00 wrote
On Japan's trains--VERY TRUE, they have an awesome setup for densely populated urban areas.. but everything here is so spread out, and there's the weather to contend with too.. I mean, I'm thinking heavy supply transit more than just ppl transit.. ah fuck it, soup the shit outta Canada's current transcontinental rail systems. That's probably step 1
Vickrin t1_iy5epcy wrote
>but everything here is so spread out
Build longer tracks?
Japan's rail system covers the entire country. It's not just metro areas.
A40 t1_iy5ejua wrote
I was wondering about gas storage cars on the trains, like old-timey coal tenders. Liquid hydrogen tanks?
Vickrin t1_iy5ewxj wrote
Hydrogen is not energy dense, it would require extremely high pressure storage which is heavy as hell and expensive.
A40 t1_iy5fzn0 wrote
Diesel has an energy density of 45.5 megajoules per kilogram (MJ/kg), slightly lower than gasoline, which has an energy density of 45.8 MJ/kg. By contrast, hydrogen has an energy density of approximately 120 MJ/kg, almost three times more than diesel or gasoline. What this really means is that 1 kg of hydrogen, used in a fuel cell to power an electric motor, contains approximately the same energy as a gallon of diesel (rmi.org). site
As for storage weight: train, locomotive. Expensive: probably, until it's a mature industry.
Vickrin t1_iy5hgyq wrote
1kg of diesel can sit in a metal tank, at room temperature, no pressure needed.
Do you know how much space 1kg of hydrogen takes up?
Liquid hydrogen needs to be stored at -250c at 1 bar or more of pressure. This requires high strength storage. This means your 1kg of hydrogen ends up actually weighing a hell of a lot more than 1kg. Keeping it cool also requires energy which means you get even less out of your hydrogen fuel.
Sure you could store it as a gas but that would require 350-700 bar of pressure which requires even MORE expensive storage.
It's not as simple as the raw maths.
Can you imagine the damage if a train derailed with high pressure hydrogen tanks? Diesel doesn't explode and neither does electricity.
A40 t1_iy5nvj8 wrote
Thanks for the info!
So a hydrogen jet engine is... less than useless?
Vickrin t1_iy5ohqn wrote
Exploring the concept is never wasted, people might learn something.
Putting a hydrogen engine in an aircraft is not going to be a viable option for the forseeable future.
Aircraft are probably one of the hardest things to move to a green fuel source.
Batteries are also awful when it comes to aircraft.
Xe6s2 t1_iy5r1zo wrote
Plus hydrogen leaks the most out of all fuels. Magnetic bottles would work better imo.
Funktron3000 t1_iy6tud0 wrote
What if we just used it at lower pressures and filled blimps with it?
Vickrin t1_iy78740 wrote
What could go wrong?
lestofante t1_iy7knjd wrote
Not really, Remeber, the most powerful rocket are hydrogen+oxigen.
The bigger the amount you want to store, the less is the coat of the container, as container weight grow as square(perimeter), while volume contained grow as cube.
A hydrogen train make a lot of sense and they have been already successful experimented, but will never take off until cost of diesel is cheaper.
AzzaClazza t1_iy7zccq wrote
1kg of liquid hydrogen takes up 14L of volume, plus the tank itself.
Vickrin t1_iy98rkb wrote
And a tank that can hold hydrogen weighs a lot
Kinexity t1_iy5ayzf wrote
Two words: Transsiberian Railway
aaaaaaaarrrrrgh t1_iy4v0el wrote
>hydrogen locomotives
Electrification is easier and better
A40 t1_iy5438b wrote
Distances are different. Canada is thousands of miles across and very sparsely populated compared to Europe. Electrifying 5,000+ km of freight rail is not at all practical.
TheLianeonProject t1_iy3cyjz wrote
The problem with hydrogen is the energy density. It is simply far too low. Some planes are already flying with leftover restaurant grease, which seems promising.
jdmgto t1_iy42tj5 wrote
Bingo, getting an engine to run on hydrogen isn’t astounding. The problem is how awful hydrogen is for storage. You’ve got basically two options, absurdly high pressure storage tanks, like 10,000 psi+, or cryogenically. Neither will work with existing aircraft. Commercial aircraft store most of their fuel in the wing structure. You cannot reinforce those structures enough for 10,000 psi storage of gaseous hydrogen, and I know the FAA wouldn’t approve of it. Similarly those structures cannot be retrofitted with adequate insulation to store cryogenic fuels, never mind cryogenic containers which will handle the flex of an aircraft wing without snapping. Which leaves filling up the cargo area with tanks, either high pressure or cryo, which both loses all your cargo space and is inefficient weight wise. And I’m pretty sure if you showed the FAA the plans to turn the entire cargo space of a 737 into a 10,000 psi storage tank they’d retroactively pull the airworthiness certificate of every plane you’ve ever built just on general principle. I’m not even sure if you went full cryo that you could get enough hydrogen onboard an airplane to do much more than short range domestic flights.
FalconX88 t1_iy5490u wrote
> commercial aircraft store most of their fuel in the wing structure.
I wouldn't expect planes to look like they do now. There are a lot of different concepts of planes, look at Airbus Maveric. That blended design would create a lot of volume that can be used.
shwag945 t1_iy5rggt wrote
Commercial passenger planes will probably look the same as they do now because of windows. Windows are important for reducing passenger stress during flight and safety in case of emergencies.
Windowless planes have been a commercial dead end for a long time.
FalconX88 t1_iy7zdsv wrote
Most long haul flights I've been on the past years basically had the windows closed for most of the flight anyway. And in a 10 abreast most people don't have window access right now. However, there are also solutions for that, like fake windows with screens or ceiling windows that let in some sunlight.
jdmgto t1_iy7ucth wrote
MacDonald Douglas/Boeing’s original blended wing body BWB from the late 90’s early 00’s was toyed with but passengers hated it. Most of your passengers wind up in the middle of the plane, far from any windows. You’ve also got issues with trying to get everyone off the plane in an emergency. The FAA has some pretty stringent rules about how long you’ve got to do that. You could, in theory, turn the center of the plane into a giant cryo tank and seat people on the sides near the windows but… well you’re building a huge aircraft and then spending most of the volume on a giant thermos instead of things that make you money.
FalconX88 t1_iy7z38a wrote
> Most of your passengers wind up in the middle of the plane, far from any windows
As they do now, but now we have personal inflight entertainment and on long haul you often got the shades closed almost all flight so not that big of a deal any more.
I agree that there are also challenges, but I wouldn't assume in 50 years planes will look the same
mektel t1_iy6lt3t wrote
Just means the current model for aircraft may need a revamp.
Not that I think hydrogen is the way to go, but we settled on this design based on the fuel we currently use. Future aircraft may very well be of a very different design to support alternative fuel sources or constraints.
westbamm t1_iy3hm00 wrote
Depends on how you look at it I suppose, volume or weight.
JadedIdealist t1_iy3r08e wrote
If you include the weight of the container hydrogen goes back to being abysmal though.
[deleted] t1_iy3s27e wrote
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JadedIdealist t1_iy3smq7 wrote
If you store a low density fuel then your container needs to be bigger (and therefore heavier) to hold the same weight of fuel.
[deleted] t1_iy3sspo wrote
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dinosaurkiller t1_iy3ugqt wrote
If it’s a bigger tank for the same fuel it’s completely true. The context very much matters and you’re making a lot of assumptions.
[deleted] t1_iy3ux7z wrote
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RevolutionaryMove357 t1_iy3x901 wrote
Right? Look at rockets. Destin from Smarter Every Day on YT toured a ULA facility and the tanks for hydrogen and other fuels are insanely, insanely thin.
jdmgto t1_iy44jex wrote
Just… ok… so, no. Rocket fuel tanks do not operate at anything like gaseous hydrogen tank pressures. Every rocket that uses hydrogen fuel is cryogenic, and they are all designed with pressure relief valves specifically so that as the hydrogen boils off the pressure is released. None of them are designed to operate at any significant pressure. Even then, while the actual structural component of the tank is thin, it’s covered in a lot of insulation to prevent the hydrogen from boiling off. Also rockets are designed to be loaded in a single direction, longitudinally and aircraft… aren’t.
Cryogenic hydrogen is just an ungodly pain in the ass to work with which is why every non-rocket utilization of hydrogen as a fuel uses pressurized gaseous hydrogen instead.
RevolutionaryMove357 t1_iy46vkg wrote
Thank you for clarifying that for me. I did not know that.
lestofante t1_iy7lxxl wrote
Yes but also that is why Airbus is researching on this.
They think tech may ready to be able to overcome those issues and are gonna try make 3 different demonstrator, one normal frame that burn hydrogen, one lifting body, and one normal frame but fuel cell propeller.
As they are one of the 2 biggest company about planes, I think they know what they can achieve
jdmgto t1_iy7s01s wrote
It's not that you can't make a hydrogen powered aircraft, you can. The problem is that barring the government just straight up banning conventionally powered jets they won't be able to compete. It is just a physical fact that hydrogen’s energy density is awful and working with it is painful. Any aircraft running on hydrogen will either carry less cargo (people or stuff) or have significantly shorter range or some combo of both.
jdmgto t1_iy43exb wrote
>Carbon fibre, kevlar and other materiels are good for the job and weigh less than convential plane fuel tanks.
No, they don’t, because conventional plane fuel tanks are the structure of the wing. Never mind that they aren’t the right shape. Super high pressure storage containers are spheres or cylinders for a reason. Aircraft fuel tanks are long flat rectangles, just about the worst shape to make a pressure vessel out of.
[deleted] t1_iy45do5 wrote
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jdmgto t1_iy47q2c wrote
It’s only strange if you have no clue how modern jetliners function, are built, or how hydrogen storage works. Fuel is stored in the wing because fuel is a liquid and can fill odd shapes that are inefficient for anything else. Wings are necessary for aircraft and by their construction have a lot of odd unusable space for cargo. They’re easy to use for fuel storage. Storing fuel in the wing structure is popular because it’s effectively weightless, you had to build the structure regardless. The work to turn them into fuel tanks is pretty trivial and largely what you’d have to do for a single purpose tank. Second, it frees up the fuselage for passengers and cargo, the stuff that makes money. Fuel storage in the fuselage is taking up space that you now can’t sell to make money. And no, there isn’t enough room in the wings for cylinder storage, at least not useful storage. The structure of the wings, the part that holds the fuel is made up of various box girders which are rectangular. The only pressure tanks you could fit in them would be many long, thin, incredibly wasteful tanks that add a lot of points of failure for not a lot of fuel storage.
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jdmgto t1_iy4eywf wrote
It’s condescending because you don’t understand the fundamental reasons why aircraft are built the way they are, how hydrogen storage works, or just basic concepts but you speak authoritatively as if you do. Do you know why the tank in the 737’s wing is that shape? Because the slats and flaps and their equipment take up the leading and trailing edges of the wing. The fuel is contained in the long, rectangular structural box that runs down the center of the wing. That’s what I’m talking about, you don’t understand even the basics of how airplanes work. It’s got nothing to do with balance.
And no, it couldn’t be used for cargo. Aside from the structural problems of opening that up enough to pack it full of bags which are just horrifying. Do you know how cold that space would be? I doubt passengers would be ok with having their bags frozen solid. Never mind the bag handling issues as you’ve gotta individually Jenga the bags into the wing every time you load it versus chucking it in the hold.
There is a reason about the only place hydrogen is regularly used as a fuel is rockets, and even that’s not universal. Could you build a hydrogen powered aircraft? Sure, but you’ll also see the cost of air travel increase dramatically. Like it or not, baring governments just outlawing conventional jets entirely in favor of hydrogen ones, no ones gonna buy them.
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jdmgto t1_iy463xm wrote
Cryogenic hydrogen is just an ungodly pain in the ass to work with which is why every non-rocket utilization of hydrogen as a fuel uses pressurized gaseous hydrogen instead. First off the energy usage to create the hydrogen, then chilling it to just a few degrees above absolute zero, then trying to maintain it is just ridiculous.
As far as aircraft, the problem becomes insulation and boil off. The wings of a conventional commercial aircraft aren’t thick enough to store any significant amount of cryogenic hydrogen once you factor in insulation. Never mind trying to keep it chilled in what amounts to a giant radiator. That leaves the body of the aircraft which is, you know, where you put the people and the cargo. You’re losing a lot of your money making space filling it with fuel tank. Never mind the operational problems of cryogenic hydrogen, even the best tanks boil off hydrogen constantly, in flight, everywhere. Rockets can get away with it because they can constantly top off the tanks while they wait to launch then only operate for minutes. An airliner has to operate for hours, and might even be waiting to take off for hours. I’m just imagining a cryogenic airliner stuck on the tarmac in Dubai waiting to take off.
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jdmgto t1_iy49rgc wrote
First off, they’re loading those hydrogen tanks into the area the Dash 8 uses for cargo and it looks like a couple rows of seats to boot. They’re gonna lose even more seats because people aren’t going to be ok with a “no luggage” rule on their flight. Second, the normal range of a Dash 8 is two to nearly three times that. I know the three things airlines are always willing to give up on are cargo volume, passenger count, and range. Also, one conspicuous detail I didn’t see in the article is anyone asking the FAA if they’re ok with this idea and I just can’t help but think they might have a little tiny problem loading up six tanks into the back of a passenger plane, the failure of any of which will literally blow the aircraft in half.
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jdmgto t1_iy4ggr4 wrote
Because when it comes to its use as a fuel that is hydrogen’s only positive. The negatives include the collapse of global air travel back into the domain of the wealthy alone. Global air travel’s piece of the global warming pie is only about 3% which is not insignificant but it’s also not what’s killing our planet. You know what does have tremendous benefits, minimal if no downsides and even some upsides for consumers, and will have dramatically bigger GHG savings? Electrification of railways and vehicles, improving public transit, and transitioning to nuclear power.
Yeah, a 1,200 liter, 10,000 psi tank catastropic failure, I’m absolutely sure you’re right and that flying tin can will tank that like a boss. I'm sure there's absolutely no test footage of much, much smaller tanks turning the back end of cars into so much confetti.
E_Snap t1_iy40400 wrote
Which requires enormous amounts of heavy insulation on aircraft fuel tanks and actively cooled cryogenic plants at airports.
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The-Protomolecule t1_iy3k3ro wrote
What you said makes no sense.
merien_nl t1_iy3l31b wrote
It did. Energy density of h2 is 3x that of kerosene, by weight. By volume it is a very different story.
mgt-kuradal t1_iy3ndjq wrote
It does. Energy density of 1 gram of hydrogen vs 1 gram of any other fuel compared to 1 liter of hydrogen vs 1 liter of any other fuel. They are different measures.
Both are valid ways of measuring energy density.
HuckleSmothered t1_iy5odj2 wrote
What weighs more a pound of feathers, or never learning past 5th grade?
syuvial t1_iy3qbi4 wrote
im not really sold on hydrogen either, but weight is actually extremely important when it comes to shipping and transport fuel efficiency. You literally burn less fuel moving less weight.
Philo_T_Farnsworth t1_iy50cx0 wrote
Thank you for flying Tender Air. The only airline where every flight is powered by the very chicken tenders that you, the passengers on this flight, consume. Eat well, travelers. And welcome aboard.
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merien_nl t1_iy3dagy wrote
Getting a jet engine running on hydrogen is not the main issue. Creating enough green hydrogen, transporting it to the airport, carrying it in the airplane are all much bigger issues.
Claiming landmark achievement for something that already has been done in Sovjet Russia 30+ years ago and is the lesser of your challenges is pushing it.
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Hank_moody71 t1_iy4rgf1 wrote
As a pilot the thing I’m deathly afraid of is fire on a plane. Now a fire becomes huge explosion. It’ll take a bit to convince me this is safe
jesterjared t1_iy5msaf wrote
Because current jet fuel isn’t a fire hazard already?
Hank_moody71 t1_iy5otev wrote
It’s not as explosive as hydrogen
HuckleSmothered t1_iy5o5ss wrote
Cool, now figure out a way to store as much hydrogen for the same specific volume and weight of jet fuel.
I’ll wait….
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skb239 t1_iy3ru4q wrote
Why don’t we have hydrogen creation as battery storage for solar and wind? Is it really that inefficient?
Diniden t1_iy3wf2d wrote
Yes. Hydrogen as energy storage has more “steps” than other methodologies and changes in the form of potential energy. Basically every conversion that happens has an efficiency cost. So in theory, less conversions will generally beat more conversions.
Most cases we want electricity, so if we can just manipulate electrons as much as possible and stay away from chemical reactions, the better off the system will be.
This is why super/ultra capacitors are still in the race for solving the storage problems. They have even less conversions than batteries when working with electricity.
You can see how hard it is to make hydrogen by simply sticking two DC electrical sources in some water and split it into hydrogen and oxygen. Takes a lot of current and a lot of time. Hydrogen has a lot of energy potential, but takes a lot of energy to isolate it.
NotPortlyPenguin t1_iy47lzd wrote
Exactly why hydrogen as fuel should be limited to places where we don’t have much choice. Trains? No, electrify the tracks. Airplanes? Well, too long an extension cord. Need another fuel.
DeafHeretic t1_iy41vzc wrote
TL;DR
But it isn't surprising IMO - turbines will run on just about any combustible fuel if tuned for the fuel.
PadishahSenator t1_iy4te91 wrote
Isn't water vapor also a greenhouse gas?
Skookmehgooch t1_iy52i3s wrote
Yes, and it is actually worse than CO2 if I remember right.
mrs_shrew t1_iy558ta wrote
Yes I remember that too, but water has the added benefit of buggering off into a raincloud, so the results are net positive.
FalconX88 t1_iy56e8b wrote
yes, but if you burn normal fuel you'll also create a lot of water.
abiabi2884 t1_iy4u3vp wrote
Tbh I am a little sad about no video material
Foxmccloskey11 t1_iy57ide wrote
I wonder what happens to prices of flying once they figure out how to get free fuel?
Salt_Shaker999 t1_iy5r7rb wrote
I thought there was intensive electric power use required to generate hydrogen. Has a more efficient way been developed?
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Formal-Appearance210 t1_iy7aipg wrote
Uh-huh.
I expect to see this put into actual use... sometime after I'm dead in a few decades.
CMG30 t1_iy8wreq wrote
Unfortunately, people have missed the boat here. The problem is not burning hydrogen to make things go, the problem is finding places to store the hydrogen on the plane. Hydrogen has an incredibly LOW energy density by VOLUME.
vivanetx t1_iy3pgnu wrote
In this thread: lots of hate on batteries for some reason?
Tarcye t1_iy42zs1 wrote
Batteries are nonviable for Aircraft. Weight is serious issue with Aircraft.
Even Current Aircraft have problems with weight. A big part of the reason why Aircraft have to dump fuel before they land is becuese they are too heavy.
And for batteries to be able to power a commercial Aircraft they would need to be much denser. Which contributes to problem #1.
Might be solved decades into the future but for right now nothing is going to be changing when it comes to Aircraft since no viable alternatives are even close to being viable.
Including this Achievement the article is talking about. Since hydrogen has powered aircraft before.
shiroboi t1_iy3spl5 wrote
Batteries are really heavy. Might power a short range plane but just doesn’t have enough juice for a commercial airliner to fly long distances
chmilz t1_iy4cn85 wrote
And the immediate response is that batteries are not viable in their current state. As is hydrogen. And that response goes on to talk about how theoretical future hydrogen technology will make it viable, while ignoring the same theoretical battery technology.
With one major caveat: hydrogen is a known quantity - the energy density cannot change, it will never get better than what it is now. We're increasing battery storage density while reducing weight and other challenges constantly. Over time, I see no scenario where hydrogen beats battery. We currently have no theoretical limit to what we can achieve with batteries. We can't extract more energy out of liquid hydrogen than we do now.
Spudgunhimself t1_iy51i17 wrote
You absolutely have a limit on what you can store with batteries. That limit is 1 electron per lithium atom. Even if you used pure lithium metal as your electrode, that is still three times as heavy as hydrogen per electron.
chmilz t1_iy52jss wrote
We're limited to lithium?
FalconX88 t1_iy556ch wrote
I mean beryllium would be slightly better, but everything is worse than hydrogen. Hydrogen has the highest (useable) electron to weight ratio.
Spudgunhimself t1_iy5sg4c wrote
Well the only lighter reactive element than lithium is hydrogen, so at that point you'd just be making a hydrogen fuel cell 😂
Thaflash_la t1_iy4td8e wrote
All of these threads rely on hardheaded rejection of any non-fossil fuel advancements for engagement.
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MiyamotoKnows t1_iy4usnu wrote
Keep Elon away from these companies before he buys and destroys them too.
Edit: Hey Elon fans you can down vote all you want but you can't face the truth. I have personally lost tens of thousands this year on TSLA and it isn't coming back because this asshat is actively destroying his brand. Go pull up a stock chart and look for yourself at what he is doing to his businesses.
spikek1 t1_iy51nuw wrote
All I got out of that was “major milestone” and “huge step forward.” Lots of back patting, no technicals.
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destraight t1_iy459rd wrote
But it's by rolls Royce. So it's going to be fucking dumb
wairdone t1_iy53feh wrote
Rolls Royce, one of the most well-known engine manufacturers in the world, is dumb to you?
destraight t1_iy5wa7h wrote
Their shit is too expensive
wairdone t1_iy68wcs wrote
And it is of some of the highest quality on the market. Your point?
FalconX88 t1_iy568e5 wrote
Rolls Royce is one of the most successful engineering companies there is. They are building aircraft engines for over 100 years now. If you are on a long haul flight on a wide body airplane, the chances are about 1 in 3 the plane uses Rolls Royce engines.
destraight t1_iy5w8fh wrote
It is still going to be expensive.
FalconX88 t1_iy7zo94 wrote
As all engines are. A Trent 1000 engine (e.g. on the dreamliner) is about 20 million dollar and a lot in maintenance.
nmezib t1_iy5hv0l wrote
Rolls Royce is an engine manufacturer, BMW makes the cars.
Meatball_pressure t1_iy3dz3m wrote
Technology baby! Fuck batteries
wedontlikespaces t1_iy3gcp9 wrote
The fact that hydrogen is usable as a fuel is not really revolutionary. If they have figured out a way to make large quantities of hydrogen in an environmentally friendly way, that would be something.
But we're still going to use batteries because hydrogen fuel cells take a lot of space and are more complicated than a simple battery.
XonikzD t1_iy3sggg wrote
Also, fuel cells deliver power to a battery, so...
AldoLagana t1_iy3ank3 wrote
I don't like flying, but hydrogen/oxygen made from sea water with wind/solar power. That is green aircraft fuel. Right now, hydrogen is made with fossil fuels, so again...better...just not good enough...yet.