Just so you know, while H is the smallest atom in the periodic table, it is NOT the smallest molecule because it is diatomic. Helium is the smallest (and maybe the leakiest) because it is monoatomic.
Yo mentour, my endless watching of your channel finally paid off in real life, some of my donut friends were mindlessly discussing something and i stepped in with full correct technical flight analysis 🍻 nice work
I retired with about ten patents on fuel cell and related technologies and am subject matter expert on hydrogen safety. Virtually all commercial hydrogen comes from “reformed” natural gas. Burning hydrogen in cars and airplanes doesn’t produce tailpipe emission of CO2, but the large centralized plants that reform the natural gas to make the hydrogen do, and they discharge all that carbon into the air as CO2, just like a tailpipe would, except the release is highly concentrated. Of course, *where* CO2 is released (distributed or concentrated at one source) doesn’t matter for global warming. Rather like @jacobschneck wrote here, fuel cell-powered vehicles have been just five years in the future for over 30 years. Today, everyone promoting their hydrogen technology is trying to cash in on government grants overseen by bureaucrats dolling out taxpayer money without even 1% of the due diligence a private investor would devote. But if you press these *“Hydrogen of the F-U-T-U-R-E!!!”* people about where this magical green hydrogen (not from natural gas) will come from, they’ll admit that it all depends on the Pleasant Outcome Fairy bestowing humanity with some new energy source (fusion, solar, you dream it) that is so phenomenally cheap and nice-nice and bunny hugging that it will make the production of hydrogen-cracked from a green source like water-practical. And in the final analysis, this future green hydrogen would as much as fuel *source* as water was when one referred to an 1880-era locomotive a “steam powered” engine. Steam is just a *carrier* of energy; the actual energy, of course, came from wood and/or coal. And so it will be for hydrogen; if it doesn’t come from natural gas, it’s just an intermediate energy carrier. And it’s an exceedingly dangerous one. If we could just find the equivalent of “free coal” to make that hydrogen…
Petter H is from Europe. So, he has a smile through out this video? On a serious note, I have a post graduate degree in Chemistry. Nearly 35 years in Aviation. I don’t see hydrogen powered engines developed out of current engines as a viable alternate. Redesigning is needed. That means - time, engineers and lots of cash. Till then, sitting back, relaxing and enjoying Mentour Pilot’s videos!
Hydrogen resides in this weird anti-goldilocks zone. It burns way too hot to be practical without injecting cooling water, which reduces thermodynamic efficiency of combustion and offsets most of the gains. It doesn't liquifies in any practical way, so it needs very large extremely heavy highly pressurized tanks, and the amount of gaseous hydrogen at this pressure is only a small fraction of its liquid form, so you need more tanks. Not to mention using water leaves you with even less useful weight and space capacity. Finally, there's no way to produce hydrogen in a green way. Practical option #1 is to get it through cracking tower at oil refineries, practical option #2 is electrolysis. Neither are good, and the electrolysis option in particular is less than 30% efficient round-trip. Using electric fans and fuel cells sidesteps some of the issues, but hydrogen fuel cell total system efficiency is even less than combustion. Which some readers might not see as an issue but aircraft fuel burn, flight range and payload capacity is a very big deal to airlines.
@@michaelbuckersI find it strange that all of this excess heat cannot be used to further the propulsion. I'm no expert, and obviously, brand new engines would need to be desiged, but excess heat seems to be going to waste. Eg. If an engine was 100% efficient then this excess heat, caused by burning hydrogen, would be a good thing, no?
The problem with hydrogen is the very low volumetric energy density. As a result you need to compress it to extremely high pressures or liquify it by reducing it to very very low temperatures to reduce the fuel tanks to a reasonable size. Pressure vessels or tanks for liquified hydrogen today are very heavy. This doesn’t leave very much weight left for passengers and cargo. I’ve heard that at least with today’s technology it might be possible for short range aircraft but impractical for long range aircraft. I have a friend in the aircraft engine business who has been working on hydrogen but who is very skeptical that hydrogen will take off in aircraft mainly because of the weight of the fuel tanks.
I dont think hydrogen tanks are necessarily heavy. Rockets have used them succesfully for years and weight there is even more important than for airplanes. additionally hydrogen is the highest mass energy density fuel that exists. So i am sure that this can be done. I do think that pressure vessels are the wrong choice and cryogenic hydrogen is much safer/ lower mass and simpler. This likely means that cryogenic hydrogen is the future.
@@thijsstavenga4350 You forget rocket tanks are filled just before ignition and emptied relatively quickly after that. There is no need to keep the hydrogen cold for very long. A long range aircraft on the other hand would need to keep liquid hydrogen several hundreds of degrees below zero for on the order of 5-10 hours or more. Typically cryogenic tanks meant for long term storage of hydrogen contain multiple walls with a vacuum in between as an insulator. They are heavy.
@@GeoffreyEngelbrecht Rockets dont have much thermal insulation, because the fuel gets used so quickly. In an airplane this can definitely be done, the boil off rate will probably be lower than the fuel consumption anyway. Current airplanes use several liters per second of kerosine, I cannot imagine a boil off rate of several liters of liquid hydrogen per second, that is way too high. I work with 100s of liters of liquid nitrogen and the boil off rate is less than a liter per day. Also in storage the liquid hydrogen can be super cooled, which lowers boil off rate. Although this likely costs a lot of energy.
@@thijsstavenga4350Long term prospects of hydrogen rocket propulsion for first stage rockets in Earth atmosphere is a dead end, and it is unappealing for aviation use due to similar reasons. There is no pure hydrogen first stage in rockets because the mass overhead for insulated hydrogen vessel results in a rocket stage that cannot really lift its own weight, and perhaps barely even if it can. This requires use of solid rocket boosters to augment the thrust, which doesn’t make economical sense where first stage reuse is pretty much a requirement for cost competitiveness. While non-hydrogen liquid fuel boosters can also be used, at that point the use of hydrogen first stage is superfluous as it’s easier to just make the first stage use the alternative fuel. Hydrogen chemical propulsion does have an edge for deep space propulsion in vacuum where the efficiency (specific impulse) is king and TWR doesn’t matter as much, but it’s not really comparable to the aviation environment.
It's just called "hydrogen" because most of the energy comes from removing the hydrogen atom from the fuel, and combining it with atmospheric oxygen to form water, releasing a lot of energy in the process. The system we're eventually going to settle on will probably be to use the hydrogen as feedstock to create another hydrogen-based fuel like alcohol or ammonia. And use those materials (which have volumetric energy density similar to avgas, and much better gravimetric energy density than batteries) as the fuel stored in the plane's wings.
I love the engine technology videos; they really round out the channel as a source for not only the past and present of aviation, but the future as well!
I like those stories best, too. Hydrogen has such fantastic energy density per kg that it merits a lot of adaptation to accommodate its difficult problems. For practical use it needs to be carried in liquid form, but the tanks won't fit in the wings, and you _absolutely_ don't want unavoidably-leaky tankage and plumbing in the fuselage. Furthermore, you don't want ground crews fooling with cryo hoses. The practical alternative, then, is removable tank nacelles hung under the wings, trucked out full and hung immediately before each flight. The fuel is oxidized entirely in the wings, whether in combustion turbines or in fuel cells driving electric turbines. For more range, hang more nacelles. A huge advantage of LH2 rarely noted is that the fuel may be produced on-site at the airport, from wired-in power during peak-production / mimimum-price periods, eliminating a big operational expense. Storage underground makes insulation easy. Solar mounted above long-term parking would protect passengers' cars from weather, though that could produce only a fraction of the needed energy. Atmospheric carbon capture might make on-site production of hydrocarbon fuels possible, but it would probably take up more space than most airports could spare. Burning hydrogen in turbines at higher temperature would give you increased NOx production, possibly a big problem, at least if it happens at low altitudes. That favors fuel cells. One wonders if electric-drive assist could fit into jet-fuel burning turbines...
@@Akio-fy7ep As far as NOx production in the combustor, that seems to be controllable as there is a wide range of methods to deal with it. It is a complex issue but there is already a number of ground based turbine solutions.
@@Mentaculus42 I think they inject ammonia into natural gas turbines to mop up the NOx. Presumably they would do the same with hydrogen turbines. NOx is, notably, another greenhouse gas, alongside CO2, methane, hydrogen, and water vapor, and at altitude depletes ozone. The atmosphere's capacity to clear hydrogen is strictly limited, so that above a certain leakage rate H2 accumulates like CO2.
i dont see how hydrogen would work? its extremely difficult to store. the planes would have so much boil off/leaks and hydrogen is very flammable so seems like a huge safety concern as far as civil aviation goes
In the UK, we converted one of our power stations to run on woodchip pellets. It too, was supposed to only use waste products as opposed to cutting down trees specifically to produce these pellets. The latter scenario is what has come to pass. We import this "biofuel" all the way from Canada. The politicians and CEO$ laugh as they receive their green stars.
That's capitalism for you, why stop at waste products if you can get way more money burning everything around you too and nobody is going to double check how green it is either.
The SE US also supplies wood chip pellets to Europe. That means machines harvesting the trees, trucks transporting the logs to a mill, the mill grinding logs into pellets, railroads taking pellets to the coast, ships transporting them to Europe and trains transporting them to power plants. I would not be surprised if that requires more energy than that coming from the pellets. It is insane but "renewable" since new trees can be planted for the ones consumed.
Fun fact: The first jet engine ever operating had its first test runs on hydrogen since it was easier to get the combustion stable and Hans Papst von Ohain was on a tight schedule from his boss Ernst Heinkel to show a working engine.
@@rogerphelps9939 As far as I can tell it was quite close, but Ohain's first runs preceded Whittle's by a few weeks (using Hydrogen and still a number of problems, but running)
Mentour listed 3 reasons Airbus wants US companies to "invest" more but he missed the real #1 reason. Airbus doesn't want to be the only one wasting $billions on trying to develop the technology. We cannot even supply hydrogen economically for cars. We will need some significant developments before hydrogen will be realistic for aviation. Mentour also didn't go into any detail on just how extensive the modifications would have to be at airports to be able to handle hydrogen as well. It is WAY too premature to be putting any eggs into the aviation hydrogen basket.
Agreed. Hydrogen powered ships and cars are very likely to come before aviation. Which makes sense. Aviation is far riskier and needs technologies that are more fleshed out. A broken engine in a ship (which usually has multiple) or a car isn't that big of a deal. A broken engine on a plane can be life threatening.
Hydrogen-powered cars and land transport in general are a massive waste of resources compared to wayside power supply and batteries. Those aren't an option for aviation so if you're going to invest in hydrogen technologies, aviation should have priority.
@@alexsis1778 hydrogen cars a vanishing from the international market. They started developing in this new era pretty evenly with eclectric cars, and fell behind. Even in countrys where many hydrogen cars were driven (i.e. japan) they fall behind. If hydrogen is coming as a fuel or fuel source, it will only be in things like aviation and marine traffic. Because there won't be enough for cars, and it's much easier to fuel cars electric than with hydrogen (let alone hydrogen cars need much more energy than electric ones because electric cars are about 4-5 times more efficient)
The usage of fuel for land based vehicles is so much higher than aviation. And the availability of en route refueling is way easier on land based vehicles than on planes.
I read somewhere that 90 million tons of H2 are currently used, all made from methane. The process is lossy and leaks both gases with higher greenhouse effects than CO2. It needs to be replaced as it is a significant greenhouse problem. Now, H2 made from electricity requires 33KW/ kg, and very little is produced. Scaling renewable H2 to replace our chemical usage will be difficult enough. Factoring in an aviation requirement requires significant investment, which is unlikely. There is also difficulty in transporting H2 in the volumes that will be required. We may need H2 production at airports using modular nuclear reactors, but we might get some opposition. I don't see these problems getting solved before the 2035 timeline.
A surprisingly large number of ways of producing hydrogen have been developed since the first one in 1520, one of the alternatives may well come to the fore.
@@alanhat5252 Meanwhile, CNG - or basically using the methane as-is works, is worlds cheaper, and we understand the technology incredibly well ( storing it at airports is a literal non-issue as well ). I don't understand their rabid insistence on 0% versus 2 or 3% that works. The planet can handle a small amount of pollution, as any reduction in a major industry at all is a huge difference. We need to work on reducing first, before we go cold turkey.
@@plektosgaming Our mistake has been listening to these nut jobs!!! Remember these are the same people who can't tell the difference between a man and a woman!!! We must realize that these people have gained the ear of the world, and everyone is bowing down to their demands; the conclusion/statements from experts must be taken with a large grain of salt! We can infer the objective of these people as the destruction of the world as we currently know it! Those who can see it happening, know the best strategy is to ignore their insanity!!!
The author clearly specified “green hydrogen” made from renewable energy and not the older steam-generated one which does indeed have the short-comings that you identified.
If you are already spending the energy to create the hydrogen, you may as well go a bit further and make it into Methane or even something heavier to get the fuel density up. At that point the energy efficiency of creating the fuel doesnt really matter as its all green anyways.
IMO synthetic SAF is the solution, as storing hydrogen onboard aircraft is terribly cumbersome and adds LOTS of extra weight. And for the short haul - batteries or... high speed railway.
Frankly, high speed railway should be the default for transporting a lot of ppl across distances where such railways can be built. For sure, we definitely could eliminate a lot of passenger flights in the US by building (and actually running) high speed railways along frequently traveled routes. Well, such would likely require some kind of regulatory/legislative intervention by regulators/the Federal government to actually get established in the first place, but we're already speaking in hypotheticals here - might as well add in politicians doing more than serving their donors while we're at it, right? (I'm in a cynical mood today. lol)
Im an aspiring 13 year old pilot . these vids are quality content worth watching..... thank you to petter and the team!☺Love both of your channels a lot Edit: Thanks for your likes Guys!❤
Given the history of hydrogen as a "fuel" and hype around it, I feel confident in saying "the hydrogen economy" is never going to happen. The statement that hydrogen is the most abundant element I think demonstrates a lack of understanding of what constitutes a fuel source.
@@matthewhorton871 yes to all those issues. But something like aviation fuel might be a place where convenience and weight matter the most, so it could be excused.
The little tiny issue that “hydrogen haters” seem to overlook is that huge amounts of clean hydrogen will be needed for things that don’t use it as fuel, like ammonia. There will be a clean hydrogen economy, the question is how large not if. Once the demand for these other hydrogen needs are being met, a price will be established for hydrogen that will determine if it grows beyond that. It really is an economic problem not an efficiency issue. Japan will be the proving grounds for hydrogen as an energy transfer medium, mostly in the form of ammonia. If the price is competitive (and many people are of the opinion that it will not be) then it will happen, otherwise not. The “PRICE” is a very complex issue with regard to clean hydrogen (subsidies and all). Besides, that price will not be determined for another ten years at least.
@@Mentaculus42 I agree it is a "little issue" as in probably not significant. About 3% of natural gas is used as feedstock. To put things in perspective, fossil fuels are 81% of energy use, NG is 23% of that. A clean supply of hydrogen for feedstock is one thing, but to replace all NG uses would need 33 times that amount. To replace liquid fuels with hydrogen (as in this case) would need even greater supply. Given the technical difficulties with hydrogen, and the need to create new infrastructure, it is not going to be a cheap or quick solution. It also begs the question : what is the actual energy source for hydrogen? If it is wind/solar/nuclear, it makes much more sense to use electricity directly as we already have the infrastructure and technology for terrestrial use. Hydrogen makes no sense for aviation. Possibly it makes sense for shipping. Of course, the goal of 2050 for "zero carbon" is just wishful thinking, so rushing to a solution to meet that goal will probably lead to bad decisions. In the short term we should be electrifying wherever possible, while SAF may not be perfect it is probably the best solution in aviation.
“Hydrogen is the most abundant element” is a trick statement since those only on the Sun whereas on Earth near 0 elemental Hydrogen is available. This statement misleads most people into blindly thinking that water is all the fuel source we need without recognizing that water is essentially not much more a fuel that what comes out of your car’s exhaust because water is burnt Hydrogen.
@@willemm9356 The claim that hydrogen leaks were not responsible for the Hindenberg conflagration turns out to be propaganda. The highly visible flames were largely kerosene, but the failure started with a hydrogen fire.
Hydrogen is weird stuff to handle. It does like to escape, but it also dissipates pretty easily compared to heavier gaseous fuels like methane and propane. There is always a risk of fire, but except for a narrow range of conditions*, I am more frightened of gasoline fires than gaseous fuels. Personally, I think the finicky nature of hydrogen handling and storage makes it a tough hill to climb, but not technically unfeasible. *foremost condition is that if a gasoline tank is on fire, run a 100 meters or so. If a pressurized fuel tank is on fire, run 1000 meters and then keep running.
The thing with hydrogen is that it's so light it can't linger around enough to make an explosive fuel-air mixture around the leak site. Worst case scenario you get a blow torch until it runs out of pressure.
Hydrogen definitely can be an issue in enclosed spaces (probably not relevant to aviation) but look at what happened at Fukushima with the hydrogen explosion that happened there.
If the hydrogen is produced on-site at airports, storage may not be that much of an issue. It's also important to remember that we don't need to have a singular solution. Hydrogen for short range flights and SAF for long haul flights would work just fine.
@@dbattleaxe What if we take it one step further and produce the hydrogen on the aircraft? I remember creating hydrogen and oxygen in high school chemistry. Might have to carry a small tank of hydrogen for take off and landing purposes but perhaps cruise demands would be met by the generator supplying hydrogen to fuel cells.
@@dbattleaxe The problem with SAF is that the amount of land required to produce the fuel for just one jet aircraft is huge. Photosynthesis is a far less efficient way of capturing solar energy than solar photovoltaic panels or even wind turbines.
Doesn't anyone think we're missing the woods for the trees? Jet fuel is only 10% of the barrel. We can, far easier and cheaper, replace HSFO (used for bunkers in vessels), diesel and some naphtha used for gasoline blending by hydrogen and batteries. Paraffinic naphtha will still be required for a long while yet (plastics), but we can reduce hydrocarbon usage by 80% very easily. Switching the refinery slate from crude to condensate would allow that to ensure no heavy ends left to burn.
@@CaptHollisteryou've missed the point - overall decarbonization can possibly be more easily achieved by decarbonizing something else. I'm all for decarbonizing everything but that's not the point raised.
@@alanhat5252 Agreed. Shipping is incredibly dirty because they generally use the absolute lowest energy fuel simply because nobody else can suffer the low fuel density and extreme weight required to get usable power outputs. This makes it perfect for testing out things like hydrogen which have a low fuel density and can tolerate bulkier less perfected engines. It also will help build out the necessary infrastructure and fuel distribution for aircraft to take advantage of. Not to say we should stop working on engines to use these fuels. Just that the conversion is most likely to start in an industry other than aviation.
Well, the thing is: You still retrieve the nafta out of the ground with crude oil. You have exactly as much nafta as there is, and it's cheap, because: (1) It's abundand. (2) Nobody else wants it. Once/if we use less cruse oil, there'll be less nafta available and ships will switch. But please, before you come to the conclusion that "ship can use hydrogen more easily", remember that for them, "storing" means storing for many days. In an commuter aircraft, you need to store it for a couple hours.
One of my hobbies is studying how society worked in past periods. In particular I have studied thousands of pages of early 20th century censuses. One big industry back then was converting used cooking oil into lighting oil for kerosene/coal oil lamps.
Fascinating video as always. I've been working in the economics of low-carbon hydrogen production the last year, and one thing that is now widely understood is that it is going to be WAY more expensive than what we thought a few years back. A lot of governments, private companies and other institutions hoped that hydrogen would play a big part in decarbonising a lot of industries where electrification is expensive or outright impossible, but with the most up to date cost estimates it is now uneconomical to do so, and aviation is certainly one of the industries that fall under this category unfortunately. Will be really interesting to see what happens though (and who pays the final bill)
Yep. The answer seems to be to fly many fewer times. The aviation industry does not have a viable path to sustainability unless it becomes 2 to 3 times as expensive as it is now. Build high speed rails and only keep long hall flights
So basically the same exact reasons why hydrogen has never come close to being a regular fuel source still exists? Way too volatile require large and very heavy containers, and the fact that you'd have to build an entirely new fuel infrastructure. Anyone who's done the math knows only an idiot would think hydrogen would be used in any major scale as a regular fuel source, it simply just isn't worth the trouble.
Obviously. If if was a smart investment, smart investors would be investing in it. But in the meantime, the right people will become millionaires behind convincing governments to pay them until they can no longer keep up the charade.
Yeah it seems like a major fools errand in most applications. Green hydrogen uses so much electricity, and anything less is barely better for the climate. It has its places in factories but it's a much worse fuel than just using the electricity to power the thing you want in the first place. Planes are an issue though, can't plug that in or use batteries! What's the alternative to hydrogen here? The equally expensive saf?
The safety concerns around hydrogen are, in my opinion, the most important questions here. Catastrophic landings would likely mean an increase in fatalities, crashes on departure into populated areas would also increase the potential number of casualties beyond the aircraft. The storage, transportation, and the transferring of hydrogen is a huge issue as well. Hydrogen has a higher flammability range and lower ignition point than standard hydrocarbon fuels. It's not an impossible hurdle by any means, but every inch of engineering is going to have to be bang on with nearly zero room for errors.
Yet, CNG solves this. Not 100% "clean" ( nearly so, though ), but won't combust as easily, lighter than air, and in an emergency, it is proven to be fairly safe. ( any impact that would crush a tank would probably have the plane in small pieces anyways. ) Hydrogen is.. problematic. lol. very much so. CNG storage at an airport also would be a non-issue as many already do it on a smaller scale for their busses.
Catastrophic landings usually don't have (m)any survivors anyways, so I'm not sure how relevant that point would be. Populated areas obviously might be. Other comments here have discussed hydrogen-based city busses burning up when their tanks got punctured. They noted how a flame just popped out, until the pressure in the tank had vented. But those were stationary tanks - I doubt they'd maintain structural integrity should a plane nose dive into a city (like the Boeing Max did). So yeah, if that turned any plane into a massive flying pipe bomb, I suppose people would have a problem with that.... (and making it hard enough, like a black box, would surely be cost-prohibitive)
Great Video! As someone working on a hydrogen-powered Sling High Wing at ETH Zürich (Cellsius Project H2), I can say that while hydrogen presents significant challenges with its volumetric energy density, many of the safety concerns mentioned here in the comments are often exaggerated. With proper engineering and precautions, hydrogen can be just as safe-if not safer-than traditional fuels. Although hydrogen will leak through most materials, the leak rate is extremely manageable with common materials. The high diffusivity of hydrogen also helps since unless there are locations in the airframe where hydrogen can collect, hydrogen typically disperses too quickly to reach the necessary 4% concentration to be flammable, say in the inevitable boil-off venting of cryogenic tanks. Another aspect often overlooked is that cryogenic tanks usually work "too well" because the boil-off rate is too low for the amount of hydrogen required for the reaction. At least in my opinion, the most significant challenges facing hydrogen in aviation are the low volumetric energy density, the weight of cooling systems for fuel cells, and the NOx challenge for combustion. Hydrogen has immense potential as an exciting next step in aviation!
For the cooling part, why isn't a regenerative cooling type solution like those on rocket engines, be also adopted in some ways for aircraft turbine engines?
I just made this calculation. If you take the example of a 373 MAX, it can load about 29 cubic meters of fuel. If you convert the energy of that amount of jet fuel to H2 at 700 Bar pressure (typical non liquid use) it takes up 170 cubic meters, not counting the tanks. If you use a single big tank, the most efficient weight to volume ratio, it will take about 200 cubic miters. How much is that? Well, it's about the size of the full cabin, so you are left with no room for the passengers. If you go to cryogenic H2, the volume goes down to one half. about 80 cubic meters, but the tank size will grow considerably, as well as the weigh. Besides that, if you have an accident with structural failiure and it gets to the tank(s), the Hindenburg accident will look like a campfire in comparaison. Just imagine having to fly an A380 with only the passengers of the upper deck. If only one accident took travellers away from the Concorde, imagine an accident where the plane dissapears just in seconds.
Yet using CNG ( basically taking the methane and using it as-is ) results in 1/4 of the space required. Not great, but not entirely unreasonable to engineer around. ie - going from 29 to 50 cubic meters.. might be possible. It also isn't going to make metals brittle, and burns nearly as cleanly. Is it safe? Well, we're talking about 250 Bar, which is considerably safer. Not entirely so, of course, but better than hydrogen by far. Hydrogen is as you point out, very nasty stuff that is really doing its best to ruin your day.
@@luiscarbonell5961 Which isn't possible due to the 50% mix limit. So.. reduce carbon footprint by 40% in reality (but say 0% on paper) versus 30-40% in reality. The net effect is roughly the same, but implementing one is vastly safer and already technologically developed.
Thus, obviously nobody would use gaseous H2 for aircraft fuel. What will be used instead is LH2 in insulated under-wing nacelles delivered filled to aircraft, and mounted immediately before use, so that ground crews need not fool with cryogenic hoses.
@@Akio-fy7ep But the energy requirements - several terawatts - of energy - for the fuel is not going to be free or "green", as most of it has to be made near to the airport(s). You can't safely move billions of gallons of cryogenic H2 all over the planet.
"The range limitation is not a problem because most flights are such a small fraction of the range anyhow." Trains. That's what TRAINS are for. Stop using aircraft where they don't make sense to use! High speed trains should be replacing the short routes.
Trains don't make much sense for skydiving! Skydiving is likely to be one of the first use cases for electric (probably battery-powered) aircraft. Limited range doesn't matter, while low noise is an advantage.
Hydrogen will almost certainly never be a major fuel source in aviation. Even assuming we figure out an energy efficient means of production someday (far from assured), hydrogen doesn't like to be stored. It REALLY doesn't like being stored. To carry a reasonable amount of fuel, cryogenics will be required.
We have decently efficient ways of producing it, the problem is that instead of digging energy out of the ground we have to generate it ourselves (just as with batteries).
Yeah. The engineers know about the challenges - they're not stupid. But they're doing it anyway - it's almost like they know more than you. Crazy right?
@@erikb6836 Do we really? Cheapest hydrogen is still produced from natural gas. The only way to make hydrogen economically viable is to ban/tax other fuels so much, that it's going to offset real world cost disadvantages of hydrogen. Given current poor economic situation of EU and even bleaker outlooks in the future, I don't think that's the right way to go.
@@JohnnyWednesday So you just assume he isn't an engineer or has some sort of experience, yeah I would work on just about anything too even if it had zero chance of going anywhere if I were getting paid extremely well to do it...
The irony of us treating tallow as a waste product for use as aviation fuel whilst feeding ourselves inedible (without refinery style processing) seed oils is very striking to me.
Until 50 years ago, most of the global premature deaths were caused by starvation. Now so many premature deaths are the result of overeating. The irony is palpable.
This idea of turning a plane into a hybrid just doesn’t seem economical to me. Now you’re adding cost, operational complexity, more parts to repair and replace, more things to go wrong, more things to add to regular scheduled maintenance, need of a bigger more skilled maintenance team, more inventorying of parts, more things for the pilots to know in case of an emergency. From the company’s point of view you’re adding build complexity, adding potential supply chain issues, greater cost to produce, difficulty scaling, lower margins. As Elon Musk says, “The best part is no part.” Given his success in mfg and scaling, these aircraft mfgs should probably schedule a sit down with Elon. One last thought: complexity appeals to stupidity!
Also sticking a large sphere of hydrogen under the wings definitely won't reduce the amount of lift, the handling characteristics, or the efficiency of the aircraft by any significant amount.
Isn’t a hybrid SAF/diesel the cause of the Francis Scott Key Bridge impact by MV Dali? A real world application of the complexities being considered…. Or maybe we will need to restore Flight Engineers to the cockpits?! 😂
I used to work at several resteraunts, every one had a company that paid for the used oil (pennies on the gal), after talking to the driver that did the pickup he said the company converts it to heating oil and heavy fuel oil.
What about accidents? I think this is the worst part of using hydrogen... "Hydrogen possesses the NFPA 704's highest rating of four on the flammability scale because it is flammable when mixed even in small amounts with ordinary air." "... its flame is nearly invisible during daylight hours."
i mean jet fuel is also kind of a big deal in accidents already. not like accidents are safe right now and the introduction of hydrogen is what will make them dangerous
The flammability ratio in air is between 4% and 75%. CNG is 5% and 15%. Gasoline vapors are 1.4% and 7.6% for comparison. It's extremely nasty stuff to work with and one tiny mistake and you have a disaster on your hands.
What I don’t see discussed is that making hydrogen fuel takes more energy then the hydrogen can deliver. It takes very little energy to pump oil from the ground and we already have an infrastructure built for it.
And we need to produce it in quantity without the use of fossil fuels. Unless you are in Iceland and have geothermal, it is a wash. It takes more energy to create hydrogen than you get from burning it, because generating it is not nearly 100% efficient. The only realistic way to power hydrogen generation cleanly is nuclear electric plants. And nobody objects to those, right? LOL.
It's not like extracting, refining and transporting crude oil and its products doesn't take significant amounts of energy. For each MJ of heat that can be generated from the gasoline in your cars tank, about 2 MJ of energy have been spend for the mentioned purposes. It's definetely less energy intensive than producing green hydrogen, but not by nearly as much as ne might think.
The EU hydrogen polcity appears to be a way for Germany to justify expanding its reliance on coal (instead of switching towards nuclear / natural gas / renewables).
There are numerous logistical challenges that need to be overcome for hydrogen to be practical as an aviation fuel ... but in the US specifically, the petroleum companies have proven highly effective at a practice we euphemistically refer to as 'regulatory capture', that is, lobbying for regulations and laws that are favorable to their industry and disadvantageous to competitive energy sources.
The volume requirements for hydrogen are crazy. That's why on the Saturn V moon rocket, the first stage burned kerosene, and only the upper two stages burned hydrogen.
Yes, despite 25% more Isp, there are no more hydrogen 1st stages. Delta IV was the last. Yes, I know SLS, but at 1 launch/year and 2 Billion/launch, it does not count as a serious rocket.
Japan launches its payloads on the Mitsubishi H2A and H3 which have hydrogen first and second stages (plus strap on SRBs) but we know that Japan has a weird thing for hydrogen as a fuel.
@@danzjz3923Only for the first minute or so. By the time the main engines cut off ~5 minutes later, they've put many times more kinetic energy into the vehicle. The best attribute of hydrogen rocket motors is that their specific impulse can't be beat. But the common factor of all the hydrogen rockets (Delta, SLS, MHI) is that they are all huge. Not so practical for a passenger airliner.
One problem with green hydrogen is the energy required to produce it. To produce one ton of hydrogen, approximately 50,000 kWh of energy is needed. If this is to be achieved using green technology, it quickly becomes apparent that this will involve enormous challenges.
An issue with electricity by wind/sun is often that it’s produced not when it’s required, but when the weather is there for it. Using the excess energy to produce hydrogen may be an elegant way to turn two disadvantages into a solution.
@@neodym5809the problem is storage and production. To store the amount of hydrogen in amounts of GWh of hydrogen you would need giant high pressure thanks. One solution could be making Methan Out of hydrogen and carbon because you could store it in existing gas infrastructure. But the second problem is that you need giant factorys to produce all that so you can't ramp up the production daily in the summer because there is a surplus of solar energy. It will be expensive to be emission zero 🫣
As I understand it there are financial concerns... as in, politicians taking money and then advice from companies developing hydrogen technology... they're not getting a full scientific/mathematic breakdown from an independent actor.
One issue with fuel cells is their main 'waste' product is water. Which is not a big deal at room temperature but is at low temperatures, like cruising altitudes it freezes. It's a solvable problem (take some of the electricity produced and use it to heat the areas where water exists) but that lowers the overall efficiency. The other problem, as mentioned, is the small size of hydrogen atoms. Hydrogen leaks have been an ongoing problem in the space industry (witness the problems Nasa's SLS had a couple of years back and several shuttle launch delays). That's part of the reason SpaceX is using liquid methane for Starship, methane molecules are bigger and are easier to contain. Using hydrogen to produce SAF makes sense because you can put the H2 generating plant at the same facility that's producing the liquid fuel. The distances involved for transporting the H2 are trivial compared to getting it to and on board aircraft directly. Seems like there's fewer problems to solve with SAF than direct hydrogen. And then there's the fueling time for H2, a problem Toyota found when experimenting with their hydrogen powered cars in CA. It took much longer to fill up an H2 tank than the energy equivalent in gasoline.
Hydrogen has been the fuel of FCEV (Fuel Cell EV) for more than 16 years. However, if recent development regarding Toyota Mirai FCEV lawsuits are any indication, hydrogen is quite a bust, even in its most feasible place on earth: California, where there are more concentration of hydrogen filling station than elsewhere. From expensive fuel that quickly empties Toyota's gift card balance, to hyper-cooled fuel that made the nozzle frozen stuck into the car (for hours, and nobody recommends heating because hydrogen + heat kinda reminds people of Hindenburg), after somebody done pressurising their tanks with hydrogen, you need to wait for quite some time for the fuel pump to repressurise (longer than supercharging battery EV) and the broken promise of practicality - since many stations in California ran out of hydrogen or closed already - and Mirai's range isn't as great as promised. Aviation is in serious trouble, because every other modes are finding their way out into Net Zero, ships can have electric sails, trains have always been electrified and currently the most energy efficient, cars are already electric - and soon they will no longer use Lithium (Sodium ion battery), ditch conflict metal like Cobalt, and solid state battery. The widely quoted 2% carbon contribution figure will grow and grow until planes become the focus target of even non-enviromentalist.
Hydrogen is after all only a storage system. Producing hydrogen without emissions or competing with food production will be extremely different. It is arguably just another SAF with the same issues. Fuel cells can be efficient but making the hydrogen requires huge amounts of energy and probably emissions. Then of course there are the huge issues of low density and high flammability. I'm not holding my breath for it to arrive.....
I totally agree with you about the NEED for investment in alternative fuels. As someone who is not an expert in fossil fuels, or green energy, or what have you, I think it's silly to think that all the fossil fuels the world burns simply doesn't have an effect on the climate. I think a government should be the steward of future thinking .... what's coming next what's going to be needed tomorrow and helping to fund development. Just like I believe infrastructure ( aka roads, bridges, rail, airports ) should be a government investment that benefits all citizens.
Switching all aviation to hydrogen or battery power is going to make flying much more expensive. That will push consumers to alternatives such as electric trains except for crossing oceans, etc..
@@conveyor2 China is held up as the gold standard in high speed passenger rail yet a significant part of the country has no service or is undeserved. Since 2015, interest payments have exceeded operating profits. If they charged enough for HSR to break even it would loose even more. They have reported profits in 2024 but there is no reason to trust this figure. More likely a CCP mandated PR adjustment.
If you think I'm gonna sit in a tube between 2 highly pressurised tanks full of hydrogen on a vehicle built by Boeing, you've got another thing coming.
Anytime you fly, you're sitting between 2 big tanks of equally explosive Jet-A, so it hardly makes a big difference. I also noticed that Peter didn't even mention Boeing in this one, as it's Airbus making the most effort anyway.
Governments will need to fund the development of new engines. Governments will need to fund the adaptation of airports. To fund this, government will need a lot of cash. When governments need a lot of cash, there is only one way to get it: stealing via taxes. Well, I think we have found the most interested one in this whole decarbonization madness, haven't we? Oh, yes, decarbonization is important because of global warming alerted by scientists funded by governments.
Frankly it feels like the industry is being pushed in the wrong direction. Too much focus on emissions instead of maximizing fuel economy. At some point it becomes more environmentally friendly to use what you have better than to use half baked alternatives.
The aviation industry is constantly growing still. Since we aren't willing to curb that growth, the increasing numbers eat up the efficiency gains easily and have been for decades. We have about 15% left in engine development before we reach the practical limit, 20-25% before we reach the theoretical limit for gas turbine efficiency. There are a few percent to be gained by more efficient routing and lower flight altitude to reduce non CO2 greenhouse effects of engine exhaust. Maybe 20% with Blended Wing Bodies. All of those things will take decades to certify, convince the public it's safe and implement throughout fleets. We aren't getting out of the problem with fuel economy. Novel fuels are necessary to work in concert with other areas.
@@neodym5809 I believe efforts to find alternative sources of oil are more realistic. Crude oil from alge for example because once you have the oil the rest of the infrastructure is already there and built. As we have seen with EV car adoption the infrastructure or lack thereof is the first and biggest nail in general ownership before you even get to the shortcomings of the platform. Emissions is not a good reason to adopt a new fuel source, economic viability and sustainability is. Focusing on fuel efficiency even at the expense of increased emissions is again more desirable and more easily felt by all then another 0.0001% decrease in emissions.
@@MentourNow I disagree, it's only partial, because it does not benefit from governmental money (=our money), like the hydrogen greenwashing does. Let me give you only one example. Energy consumed is proportional to speed squared. Design planes with glider-like aspect ratio wings that will fly 20% slower at the same altitude and consume 44% less fuel, and, to compensate, speed up the boarding process. A side benefit is that it will need engines 73% less powerful (cheaper, lighter) - power needed is proportional to speed cubed. If hydrogen money goes in this direction, I'm sure progress will be real, as opposed to the greenwashing you also, unfortunately, promote. Let's tax 20% the aviation fuel (with a 10 year grace period) and invest from the start (from now) the next 20 years' tax in more efficient planes. What do you think the results in 10 years will be, @MentourNow? Do you see, for the first time in the last 50 years, a new plane type? I do.
Thank you for these amazingly informative videos, Petter! They are teaching me a lot about the industry and things to understand once I get my pilot's license, and also how things will look in the future.
I like the Mentour Pilot videos a lot and I spend time watching them and reading the comments. But I'd like to add a bit of a controversial comment here as well: I think people fly way to much. The solution of the environmental impact of aviation is not looking for better fuel, but is flying much less. I haven't been on a plane for over 10 years now and I'm still a happy person
If you don't travel much that's great. If you live in a small country, that's great too. But a country the size of, let's say, the US, make flying necessary if you don't want to spend five days in a car crossing from one coast to the other. And for that same reason, high speed trains are utterly impractical.
Great video. I have been watching and enjoying many of your videos over the past month. This one has convinced me to sign up as a Patreon member. I wish your Mentour videos had existed when I was a young pilot, many years ago.
I think the most visible option is an electric aircraft. Why? When you build an electric device it is actually a flex-fuel device. An electric car is “fueled” by whatever was used to generate the electricity to used to charge its batteries. It can be renewables or fossil fuels. Hopefully renewables, but in a pinch it can be anything. Flexible means highly adaptable and reliable. If we build fuel cell powered electric aircraft, they likely could be retrofitted if (or when, I would argue), energy storage advances to the point that we can get long ranges from a single charge from advanced batteries. I think we should be building a transportation infrastructure that can use whatever energy storage methods make sense for the time and place and where advances in energy storage do not make obsolete massive fleets of transportation equipment.
Not for a very long time, or without a huge breakthrough in battery energy storage vs. weight. Two years ago a Cessna 208 was converted to electric. With the batteries installed there was enough useful load left for... the pilot.
Ideally, you'd want the centre fuselage to be your LH2 tank, which minimises structural penalty by keeping most of the airplane's weight near its source of lift, and avoids CG shifts as the fuel burns off. But I understand current regulations don't allow the cabin to be split like that. Medical emergency seat B2, is there a doctor onboard? Yes, he's in the aft cabin and can't get to the patient...
My understanding of the rubber seal problem, is that the the aromatics in standard fuel slowly replace the natural's in the rubber, making the rubber totally dependant on the standard fuel. If you start with SAF and stay exclusively with it then there is not the problem with the seals. This problem is also in other industries.
The other aspect of aviation that I have never seen addressed is oil loss / consumption. Take a regional airline with 100 planes. Each engine will use, either thru blowby or consumption an average of two to three quarts daily. So x2 engines per plane or at least a gallon of oil per operating acft daily. Let's figure acft out of service may approach 20% so 80 aircraft pushing 5 to 8 legs a day could use 80 gallons of oil, the majority deposited at 30k feet for us all to ingest. There are about 45000 flights each day within US airspace alone. Some bigger turbines have direct draft tubes blowing oil mist look up a Rolls BR710 or BR725. Heres another tidbit, an average size turbine in the 4000-5000 shaft hp range will burn about 3600 lbs per hour at thrust set. A three minute performance run with both engines will consume 53 gallons of fuel.
High speed rail could take the place of probably 90 percent of all air travel and be faster (overall) and way more convenient. Imagine how much of this infrastructure could have been build in US had they not wasted trillions on wars over the last 30 years.
Exactly! Yet we’re stuck with out dated 2-day train trips from Jacksonville, Florida to Chicago, Illinois. I long for the American train transportation system to be upgraded. 💯👀💅🏾
The real big problem with hydrogen is the way it is generated, most hydrogen generated nowdays is generated in methods that release a lot of CO2. That would offset any gains that would be ontained by replacing current aviation fuels.
A small rise in the cost of jet fuel would knock out frivolous use of air travel significantly. It's a luxury, but people don't see it that way. Hit their pockets, and they will wise up quick. Domestic vacation spots will appreciate the extra custom, and competition there will lead to many more options currently suppressed due to jet fuel being untaxed whereas vehicle fuel is heavily taxed. Charity begins at home.
it is also worth remembering that in the EU the percentage of SAF use may be higher, because the overall fuel consumption is much lower, because there are MUCH fewer short flights for just a dozen or so passengers popular in the US
Thank you very much, Peter, for this new video on sustainable aviation which looks at the scaling up issue. This is a major point that was not enough covered in the previous ones you made and this is necessary to speak realistically on this topic. By the way, you seem to consider that sustainable hydrogen is easy to scale up. As far as I know, this is far from being the case because all industries and countries fight for sustainable electricity which is also complex to develop at scale. And I also regret that, as an aviation enthusiast, you never look at the issue of traffic reduction.I am convinced (and it has been demonstrated by many studies) that the sustainability target will not be met without a traffic reduction. The growth of traffic in the past decades is not sustainable AT ALL ! 1980 : 642 M passengers 1990 : 1 000 M passengers 2000 : 1 670 M passengers 2010 : 2 670 M passengers 2024 : 5 000 M passengers expected ...
Hydrogen is more likely than bio fuel because of availability. And I agree with Airbus that hydrogen engines will only be viable if there's infrastructure. And infrastructure will only exist with nuclear energy. China is building a lot of nuclear energy power plants, unlike Europe and USA. Modern nuclear power reactors are safe (can't have Chernobyl style meltdowns).
Modern nuclear reactors are generally one thing: An incredibly expensive way to produce power. Even China's nuclear expansion is only a very small fraction of their energy expansion. Most is solar and wind. Nuclear is a technology chosen for national pride, military strategy and fall-cost fallacy, not because it is practical, fast or cost effective.
@@nanotyrannus5435 Most delays and cost of nuclear is just unnecessary red tape. The best build times and costs for nuclear readily compete with any other energy source, and a modern nuclear reactor will still be producing energy 60-100 years from now, when other sources will be being replaced in 20.
Only 5% of China's electricity is generated by nuclear power. For contrast, the USA generates 18%. The reactors currently under construction in China will increase their percentage to only 7% to 8%.
Here in New Zealand we use bio diesel which waste frying oil and other fats that are converted to the biofuel. There is a lot of discussion on the how the necessary plants re grown and where. The problem that the production of biofuels could impact on food production is real and we need to make sure the proper regulations protect food production.
It's worth mentioning that making hydrogen is way too expensive right now to compete. As is the 2.5x as expensive other alternative fuel. Right now I don't see either of them being able to be the future.
Great video Petter. Loved it! I also think scaling up the production of green hydrogen is yet another pressing issue which needs to be addressed if we truly want to make it an alternative to jet fuel.
All this 2035, 2050, 2060 goal stuff basically tells me that, no, humanity broadly has no grasp whatsoever on the severity, magnitude, and time horizons of climate change. Yesterday was already way too late.
Sadly I have to agree with you. Unfortunately people would rather hear things they like o hear rather than the truth. That is how the oil industry is successful in spreading FUD about electric cars and Toyota can get away with its self charging hybrid nonsense.
@@zk4654 I agree there's no too late, but it will be really funny when hundreds of millions of people from the equator will migrate north. WW2 will be children's play.
You are absolutely correct regarding the lead time for a hydrogen powered aircraft. It doesn't matter what the decision is regarding concepts. Firstly the stage where an engine design that is tested and certified has to be reached. Just the certification process will most likely take several years. Before that there will be a number of full scale test engines built. Once certification has been achieved and the engine builders can start looking into production there will need to be orders in the order book. Then once the green light has been given to start production and the production engineering phase is initiated it will take several years to create production methods that can certified. In many cases today production engineering is the limiting factor for more efficient gas turbine engines. The materials used to make the parts are so difficult to machine. It takes a long time to develop maching methods for these high temperature materials After that machine tools and other equipment has be sourced and commissioned In my opinion the time scale from where we are today to being able to mass produce hydrogen powered aircraft is at the earliest 30 years probably 50 years. 8 years is not long enough to even create working concepts that can be evaluated by the different areas of aircraft manufacturing. Maybe the scientists in the laboratories will be close to being able to present concepts that can be discussed within the industry. That will be about it.
@@lenwhatever4187 I suppose that is really my point. This is a chicken and egg thing and we don't even have the chicken. It is far from clear if hydrogen is the way to go. The policies politicians are making are just not achievable. Before anyone can commit to new technical concepts for aircraft engines there needs to be a decision regarding the fuel that will be available. As I mentioned we are 30 to 50 years away from mass produced fossil free aircraft. In reality we are waiting for the real breakthrough in fuel. Nothing on large scale will happen before then
Let's be realistic, in 2050 we won't have: net zero CO², 100% cars in the world being electric, hydrogen or electric propulsion in commercial aviation.
Cars: by 2050 gas cars will be a hobbiest item in most of the industrial world. Gasoline relys on volume wich means as electrics hit the market in volume economy of scale will be lost.
Likely true - but if we dont, the consequences will be difficult (in human terms - suffering, mass migration etc) and VERY expensive - so we either start investing now and do the best we can, or say “screw our old age and our kids future” and party like its 1999….
What I want know is why net zero emission of carbon dioxide/monoxide? Why is everyone in a panic over global warming? Do they not realize that thing that they should worried about is global cooling. Wait! What am I talking about? The vast majority of people will not realize how bad cooling is until their sewers freeze up and all that nasty fluid starts backing up in their tubs, sinks and commodes. Increased carbon dioxide means larger crop yields, warmer weather and therefore more food to go around. The human population is in decline, which means that the future may well be dystopian, but that dystopia will certainly result from the machinations of over eager politicians than any foreseeable global warming.
If lithium battery technology continues to improve at its current compounding rate of about 1% per annum combined with other technology improvements then BEAs could become a viable option for the short haul airline industry sooner than people expect.
Why not just exclude aviation from this artificial net zero date? I know it makes the tree huggers feel warm and fuzzy, but why pin yourself into a corner unnecessarily? Politicians have really screwed up with these arbitrary targets. It should be a 100+ year project, not multi decade.
Because politicians are run by capitalism and don't care for the future after the next election date. That's why the numbers are all over the place, they have to work within a 4 year time period. Plus with most political parties spending 2-3 years undoing what the previous government implemented, there's simply no time to properly put factual goals into practice. Welcome to every government on the planet.
What's allways missing from this type of discussion is the energy required to make products like SAF. Currently that comes from FOSSIL fuels. Same with electricity for battery electric cars. There will never be enough energy from wind or solar to provide the world with the energy it uses now that has provided the standard of living we have. Only nuclear will provide that level. Then SAF or hydrogen will be possible.
"Hydrogen could be used by other vehicles" And therein lies the problem. The oil industry does not want to see alternative fueled vehicles. They are constantly publishing lies about EVs because they don't want this cutting into ICE vehicle productions. The oil industry has a large lobby in both the US and Canada which is trying to discourage alternative fuel.
Once again, they ignore the best fuel that we have to deal with the transition, which is CNG. It burns very cleanly and is an easy retrofit for most vehicle and planes. The main issue is the space required for the tanks, but that's really not such an issue given the light weight of the tanks and low pressures involved. You can get about 2/3 the range without doing much of anything major to the design, provided you have enough space. Not perfect, but far closer than chasing electric or hydrogen that might work.. eventually. Yes, we have similar scaling issues, but the infrastructure is far more robust than hydrogen, as most of the world's major city busses use CNG or LNG.
Getting our old airliners to do the trick is the thing, i think we in the west are doing a lot running before we can walk, thorium nuclear reactors produce little nuclear waste, its an abundant energy resource, if we build build the reactors. We can can make synthetic fuels bonding carbon to hydrogen atoms, so we can use our old airliners guilt free. We have been fiddling with hydrogen for decades, it is terribly difficult resource to transport and from watching this space over my life time, the rules of nature do not change, Hydrogen is difficult. that jet fuel, the regular fuel in our cars, the heating fuel, it works great, if we want to replace it, it needs to be as good. Airbus sound like they have been spending billions on a box ticking exercise, instead of lobbying governments in to making better power generation, or even spend those lost billions in to thorium reactors.
MSc Engineering Physics with a thesis in optimizing hydrogen generation and storage and a pilot study on wing integrated LH2 tanks here. Sooo excited to hopefully be part of this developing industry in the future! Intressant video, som alltid ✈️
Contrails also seed clouds. The removal of sulfur from ship fuel is starting to look like the main cause of significant Atlantic Ocean temperature rises since 2019/2020. We need to start looking at this holistically opposed to item by item.
Some major issues with hydrogen. The main issue is sourcing it. You can find natural pockets, but it's not as readily available as our leaders and car manufacturers make it sound. You will still have to locate and drill. The other thing is it taxes the power grid to make it and means you are using up water sources to make it. Sure a by product is water when it burns but you are spreading it out over your distance and not returning it to the spot you sourced it from. If you ise ocean water you have to desslinate it first which requires more energy consumption. This all hinges on so many variables that actually drive up costs. Storage isn't really any more dangerous than others but I have done work in 2 factories that could level each of their respective towns with what they store, which isn't hydrogen. This is not practical in the long term.
"Hydrogen is the most abundant element in our universe". It is, and we can do it. But that argument wouldn't work with Helium, the second most abundant element in our universe, because it ain't abundant down here. :-)
You don't need to choose between combustion or fuel cells... You can do both where they shine =) But you forgot (or omitted) ammonia. The transformation from ammonia to hydrogen is done by a catalyst at ~900°, hot but not unreachable with hydrogen combustion. So you could create ammonia with green energy to encapsulate hydrogen in a more "usual" fuel and fuel the planes. Then, when it's time to burn it, go through the catalyst to separate hydrogen and nitrogen (keeping it is really important), and then burn hydrogen as a greener fuel than normal jet-a1, SAF, etc.
@@rogerphelps9939 I know that nox is not the best gas to get, but with our actual infrastructure, it’s the less difficult option to get…, and afterwards the engineers can work on that byproduct with some kind of catalyst? Idk, but it’s seem to to be the less unrealistic idea to have
The recent developments in Solid State Lithium Ion batteries may leave hydrogen aviation in the dust. There are two companies making them, one Amprius, has third party verification of their batteries and is making initial products to go into things like smart watches. The energy density is claimed to be 500Wh/kg, making it over 4x more dense than the current 110Wh/kg. I've been watching the electrificaiton of aviation for a while and I think experimental aviation has the chance to make breakthroughs the airline industry can't immediately adopt.
Hydrogen fuel isn't about saving the environment its about money. In the U.S. we have ~35 million acres of farm land used to grow ethanol. By the time the corn is processed and in the gas/petrol the environmental savings is gone. It also made the U.S. less reliable of foreign oil- a now irrelevant cause.
Biggest problem with hydrogen is sourcing and energy density. Currently most hydrogen comes from hydrocarbons. Oil. Hydrogen from sustainable energy sources like wind and solar being used to split water and harvest hydrogen yield hydrogen at atmospheric pressure, then huge amounts of additional energy must be expended to compress the hydrogen to high enough density. The resulting carbon footprint is within the same order of magnitude as burning hydrocarbons.
It's a great video as usual Peter! However, make me mad when the industry advertise any kind of incremental efficiency gain as a serious effort towards to be less polluted. In the end always will be worse (take a look at jevon's paradox) but more lucrative. The only way out will be a complete disrupted new kind of engine, just like jet was, but will never be economic feasible until will be too late.
You mention that reducing the contrails would help reducing the trapping of heat. I am not convinced. On days when there are a lot of contrails, they reflect a lot of sunlight out of the earth, which results in that the earth is absorbing less heat from the sun.
Rocket engine manufactures have to find complex ways to keep some hydrogen engines within temperature limitations. Making sure pipes don't freeze, but also making sure engine nozzles dont melt. I find it really interesting then that both Boeing and Airbus have contacts who make rocket engines and deal with hyrdogen propulsion and storage, yet seem to be struggling to develop hydrogen engines. Im not a rocket scientist, but common methods of keeping things cool are running the super cold hydrogen around the hot parts of the engine, so the fuel itself acts like a coolant. Something that does interest me is how they plan to deal with boil off. As liquid hydrogen gets warm, it expands and has to be vented to the best of my knowledge.
@@danzjz3923 In most rocket engines, as they sit on the launchpad, they vent some hydrogen (and liquid oxygen) overboard. So would a aeroplane need to do the same if it is taxing or at the gate for a long period of time?
As always, the problem with "clean hydrogen" is that it's (mostly) produced from dirty fossil fuels. It burns clean, for sure, but that's the only "clean" part using hydrogen. There's also a HUGE issue of storage.
Don't forget at the same time also other industries are changing to alternative fuels like the ship's worldwide, so any sources needs to have a good production rate and low price.
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Derwent is pronounced as it is written. No Vs!!
FYI, there is solid hydrogen.
It is freed from solid state via laser. The company is out of Phoenix Az. I think it was done back in 2017..
Debunked Tom, a long time ago.
Just so you know, while H is the smallest atom in the periodic table, it is NOT the smallest molecule because it is diatomic. Helium is the smallest (and maybe the leakiest) because it is monoatomic.
Yo mentour, my endless watching of your channel finally paid off in real life, some of my donut friends were mindlessly discussing something and i stepped in with full correct technical flight analysis 🍻 nice work
We have only been 20 years away from fusion for over 50 years. Hydrogen technology is only slightly behind.
I'm sure we'll get graphene components before then
I retired with about ten patents on fuel cell and related technologies and am subject matter expert on hydrogen safety.
Virtually all commercial hydrogen comes from “reformed” natural gas. Burning hydrogen in cars and airplanes doesn’t produce tailpipe emission of CO2, but the large centralized plants that reform the natural gas to make the hydrogen do, and they discharge all that carbon into the air as CO2, just like a tailpipe would, except the release is highly concentrated. Of course, *where* CO2 is released (distributed or concentrated at one source) doesn’t matter for global warming.
Rather like @jacobschneck wrote here, fuel cell-powered vehicles have been just five years in the future for over 30 years. Today, everyone promoting their hydrogen technology is trying to cash in on government grants overseen by bureaucrats dolling out taxpayer money without even 1% of the due diligence a private investor would devote.
But if you press these *“Hydrogen of the F-U-T-U-R-E!!!”* people about where this magical green hydrogen (not from natural gas) will come from, they’ll admit that it all depends on the Pleasant Outcome Fairy bestowing humanity with some new energy source (fusion, solar, you dream it) that is so phenomenally cheap and nice-nice and bunny hugging that it will make the production of hydrogen-cracked from a green source like water-practical.
And in the final analysis, this future green hydrogen would as much as fuel *source* as water was when one referred to an 1880-era locomotive a “steam powered” engine. Steam is just a *carrier* of energy; the actual energy, of course, came from wood and/or coal. And so it will be for hydrogen; if it doesn’t come from natural gas, it’s just an intermediate energy carrier. And it’s an exceedingly dangerous one. If we could just find the equivalent of “free coal” to make that hydrogen…
@@jgmm26we have graphene components now.
I retired with ten patents on hydrogen and hydrogen-safety-related technologies. We won’t ever see hydrogen power as an affordable energy source.
Is there any _particular_ "hydrogen technology" you're trying to single out? We've had technology directly involving hydrogen for 500 years.
Petter H is from Europe. So, he has a smile through out this video?
On a serious note, I have a post graduate degree in Chemistry. Nearly 35 years in Aviation. I don’t see hydrogen powered engines developed out of current engines as a viable alternate. Redesigning is needed. That means - time, engineers and lots of cash.
Till then, sitting back, relaxing and enjoying Mentour Pilot’s videos!
Also liquid hydrogen explosions are scary
Hydrogen resides in this weird anti-goldilocks zone. It burns way too hot to be practical without injecting cooling water, which reduces thermodynamic efficiency of combustion and offsets most of the gains. It doesn't liquifies in any practical way, so it needs very large extremely heavy highly pressurized tanks, and the amount of gaseous hydrogen at this pressure is only a small fraction of its liquid form, so you need more tanks. Not to mention using water leaves you with even less useful weight and space capacity. Finally, there's no way to produce hydrogen in a green way. Practical option #1 is to get it through cracking tower at oil refineries, practical option #2 is electrolysis. Neither are good, and the electrolysis option in particular is less than 30% efficient round-trip. Using electric fans and fuel cells sidesteps some of the issues, but hydrogen fuel cell total system efficiency is even less than combustion. Which some readers might not see as an issue but aircraft fuel burn, flight range and payload capacity is a very big deal to airlines.
It will never be practical to store, either
@@michaelbuckersI find it strange that all of this excess heat cannot be used to further the propulsion. I'm no expert, and obviously, brand new engines would need to be desiged, but excess heat seems to be going to waste.
Eg. If an engine was 100% efficient then this excess heat, caused by burning hydrogen, would be a good thing, no?
@@michaelbuckersGreat comment too. I agree.
The problem with hydrogen is the very low volumetric energy density. As a result you need to compress it to extremely high pressures or liquify it by reducing it to very very low temperatures to reduce the fuel tanks to a reasonable size. Pressure vessels or tanks for liquified hydrogen today are very heavy. This doesn’t leave very much weight left for passengers and cargo. I’ve heard that at least with today’s technology it might be possible for short range aircraft but impractical for long range aircraft. I have a friend in the aircraft engine business who has been working on hydrogen but who is very skeptical that hydrogen will take off in aircraft mainly because of the weight of the fuel tanks.
I dont think hydrogen tanks are necessarily heavy. Rockets have used them succesfully for years and weight there is even more important than for airplanes. additionally hydrogen is the highest mass energy density fuel that exists. So i am sure that this can be done. I do think that pressure vessels are the wrong choice and cryogenic hydrogen is much safer/ lower mass and simpler. This likely means that cryogenic hydrogen is the future.
@@thijsstavenga4350 You forget rocket tanks are filled just before ignition and emptied relatively quickly after that. There is no need to keep the hydrogen cold for very long. A long range aircraft on the other hand would need to keep liquid hydrogen several hundreds of degrees below zero for on the order of 5-10 hours or more. Typically cryogenic tanks meant for long term storage of hydrogen contain multiple walls with a vacuum in between as an insulator. They are heavy.
@@GeoffreyEngelbrecht Rockets dont have much thermal insulation, because the fuel gets used so quickly. In an airplane this can definitely be done, the boil off rate will probably be lower than the fuel consumption anyway. Current airplanes use several liters per second of kerosine, I cannot imagine a boil off rate of several liters of liquid hydrogen per second, that is way too high. I work with 100s of liters of liquid nitrogen and the boil off rate is less than a liter per day. Also in storage the liquid hydrogen can be super cooled, which lowers boil off rate. Although this likely costs a lot of energy.
@@thijsstavenga4350Long term prospects of hydrogen rocket propulsion for first stage rockets in Earth atmosphere is a dead end, and it is unappealing for aviation use due to similar reasons.
There is no pure hydrogen first stage in rockets because the mass overhead for insulated hydrogen vessel results in a rocket stage that cannot really lift its own weight, and perhaps barely even if it can. This requires use of solid rocket boosters to augment the thrust, which doesn’t make economical sense where first stage reuse is pretty much a requirement for cost competitiveness. While non-hydrogen liquid fuel boosters can also be used, at that point the use of hydrogen first stage is superfluous as it’s easier to just make the first stage use the alternative fuel.
Hydrogen chemical propulsion does have an edge for deep space propulsion in vacuum where the efficiency (specific impulse) is king and TWR doesn’t matter as much, but it’s not really comparable to the aviation environment.
It's just called "hydrogen" because most of the energy comes from removing the hydrogen atom from the fuel, and combining it with atmospheric oxygen to form water, releasing a lot of energy in the process.
The system we're eventually going to settle on will probably be to use the hydrogen as feedstock to create another hydrogen-based fuel like alcohol or ammonia. And use those materials (which have volumetric energy density similar to avgas, and much better gravimetric energy density than batteries) as the fuel stored in the plane's wings.
I love the engine technology videos; they really round out the channel as a source for not only the past and present of aviation, but the future as well!
Thanks for watching and for the kind words! 💕 I love having you here
I like those stories best, too. Hydrogen has such fantastic energy density per kg that it merits a lot of adaptation to accommodate its difficult problems. For practical use it needs to be carried in liquid form, but the tanks won't fit in the wings, and you _absolutely_ don't want unavoidably-leaky tankage and plumbing in the fuselage. Furthermore, you don't want ground crews fooling with cryo hoses. The practical alternative, then, is removable tank nacelles hung under the wings, trucked out full and hung immediately before each flight. The fuel is oxidized entirely in the wings, whether in combustion turbines or in fuel cells driving electric turbines. For more range, hang more nacelles.
A huge advantage of LH2 rarely noted is that the fuel may be produced on-site at the airport, from wired-in power during peak-production / mimimum-price periods, eliminating a big operational expense. Storage underground makes insulation easy. Solar mounted above long-term parking would protect passengers' cars from weather, though that could produce only a fraction of the needed energy.
Atmospheric carbon capture might make on-site production of hydrocarbon fuels possible, but it would probably take up more space than most airports could spare.
Burning hydrogen in turbines at higher temperature would give you increased NOx production, possibly a big problem, at least if it happens at low altitudes. That favors fuel cells. One wonders if electric-drive assist could fit into jet-fuel burning turbines...
@@Akio-fy7ep
As far as NOx production in the combustor, that seems to be controllable as there is a wide range of methods to deal with it. It is a complex issue but there is already a number of ground based turbine solutions.
@@Mentaculus42 I think they inject ammonia into natural gas turbines to mop up the NOx. Presumably they would do the same with hydrogen turbines. NOx is, notably, another greenhouse gas, alongside CO2, methane, hydrogen, and water vapor, and at altitude depletes ozone. The atmosphere's capacity to clear hydrogen is strictly limited, so that above a certain leakage rate H2 accumulates like CO2.
i dont see how hydrogen would work? its extremely difficult to store. the planes would have so much boil off/leaks and hydrogen is very flammable so seems like a huge safety concern as far as civil aviation goes
wonder if methane could be an alternative? not as good as jet fuel or hydrogen, but could still maybe work?
@@brianhillier7052sure but Methene is 30x worse than Kerosine for contributions to Climate change
Don't tell Toyota
That's the point, the average joe can't create it at home as opposed to battery stored electricity
Aviation engineers are smarter than they look. Theyll find a way to make it work.
In the UK, we converted one of our power stations to run on woodchip pellets. It too, was supposed to only use waste products as opposed to cutting down trees specifically to produce these pellets. The latter scenario is what has come to pass. We import this "biofuel" all the way from Canada. The politicians and CEO$ laugh as they receive their green stars.
That's capitalism for you, why stop at waste products if you can get way more money burning everything around you too and nobody is going to double check how green it is either.
It is supposed to be from sustainable forest where the trees are part of a multi year crop rotation.
@@rogerphelps9939 you're right, my mistake. Wasn't part of the controversy that they were supposedly only using wood that wasn't desirable for timber.
The SE US also supplies wood chip pellets to Europe. That means machines harvesting the trees, trucks transporting the logs to a mill, the mill grinding logs into pellets, railroads taking pellets to the coast, ships transporting them to Europe and trains transporting them to power plants. I would not be surprised if that requires more energy than that coming from the pellets. It is insane but "renewable" since new trees can be planted for the ones consumed.
@@Inkling777 and a 40 to 60 year cycle to the next harvest.
Fun fact: The first jet engine ever operating had its first test runs on hydrogen since it was easier to get the combustion stable and Hans Papst von Ohain was on a tight schedule from his boss Ernst Heinkel to show a working engine.
Frank Whittle.
@@rogerphelps9939 As far as I can tell it was quite close, but Ohain's first runs preceded Whittle's by a few weeks (using Hydrogen and still a number of problems, but running)
How is that even fun.
@@GoldenEDM_2018don't worry, you're not obliged to experience _fun,_ some of us quite like it though.
@@alanhat5252 i dont care. I didn't asked. Who are you anyway?
Mentour listed 3 reasons Airbus wants US companies to "invest" more but he missed the real #1 reason. Airbus doesn't want to be the only one wasting $billions on trying to develop the technology. We cannot even supply hydrogen economically for cars. We will need some significant developments before hydrogen will be realistic for aviation. Mentour also didn't go into any detail on just how extensive the modifications would have to be at airports to be able to handle hydrogen as well. It is WAY too premature to be putting any eggs into the aviation hydrogen basket.
Agreed. Hydrogen powered ships and cars are very likely to come before aviation. Which makes sense. Aviation is far riskier and needs technologies that are more fleshed out. A broken engine in a ship (which usually has multiple) or a car isn't that big of a deal. A broken engine on a plane can be life threatening.
The logistics and costs with creating a reliable supply is one of the main barriers.
Hydrogen-powered cars and land transport in general are a massive waste of resources compared to wayside power supply and batteries. Those aren't an option for aviation so if you're going to invest in hydrogen technologies, aviation should have priority.
@@alexsis1778 hydrogen cars a vanishing from the international market. They started developing in this new era pretty evenly with eclectric cars, and fell behind. Even in countrys where many hydrogen cars were driven (i.e. japan) they fall behind.
If hydrogen is coming as a fuel or fuel source, it will only be in things like aviation and marine traffic.
Because there won't be enough for cars, and it's much easier to fuel cars electric than with hydrogen (let alone hydrogen cars need much more energy than electric ones because electric cars are about 4-5 times more efficient)
The usage of fuel for land based vehicles is so much higher than aviation. And the availability of en route refueling is way easier on land based vehicles than on planes.
I read somewhere that 90 million tons of H2 are currently used, all made from methane. The process is lossy and leaks both gases with higher greenhouse effects than CO2. It needs to be replaced as it is a significant greenhouse problem.
Now, H2 made from electricity requires 33KW/ kg, and very little is produced. Scaling renewable H2 to replace our chemical usage will be difficult enough. Factoring in an aviation requirement requires significant investment, which is unlikely. There is also difficulty in transporting H2 in the volumes that will be required. We may need H2 production at airports using modular nuclear reactors, but we might get some opposition.
I don't see these problems getting solved before the 2035 timeline.
A surprisingly large number of ways of producing hydrogen have been developed since the first one in 1520, one of the alternatives may well come to the fore.
@@alanhat5252 Meanwhile, CNG - or basically using the methane as-is works, is worlds cheaper, and we understand the technology incredibly well ( storing it at airports is a literal non-issue as well ). I don't understand their rabid insistence on 0% versus 2 or 3% that works. The planet can handle a small amount of pollution, as any reduction in a major industry at all is a huge difference. We need to work on reducing first, before we go cold turkey.
It's impossible to transport that much Hydrogen. Production would have to be local, at least for the big airports.
@@plektosgaming Our mistake has been listening to these nut jobs!!! Remember these are the same people who can't tell the difference between a man and a woman!!! We must realize that these people have gained the ear of the world, and everyone is bowing down to their demands; the conclusion/statements from experts must be taken with a large grain of salt! We can infer the objective of these people as the destruction of the world as we currently know it! Those who can see it happening, know the best strategy is to ignore their insanity!!!
The author clearly specified “green hydrogen” made from renewable energy and not the older steam-generated one which does indeed have the short-comings that you identified.
Commercial aviation will likely never use hydrogen. The fuel density is far too low and dealing with cryogenic hydrogen is no small feat either.
I wouldn’t be so sure.. but it’s tricky, that’s for sure
Nuclear would be more likely, lol
@@MentourNow trick means expensive and unreliable
If you are already spending the energy to create the hydrogen, you may as well go a bit further and make it into Methane or even something heavier to get the fuel density up. At that point the energy efficiency of creating the fuel doesnt really matter as its all green anyways.
@@demondoggy1825 that would decrease the efficiency of the whole process (Thermodynamics is a harsh mistress)
IMO synthetic SAF is the solution, as storing hydrogen onboard aircraft is terribly cumbersome and adds LOTS of extra weight. And for the short haul - batteries or... high speed railway.
Frankly, high speed railway should be the default for transporting a lot of ppl across distances where such railways can be built. For sure, we definitely could eliminate a lot of passenger flights in the US by building (and actually running) high speed railways along frequently traveled routes.
Well, such would likely require some kind of regulatory/legislative intervention by regulators/the Federal government to actually get established in the first place, but we're already speaking in hypotheticals here - might as well add in politicians doing more than serving their donors while we're at it, right? (I'm in a cynical mood today. lol)
Im an aspiring 13 year old pilot . these vids are quality content worth watching..... thank you to petter and the team!☺Love both of your channels a lot
Edit: Thanks for your likes Guys!❤
That’s awesome! Glad you’re enjoying the content, keep working towards your pilot training!
@@MentourNow Sure!
I got my start in flying through the Chuck Yeager's Young Eagles. It's worth looking into IMO
@@Blinkerd00d Thats surely fascinating!
Given the history of hydrogen as a "fuel" and hype around it, I feel confident in saying "the hydrogen economy" is never going to happen. The statement that hydrogen is the most abundant element I think demonstrates a lack of understanding of what constitutes a fuel source.
Can your extrapolate further? Are you referring to cost, safety or processing issues?
@@matthewhorton871 yes to all those issues. But something like aviation fuel might be a place where convenience and weight matter the most, so it could be excused.
The little tiny issue that “hydrogen haters” seem to overlook is that huge amounts of clean hydrogen will be needed for things that don’t use it as fuel, like ammonia. There will be a clean hydrogen economy, the question is how large not if. Once the demand for these other hydrogen needs are being met, a price will be established for hydrogen that will determine if it grows beyond that. It really is an economic problem not an efficiency issue. Japan will be the proving grounds for hydrogen as an energy transfer medium, mostly in the form of ammonia. If the price is competitive (and many people are of the opinion that it will not be) then it will happen, otherwise not. The “PRICE” is a very complex issue with regard to clean hydrogen (subsidies and all). Besides, that price will not be determined for another ten years at least.
@@Mentaculus42 I agree it is a "little issue" as in probably not significant. About 3% of natural gas is used as feedstock. To put things in perspective, fossil fuels are 81% of energy use, NG is 23% of that. A clean supply of hydrogen for feedstock is one thing, but to replace all NG uses would need 33 times that amount. To replace liquid fuels with hydrogen (as in this case) would need even greater supply.
Given the technical difficulties with hydrogen, and the need to create new infrastructure, it is not going to be a cheap or quick solution. It also begs the question : what is the actual energy source for hydrogen? If it is wind/solar/nuclear, it makes much more sense to use electricity directly as we already have the infrastructure and technology for terrestrial use.
Hydrogen makes no sense for aviation. Possibly it makes sense for shipping. Of course, the goal of 2050 for "zero carbon" is just wishful thinking, so rushing to a solution to meet that goal will probably lead to bad decisions. In the short term we should be electrifying wherever possible, while SAF may not be perfect it is probably the best solution in aviation.
“Hydrogen is the most abundant element” is a trick statement since those only on the Sun whereas on Earth near 0 elemental Hydrogen is available. This statement misleads most people into blindly thinking that water is all the fuel source we need without recognizing that water is essentially not much more a fuel that what comes out of your car’s exhaust because water is burnt Hydrogen.
Because flying with hydrogen has never gone wrong. Ever.
As long as they don't cover the hydrogen tanks in highly flammable paint it'll be fine.
@@willemm9356 The claim that hydrogen leaks were not responsible for the Hindenberg conflagration turns out to be propaganda. The highly visible flames were largely kerosene, but the failure started with a hydrogen fire.
Hydrogen is weird stuff to handle. It does like to escape, but it also dissipates pretty easily compared to heavier gaseous fuels like methane and propane. There is always a risk of fire, but except for a narrow range of conditions*, I am more frightened of gasoline fires than gaseous fuels. Personally, I think the finicky nature of hydrogen handling and storage makes it a tough hill to climb, but not technically unfeasible.
*foremost condition is that if a gasoline tank is on fire, run a 100 meters or so. If a pressurized fuel tank is on fire, run 1000 meters and then keep running.
The thing with hydrogen is that it's so light it can't linger around enough to make an explosive fuel-air mixture around the leak site. Worst case scenario you get a blow torch until it runs out of pressure.
Hydrogen definitely can be an issue in enclosed spaces (probably not relevant to aviation) but look at what happened at Fukushima with the hydrogen explosion that happened there.
If the hydrogen is produced on-site at airports, storage may not be that much of an issue. It's also important to remember that we don't need to have a singular solution. Hydrogen for short range flights and SAF for long haul flights would work just fine.
@@dbattleaxe What if we take it one step further and produce the hydrogen on the aircraft? I remember creating hydrogen and oxygen in high school chemistry. Might have to carry a small tank of hydrogen for take off and landing purposes but perhaps cruise demands would be met by the generator supplying hydrogen to fuel cells.
@@dbattleaxe The problem with SAF is that the amount of land required to produce the fuel for just one jet aircraft is huge. Photosynthesis is a far less efficient way of capturing solar energy than solar photovoltaic panels or even wind turbines.
Doesn't anyone think we're missing the woods for the trees?
Jet fuel is only 10% of the barrel. We can, far easier and cheaper, replace HSFO (used for bunkers in vessels), diesel and some naphtha used for gasoline blending by hydrogen and batteries. Paraffinic naphtha will still be required for a long while yet (plastics), but we can reduce hydrocarbon usage by 80% very easily. Switching the refinery slate from crude to condensate would allow that to ensure no heavy ends left to burn.
Decarbonizing aviation and decarbonizing shipping are not mutually exclusive. This channel is about aviation and discusses developments in that field.
@@CaptHollisteryou've missed the point - overall decarbonization can possibly be more easily achieved by decarbonizing something else.
I'm all for decarbonizing everything but that's not the point raised.
@@alanhat5252 Agreed. Shipping is incredibly dirty because they generally use the absolute lowest energy fuel simply because nobody else can suffer the low fuel density and extreme weight required to get usable power outputs. This makes it perfect for testing out things like hydrogen which have a low fuel density and can tolerate bulkier less perfected engines. It also will help build out the necessary infrastructure and fuel distribution for aircraft to take advantage of. Not to say we should stop working on engines to use these fuels. Just that the conversion is most likely to start in an industry other than aviation.
Well, the thing is: You still retrieve the nafta out of the ground with crude oil. You have exactly as much nafta as there is, and it's cheap, because: (1) It's abundand. (2) Nobody else wants it. Once/if we use less cruse oil, there'll be less nafta available and ships will switch.
But please, before you come to the conclusion that "ship can use hydrogen more easily", remember that for them, "storing" means storing for many days. In an commuter aircraft, you need to store it for a couple hours.
One of my hobbies is studying how society worked in past periods. In particular I have studied thousands of pages of early 20th century censuses. One big industry back then was converting used cooking oil into lighting oil for kerosene/coal oil lamps.
Fascinating video as always. I've been working in the economics of low-carbon hydrogen production the last year, and one thing that is now widely understood is that it is going to be WAY more expensive than what we thought a few years back. A lot of governments, private companies and other institutions hoped that hydrogen would play a big part in decarbonising a lot of industries where electrification is expensive or outright impossible, but with the most up to date cost estimates it is now uneconomical to do so, and aviation is certainly one of the industries that fall under this category unfortunately. Will be really interesting to see what happens though (and who pays the final bill)
We will just have to use very sophisticated virtual reality as a substitute for travelling to distant places. A lot cheaper too.
Yep. The answer seems to be to fly many fewer times. The aviation industry does not have a viable path to sustainability unless it becomes 2 to 3 times as expensive as it is now. Build high speed rails and only keep long hall flights
So basically the same exact reasons why hydrogen has never come close to being a regular fuel source still exists? Way too volatile require large and very heavy containers, and the fact that you'd have to build an entirely new fuel infrastructure. Anyone who's done the math knows only an idiot would think hydrogen would be used in any major scale as a regular fuel source, it simply just isn't worth the trouble.
Obviously. If if was a smart investment, smart investors would be investing in it.
But in the meantime, the right people will become millionaires behind convincing governments to pay them until they can no longer keep up the charade.
Yeah it seems like a major fools errand in most applications. Green hydrogen uses so much electricity, and anything less is barely better for the climate. It has its places in factories but it's a much worse fuel than just using the electricity to power the thing you want in the first place. Planes are an issue though, can't plug that in or use batteries! What's the alternative to hydrogen here? The equally expensive saf?
The safety concerns around hydrogen are, in my opinion, the most important questions here. Catastrophic landings would likely mean an increase in fatalities, crashes on departure into populated areas would also increase the potential number of casualties beyond the aircraft. The storage, transportation, and the transferring of hydrogen is a huge issue as well. Hydrogen has a higher flammability range and lower ignition point than standard hydrocarbon fuels. It's not an impossible hurdle by any means, but every inch of engineering is going to have to be bang on with nearly zero room for errors.
Yet, CNG solves this. Not 100% "clean" ( nearly so, though ), but won't combust as easily, lighter than air, and in an emergency, it is proven to be fairly safe. ( any impact that would crush a tank would probably have the plane in small pieces anyways. ) Hydrogen is.. problematic. lol. very much so. CNG storage at an airport also would be a non-issue as many already do it on a smaller scale for their busses.
Catastrophic landings usually don't have (m)any survivors anyways, so I'm not sure how relevant that point would be.
Populated areas obviously might be.
Other comments here have discussed hydrogen-based city busses burning up when their tanks got punctured.
They noted how a flame just popped out, until the pressure in the tank had vented.
But those were stationary tanks - I doubt they'd maintain structural integrity should a plane nose dive into a city (like the Boeing Max did).
So yeah, if that turned any plane into a massive flying pipe bomb, I suppose people would have a problem with that....
(and making it hard enough, like a black box, would surely be cost-prohibitive)
Great Video! As someone working on a hydrogen-powered Sling High Wing at ETH Zürich (Cellsius Project H2), I can say that while hydrogen presents significant challenges with its volumetric energy density, many of the safety concerns mentioned here in the comments are often exaggerated. With proper engineering and precautions, hydrogen can be just as safe-if not safer-than traditional fuels. Although hydrogen will leak through most materials, the leak rate is extremely manageable with common materials.
The high diffusivity of hydrogen also helps since unless there are locations in the airframe where hydrogen can collect, hydrogen typically disperses too quickly to reach the necessary 4% concentration to be flammable, say in the inevitable boil-off venting of cryogenic tanks. Another aspect often overlooked is that cryogenic tanks usually work "too well" because the boil-off rate is too low for the amount of hydrogen required for the reaction.
At least in my opinion, the most significant challenges facing hydrogen in aviation are the low volumetric energy density, the weight of cooling systems for fuel cells, and the NOx challenge for combustion. Hydrogen has immense potential as an exciting next step in aviation!
where are they going to get the geen hydrogen from? i know they found a few deposits underground. is solar or wind enough for the growing industry?
@@michaelotoole1807 Green hydrogen actually costs more than race fuel for cars (110 octane rated). Toyota knows that too well...
So, can you use street people for the maintenance of the hydrogen fueling systems ?
For the cooling part, why isn't a regenerative cooling type solution like those on rocket engines, be also adopted in some ways for aircraft turbine engines?
The best hydrogen source is one in which the hydrogen atoms are bonded to carbon atoms, namely hydrocarbons.
I just made this calculation. If you take the example of a 373 MAX, it can load about 29 cubic meters of fuel. If you convert the energy of that amount of jet fuel to H2 at 700 Bar pressure (typical non liquid use) it takes up 170 cubic meters, not counting the tanks. If you use a single big tank, the most efficient weight to volume ratio, it will take about 200 cubic miters. How much is that? Well, it's about the size of the full cabin, so you are left with no room for the passengers. If you go to cryogenic H2, the volume goes down to one half. about 80 cubic meters, but the tank size will grow considerably, as well as the weigh. Besides that, if you have an accident with structural failiure and it gets to the tank(s), the Hindenburg accident will look like a campfire in comparaison.
Just imagine having to fly an A380 with only the passengers of the upper deck. If only one accident took travellers away from the Concorde, imagine an accident where the plane dissapears just in seconds.
Yet using CNG ( basically taking the methane and using it as-is ) results in 1/4 of the space required. Not great, but not entirely unreasonable to engineer around. ie - going from 29 to 50 cubic meters.. might be possible. It also isn't going to make metals brittle, and burns nearly as cleanly. Is it safe? Well, we're talking about 250 Bar, which is considerably safer. Not entirely so, of course, but better than hydrogen by far. Hydrogen is as you point out, very nasty stuff that is really doing its best to ruin your day.
@@plektosgaming The idea was to go to to non fossil fuels. Zero carbon footprint.
@@luiscarbonell5961 Which isn't possible due to the 50% mix limit. So.. reduce carbon footprint by 40% in reality (but say 0% on paper) versus 30-40% in reality. The net effect is roughly the same, but implementing one is vastly safer and already technologically developed.
Thus, obviously nobody would use gaseous H2 for aircraft fuel. What will be used instead is LH2 in insulated under-wing nacelles delivered filled to aircraft, and mounted immediately before use, so that ground crews need not fool with cryogenic hoses.
@@Akio-fy7ep But the energy requirements - several terawatts - of energy - for the fuel is not going to be free or "green", as most of it has to be made near to the airport(s). You can't safely move billions of gallons of cryogenic H2 all over the planet.
"The range limitation is not a problem because most flights are such a small fraction of the range anyhow."
Trains. That's what TRAINS are for. Stop using aircraft where they don't make sense to use! High speed trains should be replacing the short routes.
Trains don't make much sense for skydiving! Skydiving is likely to be one of the first use cases for electric (probably battery-powered) aircraft. Limited range doesn't matter, while low noise is an advantage.
Hydrogen will almost certainly never be a major fuel source in aviation. Even assuming we figure out an energy efficient means of production someday (far from assured), hydrogen doesn't like to be stored. It REALLY doesn't like being stored. To carry a reasonable amount of fuel, cryogenics will be required.
We have decently efficient ways of producing it, the problem is that instead of digging energy out of the ground we have to generate it ourselves (just as with batteries).
Yeah. The engineers know about the challenges - they're not stupid. But they're doing it anyway - it's almost like they know more than you. Crazy right?
@@erikb6836 Do we really? Cheapest hydrogen is still produced from natural gas. The only way to make hydrogen economically viable is to ban/tax other fuels so much, that it's going to offset real world cost disadvantages of hydrogen. Given current poor economic situation of EU and even bleaker outlooks in the future, I don't think that's the right way to go.
@@JohnnyWednesday So you just assume he isn't an engineer or has some sort of experience, yeah I would work on just about anything too even if it had zero chance of going anywhere if I were getting paid extremely well to do it...
ammonia would be a far more sensible fuel, with the same benefit of being carbon free
The irony of us treating tallow as a waste product for use as aviation fuel whilst feeding ourselves inedible (without refinery style processing) seed oils is very striking to me.
Until 50 years ago, most of the global premature deaths were caused by starvation. Now so many premature deaths are the result of overeating. The irony is palpable.
No kidding.
This idea of turning a plane into a hybrid just doesn’t seem economical to me. Now you’re adding cost, operational complexity, more parts to repair and replace, more things to go wrong, more things to add to regular scheduled maintenance, need of a bigger more skilled maintenance team, more inventorying of parts, more things for the pilots to know in case of an emergency. From the company’s point of view you’re adding build complexity, adding potential supply chain issues, greater cost to produce, difficulty scaling, lower margins.
As Elon Musk says, “The best part is no part.” Given his success in mfg and scaling, these aircraft mfgs should probably schedule a sit down with Elon.
One last thought: complexity appeals to stupidity!
Also sticking a large sphere of hydrogen under the wings definitely won't reduce the amount of lift, the handling characteristics, or the efficiency of the aircraft by any significant amount.
Isn’t a hybrid SAF/diesel the cause of the Francis Scott Key Bridge impact by MV Dali? A real world application of the complexities being considered…. Or maybe we will need to restore Flight Engineers to the cockpits?! 😂
I used to work at several resteraunts, every one had a company that paid for the used oil (pennies on the gal), after talking to the driver that did the pickup he said the company converts it to heating oil and heavy fuel oil.
I remember that long ago, the restaurant had to pay THEM to take it away.
ok
In the US this has been done for a long time.
Hopefully a side effect of increased use of SAF is the cabin smelling like a McDonald’s.
"New revolution.
They mean: New higher prices.
What about accidents? I think this is the worst part of using hydrogen... "Hydrogen possesses the NFPA 704's highest rating of four on the flammability scale because it is flammable when mixed even in small amounts with ordinary air." "... its flame is nearly invisible during daylight hours."
yeah i agree with that
its a huge liability in the case of an incident
i mean jet fuel is also kind of a big deal in accidents already. not like accidents are safe right now and the introduction of hydrogen is what will make them dangerous
The flammability ratio in air is between 4% and 75%. CNG is 5% and 15%. Gasoline vapors are 1.4% and 7.6% for comparison. It's extremely nasty stuff to work with and one tiny mistake and you have a disaster on your hands.
What I don’t see discussed is that making hydrogen fuel takes more energy then the hydrogen can deliver. It takes very little energy to pump oil from the ground and we already have an infrastructure built for it.
Wrong.
And we need to produce it in quantity without the use of fossil fuels. Unless you are in Iceland and have geothermal, it is a wash.
It takes more energy to create hydrogen than you get from burning it, because generating it is not nearly 100% efficient.
The only realistic way to power hydrogen generation cleanly is nuclear electric plants. And nobody objects to those, right?
LOL.
If you want green hydrogen than he's right. You have to put more energy than the one you obtain.
So what? You use solar or wind or wave energy to create hydrogen. Of course there is going to be an energy loss in any such process.
It's not like extracting, refining and transporting crude oil and its products doesn't take significant amounts of energy.
For each MJ of heat that can be generated from the gasoline in your cars tank, about 2 MJ of energy have been spend for the mentioned purposes.
It's definetely less energy intensive than producing green hydrogen, but not by nearly as much as ne might think.
I can imagine chemists and physicists getting angry at this due to the whole obvious scam aspect.
Anyone capable of mathematics and a basic understanding of specific energy and energy density can grasp it.
The EU hydrogen polcity appears to be a way for Germany to justify expanding its reliance on coal (instead of switching towards nuclear / natural gas / renewables).
There are numerous logistical challenges that need to be overcome for hydrogen to be practical as an aviation fuel ... but in the US specifically, the petroleum companies have proven highly effective at a practice we euphemistically refer to as 'regulatory capture', that is, lobbying for regulations and laws that are favorable to their industry and disadvantageous to competitive energy sources.
The volume requirements for hydrogen are crazy. That's why on the Saturn V moon rocket, the first stage burned kerosene, and only the upper two stages burned hydrogen.
Yes, despite 25% more Isp, there are no more hydrogen 1st stages. Delta IV was the last. Yes, I know SLS, but at 1 launch/year and 2 Billion/launch, it does not count as a serious rocket.
Japan launches its payloads on the Mitsubishi H2A and H3 which have hydrogen first and second stages (plus strap on SRBs) but we know that Japan has a weird thing for hydrogen as a fuel.
you two forgot the SRBs generate most of the thrust on takeoff
@@danzjz3923Only for the first minute or so. By the time the main engines cut off ~5 minutes later, they've put many times more kinetic energy into the vehicle. The best attribute of hydrogen rocket motors is that their specific impulse can't be beat.
But the common factor of all the hydrogen rockets (Delta, SLS, MHI) is that they are all huge. Not so practical for a passenger airliner.
@@rabidpb Yes, you're right, I forgot about them.
One problem with green hydrogen is the energy required to produce it. To produce one ton of hydrogen, approximately 50,000 kWh of energy is needed. If this is to be achieved using green technology, it quickly becomes apparent that this will involve enormous challenges.
An issue with electricity by wind/sun is often that it’s produced not when it’s required, but when the weather is there for it. Using the excess energy to produce hydrogen may be an elegant way to turn two disadvantages into a solution.
Or just use nuclear power@@neodym5809
Nuclear
@@neodym5809the problem is storage and production.
To store the amount of hydrogen in amounts of GWh of hydrogen you would need giant high pressure thanks.
One solution could be making Methan Out of hydrogen and carbon because you could store it in existing gas infrastructure.
But the second problem is that you need giant factorys to produce all that so you can't ramp up the production daily in the summer because there is a surplus of solar energy. It will be expensive to be emission zero 🫣
As I understand it there are financial concerns... as in, politicians taking money and then advice from companies developing hydrogen technology... they're not getting a full scientific/mathematic breakdown from an independent actor.
Amazing time to be alive, techwise! Cant help wonder if the longterm answer/future will be horse, cart and sail in centuries to come
also, decarbonizing warfare is likely to mean a return to the use of clubs 😂
there is a lot of R&D on wind power for shipping at the moment...
One issue with fuel cells is their main 'waste' product is water. Which is not a big deal at room temperature but is at low temperatures, like cruising altitudes it freezes. It's a solvable problem (take some of the electricity produced and use it to heat the areas where water exists) but that lowers the overall efficiency. The other problem, as mentioned, is the small size of hydrogen atoms. Hydrogen leaks have been an ongoing problem in the space industry (witness the problems Nasa's SLS had a couple of years back and several shuttle launch delays). That's part of the reason SpaceX is using liquid methane for Starship, methane molecules are bigger and are easier to contain. Using hydrogen to produce SAF makes sense because you can put the H2 generating plant at the same facility that's producing the liquid fuel. The distances involved for transporting the H2 are trivial compared to getting it to and on board aircraft directly. Seems like there's fewer problems to solve with SAF than direct hydrogen. And then there's the fueling time for H2, a problem Toyota found when experimenting with their hydrogen powered cars in CA. It took much longer to fill up an H2 tank than the energy equivalent in gasoline.
Hydrogen has been the fuel of FCEV (Fuel Cell EV) for more than 16 years.
However, if recent development regarding Toyota Mirai FCEV lawsuits are any indication, hydrogen is quite a bust, even in its most feasible place on earth: California, where there are more concentration of hydrogen filling station than elsewhere.
From expensive fuel that quickly empties Toyota's gift card balance,
to hyper-cooled fuel that made the nozzle frozen stuck into the car (for hours, and nobody recommends heating because hydrogen + heat kinda reminds people of Hindenburg),
after somebody done pressurising their tanks with hydrogen, you need to wait for quite some time for the fuel pump to repressurise (longer than supercharging battery EV)
and the broken promise of practicality - since many stations in California ran out of hydrogen or closed already - and Mirai's range isn't as great as promised.
Aviation is in serious trouble, because every other modes are finding their way out into Net Zero, ships can have electric sails, trains have always been electrified and currently the most energy efficient, cars are already electric - and soon they will no longer use Lithium (Sodium ion battery), ditch conflict metal like Cobalt, and solid state battery. The widely quoted 2% carbon contribution figure will grow and grow until planes become the focus target of even non-enviromentalist.
It has taken a lot of crashes to make things as safe as they are now. How many more will it take to make this safe?
Hydrogen is after all only a storage system. Producing hydrogen without emissions or competing with food production will be extremely different. It is arguably just another SAF with the same issues. Fuel cells can be efficient but making the hydrogen requires huge amounts of energy and probably emissions.
Then of course there are the huge issues of low density and high flammability.
I'm not holding my breath for it to arrive.....
I totally agree with you about the NEED for investment in alternative fuels.
As someone who is not an expert in fossil fuels, or green energy, or what have you, I think it's silly to think that all the fossil fuels the world burns simply doesn't have an effect on the climate.
I think a government should be the steward of future thinking .... what's coming next what's going to be needed tomorrow and helping to fund development. Just like I believe infrastructure ( aka roads, bridges, rail, airports ) should be a government investment that benefits all citizens.
Another very complex subject explained very well thank you very much.
Thank you for the kind words!
Yeeeeaah, sounds like a terrific idea. Think about energy density, high pressure storage tanks... 'nuff said.
Switching all aviation to hydrogen or battery power is going to make flying much more expensive. That will push consumers to alternatives such as electric trains except for crossing oceans, etc..
Yep, that’s likely
Next to zero passenger rail in the US, electric or not.
Which is why it won’t happen.
Depends on the oil price compared to the hydrogen price.
@@conveyor2 China is held up as the gold standard in high speed passenger rail yet a significant part of the country has no service or is undeserved. Since 2015, interest payments have exceeded operating profits. If they charged enough for HSR to break even it would loose even more. They have reported profits in 2024 but there is no reason to trust this figure. More likely a CCP mandated PR adjustment.
If you think I'm gonna sit in a tube between 2 highly pressurised tanks full of hydrogen on a vehicle built by Boeing, you've got another thing coming.
Anytime you fly, you're sitting between 2 big tanks of equally explosive Jet-A, so it hardly makes a big difference.
I also noticed that Peter didn't even mention Boeing in this one, as it's Airbus making the most effort anyway.
@@AlexandarHullRichter it's nowhere near as "equally explosive" as hydrogen and jet fuel is far, far easier to store in a tank.
Thanks Captain 👨✈️
You're welcome!
Unfortunately, in this video, he is spreading misinformation, which is very sad.
Governments will need to fund the development of new engines. Governments will need to fund the adaptation of airports. To fund this, government will need a lot of cash. When governments need a lot of cash, there is only one way to get it: stealing via taxes. Well, I think we have found the most interested one in this whole decarbonization madness, haven't we? Oh, yes, decarbonization is important because of global warming alerted by scientists funded by governments.
Frankly it feels like the industry is being pushed in the wrong direction.
Too much focus on emissions instead of maximizing fuel economy. At some point it becomes more environmentally friendly to use what you have better than to use half baked alternatives.
There is quite a lot of focus on fuel efficiency!
Transition from fossil fuels to alternatives should not be worked on?
The aviation industry is constantly growing still. Since we aren't willing to curb that growth, the increasing numbers eat up the efficiency gains easily and have been for decades. We have about 15% left in engine development before we reach the practical limit, 20-25% before we reach the theoretical limit for gas turbine efficiency. There are a few percent to be gained by more efficient routing and lower flight altitude to reduce non CO2 greenhouse effects of engine exhaust. Maybe 20% with Blended Wing Bodies. All of those things will take decades to certify, convince the public it's safe and implement throughout fleets.
We aren't getting out of the problem with fuel economy. Novel fuels are necessary to work in concert with other areas.
@@neodym5809 I believe efforts to find alternative sources of oil are more realistic. Crude oil from alge for example because once you have the oil the rest of the infrastructure is already there and built.
As we have seen with EV car adoption the infrastructure or lack thereof is the first and biggest nail in general ownership before you even get to the shortcomings of the platform.
Emissions is not a good reason to adopt a new fuel source, economic viability and sustainability is. Focusing on fuel efficiency even at the expense of increased emissions is again more desirable and more easily felt by all then another 0.0001% decrease in emissions.
@@MentourNow I disagree, it's only partial, because it does not benefit from governmental money (=our money), like the hydrogen greenwashing does.
Let me give you only one example. Energy consumed is proportional to speed squared. Design planes with glider-like aspect ratio wings that will fly 20% slower at the same altitude and consume 44% less fuel, and, to compensate, speed up the boarding process. A side benefit is that it will need engines 73% less powerful (cheaper, lighter) - power needed is proportional to speed cubed.
If hydrogen money goes in this direction, I'm sure progress will be real, as opposed to the greenwashing you also, unfortunately, promote.
Let's tax 20% the aviation fuel (with a 10 year grace period) and invest from the start (from now) the next 20 years' tax in more efficient planes. What do you think the results in 10 years will be, @MentourNow? Do you see, for the first time in the last 50 years, a new plane type? I do.
Thank you for these amazingly informative videos, Petter! They are teaching me a lot about the industry and things to understand once I get my pilot's license, and also how things will look in the future.
That’s awesome! Keep working towards that license!
The problem with green hydrogen is… there’s nothing green about it.
I like the Mentour Pilot videos a lot and I spend time watching them and reading the comments.
But I'd like to add a bit of a controversial comment here as well:
I think people fly way to much.
The solution of the environmental impact of aviation is not looking for better fuel, but is flying much less.
I haven't been on a plane for over 10 years now and I'm still a happy person
If you don't travel much that's great. If you live in a small country, that's great too. But a country the size of, let's say, the US, make flying necessary if you don't want to spend five days in a car crossing from one coast to the other. And for that same reason, high speed trains are utterly impractical.
Europe demands 1% SAF added from 2025.😊
I think it’s a great way to have a fair competition and scale production.
That could be part of the solution, yes.
Great video. I have been watching and enjoying many of your videos over the past month. This one has convinced me to sign up as a Patreon member. I wish your Mentour videos had existed when I was a young pilot, many years ago.
I think the most visible option is an electric aircraft. Why? When you build an electric device it is actually a flex-fuel device. An electric car is “fueled” by whatever was used to generate the electricity to used to charge its batteries. It can be renewables or fossil fuels. Hopefully renewables, but in a pinch it can be anything. Flexible means highly adaptable and reliable. If we build fuel cell powered electric aircraft, they likely could be retrofitted if (or when, I would argue), energy storage advances to the point that we can get long ranges from a single charge from advanced batteries. I think we should be building a transportation infrastructure that can use whatever energy storage methods make sense for the time and place and where advances in energy storage do not make obsolete massive fleets of transportation equipment.
Not for a very long time, or without a huge breakthrough in battery energy storage vs. weight. Two years ago a Cessna 208 was converted to electric. With the batteries installed there was enough useful load left for... the pilot.
Ideally, you'd want the centre fuselage to be your LH2 tank, which minimises structural penalty by keeping most of the airplane's weight near its source of lift, and avoids CG shifts as the fuel burns off. But I understand current regulations don't allow the cabin to be split like that. Medical emergency seat B2, is there a doctor onboard? Yes, he's in the aft cabin and can't get to the patient...
Petter, a Hindenburg-zeppelin on either wing? Even compressed?
A lot of technical hurdles I think.
You and I were apparently on fairly close together in terms of time. I'm with you, a "21st century Hindenburg" .. NO WAY
Liquified, obviously.
My understanding of the rubber seal problem, is that the the aromatics in standard fuel slowly replace the natural's in the rubber, making the rubber totally dependant on the standard fuel. If you start with SAF and stay exclusively with it then there is not the problem with the seals. This problem is also in other industries.
Well, I think at this point, Europe is falling behind Europe in Hydrogen.
Nice! 😂
The other aspect of aviation that I have never seen addressed is oil loss / consumption. Take a regional airline with 100 planes. Each engine will use, either thru blowby or consumption an average of two to three quarts daily. So x2 engines per plane or at least a gallon of oil per operating acft daily. Let's figure acft out of service may approach 20% so 80 aircraft pushing 5 to 8 legs a day could use 80 gallons of oil, the majority deposited at 30k feet for us all to ingest. There are about 45000 flights each day within US airspace alone. Some bigger turbines have direct draft tubes blowing oil mist look up a Rolls BR710 or BR725. Heres another tidbit, an average size turbine in the 4000-5000 shaft hp range will burn about 3600 lbs per hour at thrust set. A three minute performance run with both engines will consume 53 gallons of fuel.
High speed rail could take the place of probably 90 percent of all air travel and be faster (overall) and way more convenient. Imagine how much of this infrastructure could have been build in US had they not wasted trillions on wars over the last 30 years.
Exactly! Yet we’re stuck with out dated 2-day train trips from Jacksonville, Florida to Chicago, Illinois.
I long for the American train transportation system to be upgraded. 💯👀💅🏾
The real big problem with hydrogen is the way it is generated, most hydrogen generated nowdays is generated in methods that release a lot of CO2. That would offset any gains that would be ontained by replacing current aviation fuels.
But but but… white hydrogen in France… 😝
7:00 I think the graph isn't right, the green should be marked as conventional fuel instead of saf?
Great catch
maybe we should just stop flying as much to save the environment
A small rise in the cost of jet fuel would knock out frivolous use of air travel significantly. It's a luxury, but people don't see it that way. Hit their pockets, and they will wise up quick. Domestic vacation spots will appreciate the extra custom, and competition there will lead to many more options currently suppressed due to jet fuel being untaxed whereas vehicle fuel is heavily taxed. Charity begins at home.
Yes, stop growing food and grow fuel, what could go wrong? Then put super pressurized hydrogen tanks inside a plane, sounds super safe to me...
it is also worth remembering that in the EU the percentage of SAF use may be higher, because the overall fuel consumption is much lower, because there are MUCH fewer short flights for just a dozen or so passengers popular in the US
The industry and politics have to move rapidly forward. I want to fly again.
Well… buy a ticket and fly. Easy as pie!
Thank you very much, Peter, for this new video on sustainable aviation which looks at the scaling up issue. This is a major point that was not enough covered in the previous ones you made and this is necessary to speak realistically on this topic.
By the way, you seem to consider that sustainable hydrogen is easy to scale up. As far as I know, this is far from being the case because all industries and countries fight for sustainable electricity which is also complex to develop at scale.
And I also regret that, as an aviation enthusiast, you never look at the issue of traffic reduction.I am convinced (and it has been demonstrated by many studies) that the sustainability target will not be met without a traffic reduction. The growth of traffic in the past decades is not sustainable AT ALL !
1980 : 642 M passengers
1990 : 1 000 M passengers
2000 : 1 670 M passengers
2010 : 2 670 M passengers
2024 : 5 000 M passengers expected ...
Hydrogen is more likely than bio fuel because of availability. And I agree with Airbus that hydrogen engines will only be viable if there's infrastructure.
And infrastructure will only exist with nuclear energy. China is building a lot of nuclear energy power plants, unlike Europe and USA. Modern nuclear power reactors are safe (can't have Chernobyl style meltdowns).
Modern nuclear reactors are generally one thing: An incredibly expensive way to produce power. Even China's nuclear expansion is only a very small fraction of their energy expansion. Most is solar and wind. Nuclear is a technology chosen for national pride, military strategy and fall-cost fallacy, not because it is practical, fast or cost effective.
@@nanotyrannus5435 Most delays and cost of nuclear is just unnecessary red tape. The best build times and costs for nuclear readily compete with any other energy source, and a modern nuclear reactor will still be producing energy 60-100 years from now, when other sources will be being replaced in 20.
@@iskierka8399 Communist China ain't worried about Red Tape~
lol - that sounds so bizzare as I type these words!
Only 5% of China's electricity is generated by nuclear power. For contrast, the USA generates 18%. The reactors currently under construction in China will increase their percentage to only 7% to 8%.
Here in New Zealand we use bio diesel which waste frying oil and other fats that are converted to the biofuel. There is a lot of discussion on the how the necessary plants re grown and where. The problem that the production of biofuels could impact on food production is real and we need to make sure the proper regulations protect food production.
It's worth mentioning that making hydrogen is way too expensive right now to compete. As is the 2.5x as expensive other alternative fuel.
Right now I don't see either of them being able to be the future.
Great video Petter. Loved it! I also think scaling up the production of green hydrogen is yet another pressing issue which needs to be addressed if we truly want to make it an alternative to jet fuel.
All this 2035, 2050, 2060 goal stuff basically tells me that, no, humanity broadly has no grasp whatsoever on the severity, magnitude, and time horizons of climate change. Yesterday was already way too late.
I agree. Too late with current thinking and ability. We will do better when it gets ugly. People will die. Then it will be a priority.
Sadly I have to agree with you. Unfortunately people would rather hear things they like o hear rather than the truth. That is how the oil industry is successful in spreading FUD about electric cars and Toyota can get away with its self charging hybrid nonsense.
Climate always changes. Always has thoughout the history of the planet. There is no too late.
@@zk4654 I agree there's no too late, but it will be really funny when hundreds of millions of people from the equator will migrate north. WW2 will be children's play.
Yeah, it's not sounding too good. 2050 is tomorrow in regards to big companies. This goal should have been set 30 years ago.
You are absolutely correct regarding the lead time for a hydrogen powered aircraft.
It doesn't matter what the decision is regarding concepts.
Firstly the stage where an engine design that is tested and certified has to be reached.
Just the certification process will most likely take several years.
Before that there will be a number of full scale test engines built.
Once certification has been achieved and the engine builders can start looking into production there will need to be orders in the order book.
Then once the green light has been given to start production and the production engineering phase is initiated it will take several years to create production methods that can certified.
In many cases today production engineering is the limiting factor for more efficient gas turbine engines.
The materials used to make the parts are so difficult to machine.
It takes a long time to develop maching methods for these high temperature materials
After that machine tools and other equipment has be sourced and commissioned
In my opinion the time scale from where we are today to being able to mass produce hydrogen powered aircraft is at the earliest 30 years probably 50 years.
8 years is not long enough to even create working concepts that can be evaluated by the different areas of aircraft manufacturing.
Maybe the scientists in the laboratories will be close to being able to present concepts that can be discussed within the industry.
That will be about it.
Why work on an engine where the fuel supply doesn't exist now and is about as far away fusion?
@@lenwhatever4187 I suppose that is really my point.
This is a chicken and egg thing and we don't even have the chicken.
It is far from clear if hydrogen is the way to go.
The policies politicians are making are just not achievable.
Before anyone can commit to new technical concepts for aircraft engines there needs to be a decision regarding the fuel that will be available.
As I mentioned we are 30 to 50 years away from mass produced fossil free aircraft.
In reality we are waiting for the real breakthrough in fuel.
Nothing on large scale will happen before then
Liquid hydrogen can work if they figure out how to keep the temperature for storing.
Vacuum insulated dewars
@@giantfrigginnerd Even then it is still a massive PITA. Hydrogen doesn't do evaporative cooling well, it likes to boil away very easily.
When it comes to alternative fuels my hopes are with Porsche and its eFuel 🤞
I see a great future for bootleg fake eFuel.
Let's be realistic, in 2050 we won't have: net zero CO², 100% cars in the world being electric, hydrogen or electric propulsion in commercial aviation.
Okay~
Cars: by 2050 gas cars will be a hobbiest item in most of the industrial world. Gasoline relys on volume wich means as electrics hit the market in volume economy of scale will be lost.
Likely true - but if we dont, the consequences will be difficult (in human terms - suffering, mass migration etc) and VERY expensive - so we either start investing now and do the best we can, or say “screw our old age and our kids future” and party like its 1999….
Especially when China and India and other polluters not playing along. The West is kidding itself.
What I want know is why net zero emission of carbon dioxide/monoxide? Why is everyone in a panic over global warming? Do they not realize that thing that they should worried about is global cooling. Wait! What am I talking about? The vast majority of people will not realize how bad cooling is until their sewers freeze up and all that nasty fluid starts backing up in their tubs, sinks and commodes.
Increased carbon dioxide means larger crop yields, warmer weather and therefore more food to go around. The human population is in decline, which means that the future may well be dystopian, but that dystopia will certainly result from the machinations of over eager politicians than any foreseeable global warming.
If lithium battery technology continues to improve at its current compounding rate of about 1% per annum combined with other technology improvements then BEAs could become a viable option for the short haul airline industry sooner than people expect.
Yup in about 600 years.
Why not just exclude aviation from this artificial net zero date?
I know it makes the tree huggers feel warm and fuzzy, but why pin yourself into a corner unnecessarily?
Politicians have really screwed up with these arbitrary targets. It should be a 100+ year project, not multi decade.
The date isn't real. It's just a goal. Before we hit 2050, we'll just set a new date further into the future and no one will care.
Same for the auto industry. Do so and they would miss 100 year targets.
These companies sit on their backsides then act like their dog ate their R&D.
Because politicians are run by capitalism and don't care for the future after the next election date. That's why the numbers are all over the place, they have to work within a 4 year time period. Plus with most political parties spending 2-3 years undoing what the previous government implemented, there's simply no time to properly put factual goals into practice.
Welcome to every government on the planet.
What's allways missing from this type of discussion is the energy required to make products like SAF. Currently that comes from FOSSIL fuels. Same with electricity for battery electric cars.
There will never be enough energy from wind or solar to provide the world with the energy it uses now that has provided the standard of living we have.
Only nuclear will provide that level. Then SAF or hydrogen will be possible.
"Hydrogen could be used by other vehicles" And therein lies the problem. The oil industry does not want to see alternative fueled vehicles. They are constantly publishing lies about EVs because they don't want this cutting into ICE vehicle productions. The oil industry has a large lobby in both the US and Canada which is trying to discourage alternative fuel.
The oil industry would be happy to make and sell hydrogen.
That's not the problem. Currently hydrogen costs more in fossil fuels to make and transport, than using fossil fuels directly.
Once again, they ignore the best fuel that we have to deal with the transition, which is CNG. It burns very cleanly and is an easy retrofit for most vehicle and planes. The main issue is the space required for the tanks, but that's really not such an issue given the light weight of the tanks and low pressures involved. You can get about 2/3 the range without doing much of anything major to the design, provided you have enough space. Not perfect, but far closer than chasing electric or hydrogen that might work.. eventually. Yes, we have similar scaling issues, but the infrastructure is far more robust than hydrogen, as most of the world's major city busses use CNG or LNG.
Getting our old airliners to do the trick is the thing, i think we in the west are doing a lot running before we can walk, thorium nuclear reactors produce little nuclear waste, its an abundant energy resource, if we build build the reactors. We can can make synthetic fuels bonding carbon to hydrogen atoms, so we can use our old airliners guilt free. We have been fiddling with hydrogen for decades, it is terribly difficult resource to transport and from watching this space over my life time, the rules of nature do not change, Hydrogen is difficult. that jet fuel, the regular fuel in our cars, the heating fuel, it works great, if we want to replace it, it needs to be as good. Airbus sound like they have been spending billions on a box ticking exercise, instead of lobbying governments in to making better power generation, or even spend those lost billions in to thorium reactors.
MSc Engineering Physics with a thesis in optimizing hydrogen generation and storage and a pilot study on wing integrated LH2 tanks here. Sooo excited to hopefully be part of this developing industry in the future!
Intressant video, som alltid ✈️
Hydrogen fuel is, basically, the same thing as "Plastic recycling". Greenwashing as it is.
Contrails also seed clouds. The removal of sulfur from ship fuel is starting to look like the main cause of significant Atlantic Ocean temperature rises since 2019/2020. We need to start looking at this holistically opposed to item by item.
Interesting that Airbus wants to use their first hydrogen engine on an A380, while that aircraft is not even being built anymore ^^
It’s just a test bed.. and the fact that it’s so big works well with the hydrogen tanks
@@MentourNow Thanks!
"test bed" immediately was my first thought, too
Is a perfect test bench, 4 engines, massive, and a mtow of over 1.2 million pounds
Some major issues with hydrogen. The main issue is sourcing it. You can find natural pockets, but it's not as readily available as our leaders and car manufacturers make it sound. You will still have to locate and drill.
The other thing is it taxes the power grid to make it and means you are using up water sources to make it. Sure a by product is water when it burns but you are spreading it out over your distance and not returning it to the spot you sourced it from. If you ise ocean water you have to desslinate it first which requires more energy consumption. This all hinges on so many variables that actually drive up costs.
Storage isn't really any more dangerous than others but I have done work in 2 factories that could level each of their respective towns with what they store, which isn't hydrogen.
This is not practical in the long term.
"Hydrogen is the most abundant element in our universe".
It is, and we can do it. But that argument wouldn't work with Helium, the second most abundant element in our universe, because it ain't abundant down here. :-)
Helium also has the same energy density as a brick.
@@danharold3087E=MC2 ….😂 so yep. (I know that wasn’t your point)
You don't need to choose between combustion or fuel cells... You can do both where they shine =)
But you forgot (or omitted) ammonia. The transformation from ammonia to hydrogen is done by a catalyst at ~900°, hot but not unreachable with hydrogen combustion. So you could create ammonia with green energy to encapsulate hydrogen in a more "usual" fuel and fuel the planes. Then, when it's time to burn it, go through the catalyst to separate hydrogen and nitrogen (keeping it is really important), and then burn hydrogen as a greener fuel than normal jet-a1, SAF, etc.
Hot burning means that nitrogen oxides will be produced, not from the nitrogen in the ammonia but the nitrogen in the atmosphere and that is not good.
@@rogerphelps9939 I know that nox is not the best gas to get, but with our actual infrastructure, it’s the less difficult option to get…, and afterwards the engineers can work on that byproduct with some kind of catalyst? Idk, but it’s seem to to be the less unrealistic idea to have
Surely this will be beyond near impossible to scale up?
The recent developments in Solid State Lithium Ion batteries may leave hydrogen aviation in the dust. There are two companies making them, one Amprius, has third party verification of their batteries and is making initial products to go into things like smart watches. The energy density is claimed to be 500Wh/kg, making it over 4x more dense than the current 110Wh/kg.
I've been watching the electrificaiton of aviation for a while and I think experimental aviation has the chance to make breakthroughs the airline industry can't immediately adopt.
Hydrogen? LOL…
Hydrogen fuel isn't about saving the environment its about money. In the U.S. we have ~35 million acres of farm land used to grow ethanol. By the time the corn is processed and in the gas/petrol the environmental savings is gone. It also made the U.S. less reliable of foreign oil- a now irrelevant cause.
Biggest problem with hydrogen is sourcing and energy density. Currently most hydrogen comes from hydrocarbons. Oil. Hydrogen from sustainable energy sources like wind and solar being used to split water and harvest hydrogen yield hydrogen at atmospheric pressure, then huge amounts of additional energy must be expended to compress the hydrogen to high enough density. The resulting carbon footprint is within the same order of magnitude as burning hydrocarbons.
It's a great video as usual Peter! However, make me mad when the industry advertise any kind of incremental efficiency gain as a serious effort towards to be less polluted. In the end always will be worse (take a look at jevon's paradox) but more lucrative. The only way out will be a complete disrupted new kind of engine, just like jet was, but will never be economic feasible until will be too late.
You mention that reducing the contrails would help reducing the trapping of heat. I am not convinced. On days when there are a lot of contrails, they reflect a lot of sunlight out of the earth, which results in that the earth is absorbing less heat from the sun.
Can you please let me know what your setup is? Microphone, Lighting etc? Your videos are so perfect !
Rocket engine manufactures have to find complex ways to keep some hydrogen engines within temperature limitations. Making sure pipes don't freeze, but also making sure engine nozzles dont melt. I find it really interesting then that both Boeing and Airbus have contacts who make rocket engines and deal with hyrdogen propulsion and storage, yet seem to be struggling to develop hydrogen engines. Im not a rocket scientist, but common methods of keeping things cool are running the super cold hydrogen around the hot parts of the engine, so the fuel itself acts like a coolant. Something that does interest me is how they plan to deal with boil off. As liquid hydrogen gets warm, it expands and has to be vented to the best of my knowledge.
well for a lot of rocket engines, those vents are inside of the combustion chamber
@@danzjz3923 In most rocket engines, as they sit on the launchpad, they vent some hydrogen (and liquid oxygen) overboard. So would a aeroplane need to do the same if it is taxing or at the gate for a long period of time?
As always, the problem with "clean hydrogen" is that it's (mostly) produced from dirty fossil fuels. It burns clean, for sure, but that's the only "clean" part using hydrogen.
There's also a HUGE issue of storage.
Don't forget at the same time also other industries are changing to alternative fuels like the ship's worldwide, so any sources needs to have a good production rate and low price.