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Airbus eyes hydrogen power for airliner in next decade

118 points by prostoalex 6y ago

Havoc 6y ago
That would be good. I'd love to travel more without feeling guilty about the env impact
- akkawwakka 6y ago
  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 6y ago
    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.
    - ehnto 6y ago
      General consumption drives the need for heavy industries that contribute the most to pollution, so it's indirect but still the consumer at the helm. However, I totally agree that the focus should be on those heavy polluting industries. I don't believe it's evil for humans to want to live the lives they do, with the technology we've created, and I also don't think we can change enough people to ever make a dent in those consumption requirements. Better to fix the issue more efficiently, at the source of the pollution, by switching heavily polluting industry out for greener alternatives, as the input into the consumption machine.
    - politelemon 6y ago
      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-takeaways-from-the-fight-over-the-future-of-plastics?t=1595756112035 https://www.npr.org/2020/03/31/822597631/plastic-wars-three-...
      - WalterBright 6y ago
        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.
  - lcam84 6y ago
    Aviation is responsible for 2% of carbon emissions but was growing at 4% per year. Aviation is responsible for the mass tourism that drives people out of cities to make way for airbnb's. This increases their commute. It also increases real estate speculation, i.e. more construction of houses (cement alone accounts for another 2% of emissions). We cannot take a reductionist view of the problem. Mass tourism was one of the biggest environmental problems and was based on aviation. Travelling by air is a privilege that only a small percentage of the population has access to. If everyone did that we would quickly exhaust our carbon budget.
    - PaulHoule 6y ago
      It is funny that people in the aviation business don't treat it as if it was a growth business. That is why Boeing feels entitled to keep making a 50 year old airframe forever. You couldn't do that if you were making cars. When it comes to environmental consequences aviation is a growth business, the most important thing we can do is address the 737-class airplanes that people ride in, not the widebody airplanes that are advertised in magazines. Too often ideas like blended wing body, hybrid, and hydrogen are used as excuses to delay a 737 replacement. We've been watching this movie for decades but these is enough $$$ going to the media and politicians and nothing will replace the 737 until the Chinese do it with to the C919 and then all the people who brought you this disaster will say they were blindsided. They get blindsided every time because that's what they do.
  - WalterBright 6y ago
    > You can throw a match into Jet-A and it won’t catch fire. Yeah, well, we all know jet fuel burns very well and that's why it's so useful. Fire is the worst crisis on an airliner.
    - MertsA 6y ago
      No he's right, Jet-A has plenty of energy but it's not very volatile so unless you've got a very large hot fire it will not sustain itself. https://www.youtube.com/watch?v=7nL10C7FSbE https://www.youtube.com/watch?v=7nL10C7FSbE It takes a spray nozzle atomizing it for him to actually meaningfully burn it with a blowtorch.
    - busterarm 6y ago
      Because fire consumes oxygen (which you have an enormous supply of) that people need to breathe as well as the airframe/wings you need to stay in the air and the landing gear you need to safely get back on the ground. Not because of jet fuel.
  - Melting_Harps 6y ago
    > 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. Agreed. This is why, despite being an active member in the sustainable movement for nearly 18 years now, I've never once felt 'ashamed' due to my travels all over the World and will continue to do so. The model shows that unsustainable living habits, particularly those of waste and uncaptured value due to loss in these network,s are the real glut of not just CO2 emissions, but also of CH4 and other more harmful GH gasses. If anything Travel, not to be mistaken with tourism, can open your eyes to seeing your Fellow Human as you see yourself as you interact and briefly and live as he does and in turn walk away with a Global sense of Community and an understanding that cannot be conveyed in books, TV or movies. I think it's why despite my 'radical thinking' I sincerely feel that the ICE based model for airplanes, and rockets will likely always remain. We should strive for constant refinement, not scrapping it since it accounts for so little of total GH emissions and can have a high ROI. > These are pervasive beliefs among environmentalists. Meanwhile very little attention is paid to corporate and nation level changes. No, its just not enforced up on by Nation States, as they often have strong incentives to keep things as they are, the environmentalists (I'm one) have been pushing for corporations to be held accountable for eco-cide [1], and be held accountable for all the costs it has and will incur, which in turn could help fund the remediation of those sites. > The best thing you can do for the environment is vote. This feels counterproductive but it's entirely true. No, entirely false, for the reasons listed above. The best you can do is think Globally and act locally about the problem. That is begin to get active in these matters in your community and share your ideas and build a collective of people driven to see these goals get accomplished in real-time; the State will not do it for you, and waiting and relying on them to do so is how we got to this point and why its so wide spread. People are still surprised when they're expected to use their corrupt Legal system and expect another result?! Your diffusion of PERSONAL responsibility to this apparatus is the real problem, not what specious reasoning or beliefs some 'environmentalists' may or may not have or use. Voting gives you the illusion you're doing something, when you really aren't and are only really validating a flawed concept with your continual participation, and the idea of it ever really making any difference is where you see the divide between people who actually do, and those that only talk about it. The former being where most people remain to this day on the matter(s) even as the problems continue to compound. 1: https://ecocidelaw.com/the-law/what-is-ecocide/ https://ecocidelaw.com/the-law/what-is-ecocide/
- masklinn 6y ago
  The vast majority of the existing hydrogen pipeline is sourced from fossil fuels, so that's more of a greenwashing thing than actual environmental impact improvements.
  - Someone 6y ago
    I don’t think that’s a strong argument against hydrogen. At the moment, the vast majority of everything we build uses fossil fuels, including most batteries. Most batteries are even charged using power from fossil fuels. What matters is whether hydrogen tanks can be a cheaper or better approach to storing and transporting lots of energy than competing technologies. Proponents of using hydrogen say existing electricity infrastructure has way too little capacity making hydrogen, which can be pumped through existing gas lines, an attractive approach alongside electricity for transporting power. That makes it more attractive for storage, too.
  - Havoc 6y ago
    For now. Once the hydrogen economy gains scale I would expect that to improve
- cagenut 6y ago
  Thank you for at least acknowledging it openly. A cultural shift is a necessary (though ofc not sufficient) part of this.
  - Havoc 6y ago
    It is sorta getting out there. Eg our corporate booking portal told you price and carbon emission so it was at least sorta in your face every time you fly
ncmncm 6y ago
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.
- MrBuddyCasino 6y ago
  > Hydrogen's energy-density makes it by far the best possible fuel for aviation. gasoline: 45.8 MJ/kg hydrogen: 120 MJ/kg What about safety? I visited the Zeppelin museum in Friedrichshafen last week... Wouldn't it be nice if turning CO2 into gasoline would enable us to re-use tall the existing infrastructure?
  - pfortuny 6y ago
    Zeppelins were essentially giant gaseous hydrogen balloons. That is directly flammable. AFAIK liquid hydrogen tanks are orders of magnitude safer (as in “a totally different problem”).
    - exged 6y ago
      Liquid hydrogen tanks are definitely a different problem, but I don't know if "orders of magnitude safer" is necessarily true. Many spacecraft have run into problems involving liquid hydrogen storage for a variety of reasons: - Liquid hydrogen is so cold that many metals weaken - Exposure to hydrogen itself weakens many metals (hydrogen embrittlement) - Liquid hydrogen expands rapidly if exposed to heat, so venting is needed - Hydrogen leaks through the smallest of seams Now imagine trying to build a tank that prevents all that from happening, and it has to be lightweight for usage on spacecraft / aircraft.
      - 6y ago
stormdennis 6y ago
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 6y ago
  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 6y ago
    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 6y ago
      > 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 6y ago
        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.
walrus01 6y ago
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.
- dthakur 6y ago
  Could you kindly provide a link for the hovering hexacopter please? Thanks.
  - culturestate 6y ago
    I assume they're referring to https://www.youtube.com/watch?v=_U_dHZZ3vxQ&feature=emb_title https://www.youtube.com/watch?v=_U_dHZZ3vxQ&feature=emb_titl...
    - walrus01 6y ago
      That one and also Doosan. https://www.youtube.com/c/DoosanMobilityInnovation https://www.youtube.com/c/DoosanMobilityInnovation There is more than one south Korean company working on combined packages of lightweight hydrogen tanks and fuel cell power systems. And several American companies.
- Retric 6y ago
  Hydrogen becomes significantly more efficient as you scale the tank. Don’t forget many rockets use Hydrogen over Jet-A and they really care about weight.
  - mhandley 6y ago
Kuinox 6y ago
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_ 6y ago
  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.
Gwypaas 6y ago
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 6y ago
  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 6y ago
    Compared to battery packs (the main competitor for "green" vehicles) it has a very high energy density.
    - masklinn 6y ago
      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.
  - pa7x1 6y ago
    There is two densities to care about when talking about energy sources. Energy density per volume unit and energy density per mass unit. Hydrogen has a very high energy density per mass unit (the highest of the chemical reaction energy sources). But lower energy density per volume than Li. The two figures matter for different use cases, cargo-ships and aviation want to optimize for energy density per mass, while small passenger transport (e.g. scooters, cars...) wants to optimize for energy density per volume. Energy density per mass graph: https://en.wikipedia.org/wiki/Energy_density#/media/File:Energy_density.svg https://en.wikipedia.org/wiki/Energy_density#/media/File:Ene...
baybal2 6y ago
> 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
jacquesm 6y ago
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 6y ago
  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 6y ago
    Here is an example: https://electrek.co/2019/06/11/hydrogen-station-explodes-toyota-halts-sales-fuel-cell-cars/ https://electrek.co/2019/06/11/hydrogen-station-explodes-toy... 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 6y ago
      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?
korantu 6y ago
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-lch071520.php https://www.eurekalert.org/pub_releases/2020-07/uor-lch07152...
- gus_massa 6y ago
  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.
  - guerrilla 6y ago
    Thanks for the details. On the other hand, doesn't this incentivize carbon capture by making the cost of energy storage just energy?
holoduke 6y ago
just curious, but what about nuclear powered planes. didn't the us and Russia had operational planes back in the 70s?
- jeffreyrogers 6y ago
  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.
- aunty_helen 6y ago
  When you demand power from the reactors they make a lot more radiation. There wasn't a way to shield the crew without a lot of lead plating. Lots of weight in an aircraft was the deal breaker. I think the ruskies did end up with something flying but I'm not confident about that.
alkonaut 6y ago
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.
- Thlom 6y ago
  People need to fly less.
  - keymone 6y ago
    People need to fly more.
- deleted 6y ago
  [deleted]
- iso1210 6y ago
  > If commercial flights all used 50/50 renewable fuel that would cut greenhouse emissions in half. Airline emissions aren't that bad compared with everything else, but they aren't being decarbonised at the same rate like everything else, and on top of that they are growing dramatically. In 2019 there were 4.5b passengers globally. In 2006 there were 2.25 passengers globally, so doubled in 13 years. Planes are slightly more efficient now, but there's a long tail of less efficient planes. Moving to 50:50 biofuel may save a decade of growth, but it's not a silver bullet.
- jacquesm 6y ago
  Also, Hydrogen isn't a fuel, it is a storage medium, a battery if you will.
  - 6y ago
socialdemocrat 6y ago
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 6y ago
  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-greenhouse-gas https://www.edf.org/climate/methane-other-important-greenhou...
  - Ericson2314 6y ago
    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.
fnord77 6y ago
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 6y ago
  Combustion of biofuels still produces CO2, which is one of the outputs these projects are trying to eliminate.
  - aunty_helen 6y ago
    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.
LargoLasskhyfv 6y ago
[1] https://duckduckgo.com/?t=ffsb&q=slush+hydrogen https://duckduckgo.com/?t=ffsb&q=slush+hydrogen
Simulacra 6y ago
Ok..but.. what about kaboom?
dfilppi 6y ago
Oh the humanity
kemiller 6y ago
It really seems like synthetic fuels using water and co2 and excess solar energy as inputs Is probably the best bet ultimately.
- jacknews 6y ago
  butanol was being highlighted a few years ago. I don't know it's still a good choice, or some problems were discovered.
joyj2nd 6y ago
Old news. Germans did this before. https://www.history.com/.image/c_limit%2Ccs_srgb%2Cq_auto:good%2Cw_686/MTU3ODc4NjAzMjQ3ODU1MzI3/image-placeholder-title.webp https://www.history.com/.image/c_limit%2Ccs_srgb%2Cq_auto:go...
credit_guy 6y ago
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-fuel-seawater-0423432/ https://www.zmescience.com/research/us-navy-synthetic-jet-fu...
- Hypx 6y ago
  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 6y ago
    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 6y ago
      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.

118 points by prostoalex 6y ago

Havoc 6y ago

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

akkawwakka 6y ago
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 6y ago
  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.
  - ehnto 6y ago
    General consumption drives the need for heavy industries that contribute the most to pollution, so it's indirect but still the consumer at the helm. However, I totally agree that the focus should be on those heavy polluting industries. I don't believe it's evil for humans to want to live the lives they do, with the technology we've created, and I also don't think we can change enough people to ever make a dent in those consumption requirements. Better to fix the issue more efficiently, at the source of the pollution, by switching heavily polluting industry out for greener alternatives, as the input into the consumption machine.
  - politelemon 6y ago
    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-takeaways-from-the-fight-over-the-future-of-plastics?t=1595756112035 https://www.npr.org/2020/03/31/822597631/plastic-wars-three-...
    - WalterBright 6y ago
      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.
- lcam84 6y ago
  Aviation is responsible for 2% of carbon emissions but was growing at 4% per year. Aviation is responsible for the mass tourism that drives people out of cities to make way for airbnb's. This increases their commute. It also increases real estate speculation, i.e. more construction of houses (cement alone accounts for another 2% of emissions). We cannot take a reductionist view of the problem. Mass tourism was one of the biggest environmental problems and was based on aviation. Travelling by air is a privilege that only a small percentage of the population has access to. If everyone did that we would quickly exhaust our carbon budget.
  - PaulHoule 6y ago
    It is funny that people in the aviation business don't treat it as if it was a growth business. That is why Boeing feels entitled to keep making a 50 year old airframe forever. You couldn't do that if you were making cars. When it comes to environmental consequences aviation is a growth business, the most important thing we can do is address the 737-class airplanes that people ride in, not the widebody airplanes that are advertised in magazines. Too often ideas like blended wing body, hybrid, and hydrogen are used as excuses to delay a 737 replacement. We've been watching this movie for decades but these is enough $$$ going to the media and politicians and nothing will replace the 737 until the Chinese do it with to the C919 and then all the people who brought you this disaster will say they were blindsided. They get blindsided every time because that's what they do.
- WalterBright 6y ago
  > You can throw a match into Jet-A and it won’t catch fire. Yeah, well, we all know jet fuel burns very well and that's why it's so useful. Fire is the worst crisis on an airliner.
  - MertsA 6y ago
    No he's right, Jet-A has plenty of energy but it's not very volatile so unless you've got a very large hot fire it will not sustain itself. https://www.youtube.com/watch?v=7nL10C7FSbE https://www.youtube.com/watch?v=7nL10C7FSbE It takes a spray nozzle atomizing it for him to actually meaningfully burn it with a blowtorch.
  - busterarm 6y ago
    Because fire consumes oxygen (which you have an enormous supply of) that people need to breathe as well as the airframe/wings you need to stay in the air and the landing gear you need to safely get back on the ground. Not because of jet fuel.
- Melting_Harps 6y ago
  > 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. Agreed. This is why, despite being an active member in the sustainable movement for nearly 18 years now, I've never once felt 'ashamed' due to my travels all over the World and will continue to do so. The model shows that unsustainable living habits, particularly those of waste and uncaptured value due to loss in these network,s are the real glut of not just CO2 emissions, but also of CH4 and other more harmful GH gasses. If anything Travel, not to be mistaken with tourism, can open your eyes to seeing your Fellow Human as you see yourself as you interact and briefly and live as he does and in turn walk away with a Global sense of Community and an understanding that cannot be conveyed in books, TV or movies. I think it's why despite my 'radical thinking' I sincerely feel that the ICE based model for airplanes, and rockets will likely always remain. We should strive for constant refinement, not scrapping it since it accounts for so little of total GH emissions and can have a high ROI. > These are pervasive beliefs among environmentalists. Meanwhile very little attention is paid to corporate and nation level changes. No, its just not enforced up on by Nation States, as they often have strong incentives to keep things as they are, the environmentalists (I'm one) have been pushing for corporations to be held accountable for eco-cide [1], and be held accountable for all the costs it has and will incur, which in turn could help fund the remediation of those sites. > The best thing you can do for the environment is vote. This feels counterproductive but it's entirely true. No, entirely false, for the reasons listed above. The best you can do is think Globally and act locally about the problem. That is begin to get active in these matters in your community and share your ideas and build a collective of people driven to see these goals get accomplished in real-time; the State will not do it for you, and waiting and relying on them to do so is how we got to this point and why its so wide spread. People are still surprised when they're expected to use their corrupt Legal system and expect another result?! Your diffusion of PERSONAL responsibility to this apparatus is the real problem, not what specious reasoning or beliefs some 'environmentalists' may or may not have or use. Voting gives you the illusion you're doing something, when you really aren't and are only really validating a flawed concept with your continual participation, and the idea of it ever really making any difference is where you see the divide between people who actually do, and those that only talk about it. The former being where most people remain to this day on the matter(s) even as the problems continue to compound. 1: https://ecocidelaw.com/the-law/what-is-ecocide/ https://ecocidelaw.com/the-law/what-is-ecocide/
masklinn 6y ago
The vast majority of the existing hydrogen pipeline is sourced from fossil fuels, so that's more of a greenwashing thing than actual environmental impact improvements.
- Someone 6y ago
  I don’t think that’s a strong argument against hydrogen. At the moment, the vast majority of everything we build uses fossil fuels, including most batteries. Most batteries are even charged using power from fossil fuels. What matters is whether hydrogen tanks can be a cheaper or better approach to storing and transporting lots of energy than competing technologies. Proponents of using hydrogen say existing electricity infrastructure has way too little capacity making hydrogen, which can be pumped through existing gas lines, an attractive approach alongside electricity for transporting power. That makes it more attractive for storage, too.
- Havoc 6y ago
  For now. Once the hydrogen economy gains scale I would expect that to improve
cagenut 6y ago
Thank you for at least acknowledging it openly. A cultural shift is a necessary (though ofc not sufficient) part of this.
- Havoc 6y ago
  It is sorta getting out there. Eg our corporate booking portal told you price and carbon emission so it was at least sorta in your face every time you fly

ncmncm 6y ago

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.

MrBuddyCasino 6y ago
> Hydrogen's energy-density makes it by far the best possible fuel for aviation. gasoline: 45.8 MJ/kg hydrogen: 120 MJ/kg What about safety? I visited the Zeppelin museum in Friedrichshafen last week... Wouldn't it be nice if turning CO2 into gasoline would enable us to re-use tall the existing infrastructure?
- pfortuny 6y ago
  Zeppelins were essentially giant gaseous hydrogen balloons. That is directly flammable. AFAIK liquid hydrogen tanks are orders of magnitude safer (as in “a totally different problem”).
  - exged 6y ago
    Liquid hydrogen tanks are definitely a different problem, but I don't know if "orders of magnitude safer" is necessarily true. Many spacecraft have run into problems involving liquid hydrogen storage for a variety of reasons: - Liquid hydrogen is so cold that many metals weaken - Exposure to hydrogen itself weakens many metals (hydrogen embrittlement) - Liquid hydrogen expands rapidly if exposed to heat, so venting is needed - Hydrogen leaks through the smallest of seams Now imagine trying to build a tank that prevents all that from happening, and it has to be lightweight for usage on spacecraft / aircraft.
    - 6y ago

stormdennis 6y ago

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 6y ago
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 6y ago
  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 6y ago
    > 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 6y ago
      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.

walrus01 6y ago

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.

dthakur 6y ago
Could you kindly provide a link for the hovering hexacopter please? Thanks.
- culturestate 6y ago
  I assume they're referring to https://www.youtube.com/watch?v=_U_dHZZ3vxQ&feature=emb_title https://www.youtube.com/watch?v=_U_dHZZ3vxQ&feature=emb_titl...
  - walrus01 6y ago
    That one and also Doosan. https://www.youtube.com/c/DoosanMobilityInnovation https://www.youtube.com/c/DoosanMobilityInnovation There is more than one south Korean company working on combined packages of lightweight hydrogen tanks and fuel cell power systems. And several American companies.
Retric 6y ago
Hydrogen becomes significantly more efficient as you scale the tank. Don’t forget many rockets use Hydrogen over Jet-A and they really care about weight.
- mhandley 6y ago

Kuinox 6y ago

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_ 6y ago
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.

Gwypaas 6y ago

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 6y ago
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 6y ago
  Compared to battery packs (the main competitor for "green" vehicles) it has a very high energy density.
  - masklinn 6y ago
    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.
- pa7x1 6y ago
  There is two densities to care about when talking about energy sources. Energy density per volume unit and energy density per mass unit. Hydrogen has a very high energy density per mass unit (the highest of the chemical reaction energy sources). But lower energy density per volume than Li. The two figures matter for different use cases, cargo-ships and aviation want to optimize for energy density per mass, while small passenger transport (e.g. scooters, cars...) wants to optimize for energy density per volume. Energy density per mass graph: https://en.wikipedia.org/wiki/Energy_density#/media/File:Energy_density.svg https://en.wikipedia.org/wiki/Energy_density#/media/File:Ene...

baybal2 6y ago

> 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

jacquesm 6y ago

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 6y ago
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 6y ago
  Here is an example: https://electrek.co/2019/06/11/hydrogen-station-explodes-toyota-halts-sales-fuel-cell-cars/ https://electrek.co/2019/06/11/hydrogen-station-explodes-toy... 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 6y ago
    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?

korantu 6y ago

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-lch071520.php https://www.eurekalert.org/pub_releases/2020-07/uor-lch07152...

gus_massa 6y ago
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.
- guerrilla 6y ago
  Thanks for the details. On the other hand, doesn't this incentivize carbon capture by making the cost of energy storage just energy?

holoduke 6y ago

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

jeffreyrogers 6y ago
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.
aunty_helen 6y ago
When you demand power from the reactors they make a lot more radiation. There wasn't a way to shield the crew without a lot of lead plating. Lots of weight in an aircraft was the deal breaker. I think the ruskies did end up with something flying but I'm not confident about that.

alkonaut 6y ago

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.

Thlom 6y ago
People need to fly less.
- keymone 6y ago
  People need to fly more.
deleted 6y ago
[deleted]
iso1210 6y ago
> If commercial flights all used 50/50 renewable fuel that would cut greenhouse emissions in half. Airline emissions aren't that bad compared with everything else, but they aren't being decarbonised at the same rate like everything else, and on top of that they are growing dramatically. In 2019 there were 4.5b passengers globally. In 2006 there were 2.25 passengers globally, so doubled in 13 years. Planes are slightly more efficient now, but there's a long tail of less efficient planes. Moving to 50:50 biofuel may save a decade of growth, but it's not a silver bullet.
jacquesm 6y ago
Also, Hydrogen isn't a fuel, it is a storage medium, a battery if you will.
- 6y ago

socialdemocrat 6y ago

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 6y ago
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-greenhouse-gas https://www.edf.org/climate/methane-other-important-greenhou...
- Ericson2314 6y ago
  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.

fnord77 6y ago

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 6y ago
Combustion of biofuels still produces CO2, which is one of the outputs these projects are trying to eliminate.
- aunty_helen 6y ago
  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.

LargoLasskhyfv 6y ago

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

Simulacra 6y ago

Ok..but.. what about kaboom?

dfilppi 6y ago

Oh the humanity

kemiller 6y ago

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

jacknews 6y ago
butanol was being highlighted a few years ago. I don't know it's still a good choice, or some problems were discovered.

joyj2nd 6y ago

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

credit_guy 6y ago

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-fuel-seawater-0423432/ https://www.zmescience.com/research/us-navy-synthetic-jet-fu...

Hypx 6y ago
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 6y ago
  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 6y ago
    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.