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Buddy as an aerospace engineer who has spent 30+ years in industrial control systems and automation INCLUDING BEING FORMALLY TRAINED in Electrical Equipment in Hazardous Areas (EEHA) you are completely misunderstanding the nature and risk of hydrogen. Sorry this is long but everyone thinking hydrogen is the magic solution needs to understand that it has some fantastic properties and I really do think it will be a major part of future energy, but it has some very serious risks. *I am proposing 2 new massive power station projects here in Australia that are partly fueled by hydrogen BUT and I can't stress enough how hard hydrogen is to engineer around.* Your comment comparing kerosene to hydrogen is so far off the mark its scary. In terms of safety Hydrogen is nothing like kerosene. If I compared your skills and training as an airline pilot to a bus driver in the same way you have compared Hydrogen to Kerosene you'd be insulted. I have a pilots license so I know what that means. Here are some basic facts that they teach engineers. 1) You need 3 things to have combustion or an explosion which is basically hyper-rapid combustion. FUEL + OXIDISER + IGNITION SOURCE. Fuel alone does nothing. Fuel with just an ignition source does nothing. Fuel with just an oxidiser does nothing. You must have all 3. The reason solid rocket propellants like gunpowder & C4 explosive can be so dangerous is because they combine the fuel and oxidiser. Its why they are impossible to extinguish once ignited. Once the Space Shuttle and Artemis boosters are lit they will go until the fuel is consumed. All that can be done is detach them. 2) Flammable liquids DO NOT actually burn or ignite. *The vapor above the surface burns.* There's videos shown to engineering students where they drop a lit match into a jar of gasoline and it just goes out because below the surface there's no oxygen. This is also why cars don't explode when the fuel tank has a submerged pump. Because its submerged and totally surrounded by fuel there's no oxygen. Its also why cars can explode if the fuel level sensor gets a shot circuit because you can get a spark in the vapor space above the fuel level. Its why empty fuel tanks with vapor are far more dangerous than full fuel tanks where there's almost no vapor. 3) A droplet of liquid fuel does NOT BURN its surface burns because the heat boils off the liquid and that allows it to mix with air and meet oxygen molecules and react. This is why fuel injection in cars and trucks works so much better than a carburetor. There's not only finer droplets with more surface area but the droplet size is more consistent making combustion more stable and more reliable. 4) Gases and vapors at the right mixture can EXPLODE. For almost any gas you can find 2 numbers given in percentage called the LEL (lower explosive limit) and UEL (upper explosive limit). Between the LEL and UEL the mixture explodes. In room temperature air: - Methane has an LEL of 5% and UEL of 15% - Hydrogen has an LEL of 4% and UEL of 74% So hydrogen wants to EXPLODE over a much wider range of fuel-air ratios. This is also why its been so hard to get it to burn reliably in engines. It reacts so fast its hard to get a stable flame. 5) Everything that can burn or explode has an ignition energy usually expressed as MIE (minimum ignition energy) with the units mJ (milli-joules). Hydrogen has the lowest of all MIEs at 0.017 mJ (in air) and 0.011 mJ (in oxygen). By comparison methane 0.26mJ gasoline is 0.80 mJ and Kerosene is 20 mJ. *Kerosene takes just over 1176 times the energy to ignite than hydrogen.* A kerosene leak compared to a hydrogen leak is nothing in terms of risk. 6) Many gases and flammable substances can ignite from temperature. Again Hydrogen is very low on that scale compared to most other substances. When you select equipment that is in a area with hydrogen you have to check the temperature rating as well as all the other factors. 7) The Hydrogen molecule is the smallest molecule in the universe. That makes sealing everything incredibly hard. You can't just by valves, pistons, pumps, pipe fittings like you do for other gases. It will leak from the tiniest of holes and narrowest of gaps. If you have any leak in a place that's not well ventilated it gets very dangerous. Hydrogen is amazing. Its actually very easy to make through electrolysis of water, but its also a hassle to use which is why its never really been used as much as people think it should have been. Sorry if this feels like I am yelling but its a very serious topic. I 100% believe the hydrogen economy is going to boom and be a major part of our energy future, but I also expect some tragic outcomes because people will simply ignore what people with expertise warn them about.
Mentour please take the time to ask those working in the energy industry with a solid understanding of the economics and viability of these technologies, capturing CO2 from the atmosphere is *insane*, way more expensive than other ways of getting CO2 (if we even want to go down that road), also it would be at pressure in the tanks shown surely
On the capturing CO2 from the atmosphere its all dependent on how its done. I'm an engineer and the major problem we collectively isn't so much we are having to transfer from dirty to clean energy, its that we are at the next great energy transition. Just as we moved on from horse & sail to coal & steam then onto oil & gas and then 1/2 way to nuclear, we are now at the next great energy transition. Its being heavily influenced by the need for clean energy *but we'd be making a transition anyway.* The single biggest factor is efficiency. We have more people and that means more energy is needed but that actual supply of raw materials isn't keeping up. I'm in Australia and we had a power station called Hazelwood. It was old an dirty, but worst of all was its was hopelessly inefficient. Most coal fired power stations could get about 30-35% efficiency with the very best ones with advanced boiler technology could get over 42% thermal efficiency. When it closed Hazelwood was getting about 20% thermal efficiency. So it was burning twice as much coal per watt of electricity. Hazelwood was closed NOT because it worked but because it was so inefficient. Right now we have another power station at Newport which is an old gas thermal. If we simply replace it with a gas turbine we can save about 30% on raw gas input. If we add a steam turbine to the exhaust we can increase the power output by 60%. If we then added a hydrogen supply we'd reduce the emissions by another 50% down to 30% of where it now is. This is actually a hard thing to discuss with non-engineers. If you are not being efficient with energy then ANYTHING can be insanely expensive. Also some things that look or sound inefficient aren't when you take into consideration of the overall system efficiency. With direct CO2 extraction a lot will depend on where they get the energy from and then how they use it. I think the real problem with it will be that it just can't do enough. When you look at how much needs doing the real problem is being able to do in engineering what green vegetation does already. I think it will end up with systems that blend what we can do in engineering with what we can do with plants.
Petter, can you please make a video about electric aircraft. Hydrogen has its merits, but fuel cells are not much more efficient than burning the H₂, whereas direct use of electricity to power motors is much better. Battery technology is advancing rapidly, to the point that recent new designs have almost three times the gravimetric energy density of cells which are on the market today. It's not going to be very many more years until fully electric short and medium haul aircraft will be feasible. We're already seeing light aircraft with up to a couple of hours of flight endurance, with a 30 minute reserve. There are also great running and maintenance cost advantages to be had from battery technology. Sure, batteries have lower energy density than conventional fuels, but they're a lot safer to use, and certainly much easier to handle than Hydrogen. You mentioned H₂ leaking from containers, but you didn't mention the facts that a 5% Hydrogen/air mixture is potentially explosive, and that H₂ embrittles various metals quite quickly, or that synthetic storage vessels need replacing every five years or so because the Carbon fibre and resin degrade steadily because of the fuel, the cold temperatures and the pressures involved. Nor did you mention how big the airport storage tanks will need to be. To give a sense of the scale differences, a standard gasoline or Diesel fuel storage tank at your car's filling station could refuel perhaps 300 cars, but a Hydrogen storage tank of the same internal volume can only refuel around 10 cars. Hydrogen tanks will also need refrigerators and thermal insulation. The cooling system causes an inherent energy drain which cannot be avoided, and the thermal insulation adds to the overall size of the tanks. Perhaps a much easier fuel to use would be Methane; CH₄, because each molecule contains twice as much H₂ as a Hydrogen molecule. It doesn't leak so readily, doesn't embrittle metals, requires much less cooling and can be produced cheaply from CO₂ and H₂ O. (High temperature steam reacts with Carbon Dioxide.) When burned with O₂ it exhausts mainly the initial Carbon Dioxide and Water.. A useable production method for Methane has been employed on the ISS for many years, but they want the Oxygen and water in a process which removes CO₂ from cabin air, and they discard the Methane to vacuum.
It should be noted that after over 60 years of working with liquid hydrogen, NASA still struggles to get a good seal on fluid coupling interfaces, and they would never authorize ground personnel to be anywhere near the vehicle while it is being loaded with liquid hydrogen. During the Space Shuttle program, NASA learned that each time they load cryogenic propellant into the vehicle, the thermal contraction/expansion cycle affects the geometry enough to require certain bolts to be re-torqued in order to get a good seal the next time. Even though the new SLS rocket is similar to the Space Shuttle in many respects, it's different enough that they had to re-learn through trial and error how to tweak the bolts between thermal cycles. Commercial aviation is a lot less forgiving in this respect. If there's a way to close a cargo door incorrectly without a very obvious indication, a well-meaning worker will find that way. If NASA's technicians can't be sure that they've connected a fuel line so it won't leak, airport workers don't stand a chance.
Hydrogen is one of the most difficult and dangerous forms of fuel. It cannot be used in commercial aviation unless regulators are willing to sacrifice safety. I won't say it will never happen, because I've seen lots of crazy sh*t done in the name of the Green agenda.
@manitoba2445 Ok but their point still applies. Just because a different group does it doesn't make much difference. They will still have to touch the airplane and have some ground crew experience.
@@manitoba-op4jx The inherent difficulty still applies. And "grunt work" of making physical connections, etc. is still going to be done by people being paid "grunt work" wages. Some of these people will be highly skilled and take tremendous pride in their work. Some will be marking time and doing the least they can get away with.
Your points are interesting BUT only affect cryogenic storage. The tanks on Boeing or a Nissan Mirai are not cooled to phase change temperatures, instead they are very high pressure COPVs. I actually can tank any car that is equipped with hydrogen tanks and fuel lines myself at the gas station here in Germany. It is an easy twist hose, which will automatically check for leakage.
So rare to see a discussion of hydrogen that doesn't gloss over its issues and hype it up as a magical wonder solution. Thanks for the excellent video.
Oh wow! I flew that Dash-8-300 back in 2006 when I flew as an FO for Piedmont Airlines. N330EN... I thought I recognized that N number, and sure enough it's in my logbook. Nice to see it still flying!
The CSIRO in Australia has already determined the best way to store, transport and use hydrogen as a fuel is via Ammonia (NH3). It is a liquid at reasonably high temps and you can see it has 3 hydrogen atoms and one nitrogen. All the cryogenic and high pressurisation issues go away. The only potential problem is if you get a leak into the cabin, all the passengers and crew will also go away. Rather quickly.
I'm pretty sure they settled on ammonia because cracking it to release hydrogen doesn't create CO2. Which buys into the common misconception that hydrogen and electric vehicles are zero emissions. They're not. They just shift the emissions to the power plant. Generally, hydrocarbons have the highest energy density. If the hydrocarbon you use to store the energy (hydrogen) is created using atmospheric CO2 (e.g. plants take in atmospheric CO2, and use photosynthesis to create sugars which you convert into alcohols), then it's a closed cycle and there's no net CO2 created even if burning the fuel creates CO2. So it doesn't matter that it's not "zero emissions" at the plane. Volumetric energy density (MJ/L): 11.5 - liquid ammonia (-33 C boiling point) 15.6 - methanol 22.2 - liquid methane (-161 C boiling point) 24 - ethanol 25.3 - liquid propane (~ 22 atmospheres) 27.7 - liquid butane (~ 2 atmospheres) 34.2 - gasoline 35 - fat 35.0 - kerosene (jet fuel) 38.6 - diesel Specific energy (MJ/kg): 18.6 - liquid ammonia (-33 C boiling point) 19.7 - methanol 30 - ethanol 38 - fat 43 - kerosene (jet fuel) 45.6 - diesel 46.4 - gasoline 49.1 - liquid butane (~ 2 atmospheres) 49.6 - liquid propane (~ 22 atmospheres) 53.6 - liquid methane (-161 C boiling point)
@@solandri69 : Ammonia is tempting as a packaging for hydrogen because it's easily liquified, because there's a lot more nitrogen in the air than carbon, and because ammonia is useful in itself. Not because engineers don't understand carbon cycles.
The tail vent is not for abnormal leaks. Almost regardless of how well the tank is insulated, liquid hydrogen will gradually boil, increasing the pressure inside the tank. With the engines running at high power, this is fine because there needs to be a gas to fill the empty space in the tank as the liquid is consumed. In some cases, passive boil-off won't be sufficient for tank pressurization, requiring a heat exchanger to make extra gaseous hydrogen, called autogenous pressurization. But if the vehicle is sitting on the ground with engines off, there needs to be somewhere for the excess hydrogen gas to go to avoid overpressurizing and rupturing the tank. For rockets sitting on the launch pad, this excess hydrogen gas vents through umbilical lines to a flare stack where it is safely burned off. Aircraft won't have that infrastructure. So they'll either be venting unburned hydrogen into the air, or that tail vent will need an ignition system to function as a flare stack, spitting fire out the top of the vertical stabilizer. When aircraft are parked overnight or for prolonged durations, they'd want to offload their liquid hydrogen, and for safety they'll need to fill the empty tank volume with an inert gas that's non-reactive with hydrogen, which would probably have to be helium. Liquid methane would be a lot easier (the Soviets figured that out). Liquid ethane would be even better, because it can be stored as a pressurized liquid at ambient temperature. But the advantages of storing non-pressurized liquid fuel in the wings are so great that sustainable aviation fuel ("green kerosene") will probably win out in the end.
No, you've just correctly pointed out why all those other technologies are more stupid than green kerosene. But it doesn't take away from the fact that green kerosene is still very stupid economically and very stupid for engine durability and consequently very stupid for passenger safety. But you're right, the other technologies are much worse.
I am really glad you talked about the problem with water vapour at hight altitudes. From what I understand it's one of the worst greenhouse gases.... which sounds counter intuitive.
Yup, the effect of CO2 is near nothing compared to water vapor. It's the height of stupidity to try and fight "global warming" by replacing CO2 with water vapor.
Yup, it's one of the worse greenhouse gas, however it's very well regulated by meteo and climactic phenomenon, meaning that for a certain temperature of the atmosphere water vapor concentration remain nearly constant, In other world if you release water vapor it won't stay long in the atmosphere (it may not apply to very big quantities of water vapor so i guess it is still a concern for aircraft, just don't feel bad when boiling pasta)
@@anosv9797 it's a bigger problem at high altitudes than at ground level (multiplying factor) but elevated levels only persist in the atmosphere for a matter of hours/days Aviation is clutching at straws in many ways (so are several other transport systems). We're on the cusp of changes as large as those wrought by the introduction of automobiles in the 1900s or the destruction of the USA public transportation system in the 1950s
Thank you for your work, Petter! Your videos are outstanding from any angle: the quality of the content and research behind, the quality of the graphics and your #absolutelyfantastic way to explain.
Great report. The major problem with hydrogen is that it is the smallest existing molecule and wants to leak everywhere. Many space launch scrub happened because of H2 leak. I hope that all technologies are there to secure fuel transfer in connectors, tubing. Good ventilation/sensors. I don't think we need burn-off igniters, lol, but H2 will always needs to be handle carefully. Easier to see a jet fuel leak than an hydrogen one. I hope this work, better to use energy hydrogen as battery than a "real" heavy weight one for aviation. Hydrogen just transport the energy, that energy has to come from elsewhere and the production ratio is not so good for renouvelable sources. We have working hydro-electrical hydrogen plant here where airport here can easily be obtained it, good. Thanks to the team.
Fantastic Video! Interestingly Hans von Ohain's first Jet engine ran on Hydrogen because the extremely fast combustion speed simplified the design of the combustion chamber. Kelly Johnson worked with Pratt & Whitney on an engine burning Liquid Hydrogen for the CL400 project. That was the predecessor to the SR71 program and Kelly/Lockheed eventually returned much of the program money to the government and declared that it wasn't practical because not enough could be stored in the airframe. Traditional vacuum Dewar's had to be spherical or cylindrical and just couldn't be packed into wings and tails like conventional fuel tanks. Of course he was also aiming for Mach 3+ which brings a different set of challenges
All this "save the earth" stuff is getting ridiculous. Plains crash. Hydrogen won't burn like kerosene. It will explode! Killing everyone on the plane and further endangering those on the ground. So while some accidents are now survivable, hydrogen will ensure certain death!
Odd thing about hydrogen is that is presented as future tech, when it's used in rocket ~80 years and Example Apollo module was powered with fuel cells. Non of the advancement have made it more scalable. It is made and used in-situ, or it's treated like rocket fuel, -Because it is. After 2019 accident most of Hydrogen stations for cars were closed at Denmark and Norway...
Yes, but COMPLETE TRIPE ! He's totally skated over the realities of doing this with fuel cells, especially their weight and the problems of getting tens of megawatts of heat out of them.
It can be further processed into methane, and (iirc) ammonia. ...Ammonia lacks the caloric oomph. Any methane that leaks is really bad for global warming. 😬 I'm not an engineer or chemist, fair warning.
@@suchirghuwalewala The leaking problem should be know to most anyone who has been paying attention to more than hydrogen promotional materials. Somehow being a fan is becoming a bad thing. So sad.
It's a tough challenge, not even talking about the ça y that the density is far lower than kerosene, and on top creating hydrogen is very bad in terms of efficiency. So just no.
Hydrogen infrastructure and logistics are *so* difficult that it brings into question whether hydrogen powered aircraft will be possible at all. It *already* seems as though when you run the numbers it's not viable for cars and ground based transportation systems generally. Aircraft and airports in particular *are* much more suited to it, but as far as I am aware it is still debatable and a relatively close call on whether we can actually make that practical and sustainable or not.
Unfortunately I suspect that some companies will charge ahead regardless of the challenges and wind up creating potential hazards as well as wasting time and money on the hydrogen infrastructure. It is a sad reality that often the risks are not fully appreciated until a tragedy happens. Hopefully no one loses their lives over this. It isn’t Hindenburg style fires that are the threat but ruptured metal tanks or cells weakened over time by hydrogen leaking through metal walls. Kerosene tanks are more stable over time than hydrogen tanks. The questionable economical viability will turn negative as insurance rates and lawsuit payments increase in reaction to tank failures in future years. The frequency of replacement of tanks could eventually be mandated to be more frequent and thus more expensive than the projections of current hydrogen fuel companies. That is all in addition to the extreme challenges of working with hydrogen even during normal operations when nothing unusual happens.
The whole “green talk” around cars and airplanes is a smokescreen. 1. Transportation is consuming only about 20% of global energy. 2. There are no substitutes for powering large portion of transport vehicles (ships, mining equipment, trains) 3. 84% of global energy is derived from fossil fuels. Electric cars and hydrogen planes don’t solve anything, just move the problem to places where electricity is generated. Still, the portion of electricity consumed by EVs and hydrogen production is minor compared to the amount consumed for heating and cooling 24x7 in all densely populated areas everywhere . But addressing that is much bigger and more difficult to solve. From technology point it is rather boring so journalists don’t want to talk about it, thus contributing to the problem. Talking about EVs and hydrogen planes is much more exciting that about improving building code and insulating old buildings. That is why we hear about EVs all the time, about hydrogen and electric planes from time to time, but never about insulating all homes everywhere, even though that is where the biggest improvement in global energy consumption could be achieved.
@@rok1475 Or the simple fact that nuclear power is as green as it gets. But nobody wants to talk about that. You could very easily replace coal and natural gas power plants to nuclear, and eliminate a HUGE amount of greenhouse gas generation. And newer designs not only generate power, but can consume nuclear waste from older designs, resulting in a net DECREASE in nuclear waste currently on the earth. But again, nuclear is simply a "forbidden" technology, regardless of the simple fact that nuclear power IS green. And i'm only talking about fission designs, not fusion. Because we have extremely promising and proven fission technology already. Fusion may be close, but they've been saying that for a very long time, and it's still not here yet. And i 100% agree with you that building insulation and increasing the efficiency of heating/cooling solutions is an obvious answer as well. It's just hard to make that work, as you have to get billions of people to spend money to fix their little piece of the problem. And, let's face it, people are self centered selfish buttholes, for the most part.
They are probably possible if you want to spend an infinite amount of money and time fixing all the problems they cause. But that doesn't mean they are smart. Planes are one of the most energy density sensitive things I can think of. As such, it's one of the hardest things to de-carbonize quickly or economically. Thus, it's likely way more efficient for airlines to simply _offset_ emissions by doing things like funding solar installations, for example. This would be an effective means of accomplishing something _immediately_ instead of just spending the same amount on research and hoping for a breakthrough which may not matter until it's too late. Carbon acts over time, so getting rid of one ton today is worth much more than one ton 20 years from now, in the same sense as compound interest and investments. We need this kind of broad, pragmatic action if we want to actually make a dent in climate change. Energy is fungible, after all, so it makes far more sense from a macro perspective to attack the easiest (most cost effective) carbon sources first, because we can have a greater effect for the same economic cost. This is a really, really, important thing to understand, because of just how vast the problem is. Better yet, we could simply pass a carbon equivalent tax to weaponize the market by actualizing hidden negative externalities like climate change... but I've given up on this being politically viable until either things get a lot worse or we fix our actual elections (FPTP, etc).
@PsRohrbaugh 2 minor nitpicks - "1 degree Celsius" is a definite temperature on the Celsius scale, i.e. 1 Celsius degree above the freezing point of water, and only means that particular temperature. When talking about increases/decreases/differences in temperature on the Celsius scale, one deals in Celsius degrees, not degrees Celsius. You mean "an increase of 1 Celsius degree is an increase of 1 kelvin [not Kelvin]"
I commented a few videos ago about whatever aviation news I read mentour now always releases a video not long after going into more detail, and you've done it again! Keep up the good work
Addendum to 13:40 regarding SpaceX, their next rocket, Starship, actually plans to use methane, and to use the same process of extracting CO2 from atmosphere in Mars and making methane from thin air as described in 4:10. They aren't using hydrogen due to a lot of the same issues described in this video (but under very different contexts from an airliner, of course, and of course rocket engines treat hydrogen/methane/kerosene as a propellant rather than an energy source for driving a motor).
I read "Skunk Works" by Ben Rich who worked for then later took over when Kelly Johnson retired. In it he describes how Kelly looked into using Hydrogen to power the SR-71up there at 100,000 ft & Mach 3 but it proved too difficult and expensive and they gave it up. I don't think it would be any different now.
If I remember correctly they couldn't get the mileage they needed on a single tank vs aviation fuel so they had to make the tanks bigger which worked against them. They couldn't seem to resolve it so they stopped the program. Ben said it was very disheartening to fuel up a plane then when you went to fly there was no fuel left in the tanks.
Petter, I love your enthusiasm for possible new technologies in aviation. Your attitude of “We can do it!” Is a breath of fresh air. This was a very interesting video - I appreciate the back-story history of using hydrogen- and gives me a tad more hope concerning our environment problems. Keep up the stellar work!!
21:31 - I understand the desire to help aleviate fear in the hydrogen tech but comparing hydrogen to kerosene isn't really a fair comparison in terms of hazards. Kerosene is a relatively benign fuel, often refusing to burn without enough heat (flash point of 38-52C[1]), being aerosolised or without a wick. Hydrogen meanwhile can ignite when you burp the cylinder (the act of briefly opening a cylinder without a hose connected to remove any FOD from the valve such as dust/dirt), it's minimum ignition energy is an order of magnitude lower than petrol and a few orders of magnitude less than kerosene (0.01mJ for H2 vs 0.8-ish for petrol, Kerosene is around 20mJ of energy, mJ == milijoule[2]). Yes with adequate controls and safety Hydrogen can be safe but saying that the industry does it with kero no worries for ages so hydrogen will be fine isn't apples to apples I am not meaning to poo poo the alternative energy as we have to get off non-renewables but the kind of mentality of "oh it's just a little more spicy than jet fuel" may lead some to not treat it with the respect it deserves. [1] www.ilo.org/dyn/icsc/showcard.display?p_lang=en&p_card_id=0663&p_version=2 [2] marinechemistassociation.com/wp-content/uploads/2018/09/Minimum_Ignition_Energy.pptx edits: corrected some typos
One of the largest problems with using hydrogen is how it would be supplied. While it's the most abundant element in the universe, it's actually quite rare in its molecular form on Earth. Therefore, it has to be manufactured, which by definition means it will take more energy to produce the necessary hydrogen than will be produced by later burning it. Sure, this could be done by water electrolysis using renewable energy like solar, but it doesn't scale well. The more common method used extracts the hydrogen from hydrocarbons (typically methane), a process which by itself produces CO2. So moving to this process doesn't help the problem, but just moves it to a different source. If anyone wants more information on how hydrogen is produced - in addition to one other issue unique to liquid hydrogen - then I'd recommend Scott Manley's video on rocket fuel production.
Massive amounts of hydrogen have been discovered underground much like oil fields but in different places. Google it. Hopefully this will be able to be tapped for energy needs.
This is a problem for most sustainable energy production from combustible fuels- it can move the CO2 production to a different point in the fuel cycle. Ammonia synthesis requires hydrogen which then requires either electrolysis (using green electricity, which is another issue) or steam reforming of natural gas/methane which creates CO2. There is also the issue of competition for ammonia with the fertiliser industry. We all need to be aware that sustainability goes beyond the final point of energy production - it has to be a holistic evaluation.
Seeing the compost trash at the beginning in conjunction with talking about fuel for jets immediately made me think of Doc Emmett Brown going through the trash (at the end of Part 1/beginning of Part 2 of Back to the Future) to find a banana peel and some other waste to put in the Delorean…which had been upgraded to be able FLY!
There was an attempt to create a thermal depolymerization plant around 2000 (Changing World Technologies). This could convert biowaste (specifically animal offal and byproducts) into diesel. It had a lot of backers, including Google. It got shut down partly because residents downwind of the test plant complained about the awful smell.
8:25 I would like to offer a little bit more physics about why fuel cells tend to be more efficient than jets: Fuel cells and electric motors are not "heat engines" and therefore are not limited in their efficiency by thermodynamics. That means that (in theory at least) you can get more useful work out of a fuel cell plus an electric motor than in any possible jet engine
This is true. However, I think the inefficiency of every step in the hydrogen chain from production to transportation to storage, to handling, etc. up UNTIL the hydrogen is actually used kills its prospects already. I think the good efficiency of electricity and batteries will put it ahead. Right now I would not advocate lithium ion batteries but battery tech is evolving fast enough that we are likely to see acceptable energy density and performance in batteries well before we can get anything truly viable out of hydrogen. What has the potential to beat both of those is synthesis of hydrocarbon chains.
Thanks for nice content! I have few things to add from a energy chemist perspective. Hydrogen can also be stored in adsorbent/absorbents. Most popular are metallic alloys (e.g. vanadium or lantanum.) The problem is that maximum content of H2 is around 5 wt% (actually is closer to 2.5%), and metals are quite heavy - this actually comes even worse than Li-ion batteries in terms of energy density per mass. Other solution is using MOFs (metal organic frameworks) which are much lighter, and have enormous specific surface area, where H2 can adsorb. The problem with actually both of them is ad/absorption isotherm plateaus lies at quite low temperature around -80C, and moreover MOF's are not structually stable, especially with repetitive load cycles. It's still interesting solution for the aviation and i hope for some decent breakthrough in next decade.
@@Macialao The Falcon 9 has Merlin engines using RP1 (aka highly refined kerosene/jet fuel). Starship/superheavy has Raptor engines using methane. SpaceX has talked about but never developed a hydrogen engine. For instance, Raptor I believe was planned to be a hydrogen engine for an improved F9 second stage.
Right now one of South East Asian countries is developing aircraft engine fuel from crude palm oil for propfan / external double fan engine research. It is called hybrid fuel when combined with fossil fuel.
You have to be aware of the fact that several South East Asian countries are destroying vast areas of pristine jungle - home to many of the region's fauna and flora - by chopping/burning/clearing them away to make way for intensive mono-culture palm-oil palm plantations. The catastrophic damage caused by these operations is incalculable - the plantations support no other vegetation than the palms, which none of the native fauna can or do eat. All the native fauna therefore die off and become extinct. And all this for palm oil which can be made into - what? ice-cream, fast foods, margarine, so-called bio fuels. But it's not those products which drive all this destruction: it's quick profits. Vast profits from death and destruction - think about that next time you write on the subject from your comfortable chair in front of your computer.
Some corrections, hydrogen is not made in petrochemical production. It's made from natural gas with steam forming (Co2 is released to the air) and then used in petrochemical processes. Also when hydrogen is stored, some of it boils off continuously and is needed to be vented. So vent-stack is for that, and not just for leaks. This is also a reason for those capsule to be odd idea, video don't show any connections on those. Tanks need good insulation and support and making them removable would mean more heavy structures and lot more connections. And capsules need to be fill-up anyway, so why extra step? Storing those capsules would mean more boil off. Also even using fuel cells and electrolysis +cryogenics; Theoretical efficiency of hydrogen is 40% (vs. 80% for BEVs). And actual real world tests, it's 22% with fuel cell and 13% with turbines.
I guess the idea of the capsules is probably that they could do the refueling of the capsules in a controlled environment, and probably capture and reuse vented gas. And ideally not have to vent during the time between when they load the capsules onboard and start the engines. But yes the connections in the plane would be a real problem unless they figure out a way to make a nearly instantaneous leak proof connector.
I hate how so many people think we need to have ONE answer for ALL our problems. I follow people like you because you think about things rationally and recognize what's really possible and what isn't. I'm sure both hydrogen combustion and fuel cells still have their killer apps, just like electric and ICE vehicles are going to exist side by side for decades to come. Hydrogen might not ever be cost efficient for airplanes, but that doesn't mean it won't be useful SOMEWHERE.
Any liquid jet fuel/petrol/kerosene is medium chain carbon-hydrogen molecules, with 8-10 ish carbon atoms. These have roughly 2 hydrogens for each carbon (you can exclude the Hs at the end of the molecule as insignificant for this purpose), so will produce ~ 1.1 x H2Os for each CO2 emitted You briefly mentioned a Russian experiment with LPG (so propane/butane), which is much more energy dense than liquified hydrogen, but has the issue with CO2 emissions still, at only ~1.3 H2Os for each Co2. Methane (natural gas, basically) would give 2x H2Os for each CO2, a much better ratio, and cutting the CO2 emissions in half. It's a much denser molecule than hydrogen, so easier to compress and store liquified. Liquified, it has ~3x the energy density of hydrogen by volume, but it does weigh more (~2.5x more ***Edit - should be more like 6x more) due to the carbon atoms. But hopefully that's enough to get it adopted sooner, especially with the easier handling plus we have amazing natural gas supplies still (and there are companies farming land fills for methane already). I also imagine it would be less costly to convert an existing turbine to run on Methane than on hydrogen. So, is it better to hope the hydrogen engines come along quickly enough for zero carbon? Or maybe look at the LPG/LNG models for a much faster conversion of existing aircraft and a drop of ~50-65% in CO2 emissions in the much shorter term? Seems to me that while hydrogen is the ultimate way (until warp plasma engines!) Methane could be such a massive step in what we're trying to achieve that it's worth doing in the interim. (my figures are very roughly calculated in ~3mins, so don't have a massive go at me please!) EDIT - just seen a news article that the vast majority of hydrogen used today is created with methane, thereby sending all that CO2 into the atmosphere anyway... Making it through electrolysis needs a huge amount of energy - and where does that come from? If not from Nuclear/wave it's likely to have a huge carbon footprint anyway.
You are right. Currently, producing hydrogen from methane or from water is not green enough. It is assumed that in the near future we will find ways to go from blue, grey, etc hydrogen to green hydrogen production. There are known theoretical solutions, for example nuclear (High-temperature gas reactor) which may work. We just need time to develop those technologies.
@@user-yt198 I really like the idea of molten salt reactors, personally, as a means of providing the power and/or heat for cracking sea water. But in the meantime any sort of nuclear devised in the last 20-30 years provides a really clean and safe source - the SMRs being built by Rolls Royce right now look like they're going to take off (no pun intended!) I think it's ironic that the MSRE at Oakridge which ran successfully in the late 60s was initially funded in the hope of producing nuclear aircraft! (All the scientists involved knew it was a stupid idea, but they at least got to build their amazing reactor!)
And it just occurred to me that if you want to produce thrust, throwing a CO2 out of the back that weighs 2.4 times what an H2O weighs is a big benefit that has to be compensated. Burning methane would still let you have a big exhaust mass advantage. Or are H2 burning engines going to run sooo much hotter to compensate? There's a reason to leave all this to the engineers and physicists - my brain hurts too much already!
I do not think about Hindenburg, but about a Norwegian hydrogen gas station that had a serious explosion. I like synthetic liquid fuel better, electricity is also fine, but we do not have good enough batteries for flying.
I am quite pessimistic about very high density storage batteries simply because of the fire risk. Batteries useful for aviation need to have a very high energy storage in those batteries at a very low weight. Having a lot of electrical potential with very thin electrical insulation that are still safe from shorting and catching fire is a challenge, I would think. We have already seen this with the older Lithium ion batteries which could spontaneous;y catch fire, and even with newer ones which have to be disposed of carefully.
I studied H₂ subject a lot, and I'm very satisfied with this video : everything is explained and well explained, even more, than I expected. There is nothing to add. If I was fussy, I would just add that most victims of Hindenburg accident were actually burnt by diesel fuel than by Hydrogen, which was exactly released in the air (remember, dihydrogen is lighter than air)
So many people in the comments are pointing flaws even though Mentour adressed them in his video.. Did you guy even watched the video before commenting? x)
Commercial aviation will continue to be energized by hydrocarbon fuels derived from refined crude oil for economic reasons. Kerosene remains cheap and readily available relative to SAFs and cryogenic hydrogen due to fracking and the well established refining industry. Hydrogen may eventually become available due to fusion reactors which will make hydrolytic hydrogen production competitive with petroleum, but that is many decades in the future. economically
The problem of safely storing hydrogen at airports is a big challenge. It would require a level of competency in ground crews that - as recent events have shown - just isn't there.
I'm glad you brought that up. I've seen comments here to the effect of "NASA figured it out for spacecraft therefore its doable," as if a NASA engineer maintaining a spacecraft is interchangeable with a ground crew person at your nearest airport. For that matter, as if a spacecraft can be maintained like a 737.
I have worked with Hydrogen Gas in a generator cooling median. It’s hard enough to keep it sealed in a generator with oil seals. This won’t ever happen in aircraft. Waste of money, guess it will pay a lot of salaries for all the “research”.
@@danafletcher2341 That is outright misinformation. You're either a Russian bot desperately wanting the world to buy more oil, or you're an oil company bot lamenting that your industry is coming to an end.
@@NeonVisual Common sense should tell you that blocking the sun lowers the amount of photosynthesis that can take place. Are you claiming that the contrails reflect only in one direction?
Hydrogen is the smallest molecule in the Universe, and it diffuses in between the atoms of all metals when you make storage tanks and pipes/tubes to handle it. You can slow down the losses, but the tanks and tubes become rather heavy when you do so. Polymers (plastics) have even larger interstital spaces between the molecules, making them poor candidates for containing hydrogen. The other problem with hydrogen is that it is quite reactive, making hydrides of metals quite readily, and reducing away metallic oxide coatings used to passivate the metals against corrosion. Hydrogen is a reducing agent, meaning that it chemically bonds to free electrons. So, between reduction and other chemical attack (hydrogen embrittlement), systems to contain and transport hydrogen will necessarily have very short service lives relative to fuel systems designed for hydrocarbon fuels. Between the heavier weight and the shorter service life, hydrogen fuel systems are more expensive.
My amateur predictions: For really short hauls, like 20-150 km, with small aircrafts: Batteries. This is a long term plan for the very extensive Norwegian STOLport network covering the vast, rural areas where land transport with multiple ferry crossings is very time consuming. Medium range, a hydrogen solution, maybe ammonia-based, or a combination of hydrogen and larger batteries for shorter routes? Long range: Traditional jets will stay for decades, of course with more bio. Maybe ammonia?
I am all in on ammonia as a hydrogen carrier but its use in an aircraft is a bit problematic due to its toxicity. The work on using ammonia as a fuel on large ships, trains, trucks and tractors already have to deal with the health issues in a less demanding environment.
@@Mentaculus42 True, ammonia is nasty stuff. Leaking or spilling is dangerous. Still, compared to the alternatives, easy to implement for ships, trains. But some research institutions are working with less dangerous methanol as an alternative, also for turbine engines. No major problem with ICE, as we know. Methanol fuel cells for battery charging already exist, but they are expensive, fragile and not very powerful.
@@janhanchenmichelsen2627 Agree with everything you said. An interesting thing is that ICEs and large turbines can be extremely close in efficiency to fuel cells but with the added issue of dealing with NOx formation.
@@Mentaculus42 Ammonia is so poisonous and volatile that it will not be used in mobile vehicles. Ocean going ships perhaps but even then I doubt it. Methanol, synthetic aviation fuel or even synthetic methane will be more practical.
Dear Mentor. as someone familiar with handling hydrogen you are unaware of the dangers and complexities of handling hydrogen. The Hindenburg is a very apt analogy.
If heat in the fuel cell is an issue, could they locate the fuel cell in the high-flow core of the fan, and even use heat-related gas expansion to squeak out a bit more efficiency while cooling the cell?
@Chris NREL has demonstrated a halving of carbon dioxide releases from electric vehicles with a current infrastructure with the potential of reducing them by 90%. Not sure where you get your ideas about EVs?
4:29 I think the reason to create synthetic fuel instead of using pure hydrogen in planes is to avoid building those big and heavy hydrogen tanks. I haven't seen any calculations but I wouldn't be surprised if hauling heavy hydrogen tanks in planes would be less effective than using somewhat less effective manufacturing process to create fully sustainable synthetic jet fuel on ground and using engines designed for jet fuel.
The very large flammable range and the very low ignition energy is another interesting problem when combined with the tendency of hydrogen to leak through seals. A slow leak in a hangar and then someone walks in wearing nylon = boom.
I've MSc in chemistry. Was working 8 years in organic synthesis, so working with pressurized hydrogen from a cilinder for me is like spreading butter on bread. So believe me: hydrogen as jet fuel is NONSENSE. Hydrogen is extremely combustible. While normal jet fuel you can not ingine with a zippo. And storing hydtogen as liquid : if something goes wrong, and it becomes gas, it is so powerful, that the back of the airplane would desappear! Back in my Uni years ( 20+ y ago...) György Oláh ( Nobel price in chemistry 1995) had a research group burning Methanol in fuel cell, to generate electricity I always surprize why this did not get more attention. Methanol when it comes for ignition point is similar to gasoline. And LIQUID at atm pressure, so you could store in the wings. And Methanol can be produced by fermentation. Thanks for reading!
Video not finished yet but the production of comercial levels of hydrogen is very energy intensive and less efficient than just burning a fossil fuel as it is generally extracted from methane using a process called steam refraction. Until there is a way to produce enough energy sustainably (not from coal like a lot of countries) to make electrolysis a viable option its just exporting the emissions to a different site and isn't really a green option
Hydrogen is extremely thin in molecular level and can get through valves and tanks . Quite dangerous as material otherwise . It will cost a lot. Don't know about ticket prices in the future otherwise. It's pretty unsure
We can be pretty sure that the ticket prices will go up in the future no matter what. Unless we can come up with a very cheap new type of energy source
@@MentourNow Not necessarily. Due to the very high cost of electricity storage, the cheapest way to convert our electricity grid to 100% renewables is to install enough solar+wind etc to meet the winter demand without seasonal storage. That means there will be a tremendous abundance of electricity during the other seasons, which we could use to manufacture fuels such as hydrogen or synthetic hydrocarbons at a fraction of the cost we see today.
I was hopeful that green hydrogen could be used for aircraft and shipping BUT after watching a video with Prof, David Cebon who is an expert in hydrogen in transport, he thinks the cost would just be to high. The complexities of storage and inefficiencies of making it on such a large scale, would not make sence without massive subsidies, The oil/gas industry are only pushing it so they can make it from gas reforming with carbon capture but that will be very expensive so again will increase the price. He said it would be better to use all the biofuels we use now for ground transport vehicles. Also lots of shorthall aircraft will go electric so its just needed for longer non stop flights.
Pursuing SAF fuels and hydrogen fuel cells for aircraft is an excellent way of diverting billions of dollars away from other projects, diverting engineers from other research, making travel less safe, making travel less affordable, and keeping global warming to the exact same pace as we would have if these projects weren't pursued at all. Great job, people.
You’d need a pair of Helion Polaris reactors - one for 3He synthesis and another for energy output - in the hands of either True Zero or Iwatani to make hydrogen cost-effective enough as a fuel. Still a year away from the first step towards that.
Thank you for your levity with the "hindenburg" reference at the end. People don't understand, the hindenburg and the technology was sound. Hindenburg just got a very explosive coat of paint put on before it's last flight that reacted very well in tandem with lightning strikes.
Not only that, but we've flown rockets using hydrogen as a fuel for decades, including ones that carried people. While there have been accidents, none of them were caused by spontaneous ignition of the hydrogen.
Yes the aluminum particles in the fabric coating have been documented and it is one of the theories that is presented as to what happened. But the anti hydrogen crowd have differing opinions. Maybe reality is somewhere in the middle.
@@Mentaculus42 "Anti-hydrogen". I see what you did there. There are certainly people who see battery-electric aircraft as the inevitable future, with hydrogen as a wonky stop-gap. Hydrogen has many problems that need to be worked out, but I think we're likely to see a mixture of the two.
@@fighteer1 Yes to both of you, but not over cities with millions of victims to those hydrogen bombs. Imagine the last accidents involving airplanes striking buildings in the middle of the city. Those tanks would have ruptured and reacted like a barometric bomb.
@@fighteer1 Absolutely, short range aircraft have a future possibility with batteries. One of the foremost world authorities on battery research (from Stanford) has stated that his “dream” is to fly on a battery powered commercially available aircraft from the Bay Area to LA in his lifetime. He is still relatively young! Have been following his research for more than 10 years and his prognostications have been a bit optimistic.
Casey Handmer's Terraform Industries is using renewable energy to to combine co2 removed from the atmosphere with hydrogen produced through electrolysis to produce net-zero methane and other hydrocarbon fuels, and they think they can do it at competitive prices within another year or two. If that works then the airline industry would be able to start going net-zero at least a decade earlier than the hydrogen conversion plans that Mentour is talking about.
Comparing Hydrogene and Methane, I think they took the wrong turn. Methane has less volume per power, higher temp and is easier to handle in lighter tanks.
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I am planning to do my Electromechanical engineering thesis on this topic, it's fascinating and a great challenge.
Good luck with hydrogen at least in the forcible future. Costly to produce, both monetarily and resources, but also handling, you almost need to think about it escaping from any container you have and it is gone. So containment and storage is very difficult. They might get it working in very well controlled test environments, but in the real world, the practical day in and day out, can't see it holding up in practice very well. Plus from what it seems the rate of return is rather dismal, put in say 100 BTU get 70 out and often right not coal or gas is where the BTU for the electrolysis comes so burn the fuel and you're already head...
I'm pretty sure the efficiency of hydrolysis is worse than 70%. But the efficiency of charging a battery (converting electrical energy to chemical), then drawing electricity out of it (convert chemical energy back to electrical) is also around 70%-80%. There are a *lot* of electrical losses that renewable advocates gloss over or pretend don't exist. e.g. Overall energy efficiency of EVs with our current power generation and grid is about the same as a diesel ICE. The main problem with battery tech is that its energy density by weight is two orders of magnitude worse than jet fuel. If you loaded up a 777 to its max take-off weight with Li-ion batteries, it would only have a range of several hundred miles. And that's with zero payload. Battery energy density has increased by about 2.5x in the last 50 years. So (assuming we're able to keep that pace of development) unless you're willing to wait ~200 years, battery-powered intercontinental airliners aren't going to happen. Airliners need a denser form of green energy storage, even if it is less efficient.
@@solandri69 Hehe, think i was trying to be optimistic and not give that bad of a efficiency % conversion rate too pessimistic ;) If memory serves me, getting hydrogen is really messed up, there are ??? types methods of getting hydrogen. all rated at how "green" they are, black was the worse and is how must hydrogen is gotten today i thought. Thus my comment if we use oil a large amount of energy to get x% energy. Double checking some of the conversion methods are at best 50->60% efficient. Great we burn 2x the oil to burn a "green" fuel. Also about battery to store it, might suggest looking at or researching John B. Goodenough. WOW! What an inspiring person, few ever event anything to effect most people in the world, he has two, soon three... Well worth checking out videos of him on youtube... First he helped developing computer ram, second Li-on batteries, and soon the third will be solid state battery. Heard they have a working prototype and finishing the final steps. Believe from what i read solid state batteries will be amazing charge super fast, allow for a lot more power cycles, they only have a slight decrease in efficiency after 1000 charges, but should last for a projected 5000. And they are suppose to have 2->2.5x the power density when compared to li-on batteries.
@@dand4485 Yeah, best efficiency I'd heard for electrolysis of water in the lab was about 65%. I believe most industrial scale processes are down around 30%-40%. There's research being done on catalysts which cause sunlight to directly break apart water into hydrogen and oxygen. Efficiency is abysmal right now, but the same was true for PV solar at first. Who knows what the future holds. The problem with lighter batteries is that lithium is already the 3rd-lightest element. There's just not much more room left for improvement. The only battery solution I've read about which might get us somewhere close to 2 orders of magnitude improvement are structural batteries. That's where you build the vehicle itself out of material which can function as a battery. That allows you to share the mass budget between both the structure and battery, essentially giving you "free" mass for energy storage.
Never forget, dedicated crops are labor a fuel intensive. Although the jets will not be using crude bases fuels, crude based fuels, natural gas, and a great deal of water will be needed to produce that net zero fuel. The process is very dynamic for a network to be green. great video!
Corn ethanol is not made from a dedicated crop, it would be too uneconomical. Rather corn ethanol is value-added from already existing feed production which leaves 100% of the protein (& other things) still available as feed in a healthier, more digestible/efficient, and more concentrated form called distillers grains. This explains how ethanol is so cheap despite the current high price of corn, they make it up with high prices for the distillers grains. With the feed factor, corn ethanol can outcompete most any other source out there including sugarcane which makes more ethanol but little else. So much so that Brazil put an import tariff on our ethanol. Iowa State University measured all the energy it takes to produce an acre of corn into a "diesel fuel equivalent" This included making of the machinery, fertilizer, chemicals, tillage, planting, spraying, harvesting, drying, trucking etc. They found it takes 34 gal of diesel to produce one acre of corn. What do we get from those 34 gallons of diesel? We get >500 gallons of ethanol. But wait, that is not the kicker. The kicker is, as I said before, we still get 100% of the protein from that acre of corn still available for an even better feed. A win, win.
Short haul flights though, are probably better replaced by rail services. Those require far less energy to begin with. And so they can be made sustainable much more easily.
In some places, definitely. In others like the US where the infrastructure investment is prohibitive, and here in New Zealand where we have low population and mountains and seas to navigate, no.
Yup, problem is that low cost carriers are so much cheaper and faster than rail. A carbon tax which 'internalised the externalities' would probably be needed.
@@chendaforest True, London-Amsterdam by train is about twice as expensive as a low cost flight. Unless you want to bring along more luggage of course. Then prices are a bit closer. But given that ticket prices are rising anyway, I think trains may become more competitive. Especially if you’re willing to pay a bit extra for CO2 emission reductions.
Love this channel! Love aviation. I worked in Avionics, in fact, when I was on active duty in the Marines. (2001-2007) For those who know what I'm even talking about, I was routed to I-level avionics (Comms/Navs - 6412/6413.) by the Navy and attended their giant schoolhouse down in BEAUTIFUL Pensacola, Florida... Thats a neat place to be 18 y/o and fresh out of Mom and Dads house because the bricks (Baracks) were right on the Gulf COoast and this is where the Blue Angel's stowe their birds at night, and it's where they often practice in the airspace over Pensacola, Florida by day ... I knew it then... and I still think of this era very fondly even after all this time. Picture this: Running a few early morning miles on the Gulf,with some of your bretheren War-Dogs, while watching the sun rise, with a smart-assed Gunny singing hilarious ditty's and you are in slight pain with wet, salty feet...But that sun is still coming up, and while running and laughing, you're out of breath....having puked up last nights St. Pats beers....then showering before reporting to the premier Aviation schoolhouse, in all of the land to learn about what you love., while being paid to be there.. Good times. 💯💯
always good to hear from another Marine avionics person! I worked on A-4 avionics from 77 to '81, which was an adventure of sorts. :-) Went on to get an electronics engineering degree and designed avionics. There's something to be said for working around aircraft, but it's also nice to work indoors when the weather is not great. Troubleshooting and problem solving is fun in both cases, though!
@@SkyhawkSteve That is Very cool. I had planned to do just that, bit when I got back home after EAS, there weren't a lot of options for avionics guys.. as our local Airport, CAE, is small....and was way smaller back then...so I went where I could get good money quick...the same place i always swore not to go..the same plant my father raised us working at....but i got into fitting pipe and that ended up in becoming a CWI (AWS Certified Welding Inspector) which turned out to be a rather lucrative thing to do too.... They always said the majority of people who came through the Corps ended up being pretty well to do...and I wont argue that I'm not capable.... But congratulations on achieving your dreams, DevilDog. Are you still running every morning? Come rain, hail, sleet or snow???
@@h.e.floydiii7259 Aviation is a small industry, so finding employment requires moving to where the jobs are. I went to McDonnell Douglas, but learned about how sensitive defense jobs are to the whims of Congress, and especially to the defeat of the USSR! I ended up designing 'tronics for earthmoving equipment, which is kinda cool too. It evolved into a "fly by wire" sort of arrangement, similar to military aircraft of 20 years earlier. As far as running, my knees were giving me trouble, so just bike riding for me. I'd been riding and building my own bikes since high school, and had bike riding friends in the Corps, so it's been a 50 year hobby so far. Still riding in all weather and rode over 9000 miles last year, so I hope the Corps isn't disappointed. 🙂
@@MentourNow Jesucristo! Thank u for taking the time to reply Petter I know u a busy a man and that means a lot to me..these videos man I can't get enough of em especially since aviation has fascinated me since I was a little boy(I'm 37 now) and being a pilot would be a dream job for me so I'm hoping I'll get there ..these videos really help and I truly appreciate em ..sorry to yap but it's also cool you're from Sweden as my greatest friend is also from Sweden and his middle name is Bo Petter and I could tell by your accent you were swedish but then I heard your name and I'm like oh now I know for sure..take care man and thank u again I'm goin to try to get on Patreon to return the favor
Planes are one of the most energy density sensitive things I can think of. As such, it's one of the hardest things to de-carbonize quickly or economically. Thus, it's likely way more efficient for airlines to simply _offset_ emissions by doing things like funding solar installations (airports have a lot of empty space! There's a super interesting proposal at Kansas City airport that could literally power most of the city for example, though there's also no need to have them be at airports either). This would be an effective means of accomplishing something _immediately_ instead of just hoping for a breakthrough which may not matter until it's too late. Carbon acts over time, so getting rid of one ton today is worth much more than one ton 20 years from now, in the same sense as compound interest and investments. We need this kind of broad, pragmatic action if we want to actually make a dent in climate change. Energy is fungible, after all, so it makes far more sense from a macro perspective to attack the easiest (most cost effective) carbon sources first, because we can have a greater effect for the same economic cost. This is a really, really, important thing to understand, because of just how vast the problem is. Better yet, we could simply pass a carbon equivalent tax to weaponize the market by actualizing hidden negative externalities like climate change... but I've given up on this being politically viable until either things get a lot worse or we fix our actual elections (FPTP, etc).
I completely agree! We need to focus on the “low hanging fruit” first, like global shipping for example. But that doesn’t stop us from also trying to innovates be prepare for a situation where normal jet fuel is no longer available.,
Production of chemicals, which includes fuels in general, require some energy to convert the raw materials into the final products. With our conventional fuels, we take the naturally occuring crude oil, and distill it into boiling point fractions, and then we beat on some of the less convenient heavier fractions with hydrogen to crack the molecules down to more useful sizes. The enrgy for the refinery is provided by the combustion of off-specification molecules which are too difficult to convert into fuels that meet the commercial standards of performance required for general use. We make hydrogen in the refineries in Steam - Methane Reformers by reacting Natural Gas (methane for the most part) with steam in high pressure, high temperature reactors over catalysts. We need this hydrogen to crack & hydro-treat otherwise useless molecules from the crude oil, and to remove sulfur and some nitrogen from the products in order to get cleaner burning fuels for consumption. The exhausts of the oil refineries are carbon dioxide, water vapor, and hot air - up until about 20 years ago, this was fully considered by almost everyone to be environmentally acceptable. Due to various theories of the environment getting pushed hard politically, and the shift in the governmentally supported scientific community from global cooling over to global warming as the climatic catastrophy to be avoided, we are now looking at making "sustainable" fuels from biomass, bypassing the millenia of high pressure fermentation in the Earth's crust, and other schemes using carbon dioxide and Green hydrogen. These renewable fuelss require that we apply energy in a more intensive fashion than allowing nature to take its own sweet time - so, on a molar basis, we need to pump in more energy than we need to refine crude oil. The energy which we need to use to due theis must also be Green, which also comes with a cost, as we do not have the necessary biomass growing, nor the cropland to pare that can be diverted from food production. Green hydrogen is produced by the use of Green electricity to reduce water from its fully oxidized state back to the constituent elements. A chemical reaction is defined as being thermodynamically spontaneous when it oxidizes the reagents to make the products - these reactions are exothermic, and have a negative Gibbs Free Energy. When you burn fuel in a fire, you are conducting a thermodynamically spontaneous reac5tion. Electrolysis of water is both endothermic and has a positive change in the Gibbs Free Eenrgy - it is not thermodynamically spontaneous, meaning that you need to supply all of the energy needed to convert your reagent to the products, plus any inefficiencies of reaction, plus your systemic losses. Now, you want to convert carbon dioxide back to a hydrocarbon fuel - again uphill against thermodynamics. But, you need to collect your CO2 first - and that takes processing energy as well - first because at 400 ppm in air, you are trying to collect a very dilute species if you are using Direct Air Capture, and second, even if you use a technology such as amine stripping to remove the CO2 from the tailgas of a power plant or similar fired device, you still need to concentrate and compress the collected material. Now, once you have completed carbon capture and the production of Green hydrogen, you introduce them into your high pressure catalytic chemical reactor, with a very complex separaotr to remove the desired fuel and recycle the unreacted syngas, and all of that takes energy - and you do not have the Green fuels to spare to provide it. Wind and solar are low intensity, low energy density power sources, requiring lots of complex equipment to produce, and only work part of the time. Hydro-electric power requires waterflows such as rivers where the combination of flow and elevation drop can produce enough power... damming up rivers, and using metals and concrete which also require high temperature energy intensive processes to produce. Or, you can build more nuclear power plants.
Ethanol is now cheaper to produce than petroleum jet fuel, gasoline, and diesel. The spot cash price of ethanol is $2.09 vs $2.54 for jet fuel. While the ethanol could be used directly in jets and with its high oxygen content be very efficient above 10,000 feet, as long as the conversion of ethanol to chemically identical SAF did not cost more than $.45/gallon, cost would be a wash.
@@danafletcher2341 Those prices are only attained for ethanol with massive government subsidies in the USA - in other words, at the taxpayers' expense.
@@chemech The Federal subsidies for corn ethanol ended back in 2011. The long-standing stated goal of the G7 Nations to end petroleum subsidies? Not so much.
@@danafletcher2341 The corn subsidy acts expired - and got replaced with other, newer subsidies... Some firms are only just now getting their ethanol projects started into design, based on subsidies that were passed into law in 2021. Oil & Gas subsidies??? Yhose only exist in propaganda - the oil refining business is at almost zero projects active right now, as they cannot make enough money to offset the new punitive regulations and restrictions that were also imposed in 2021 and 22. The engineering and construction firms that support the petrochemical industry are shifting over to take on renewable fuels projects now in order to keep the doors open. Again, this is a complete inversion of the economics from the status quo of 2020, when those ethanol and other renewables projects could not qualify for financing.
@@chemech Corn ethanol which is called generation one biofuel has been subsidy free since 2011. There were no new ones made after the VEETC. Cellulosic ethanol which is not made frail grains is called generation two had a subsidy over twice that of corn’s but it never materialized. One plant was started in Nevada, Iowa but never got off the ground. Generation two ethanol subsidy expired in January 2022. If I could post links, the DOE has a great web page of current and past alternative fuel subsidies. If you have a problem with petroleum subsidies, don’t talk to me, take it up with the G7 Nations. If you are talking about the CO2 pipelines, I think those are complete and utter folly and have nothing to do with the price of ethanol since 2011. I do not think they will get through all the landowners or that is my hope. CO2 is a resource, not something to spend money and energy liquifying and pumping across the country only to inject and bury in the ground as trash.
I have a feeling that hydrogen is not the solution for airline fuel. Looking at the wider picture we already use about 90 million tons of hydrogen per year. Less than 5% is produced from electrolysis most is being produced from natural gas, oil and coal contributing to green house gas emissions. It makes much more sense to clean up the existing industry before even contemplating hydrogen for aviation. Burning hydrogen in a jet engine will produce nitrous oxide and the amount produced will depend on the combustion temperature in the engine. The higher the temperature the higher the efficiency, but the more nitrous oxide. So to be clean fuel cells are a way to go, but given that you can manage weight and storage issues you have a heat issue. Hydrogen gets really hot when it expands from cryogenic liquid to gas so it needs cooling before going into a fuel cell, and the fuel cell gets hot too. More systems and weight required for cooling. I suggest battery electric maybe the answer for short to medium haul aviation. It does require high energy to weight ratio batteries which we don’t yet have but there are promising developments and we are seeing batteries being produced near 500 watt hours per kilogram. I think you need about 11,000 watt hours per kilogram to be of equivalent energy density to hydrocarbon fuel. However, a lot of hydrocarbon fuel energy is wasted producing heat so a battery does not need to be that energy dense to be viable. I think anything above 500 watt hours per kilogram maybe getting into the right ball park. Lithium air battery tech can get to 11,000 watt hours per kilogram but I suspect that is a long way off if ever. It should be clear that a light weight safe, rechargeable, high energy density battery is the most efficient way to power anything. We just need to develop that technology.
SpaceX is switching to liquid methane for the superheavy/starship system. They rejected hydrogen due to the difficulty of handling and producing the needed quantities to allow the very ambitious launch schedules they're aiming for.
The main reason, why CH4 is used for Starship besides beter handling than H2 as a fuel is that Mars atmoshpere is rich in CO2 and it is believed to be H20 underground. By combining CO2 and H2O you can make CH4 and O2 which means there is no need to bring fuel and oxidiser from Earth. I believe this way requires less energy than H2O electrolysis.
What about ethanol? It's slightly less energy dense than fossil-based fuels, but it is easy to store and pump. Can be produced by fermentation of agricultural waste.
GE has built ethanol jet turbine engines (dual fueled) in Brazil as an electric plant. Same turbine engines as the Boeing 747. Above 10,000 feet the high oxygen content would become very efficient. United Airlines is making chemically identical jet fuel from ethanol soon with a pilot plant in 2024 and full scale plant in 2028. The spot cash price of ethanol is $2.09 and jet fuel is $2.54/gallon.
Another excellent video! And, you mentioned my home town of Moses Lake, Washington and the Grant County airport. Back in my earliest days of flying, Grant County International was the world training center for Japan Airlines 747 pilots and crews. Before that, actually WAY before that, it was Larson AFB which was closed down in 1966. Yes, that's not a typo, I was a mere 9 years old then. Anyway, fascinating stuff!
6:43 i remember that video, it was really cool. I just watched the latest in Rolls Royce massive engine bigger than the GEN9X. Pass all in house tests in December.
There is a little difference between jetfuel and hydrogen. Put jetfuel in a cup and try to light it using a quick match. It will not burn. For hydrogen the smallest spark is enough to ignite it.
I vote for hydrocarbon gas combustion tests on medium to small size airliners. Liquid Hydrogen is very dangerous fuel and leaks everywhere. JP fuel is expensive but safer in liquid form. No airport fuel distribution system budget can afford conversion to liquid Hydrogen technology. Every passenger will remember the Hindenburg tragedy when looking at a pure hyadrogen tank fitted into the cargo bay of an airliner. JP fuel still wins. It can be used as jet turbine fuel and can stop a fire in liquid form (emergency fuel dumping). Hydrogen for fuel cells and hydrocarbon fuel (JP preferred) for combustión. Thanks.
The hydrogen vent line isn't there "in case of a leak" - it is there because despite all efforts, thermal enery *will* creep into the tanks. If the tanks were sealed, this would heat up the hydrogen, which in turn would increase pressure and eventally rupture the tanks. One way around this is to allow some of the hydrogen to literally boil off, carrying away that thermal energy and thus keeping the remainder of the hydrogen cold enough to remain liquid (think of how water in a boiling kettle stays at 100 °C even when sitting on a much hotter stove). In normal operation it might be possible to feed this gaseous hydrogen to the engines; but when they're not running (or if the engine is designed to take the hydrogen in liquid form), it needs to go somewhere else - which is where the vent line comes in. Simply put, it is an inexpensive cooling system for the tanks - either as the primary system or as a highly reliable back-up to some active system.
So what happens when u park the aircraft inside a hangar. U probably need more than just a vent on the aircraft to be sure that the hydrogen is converted to H2O or u will be unintentionally modifying the hanger’s roof. NASA learned the hard way with that on a space shuttle engine test stand. Absolutely need vents in the roof.
@@Mentaculus42 That will be a logistical problem indeed. You'll probably want to detank the airplane whenever you know you won't be using it for a while. However, the vent line might also be designed to work as a flare stack in such situations, with the boiled-off H2 being burned harmlessly.
@@CLipka2373 I was wondering about a flare or some sort of catalytic oxidizer or maybe a fuel cell that could provide a little power to help with this issue.
What a pitty I cannot like more than once... I really like your way of presenting challenges to go green in such posiitve and exciting way. Great work !!!
Another very good video!! I really like the concept and am sure the industry has worked out most of the issues regarding hydrogen's capacity to go boom, but my primary concern would be incorporating this new technology on a global scale. It would be a difficult, but not impossible task for most "first world" countries to take part in the development and eventual deployment of this technology. However, how would those countries that barely have the financial resources to satisfactorily maintain their current jet-fuelled fleets even consider making such a cost-prohibitive switch??
@@Didier88600t really comes down to an economic issue. Besides, a lot of hydrogen will be transported via ammonia. If you actually want to learn about hydrogen’s future, watch the 10s of billions of $s going into the green ammonia industry.
Good review. You may look into "hydrogen storage in metal hydrides", because it is bonded to Mg compound the low pressure tank can store several time the same volume as H2 in a high-pressure tank and it is a very safe way to store H2. It looks promising for ground applications but I don't know of the weigh aspect, which would be a decisive factor for aviation application.
Metal hydrides have been studied for decades and always hit ghe same stumbling block - the transport mechanism (metal hydride) is prohibively expensive. For stationary applications it's much cheaper to use other solutions (10% of the cost) as volume/mass aren't an issue and for transport applications you end up with a fuel tank costing significantly more than just using batteries that ALSO takes as long as (or longer than) batteries to refill (hydrides are slow release/slow to fill)
The emissions from aviation are more than just CO2. The air quality near airports is generally very poor. We’ll need a mix of electrical, gaseous and liquid fuels. It’s going to be very different from reliance we have on Jet A today.
The answer is nuclear. Not in the aircraft, mind you; unless we figure out cold fusion, putting any kind of nuclear power on an airline is going to add an unacceptable amount of weight (never mind safety concerns around fission fuels). But the cheap energy provided by abundant fission (and hopefully soon, fusion) will make the high energy demands of synthesizing hydrocarbons a smaller issue. Besides giving extra hydrocarbons to blend into the existing fuels, it'll also pull excess carbon dioxide out of the atmosphere (and possibly sea water) and reduce environmental pressure.
Any form of concentrated energy storage is dangerous, whether jet fuel, gasoline, hydrogen, or electrical batteries. If we could figure out how to accomplish work without energy storage, now THAT would change the game. Good vid!
Issue with liquid hydrogen is that it leaks. Liquid oxygen, especially when it forms by accident in labs is much more dangerous per se (just add something oxidazible, like organic fumes and kaboom), but it doesn't leak in storage.
A big disadvantage with hydrogen in aviation is that it's a chicken and the egg situation. Realistically you would need to have hydrogen fuel available at all large and medium hub airports in a particular region of the world before you can even begin to introduce hydrogen airliners. In the U.S. for example that is 65 airports. No airline will buy a plane that can only fly into 10 airports. But how many airports will install expensive cryogenic hydrogen fueling infrastructure when there are no hydrogen airliners. And what plane manufacturer will want to build a hydrogen airliner, even with subsidies, until most airports already have hydrogen. Eventually the problem can be solved, but because of the chicken and egg situation I think it will be difficult to get this started. Regional airlines might seem like a good fit because they typically fly into fewer airports than the majors. But they also fly into smaller airports that are less likely to have hydrogen. They would have to juggle aircraft around on their routes depending on the type of fuel that each one uses. Larger long haul aircraft might do better because airports at major cities like Paris and New York are more likely to have hydrogen, and airlines could simply schedule their A350 sized hydrogen planes between airports that have hydrogen. But another problem is diversions. Let's say all of 30 of the large hub airports in the U.S. have hydrogen. But that means if a hydrogen plane gets diverted its choices are very limited. If they get diverted to say Kansas City and there is no hydrogen facilities at that airport, then the plane will have to sit there until hydrogen is trucked in from several hundred miles away or more, depending on how close is the nearest cryogenic hydrogen production plant. Biofuels can be much simpler, assuming that a particular aircraft can run on either biofuel or regular jet fuel. Then they can fly into any airport they want and use biofuel whenever it's available, and if it's not available that's no problem.
I just wanted to say I really appreciate your videos. Tackling current, important topics, high production value, clear, interesting, useful. No stupid „weird face on the cover reaction videos“. Thank You.
Great video! So few people seem to understand the importance of energy density, but the airlines will be a great proving ground for energy dense green tech. Hydrogen is and ought to be at the top of that list!
Compared to the number of people having gone up in flames from current aviation fuel and plane accidents, I think that it would be safer with hydrogen, which would tend to escape quickly in case of the tank being ruptured, instead of a huge fire for minutes or more.
Well there may be two outcomes: 1. H2 does not combust. 2. When there is right mixture ratio of H2 and O2 and right temperature it can make VERY spectacular explosion similar to that on Space Shuttle Challenger tragedy. Survivability in this instance would be nearly imposible compared to fire.
Well... At the extremely high pressures needed to store gaseous hydrogen densely, a tank rupture would (1) cause quite an explosion merely from the pressure differential being released, and (2) the rapid drop in pressure would freeze a lot of nearby things including people (think of what happens to the temp as you use up a can of compressed air, and multiply it by a thousand times). That's why LH2 rockets store the hydrogen cryogenically - it's less problematic than compressing it. Any high-density energy storage medium is dangerous, whether it's avgas, hydrogen, or batteries.
@@jackyse The Challenger disaster was very different, as it was carrying both hydrogen and oxygen, in the "right" proportions, meaning BOOM. A plane accident would not have such a huge supply of oxygen available for a major immediate explosion. Sure, a fire could start, but it would not "just so" get to the explosive mix, and the hydrogen would rise while mixing. Combustion would be more gradual with the arrival of oxygen, and lots of the fire would be some distance above. Still dangerous to passengers, just not BOOM. Anyway, suggestions are that the astronauts on Challenger may very well have survived for some time, until crashing. Hard to guess if they were conscious or not. I hope not.
@@JohnnieHougaardNielsen All gaseous fuels are inherently dangerous and more so as the equipment ages. If something happened on a liquid natural gas tanker ship in port, it would be like a nuke going off.
Thank you team :-) for touching on yet another 'developing story', current affairs news ..vital to the industry. Somehow to me, the 2035 or anywhere in my lifetime it getting more widely accepted than current fuels.. seems a bit far fetched. Mainly because.. it seems like a matter of time.. when somehow nuclear fusion would be both compact enough to be made available on waterships, airships.. but also.. somehow sustainable for being incorporated to convert/use all those systems within standard long haul at-least aircraft. (If not the passenger versions, then the freighter versions). . Yes hydrogen storage without pressurisation or in liquefied stage might be a challenge.. but aviation industry would surely figure that one out in a safe, cost effective manner. . However hydrogen being highly combustible and many things in aviation still being a 'oops, we missed that' or there was a human error, lack of adherence to protocol... would mean.. that any incidents or crashes involving direct use of hydrogen as a fuel.. may not end well
Nuclear fusion’s ability to ever supply energy at economic prices is so unlikely that it should be characterized as the fossil fuel industry’s way of distracting us from viable alternatives that are in front of us right now, but not exploited because of their massive propaganda effort against renewables.
Let’s ignore the vast challenges of making, storing, moving and managing cryogenic hydrogen and also let’s ignore the challenges of the huge venting losses associated with handling hydrogen at -253 degC. Incidentally, when said quickly -253 C sounds just like it’s cold but feasible right? In fact it is in fact VERY cold: like the nighttime side of Pluto sort of cold; air is a solid at -215 deg C sort of cold and NASA etc really struggle to manage it even for relatively infrequent space rocket flights, let alone routine aircraft fuelling. No, let’s ignore all of that and let’s just look at the fundamental energy requirements for hydrogen electrolysis and cryogenic liquefaction. For an airport like Heathrow the 24/7 electrical energy demand required to replace jet fuel with liquid hydrogen is around 8GW. So that’s rough;y 8 nuclear power stations required just to supply Heathrow with aviation fuel (and yes, likely nuclear rather than renewable as the power supply needs to be sustained). More power stations would be needed for UK’s other airports. Then that same sort of supply infrastructure investment needs to be replicated for every other airport that you might want to fly to before you have an airline business. Like you say, not easy even though folks are working on it. If such abundant quantities of cheap electrical power is available in future, it may solve a lot of the issues to connect the hydrogen to carbon from the atmosphere such that a kerosene fuel is produced, thereby eliminating all the extra complication, including 100% aircraft fleet replacement.
Oh, Petter! Is hydrogen really safe to use and store these days. Accidents happen, humans make mistakes. Is hydrogen a better option to carry in the case of an air accident, than fuel. Is it less or more flammable. Was that hydrogen we saw being emitted from the ill-fated Challenger flight? I shouldn't worry as I will never fly again, given my age. But why do I worry when you don't, Petter. Compressed hydrogen or no, once hydrogen is no longer contained, does it not act and react as hydrogen would? If their was a leak or explosion at an airport, at the fuel store, or on the runway, would it be easier or more problematic for rescue services to deal with. I know I'm probably asking stupid questions, but stupid or no, I look to be assured by your superior knowledge. Forgive me and thank you.
Every time you say Hydrogen, people think of the Hindenburg!!! This will cause issues of Trust! Also both Liquid Oxygen and Liquid Hydrogen expand something like 55,000 times when becoming a gas. Then when you're talking about ultra-high concentrations of Oxygen, anything Organic (cotton, wood, humans) and even some metals (once an ignition source occurs like a burst seal venting a large flame) will BURN!!! Add in the super-rapid expansion from liquid to gas and both O2 and H2 being present = BOOM!!!!!!!!!
I'm not entirely sold that going to net zero for the aviation industry will be important. As it is the amount of green house gases emitted from the aviation industry is small compared to the major sources and I don't think flying is going to grow so rapidly that it EVER becomes a real issue. With the increases in fuel efficiency so far and what will come over the next 20 - 30 years I imagine that's going to be good enough, but I see a global economy where the typical person is tightening their belts a lot more than they are now, and even in countries where people keep wanting to say the typical person is going to be doing a lot better, I'm skeptical. You can look at China for instance and their lift has been an economic boom created by a lot of industry, but more and more their govt. upsets other govts (I don't care about who did what and why because it doesn't change the outcome) and industry is on a slow move out of China. What's clear is that wealth is leaving the middle class and going to the upper class, around the world and that's going to mean a larger percentage of the global population traveling less. So I just don't see a boom in air travel and I don't see the need to spend billions of dollars trying to solve a problem that isn't big enough to worry about. If anything trying to move to hydrogen will make flying more expensive and shrink the customer base if the industry goes that way, making emissions so trivial no govt will car about it. Today it's about 5% of emissions. It's much easier to get that other 95% down to about 5 - 10% of what it is now than it is getting that 5% down to 1%. And SAF is NOT a solution, because growing fuel is in NO WAY green. You do the research on it and it's not any better than fossil fuels but it makes farmers rich which is why large investors buy up so much land, that and collecting rents from the world.
I'm glad you mentioned the "emissions" issue with hydrogen: burning hydrogen creates water vapour which then acts as a significant green house gas even though you could claim green hydrogen is carbon zero and sustainable - those terms are a simplification of issues which hides the facts - burning hydrogen for planes should not be done as a result. Now a fuel cell can make liquid water and if its dumped at low altitude would just cause rain - so that would be not so bad. But one of the biggest arguments against green hydrogen is the very low round-trip efficiency in using it as an energy source - you use electricity to electrolyse water (18%-46% efficient) and then use a fuel cell to create power for the electric motors/turbines. When you think about that this approach is not much different to a battery - the only difference is the unchanging weight of a battery - a battery round-trip efficiency is several times that of green hydrogen/fuel cell - we just have to cope with weight. Meanwhile technology progress is reducing the weight problem because more and more energy dense batteries are being produced - the killer advantage of a battery is you do not need oxygen to run a battery, so much higher altitudes could be reached and as a result very much higher supersonic speeds achieved. Also even though a battery plane will expend more energy to get to high altitude, much of that energy could be re-cooped when reducing altitude by using the turbines to charge the battery as the plane falls (VTOL needed). Today's emphasis on hydrogen is more political than sensible - the reality is the oil companies want to produce grey or yellow hydrogen as a way of continuing their business as people steer away from carbon based energy - their excuse will be they'll do green hydrogen later and then never do more than small token amounts. I'd love you to do an episode examining battery solutions and their advantages over hydrogen.
Maybe a video can be done on the research being done on the “WET turbine engine principle” that deals with the condensation trail issue (water vapor is a green house gas) and can increase the engine efficiency. “MTU and Pratt & Whitney presented an EU Clean Sky project where they are developing an advanced engine concept based on the Pratt & Whitney GTF. The project is called SWITCH, an acronym for Sustainable Water-Injecting Turbofan Comprising Hybrid-Electrics.” AND: Pratt & Whitney’s HySIITE (Hydrogen Steam Injected, Inter‐Cooled Turbine Engine) which achieve thermal efficiency greater than fuel cells.
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Buddy as an aerospace engineer who has spent 30+ years in industrial control systems and automation INCLUDING BEING FORMALLY TRAINED in Electrical Equipment in Hazardous Areas (EEHA) you are completely misunderstanding the nature and risk of hydrogen.
Sorry this is long but everyone thinking hydrogen is the magic solution needs to understand that it has some fantastic properties and I really do think it will be a major part of future energy, but it has some very serious risks. *I am proposing 2 new massive power station projects here in Australia that are partly fueled by hydrogen BUT and I can't stress enough how hard hydrogen is to engineer around.*
Your comment comparing kerosene to hydrogen is so far off the mark its scary. In terms of safety Hydrogen is nothing like kerosene. If I compared your skills and training as an airline pilot to a bus driver in the same way you have compared Hydrogen to Kerosene you'd be insulted. I have a pilots license so I know what that means.
Here are some basic facts that they teach engineers.
1) You need 3 things to have combustion or an explosion which is basically hyper-rapid combustion.
FUEL + OXIDISER + IGNITION SOURCE.
Fuel alone does nothing. Fuel with just an ignition source does nothing. Fuel with just an oxidiser does nothing. You must have all 3. The reason solid rocket propellants like gunpowder & C4 explosive can be so dangerous is because they combine the fuel and oxidiser. Its why they are impossible to extinguish once ignited. Once the Space Shuttle and Artemis boosters are lit they will go until the fuel is consumed. All that can be done is detach them.
2) Flammable liquids DO NOT actually burn or ignite. *The vapor above the surface burns.* There's videos shown to engineering students where they drop a lit match into a jar of gasoline and it just goes out because below the surface there's no oxygen. This is also why cars don't explode when the fuel tank has a submerged pump. Because its submerged and totally surrounded by fuel there's no oxygen. Its also why cars can explode if the fuel level sensor gets a shot circuit because you can get a spark in the vapor space above the fuel level. Its why empty fuel tanks with vapor are far more dangerous than full fuel tanks where there's almost no vapor.
3) A droplet of liquid fuel does NOT BURN its surface burns because the heat boils off the liquid and that allows it to mix with air and meet oxygen molecules and react. This is why fuel injection in cars and trucks works so much better than a carburetor. There's not only finer droplets with more surface area but the droplet size is more consistent making combustion more stable and more reliable.
4) Gases and vapors at the right mixture can EXPLODE. For almost any gas you can find 2 numbers given in percentage called the LEL (lower explosive limit) and UEL (upper explosive limit). Between the LEL and UEL the mixture explodes. In room temperature air:
- Methane has an LEL of 5% and UEL of 15%
- Hydrogen has an LEL of 4% and UEL of 74%
So hydrogen wants to EXPLODE over a much wider range of fuel-air ratios. This is also why its been so hard to get it to burn reliably in engines. It reacts so fast its hard to get a stable flame.
5) Everything that can burn or explode has an ignition energy usually expressed as MIE (minimum ignition energy) with the units mJ (milli-joules). Hydrogen has the lowest of all MIEs at 0.017 mJ (in air) and 0.011 mJ (in oxygen). By comparison methane 0.26mJ gasoline is 0.80 mJ and Kerosene is 20 mJ. *Kerosene takes just over 1176 times the energy to ignite than hydrogen.* A kerosene leak compared to a hydrogen leak is nothing in terms of risk.
6) Many gases and flammable substances can ignite from temperature. Again Hydrogen is very low on that scale compared to most other substances. When you select equipment that is in a area with hydrogen you have to check the temperature rating as well as all the other factors.
7) The Hydrogen molecule is the smallest molecule in the universe. That makes sealing everything incredibly hard. You can't just by valves, pistons, pumps, pipe fittings like you do for other gases. It will leak from the tiniest of holes and narrowest of gaps. If you have any leak in a place that's not well ventilated it gets very dangerous.
Hydrogen is amazing. Its actually very easy to make through electrolysis of water, but its also a hassle to use which is why its never really been used as much as people think it should have been.
Sorry if this feels like I am yelling but its a very serious topic. I 100% believe the hydrogen economy is going to boom and be a major part of our energy future, but I also expect some tragic outcomes because people will simply ignore what people with expertise warn them about.
Mentour please take the time to ask those working in the energy industry with a solid understanding of the economics and viability of these technologies, capturing CO2 from the atmosphere is *insane*, way more expensive than other ways of getting CO2 (if we even want to go down that road), also it would be at pressure in the tanks shown surely
@@مرحبابك-ض1ن Please look at my other comment because you've set your reply function right to left and its almost impossible to reply
On the capturing CO2 from the atmosphere its all dependent on how its done.
I'm an engineer and the major problem we collectively isn't so much we are having to transfer from dirty to clean energy, its that we are at the next great energy transition. Just as we moved on from horse & sail to coal & steam then onto oil & gas and then 1/2 way to nuclear, we are now at the next great energy transition. Its being heavily influenced by the need for clean energy *but we'd be making a transition anyway.*
The single biggest factor is efficiency. We have more people and that means more energy is needed but that actual supply of raw materials isn't keeping up.
I'm in Australia and we had a power station called Hazelwood. It was old an dirty, but worst of all was its was hopelessly inefficient. Most coal fired power stations could get about 30-35% efficiency with the very best ones with advanced boiler technology could get over 42% thermal efficiency. When it closed Hazelwood was getting about 20% thermal efficiency. So it was burning twice as much coal per watt of electricity. Hazelwood was closed NOT because it worked but because it was so inefficient.
Right now we have another power station at Newport which is an old gas thermal. If we simply replace it with a gas turbine we can save about 30% on raw gas input. If we add a steam turbine to the exhaust we can increase the power output by 60%. If we then added a hydrogen supply we'd reduce the emissions by another 50% down to 30% of where it now is.
This is actually a hard thing to discuss with non-engineers. If you are not being efficient with energy then ANYTHING can be insanely expensive. Also some things that look or sound inefficient aren't when you take into consideration of the overall system efficiency.
With direct CO2 extraction a lot will depend on where they get the energy from and then how they use it. I think the real problem with it will be that it just can't do enough. When you look at how much needs doing the real problem is being able to do in engineering what green vegetation does already. I think it will end up with systems that blend what we can do in engineering with what we can do with plants.
Petter, can you please make a video about electric aircraft. Hydrogen has its merits, but fuel cells are not much more efficient than burning the H₂, whereas direct use of electricity to power motors is much better.
Battery technology is advancing rapidly, to the point that recent new designs have almost three times the gravimetric energy density of cells which are on the market today. It's not going to be very many more years until fully electric short and medium haul aircraft will be feasible. We're already seeing light aircraft with up to a couple of hours of flight endurance, with a 30 minute reserve. There are also great running and maintenance cost advantages to be had from battery technology.
Sure, batteries have lower energy density than conventional fuels, but they're a lot safer to use, and certainly much easier to handle than Hydrogen. You mentioned H₂ leaking from containers, but you didn't mention the facts that a 5% Hydrogen/air mixture is potentially explosive, and that H₂ embrittles various metals quite quickly, or that synthetic storage vessels need replacing every five years or so because the Carbon fibre and resin degrade steadily because of the fuel, the cold temperatures and the pressures involved.
Nor did you mention how big the airport storage tanks will need to be. To give a sense of the scale differences, a standard gasoline or Diesel fuel storage tank at your car's filling station could refuel perhaps 300 cars, but a Hydrogen storage tank of the same internal volume can only refuel around 10 cars. Hydrogen tanks will also need refrigerators and thermal insulation. The cooling system causes an inherent energy drain which cannot be avoided, and the thermal insulation adds to the overall size of the tanks.
Perhaps a much easier fuel to use would be Methane; CH₄, because each molecule contains twice as much H₂ as a Hydrogen molecule. It doesn't leak so readily, doesn't embrittle metals, requires much less cooling and can be produced cheaply from CO₂ and H₂ O. (High temperature steam reacts with Carbon Dioxide.) When burned with O₂ it exhausts mainly the initial Carbon Dioxide and Water.. A useable production method for Methane has been employed on the ISS for many years, but they want the Oxygen and water in a process which removes CO₂ from cabin air, and they discard the Methane to vacuum.
It should be noted that after over 60 years of working with liquid hydrogen, NASA still struggles to get a good seal on fluid coupling interfaces, and they would never authorize ground personnel to be anywhere near the vehicle while it is being loaded with liquid hydrogen. During the Space Shuttle program, NASA learned that each time they load cryogenic propellant into the vehicle, the thermal contraction/expansion cycle affects the geometry enough to require certain bolts to be re-torqued in order to get a good seal the next time. Even though the new SLS rocket is similar to the Space Shuttle in many respects, it's different enough that they had to re-learn through trial and error how to tweak the bolts between thermal cycles. Commercial aviation is a lot less forgiving in this respect. If there's a way to close a cargo door incorrectly without a very obvious indication, a well-meaning worker will find that way. If NASA's technicians can't be sure that they've connected a fuel line so it won't leak, airport workers don't stand a chance.
Excellent point.
Hydrogen is one of the most difficult and dangerous forms of fuel.
It cannot be used in commercial aviation unless regulators are willing to sacrifice safety.
I won't say it will never happen, because I've seen lots of crazy sh*t done in the name of the Green agenda.
@manitoba2445 Ok but their point still applies. Just because a different group does it doesn't make much difference. They will still have to touch the airplane and have some ground crew experience.
@@manitoba-op4jx The inherent difficulty still applies.
And "grunt work" of making physical connections, etc. is still going to be done by people being paid "grunt work" wages.
Some of these people will be highly skilled and take tremendous pride in their work. Some will be marking time and doing the least they can get away with.
Your points are interesting BUT only affect cryogenic storage. The tanks on Boeing or a Nissan Mirai are not cooled to phase change temperatures, instead they are very high pressure COPVs.
I actually can tank any car that is equipped with hydrogen tanks and fuel lines myself at the gas station here in Germany. It is an easy twist hose, which will automatically check for leakage.
So rare to see a discussion of hydrogen that doesn't gloss over its issues and hype it up as a magical wonder solution. Thanks for the excellent video.
Oh wow! I flew that Dash-8-300 back in 2006 when I flew as an FO for Piedmont Airlines. N330EN... I thought I recognized that N number, and sure enough it's in my logbook. Nice to see it still flying!
I flew that plane a few times back in 1997. The world is really small it seems.
The CSIRO in Australia has already determined the best way to store, transport and use hydrogen as a fuel is via Ammonia (NH3). It is a liquid at reasonably high temps and you can see it has 3 hydrogen atoms and one nitrogen. All the cryogenic and high pressurisation issues go away. The only potential problem is if you get a leak into the cabin, all the passengers and crew will also go away. Rather quickly.
I'm pretty sure they settled on ammonia because cracking it to release hydrogen doesn't create CO2. Which buys into the common misconception that hydrogen and electric vehicles are zero emissions. They're not. They just shift the emissions to the power plant. Generally, hydrocarbons have the highest energy density. If the hydrocarbon you use to store the energy (hydrogen) is created using atmospheric CO2 (e.g. plants take in atmospheric CO2, and use photosynthesis to create sugars which you convert into alcohols), then it's a closed cycle and there's no net CO2 created even if burning the fuel creates CO2. So it doesn't matter that it's not "zero emissions" at the plane.
Volumetric energy density (MJ/L):
11.5 - liquid ammonia (-33 C boiling point)
15.6 - methanol
22.2 - liquid methane (-161 C boiling point)
24 - ethanol
25.3 - liquid propane (~ 22 atmospheres)
27.7 - liquid butane (~ 2 atmospheres)
34.2 - gasoline
35 - fat
35.0 - kerosene (jet fuel)
38.6 - diesel
Specific energy (MJ/kg):
18.6 - liquid ammonia (-33 C boiling point)
19.7 - methanol
30 - ethanol
38 - fat
43 - kerosene (jet fuel)
45.6 - diesel
46.4 - gasoline
49.1 - liquid butane (~ 2 atmospheres)
49.6 - liquid propane (~ 22 atmospheres)
53.6 - liquid methane (-161 C boiling point)
On the positive side, at least the cabin will be very clean after a leak.
@@benoithudson7235 That's a great factual comment. Ammonia is the basis of all cleaning products.
@@solandri69 : Ammonia is tempting as a packaging for hydrogen because it's easily liquified, because there's a lot more nitrogen in the air than carbon, and because ammonia is useful in itself. Not because engineers don't understand carbon cycles.
@@solandri69 Power plants are going towards 100% emissions free.
The tail vent is not for abnormal leaks. Almost regardless of how well the tank is insulated, liquid hydrogen will gradually boil, increasing the pressure inside the tank. With the engines running at high power, this is fine because there needs to be a gas to fill the empty space in the tank as the liquid is consumed. In some cases, passive boil-off won't be sufficient for tank pressurization, requiring a heat exchanger to make extra gaseous hydrogen, called autogenous pressurization. But if the vehicle is sitting on the ground with engines off, there needs to be somewhere for the excess hydrogen gas to go to avoid overpressurizing and rupturing the tank.
For rockets sitting on the launch pad, this excess hydrogen gas vents through umbilical lines to a flare stack where it is safely burned off. Aircraft won't have that infrastructure. So they'll either be venting unburned hydrogen into the air, or that tail vent will need an ignition system to function as a flare stack, spitting fire out the top of the vertical stabilizer. When aircraft are parked overnight or for prolonged durations, they'd want to offload their liquid hydrogen, and for safety they'll need to fill the empty tank volume with an inert gas that's non-reactive with hydrogen, which would probably have to be helium. Liquid methane would be a lot easier (the Soviets figured that out). Liquid ethane would be even better, because it can be stored as a pressurized liquid at ambient temperature. But the advantages of storing non-pressurized liquid fuel in the wings are so great that sustainable aviation fuel ("green kerosene") will probably win out in the end.
No, you've just correctly pointed out why all those other technologies are more stupid than green kerosene. But it doesn't take away from the fact that green kerosene is still very stupid economically and very stupid for engine durability and consequently very stupid for passenger safety. But you're right, the other technologies are much worse.
@@suserman7775 Just curious what “smart” fuel technology do you recommend?
@@manabellum The most likely solution is a radical scale-down of the aviation industries
@@manabellum There is no smart fuel, its just conspiculous consumption.
@@churblefurbles What is not conspicuous consumption?
I am really glad you talked about the problem with water vapour at hight altitudes. From what I understand it's one of the worst greenhouse gases.... which sounds counter intuitive.
Yup, the effect of CO2 is near nothing compared to water vapor. It's the height of stupidity to try and fight "global warming" by replacing CO2 with water vapor.
Yup, it's one of the worse greenhouse gas, however it's very well regulated by meteo and climactic phenomenon, meaning that for a certain temperature of the atmosphere water vapor concentration remain nearly constant, In other world if you release water vapor it won't stay long in the atmosphere (it may not apply to very big quantities of water vapor so i guess it is still a concern for aircraft, just don't feel bad when boiling pasta)
@@anosv9797 it's a bigger problem at high altitudes than at ground level (multiplying factor) but elevated levels only persist in the atmosphere for a matter of hours/days
Aviation is clutching at straws in many ways (so are several other transport systems). We're on the cusp of changes as large as those wrought by the introduction of automobiles in the 1900s or the destruction of the USA public transportation system in the 1950s
@@anosv9797 *worst* illiterate murican
@@miscbits6399 you're brainwashed
Thank you for your work, Petter! Your videos are outstanding from any angle: the quality of the content and research behind, the quality of the graphics and your #absolutelyfantastic way to explain.
Great report. The major problem with hydrogen is that it is the smallest existing molecule and wants to leak everywhere. Many space launch scrub happened because of H2 leak. I hope that all technologies are there to secure fuel transfer in connectors, tubing. Good ventilation/sensors. I don't think we need burn-off igniters, lol, but H2 will always needs to be handle carefully. Easier to see a jet fuel leak than an hydrogen one. I hope this work, better to use energy hydrogen as battery than a "real" heavy weight one for aviation. Hydrogen just transport the energy, that energy has to come from elsewhere and the production ratio is not so good for renouvelable sources. We have working hydro-electrical hydrogen plant here where airport here can easily be obtained it, good. Thanks to the team.
Thanks!
Thank you so much!
Fantastic Video! Interestingly Hans von Ohain's first Jet engine ran on Hydrogen because the extremely fast combustion speed simplified the design of the combustion chamber. Kelly Johnson worked with Pratt & Whitney on an engine burning Liquid Hydrogen for the CL400 project. That was the predecessor to the SR71 program and Kelly/Lockheed eventually returned much of the program money to the government and declared that it wasn't practical because not enough could be stored in the airframe. Traditional vacuum Dewar's had to be spherical or cylindrical and just couldn't be packed into wings and tails like conventional fuel tanks. Of course he was also aiming for Mach 3+ which brings a different set of challenges
COPVs might help that last issue
All this "save the earth" stuff is getting ridiculous. Plains crash. Hydrogen won't burn like kerosene. It will explode! Killing everyone on the plane and further endangering those on the ground. So while some accidents are now survivable, hydrogen will ensure certain death!
Odd thing about hydrogen is that is presented as future tech, when it's used in rocket ~80 years and Example Apollo module was powered with fuel cells. Non of the advancement have made it more scalable. It is made and used in-situ, or it's treated like rocket fuel, -Because it is. After 2019 accident most of Hydrogen stations for cars were closed at Denmark and Norway...
Yes, but COMPLETE TRIPE ! He's totally skated over the realities of doing this with fuel cells, especially their weight and the problems of getting tens of megawatts of heat out of them.
As an retired airline pilot, I love tour way of thinking and teaching. I would have loved having you as instructor along my career. Thank's
Anyone watching space flight will know that Hydrogen being so small is also very very very prone to leaks. Ref SLS issues
It can be further processed into methane, and (iirc) ammonia.
...Ammonia lacks the caloric oomph. Any methane that leaks is really bad for global warming.
😬
I'm not an engineer or chemist, fair warning.
Ayy another space flight fan ! Everyday Astronaut ? Also yeah challenges for SLS are infinite lol
@@suchirghuwalewala The leaking problem should be know to most anyone who has been paying attention to more than hydrogen promotional materials. Somehow being a fan is becoming a bad thing. So sad.
It's a tough challenge, not even talking about the ça y that the density is far lower than kerosene, and on top creating hydrogen is very bad in terms of efficiency.
So just no.
Yup. Its the smallest atom.. it can fit thro anyinthing.
Hydrogen infrastructure and logistics are *so* difficult that it brings into question whether hydrogen powered aircraft will be possible at all. It *already* seems as though when you run the numbers it's not viable for cars and ground based transportation systems generally. Aircraft and airports in particular *are* much more suited to it, but as far as I am aware it is still debatable and a relatively close call on whether we can actually make that practical and sustainable or not.
Ships.
Unfortunately I suspect that some companies will charge ahead regardless of the challenges and wind up creating potential hazards as well as wasting time and money on the hydrogen infrastructure. It is a sad reality that often the risks are not fully appreciated until a tragedy happens. Hopefully no one loses their lives over this. It isn’t Hindenburg style fires that are the threat but ruptured metal tanks or cells weakened over time by hydrogen leaking through metal walls. Kerosene tanks are more stable over time than hydrogen tanks.
The questionable economical viability will turn negative as insurance rates and lawsuit payments increase in reaction to tank failures in future years. The frequency of replacement of tanks could eventually be mandated to be more frequent and thus more expensive than the projections of current hydrogen fuel companies.
That is all in addition to the extreme challenges of working with hydrogen even during normal operations when nothing unusual happens.
The whole “green talk” around cars and airplanes is a smokescreen.
1. Transportation is consuming only about 20% of global energy.
2. There are no substitutes for powering large portion of transport vehicles (ships, mining equipment, trains)
3. 84% of global energy is derived from fossil fuels.
Electric cars and hydrogen planes don’t solve anything, just move the problem to places where electricity is generated. Still, the portion of electricity consumed by EVs and hydrogen production is minor compared to the amount consumed for heating and cooling 24x7 in all densely populated areas everywhere .
But addressing that is much bigger and more difficult to solve. From technology point it is rather boring so journalists don’t want to talk about it, thus contributing to the problem. Talking about EVs and hydrogen planes is much more exciting that about improving building code and insulating old buildings.
That is why we hear about EVs all the time, about hydrogen and electric planes from time to time, but never about insulating all homes everywhere, even though that is where the biggest improvement in global energy consumption could be achieved.
@@rok1475 Or the simple fact that nuclear power is as green as it gets. But nobody wants to talk about that. You could very easily replace coal and natural gas power plants to nuclear, and eliminate a HUGE amount of greenhouse gas generation.
And newer designs not only generate power, but can consume nuclear waste from older designs, resulting in a net DECREASE in nuclear waste currently on the earth.
But again, nuclear is simply a "forbidden" technology, regardless of the simple fact that nuclear power IS green.
And i'm only talking about fission designs, not fusion. Because we have extremely promising and proven fission technology already. Fusion may be close, but they've been saying that for a very long time, and it's still not here yet.
And i 100% agree with you that building insulation and increasing the efficiency of heating/cooling solutions is an obvious answer as well. It's just hard to make that work, as you have to get billions of people to spend money to fix their little piece of the problem. And, let's face it, people are self centered selfish buttholes, for the most part.
They are probably possible if you want to spend an infinite amount of money and time fixing all the problems they cause. But that doesn't mean they are smart.
Planes are one of the most energy density sensitive things I can think of. As such, it's one of the hardest things to de-carbonize quickly or economically. Thus, it's likely way more efficient for airlines to simply _offset_ emissions by doing things like funding solar installations, for example. This would be an effective means of accomplishing something _immediately_ instead of just spending the same amount on research and hoping for a breakthrough which may not matter until it's too late. Carbon acts over time, so getting rid of one ton today is worth much more than one ton 20 years from now, in the same sense as compound interest and investments. We need this kind of broad, pragmatic action if we want to actually make a dent in climate change. Energy is fungible, after all, so it makes far more sense from a macro perspective to attack the easiest (most cost effective) carbon sources first, because we can have a greater effect for the same economic cost. This is a really, really, important thing to understand, because of just how vast the problem is.
Better yet, we could simply pass a carbon equivalent tax to weaponize the market by actualizing hidden negative externalities like climate change... but I've given up on this being politically viable until either things get a lot worse or we fix our actual elections (FPTP, etc).
Minor nitpick: Kelvin does not use "degrees" - an increase of 1 degree Celsius is an increase of 1 Kelvin.
Yes Kelvin is absolute temperature while Celsius and Fahrenheit are both relative temperature. So C and F are both degrees and K is just K.
@PsRohrbaugh 2 minor nitpicks - "1 degree Celsius" is a definite temperature on the Celsius scale, i.e. 1 Celsius degree above the freezing point of water, and only means that particular temperature. When talking about increases/decreases/differences in temperature on the Celsius scale, one deals in Celsius degrees, not degrees Celsius. You mean "an increase of 1 Celsius degree is an increase of 1 kelvin [not Kelvin]"
I commented a few videos ago about whatever aviation news I read mentour now always releases a video not long after going into more detail, and you've done it again! Keep up the good work
Addendum to 13:40 regarding SpaceX, their next rocket, Starship, actually plans to use methane, and to use the same process of extracting CO2 from atmosphere in Mars and making methane from thin air as described in 4:10. They aren't using hydrogen due to a lot of the same issues described in this video (but under very different contexts from an airliner, of course, and of course rocket engines treat hydrogen/methane/kerosene as a propellant rather than an energy source for driving a motor).
I read "Skunk Works" by Ben Rich who worked for then later took over when Kelly Johnson retired. In it he describes how Kelly looked into using Hydrogen to power the SR-71up there at 100,000 ft & Mach 3 but it proved too difficult and expensive and they gave it up. I don't think it would be any different now.
If I remember correctly they couldn't get the mileage they needed on a single tank vs aviation fuel so they had to make the tanks bigger which worked against them. They couldn't seem to resolve it so they stopped the program. Ben said it was very disheartening to fuel up a plane then when you went to fly there was no fuel left in the tanks.
Petter, I love your enthusiasm for possible new technologies in aviation. Your attitude of “We can do it!” Is a breath of fresh air. This was a very interesting video - I appreciate the back-story history of using hydrogen- and gives me a tad more hope concerning our environment problems. Keep up the stellar work!!
Good job Petter, suprised you took on such a "flammable" topic!
21:31 - I understand the desire to help aleviate fear in the hydrogen tech but comparing hydrogen to kerosene isn't really a fair comparison in terms of hazards. Kerosene is a relatively benign fuel, often refusing to burn without enough heat (flash point of 38-52C[1]), being aerosolised or without a wick. Hydrogen meanwhile can ignite when you burp the cylinder (the act of briefly opening a cylinder without a hose connected to remove any FOD from the valve such as dust/dirt), it's minimum ignition energy is an order of magnitude lower than petrol and a few orders of magnitude less than kerosene (0.01mJ for H2 vs 0.8-ish for petrol, Kerosene is around 20mJ of energy, mJ == milijoule[2]). Yes with adequate controls and safety Hydrogen can be safe but saying that the industry does it with kero no worries for ages so hydrogen will be fine isn't apples to apples
I am not meaning to poo poo the alternative energy as we have to get off non-renewables but the kind of mentality of "oh it's just a little more spicy than jet fuel" may lead some to not treat it with the respect it deserves.
[1] www.ilo.org/dyn/icsc/showcard.display?p_lang=en&p_card_id=0663&p_version=2
[2] marinechemistassociation.com/wp-content/uploads/2018/09/Minimum_Ignition_Energy.pptx
edits: corrected some typos
One of the largest problems with using hydrogen is how it would be supplied. While it's the most abundant element in the universe, it's actually quite rare in its molecular form on Earth. Therefore, it has to be manufactured, which by definition means it will take more energy to produce the necessary hydrogen than will be produced by later burning it. Sure, this could be done by water electrolysis using renewable energy like solar, but it doesn't scale well. The more common method used extracts the hydrogen from hydrocarbons (typically methane), a process which by itself produces CO2. So moving to this process doesn't help the problem, but just moves it to a different source.
If anyone wants more information on how hydrogen is produced - in addition to one other issue unique to liquid hydrogen - then I'd recommend Scott Manley's video on rocket fuel production.
Massive amounts of hydrogen have been discovered underground much like oil fields but in different places. Google it. Hopefully this will be able to be tapped for energy needs.
This is a problem for most sustainable energy production from combustible fuels- it can move the CO2 production to a different point in the fuel cycle. Ammonia synthesis requires hydrogen which then requires either electrolysis (using green electricity, which is another issue) or steam reforming of natural gas/methane which creates CO2. There is also the issue of competition for ammonia with the fertiliser industry. We all need to be aware that sustainability goes beyond the final point of energy production - it has to be a holistic evaluation.
Was glued to that all the way through. Fascinating 👍
Glad you enjoyed it! 💕
Seeing the compost trash at the beginning in conjunction with talking about fuel for jets immediately made me think of Doc Emmett Brown going through the trash (at the end of Part 1/beginning of Part 2 of Back to the Future) to find a banana peel and some other waste to put in the Delorean…which had been upgraded to be able FLY!
There was an attempt to create a thermal depolymerization plant around 2000 (Changing World Technologies). This could convert biowaste (specifically animal offal and byproducts) into diesel. It had a lot of backers, including Google. It got shut down partly because residents downwind of the test plant complained about the awful smell.
8:25 I would like to offer a little bit more physics about why fuel cells tend to be more efficient than jets:
Fuel cells and electric motors are not "heat engines" and therefore are not limited in their efficiency by thermodynamics. That means that (in theory at least) you can get more useful work out of a fuel cell plus an electric motor than in any possible jet engine
But 'Inverters' need Cooling... There are other more advanced Technologies IF only humans would discover them...
This is true. However, I think the inefficiency of every step in the hydrogen chain from production to transportation to storage, to handling, etc. up UNTIL the hydrogen is actually used kills its prospects already. I think the good efficiency of electricity and batteries will put it ahead. Right now I would not advocate lithium ion batteries but battery tech is evolving fast enough that we are likely to see acceptable energy density and performance in batteries well before we can get anything truly viable out of hydrogen.
What has the potential to beat both of those is synthesis of hydrocarbon chains.
Thanks for nice content! I have few things to add from a energy chemist perspective. Hydrogen can also be stored in adsorbent/absorbents. Most popular are metallic alloys (e.g. vanadium or lantanum.) The problem is that maximum content of H2 is around 5 wt% (actually is closer to 2.5%), and metals are quite heavy - this actually comes even worse than Li-ion batteries in terms of energy density per mass. Other solution is using MOFs (metal organic frameworks) which are much lighter, and have enormous specific surface area, where H2 can adsorb. The problem with actually both of them is ad/absorption isotherm plateaus lies at quite low temperature around -80C, and moreover MOF's are not structually stable, especially with repetitive load cycles. It's still interesting solution for the aviation and i hope for some decent breakthrough in next decade.
Oh and for Spacex. Starship with it's Merlin engines will be using hydrogen, but for now Falcon 9FT is using RP-1
@@Macialao No, Starship has Raptor engines and they use methane
@@Macialao
The Falcon 9 has Merlin engines using RP1 (aka highly refined kerosene/jet fuel).
Starship/superheavy has Raptor engines using methane.
SpaceX has talked about but never developed a hydrogen engine. For instance, Raptor I believe was planned to be a hydrogen engine for an improved F9 second stage.
Right now one of South East Asian countries is developing aircraft engine fuel from crude palm oil for propfan / external double fan engine research. It is called hybrid fuel when combined with fossil fuel.
You have to be aware of the fact that several South East Asian countries are destroying vast areas of pristine jungle - home to many of the region's fauna and flora - by chopping/burning/clearing them away to make way for intensive mono-culture palm-oil palm plantations. The catastrophic damage caused by these operations is incalculable - the plantations support no other vegetation than the palms, which none of the native fauna can or do eat. All the native fauna therefore die off and become extinct. And all this for palm oil which can be made into - what? ice-cream, fast foods, margarine, so-called bio fuels. But it's not those products which drive all this destruction: it's quick profits. Vast profits from death and destruction - think about that next time you write on the subject from your comfortable chair in front of your computer.
Some corrections, hydrogen is not made in petrochemical production. It's made from natural gas with steam forming (Co2 is released to the air) and then used in petrochemical processes.
Also when hydrogen is stored, some of it boils off continuously and is needed to be vented. So vent-stack is for that, and not just for leaks. This is also a reason for those capsule to be odd idea, video don't show any connections on those. Tanks need good insulation and support and making them removable would mean more heavy structures and lot more connections. And capsules need to be fill-up anyway, so why extra step? Storing those capsules would mean more boil off.
Also even using fuel cells and electrolysis +cryogenics; Theoretical efficiency of hydrogen is 40% (vs. 80% for BEVs). And actual real world tests, it's 22% with fuel cell and 13% with turbines.
I guess the idea of the capsules is probably that they could do the refueling of the capsules in a controlled environment, and probably capture and reuse vented gas. And ideally not have to vent during the time between when they load the capsules onboard and start the engines. But yes the connections in the plane would be a real problem unless they figure out a way to make a nearly instantaneous leak proof connector.
I hate how so many people think we need to have ONE answer for ALL our problems. I follow people like you because you think about things rationally and recognize what's really possible and what isn't. I'm sure both hydrogen combustion and fuel cells still have their killer apps, just like electric and ICE vehicles are going to exist side by side for decades to come. Hydrogen might not ever be cost efficient for airplanes, but that doesn't mean it won't be useful SOMEWHERE.
Any liquid jet fuel/petrol/kerosene is medium chain carbon-hydrogen molecules, with 8-10 ish carbon atoms. These have roughly 2 hydrogens for each carbon (you can exclude the Hs at the end of the molecule as insignificant for this purpose), so will produce ~ 1.1 x H2Os for each CO2 emitted
You briefly mentioned a Russian experiment with LPG (so propane/butane), which is much more energy dense than liquified hydrogen, but has the issue with CO2 emissions still, at only ~1.3 H2Os for each Co2.
Methane (natural gas, basically) would give 2x H2Os for each CO2, a much better ratio, and cutting the CO2 emissions in half. It's a much denser molecule than hydrogen, so easier to compress and store liquified. Liquified, it has ~3x the energy density of hydrogen by volume, but it does weigh more (~2.5x more ***Edit - should be more like 6x more) due to the carbon atoms. But hopefully that's enough to get it adopted sooner, especially with the easier handling plus we have amazing natural gas supplies still (and there are companies farming land fills for methane already). I also imagine it would be less costly to convert an existing turbine to run on Methane than on hydrogen.
So, is it better to hope the hydrogen engines come along quickly enough for zero carbon? Or maybe look at the LPG/LNG models for a much faster conversion of existing aircraft and a drop of ~50-65% in CO2 emissions in the much shorter term?
Seems to me that while hydrogen is the ultimate way (until warp plasma engines!) Methane could be such a massive step in what we're trying to achieve that it's worth doing in the interim.
(my figures are very roughly calculated in ~3mins, so don't have a massive go at me please!)
EDIT - just seen a news article that the vast majority of hydrogen used today is created with methane, thereby sending all that CO2 into the atmosphere anyway...
Making it through electrolysis needs a huge amount of energy - and where does that come from? If not from Nuclear/wave it's likely to have a huge carbon footprint anyway.
You are right. Currently, producing hydrogen from methane or from water is not green enough. It is assumed that in the near future we will find ways to go from blue, grey, etc hydrogen to green hydrogen production. There are known theoretical solutions, for example nuclear (High-temperature gas reactor) which may work. We just need time to develop those technologies.
@@user-yt198 I really like the idea of molten salt reactors, personally, as a means of providing the power and/or heat for cracking sea water. But in the meantime any sort of nuclear devised in the last 20-30 years provides a really clean and safe source - the SMRs being built by Rolls Royce right now look like they're going to take off (no pun intended!)
I think it's ironic that the MSRE at Oakridge which ran successfully in the late 60s was initially funded in the hope of producing nuclear aircraft! (All the scientists involved knew it was a stupid idea, but they at least got to build their amazing reactor!)
And it just occurred to me that if you want to produce thrust, throwing a CO2 out of the back that weighs 2.4 times what an H2O weighs is a big benefit that has to be compensated.
Burning methane would still let you have a big exhaust mass advantage. Or are H2 burning engines going to run sooo much hotter to compensate?
There's a reason to leave all this to the engineers and physicists - my brain hurts too much already!
Hi, been an airline pilot since '98. Excellent channel ,thx!.
I do not think about Hindenburg, but about a Norwegian hydrogen gas station that had a serious explosion.
I like synthetic liquid fuel better, electricity is also fine, but we do not have good enough batteries for flying.
I am quite pessimistic about very high density storage batteries simply because of the fire risk. Batteries useful for aviation need to have a very high energy storage in those batteries at a very low weight. Having a lot of electrical potential with very thin electrical insulation that are still safe from shorting and catching fire is a challenge, I would think. We have already seen this with the older Lithium ion batteries which could spontaneous;y catch fire, and even with newer ones which have to be disposed of carefully.
I studied H₂ subject a lot, and I'm very satisfied with this video : everything is explained and well explained, even more, than I expected. There is nothing to add. If I was fussy, I would just add that most victims of Hindenburg accident were actually burnt by diesel fuel than by Hydrogen, which was exactly released in the air (remember, dihydrogen is lighter than air)
Oh good, a random person on the internet approves of another random persons video.
@@SloppySalad And a random individual comments approval from a random person of another random person's video.
This individual's life must be so dull.
So many people in the comments are pointing flaws even though Mentour adressed them in his video.. Did you guy even watched the video before commenting? x)
Commercial aviation will continue to be energized by hydrocarbon fuels derived from refined crude oil for economic reasons. Kerosene remains cheap and readily available relative to SAFs and cryogenic hydrogen due to fracking and the well established refining industry. Hydrogen may eventually become available due to fusion reactors which will make hydrolytic hydrogen production competitive with petroleum, but that is many decades in the future. economically
The problem of safely storing hydrogen at airports is a big challenge. It would require a level of competency in ground crews that - as recent events have shown - just isn't there.
I'm glad you brought that up. I've seen comments here to the effect of "NASA figured it out for spacecraft therefore its doable," as if a NASA engineer maintaining a spacecraft is interchangeable with a ground crew person at your nearest airport. For that matter, as if a spacecraft can be maintained like a 737.
I have worked with Hydrogen Gas in a generator cooling median. It’s hard enough to keep it sealed in a generator with oil seals. This won’t ever happen in aircraft. Waste of money, guess it will pay a lot of salaries for all the “research”.
Almost as big as storing it in the plane.
Extremely interesting video Peter ! Clear and concise which given the number of sub-topics to grind is remarkable. Thumbs up and thank you once again.
Also, more con trails is a good thing for lowering global warming as it reflects more sunlight away from getting trapped in CO2.
It also lowers photosynthesis so plants use less CO2 and also lowers the heat radiating back into space during the nighttime.
Which hydrocarbon addict told you that?
@@danafletcher2341 That is outright misinformation. You're either a Russian bot desperately wanting the world to buy more oil, or you're an oil company bot lamenting that your industry is coming to an end.
@@danafletcher2341 Nonsense Commie.
@@NeonVisual Common sense should tell you that blocking the sun lowers the amount of photosynthesis that can take place.
Are you claiming that the contrails reflect only in one direction?
Hydrogen is the smallest molecule in the Universe, and it diffuses in between the atoms of all metals when you make storage tanks and pipes/tubes to handle it.
You can slow down the losses, but the tanks and tubes become rather heavy when you do so.
Polymers (plastics) have even larger interstital spaces between the molecules, making them poor candidates for containing hydrogen.
The other problem with hydrogen is that it is quite reactive, making hydrides of metals quite readily, and reducing away metallic oxide coatings used to passivate the metals against corrosion. Hydrogen is a reducing agent, meaning that it chemically bonds to free electrons.
So, between reduction and other chemical attack (hydrogen embrittlement), systems to contain and transport hydrogen will necessarily have very short service lives relative to fuel systems designed for hydrocarbon fuels.
Between the heavier weight and the shorter service life, hydrogen fuel systems are more expensive.
My amateur predictions: For really short hauls, like 20-150 km, with small aircrafts: Batteries. This is a long term plan for the very extensive Norwegian STOLport network covering the vast, rural areas where land transport with multiple ferry crossings is very time consuming. Medium range, a hydrogen solution, maybe ammonia-based, or a combination of hydrogen and larger batteries for shorter routes? Long range: Traditional jets will stay for decades, of course with more bio. Maybe ammonia?
I am all in on ammonia as a hydrogen carrier but its use in an aircraft is a bit problematic due to its toxicity. The work on using ammonia as a fuel on large ships, trains, trucks and tractors already have to deal with the health issues in a less demanding environment.
@@Mentaculus42 True, ammonia is nasty stuff. Leaking or spilling is dangerous. Still, compared to the alternatives, easy to implement for ships, trains. But some research institutions are working with less dangerous methanol as an alternative, also for turbine engines. No major problem with ICE, as we know. Methanol fuel cells for battery charging already exist, but they are expensive, fragile and not very powerful.
@@janhanchenmichelsen2627 Agree with everything you said. An interesting thing is that ICEs and large turbines can be extremely close in efficiency to fuel cells but with the added issue of dealing with NOx formation.
@@Mentaculus42 Ammonia is so poisonous and volatile that it will not be used in mobile vehicles. Ocean going ships perhaps but even then I doubt it. Methanol, synthetic aviation fuel or even synthetic methane will be more practical.
Dear Mentor. as someone familiar with handling hydrogen you are unaware of the dangers and complexities of handling hydrogen. The Hindenburg is a very apt analogy.
If heat in the fuel cell is an issue, could they locate the fuel cell in the high-flow core of the fan, and even use heat-related gas expansion to squeak out a bit more efficiency while cooling the cell?
@Chris NREL has demonstrated a halving of carbon dioxide releases from electric vehicles with a current infrastructure with the potential of reducing them by 90%. Not sure where you get your ideas about EVs?
4:29 I think the reason to create synthetic fuel instead of using pure hydrogen in planes is to avoid building those big and heavy hydrogen tanks. I haven't seen any calculations but I wouldn't be surprised if hauling heavy hydrogen tanks in planes would be less effective than using somewhat less effective manufacturing process to create fully sustainable synthetic jet fuel on ground and using engines designed for jet fuel.
Thank you for this very important and optimistic overview. Progress really seems bringing us close to realistic tests already 😎🇩🇪
The very large flammable range and the very low ignition energy is another interesting problem when combined with the tendency of hydrogen to leak through seals. A slow leak in a hangar and then someone walks in wearing nylon = boom.
I've MSc in chemistry. Was working 8 years in organic synthesis, so working with pressurized hydrogen from a cilinder for me is like spreading butter on bread. So believe me: hydrogen as jet fuel is NONSENSE. Hydrogen is extremely combustible. While normal jet fuel you can not ingine with a zippo. And storing hydtogen as liquid : if something goes wrong, and it becomes gas, it is so powerful, that the back of the airplane would desappear! Back in my Uni years ( 20+ y ago...) György Oláh ( Nobel price in chemistry 1995) had a research group burning Methanol in fuel cell, to generate electricity I always surprize why this did not get more attention. Methanol when it comes for ignition point is similar to gasoline. And LIQUID at atm pressure, so you could store in the wings. And Methanol can be produced by fermentation. Thanks for reading!
Video not finished yet but the production of comercial levels of hydrogen is very energy intensive and less efficient than just burning a fossil fuel as it is generally extracted from methane using a process called steam refraction. Until there is a way to produce enough energy sustainably (not from coal like a lot of countries) to make electrolysis a viable option its just exporting the emissions to a different site and isn't really a green option
Hydrogen is extremely thin in molecular level and can get through valves and tanks . Quite dangerous as material otherwise . It will cost a lot. Don't know about ticket prices in the future otherwise. It's pretty unsure
We can be pretty sure that the ticket prices will go up in the future no matter what. Unless we can come up with a very cheap new type of energy source
Hydrogen is used as a coolant for some large commercial generators...🤔
Exactly... So the comparison with kerosene is just incomprehensible.
@@MentourNow Not necessarily. Due to the very high cost of electricity storage, the cheapest way to convert our electricity grid to 100% renewables is to install enough solar+wind etc to meet the winter demand without seasonal storage. That means there will be a tremendous abundance of electricity during the other seasons, which we could use to manufacture fuels such as hydrogen or synthetic hydrocarbons at a fraction of the cost we see today.
@@markmuir7338So u r saying that over building is all it takes to have a reliable electrical grid ¿
I was hopeful that green hydrogen could be used for aircraft and shipping BUT after watching a video with Prof, David Cebon who is an expert in hydrogen in transport, he thinks the cost would just be to high. The complexities of storage and inefficiencies of making it on such a large scale, would not make sence without massive subsidies, The oil/gas industry are only pushing it so they can make it from gas reforming with carbon capture but that will be very expensive so again will increase the price. He said it would be better to use all the biofuels we use now for ground transport vehicles. Also lots of shorthall aircraft will go electric so its just needed for longer non stop flights.
Pursuing SAF fuels and hydrogen fuel cells for aircraft is an excellent way of diverting billions of dollars away from other projects, diverting engineers from other research, making travel less safe, making travel less affordable, and keeping global warming to the exact same pace as we would have if these projects weren't pursued at all. Great job, people.
SAF will make air travel unaffordable for many too.
[Before watching the video the first thing that comes to mind.] The challenges are creation, storage and power density.
You’d need a pair of Helion Polaris reactors - one for 3He synthesis and another for energy output - in the hands of either True Zero or Iwatani to make hydrogen cost-effective enough as a fuel. Still a year away from the first step towards that.
Thank you for your levity with the "hindenburg" reference at the end. People don't understand, the hindenburg and the technology was sound. Hindenburg just got a very explosive coat of paint put on before it's last flight that reacted very well in tandem with lightning strikes.
Not only that, but we've flown rockets using hydrogen as a fuel for decades, including ones that carried people. While there have been accidents, none of them were caused by spontaneous ignition of the hydrogen.
Yes the aluminum particles in the fabric coating have been documented and it is one of the theories that is presented as to what happened. But the anti hydrogen crowd have differing opinions. Maybe reality is somewhere in the middle.
@@Mentaculus42 "Anti-hydrogen". I see what you did there. There are certainly people who see battery-electric aircraft as the inevitable future, with hydrogen as a wonky stop-gap. Hydrogen has many problems that need to be worked out, but I think we're likely to see a mixture of the two.
@@fighteer1 Yes to both of you, but not over cities with millions of victims to those hydrogen bombs. Imagine the last accidents involving airplanes striking buildings in the middle of the city. Those tanks would have ruptured and reacted like a barometric bomb.
@@fighteer1 Absolutely, short range aircraft have a future possibility with batteries. One of the foremost world authorities on battery research (from Stanford) has stated that his “dream” is to fly on a battery powered commercially available aircraft from the Bay Area to LA in his lifetime. He is still relatively young! Have been following his research for more than 10 years and his prognostications have been a bit optimistic.
Casey Handmer's Terraform Industries is using renewable energy to to combine co2 removed from the atmosphere with hydrogen produced through electrolysis to produce net-zero methane and other hydrocarbon fuels, and they think they can do it at competitive prices within another year or two. If that works then the airline industry would be able to start going net-zero at least a decade earlier than the hydrogen conversion plans that Mentour is talking about.
Comparing Hydrogene and Methane, I think they took the wrong turn.
Methane has less volume per power, higher temp and is easier to handle in lighter tanks.
I am planning to do my Electromechanical engineering thesis on this topic, it's fascinating and a great challenge.
Good luck with hydrogen at least in the forcible future. Costly to produce, both monetarily and resources, but also handling, you almost need to think about it escaping from any container you have and it is gone. So containment and storage is very difficult. They might get it working in very well controlled test environments, but in the real world, the practical day in and day out, can't see it holding up in practice very well. Plus from what it seems the rate of return is rather dismal, put in say 100 BTU get 70 out and often right not coal or gas is where the BTU for the electrolysis comes so burn the fuel and you're already head...
I'm pretty sure the efficiency of hydrolysis is worse than 70%. But the efficiency of charging a battery (converting electrical energy to chemical), then drawing electricity out of it (convert chemical energy back to electrical) is also around 70%-80%. There are a *lot* of electrical losses that renewable advocates gloss over or pretend don't exist. e.g. Overall energy efficiency of EVs with our current power generation and grid is about the same as a diesel ICE.
The main problem with battery tech is that its energy density by weight is two orders of magnitude worse than jet fuel. If you loaded up a 777 to its max take-off weight with Li-ion batteries, it would only have a range of several hundred miles. And that's with zero payload. Battery energy density has increased by about 2.5x in the last 50 years. So (assuming we're able to keep that pace of development) unless you're willing to wait ~200 years, battery-powered intercontinental airliners aren't going to happen. Airliners need a denser form of green energy storage, even if it is less efficient.
@@solandri69 Hehe, think i was trying to be optimistic and not give that bad of a efficiency % conversion rate too pessimistic ;) If memory serves me, getting hydrogen is really messed up, there are ??? types methods of getting hydrogen. all rated at how "green" they are, black was the worse and is how must hydrogen is gotten today i thought. Thus my comment if we use oil a large amount of energy to get x% energy. Double checking some of the conversion methods are at best 50->60% efficient. Great we burn 2x the oil to burn a "green" fuel.
Also about battery to store it, might suggest looking at or researching John B. Goodenough. WOW! What an inspiring person, few ever event anything to effect most people in the world, he has two, soon three... Well worth checking out videos of him on youtube... First he helped developing computer ram, second Li-on batteries, and soon the third will be solid state battery. Heard they have a working prototype and finishing the final steps. Believe from what i read solid state batteries will be amazing charge super fast, allow for a lot more power cycles, they only have a slight decrease in efficiency after 1000 charges, but should last for a projected 5000. And they are suppose to have 2->2.5x the power density when compared to li-on batteries.
@@dand4485 Yeah, best efficiency I'd heard for electrolysis of water in the lab was about 65%. I believe most industrial scale processes are down around 30%-40%. There's research being done on catalysts which cause sunlight to directly break apart water into hydrogen and oxygen. Efficiency is abysmal right now, but the same was true for PV solar at first. Who knows what the future holds.
The problem with lighter batteries is that lithium is already the 3rd-lightest element. There's just not much more room left for improvement. The only battery solution I've read about which might get us somewhere close to 2 orders of magnitude improvement are structural batteries. That's where you build the vehicle itself out of material which can function as a battery. That allows you to share the mass budget between both the structure and battery, essentially giving you "free" mass for energy storage.
Never forget, dedicated crops are labor a fuel intensive. Although the jets will not be using crude bases fuels, crude based fuels, natural gas, and a great deal of water will be needed to produce that net zero fuel. The process is very dynamic for a network to be green. great video!
Corn ethanol is not made from a dedicated crop, it would be too uneconomical.
Rather corn ethanol is value-added from already existing feed production which leaves 100% of the protein (& other things) still available as feed in a healthier, more digestible/efficient, and more concentrated form called distillers grains.
This explains how ethanol is so cheap despite the current high price of corn, they make it up with high prices for the distillers grains.
With the feed factor, corn ethanol can outcompete most any other source out there including sugarcane which makes more ethanol but little else. So much so that Brazil put an import tariff on our ethanol.
Iowa State University measured all the energy it takes to produce an acre of corn into a "diesel fuel equivalent"
This included making of the machinery, fertilizer, chemicals, tillage, planting, spraying, harvesting, drying, trucking etc.
They found it takes 34 gal of diesel to produce one acre of corn.
What do we get from those 34 gallons of diesel?
We get >500 gallons of ethanol.
But wait, that is not the kicker.
The kicker is, as I said before, we still get 100% of the protein from that acre of corn still available for an even better feed. A win, win.
Short haul flights though, are probably better replaced by rail services. Those require far less energy to begin with. And so they can be made sustainable much more easily.
100%.
High speed rail all day any day! Maybe even high-speed sleepers could take over some demand for transcontinental routes?
In some places, definitely. In others like the US where the infrastructure investment is prohibitive, and here in New Zealand where we have low population and mountains and seas to navigate, no.
Yup, problem is that low cost carriers are so much cheaper and faster than rail. A carbon tax which 'internalised the externalities' would probably be needed.
@@chendaforest True, London-Amsterdam by train is about twice as expensive as a low cost flight. Unless you want to bring along more luggage of course. Then prices are a bit closer.
But given that ticket prices are rising anyway, I think trains may become more competitive. Especially if you’re willing to pay a bit extra for CO2 emission reductions.
Regional hoppers? Bring em on! No big problem is every solved easily. This starts to chip away, at the very least.
Love this channel! Love aviation. I worked in Avionics, in fact, when I was on active duty in the Marines. (2001-2007)
For those who know what I'm even talking about, I was routed to I-level avionics (Comms/Navs - 6412/6413.) by the Navy and attended their giant schoolhouse down in BEAUTIFUL Pensacola, Florida...
Thats a neat place to be 18 y/o and fresh out of Mom and Dads house because the bricks (Baracks) were right on the Gulf COoast and this is where the Blue Angel's stowe their birds at night, and it's where they often practice in the airspace over Pensacola, Florida by day ...
I knew it then... and I still think of this era very fondly even after all this time.
Picture this:
Running a few early morning miles on the Gulf,with some of your bretheren War-Dogs, while watching the sun rise, with a smart-assed Gunny singing hilarious ditty's and you are in slight pain with wet, salty feet...But that sun is still coming up, and while running and laughing, you're out of breath....having puked up last nights St. Pats beers....then showering before reporting to the premier Aviation schoolhouse, in all of the land to learn about what you love., while being paid to be there..
Good times. 💯💯
I was 6412/13 in K-Bay, Hawaii and Iwakuni, Japan 90-95. That led to many great careers.
Мені дуже приємно коли ви говорите та застосовуєте руки, мені це дуже подобається ,якось мені легко запам'ятовується😊❤.Це цікаво.Дякую.
always good to hear from another Marine avionics person! I worked on A-4 avionics from 77 to '81, which was an adventure of sorts. :-) Went on to get an electronics engineering degree and designed avionics. There's something to be said for working around aircraft, but it's also nice to work indoors when the weather is not great. Troubleshooting and problem solving is fun in both cases, though!
@@SkyhawkSteve That is Very cool. I had planned to do just that, bit when I got back home after EAS, there weren't a lot of options for avionics guys.. as our local Airport, CAE, is small....and was way smaller back then...so I went where I could get good money quick...the same place i always swore not to go..the same plant my father raised us working at....but i got into fitting pipe and that ended up in becoming a CWI (AWS Certified Welding Inspector) which turned out to be a rather lucrative thing to do too....
They always said the majority of people who came through the Corps ended up being pretty well to do...and I wont argue that I'm not capable....
But congratulations on achieving your dreams, DevilDog. Are you still running every morning? Come rain, hail, sleet or snow???
@@h.e.floydiii7259 Aviation is a small industry, so finding employment requires moving to where the jobs are. I went to McDonnell Douglas, but learned about how sensitive defense jobs are to the whims of Congress, and especially to the defeat of the USSR! I ended up designing 'tronics for earthmoving equipment, which is kinda cool too. It evolved into a "fly by wire" sort of arrangement, similar to military aircraft of 20 years earlier. As far as running, my knees were giving me trouble, so just bike riding for me. I'd been riding and building my own bikes since high school, and had bike riding friends in the Corps, so it's been a 50 year hobby so far. Still riding in all weather and rode over 9000 miles last year, so I hope the Corps isn't disappointed. 🙂
Plenty of water vapour is already present in jet exhaust contrails. Burning hydrogen only would perhaps double that amount.
Better chance of hell freezing over than getting a bad video from u my man
Thank you Antonio! 💕
@@MentourNow Jesucristo! Thank u for taking the time to reply Petter I know u a busy a man and that means a lot to me..these videos man I can't get enough of em especially since aviation has fascinated me since I was a little boy(I'm 37 now) and being a pilot would be a dream job for me so I'm hoping I'll get there ..these videos really help and I truly appreciate em ..sorry to yap but it's also cool you're from Sweden as my greatest friend is also from Sweden and his middle name is Bo Petter and I could tell by your accent you were swedish but then I heard your name and I'm like oh now I know for sure..take care man and thank u again I'm goin to try to get on Patreon to return the favor
Yup, i remember that video, that was fascinating
Planes are one of the most energy density sensitive things I can think of. As such, it's one of the hardest things to de-carbonize quickly or economically. Thus, it's likely way more efficient for airlines to simply _offset_ emissions by doing things like funding solar installations (airports have a lot of empty space! There's a super interesting proposal at Kansas City airport that could literally power most of the city for example, though there's also no need to have them be at airports either). This would be an effective means of accomplishing something _immediately_ instead of just hoping for a breakthrough which may not matter until it's too late. Carbon acts over time, so getting rid of one ton today is worth much more than one ton 20 years from now, in the same sense as compound interest and investments. We need this kind of broad, pragmatic action if we want to actually make a dent in climate change. Energy is fungible, after all, so it makes far more sense from a macro perspective to attack the easiest (most cost effective) carbon sources first, because we can have a greater effect for the same economic cost. This is a really, really, important thing to understand, because of just how vast the problem is.
Better yet, we could simply pass a carbon equivalent tax to weaponize the market by actualizing hidden negative externalities like climate change... but I've given up on this being politically viable until either things get a lot worse or we fix our actual elections (FPTP, etc).
I completely agree! We need to focus on the “low hanging fruit” first, like global shipping for example.
But that doesn’t stop us from also trying to innovates be prepare for a situation where normal jet fuel is no longer available.,
Global shipping is very efficient.
Production of chemicals, which includes fuels in general, require some energy to convert the raw materials into the final products.
With our conventional fuels, we take the naturally occuring crude oil, and distill it into boiling point fractions, and then we beat on some of the less convenient heavier fractions with hydrogen to crack the molecules down to more useful sizes.
The enrgy for the refinery is provided by the combustion of off-specification molecules which are too difficult to convert into fuels that meet the commercial standards of performance required for general use.
We make hydrogen in the refineries in Steam - Methane Reformers by reacting Natural Gas (methane for the most part) with steam in high pressure, high temperature reactors over catalysts. We need this hydrogen to crack & hydro-treat otherwise useless molecules from the crude oil, and to remove sulfur and some nitrogen from the products in order to get cleaner burning fuels for consumption.
The exhausts of the oil refineries are carbon dioxide, water vapor, and hot air - up until about 20 years ago, this was fully considered by almost everyone to be environmentally acceptable.
Due to various theories of the environment getting pushed hard politically, and the shift in the governmentally supported scientific community from global cooling over to global warming as the climatic catastrophy to be avoided, we are now looking at making "sustainable" fuels from biomass, bypassing the millenia of high pressure fermentation in the Earth's crust, and other schemes using carbon dioxide and Green hydrogen.
These renewable fuelss require that we apply energy in a more intensive fashion than allowing nature to take its own sweet time - so, on a molar basis, we need to pump in more energy than we need to refine crude oil.
The energy which we need to use to due theis must also be Green, which also comes with a cost, as we do not have the necessary biomass growing, nor the cropland to pare that can be diverted from food production.
Green hydrogen is produced by the use of Green electricity to reduce water from its fully oxidized state back to the constituent elements.
A chemical reaction is defined as being thermodynamically spontaneous when it oxidizes the reagents to make the products - these reactions are exothermic, and have a negative Gibbs Free Energy.
When you burn fuel in a fire, you are conducting a thermodynamically spontaneous reac5tion.
Electrolysis of water is both endothermic and has a positive change in the Gibbs Free Eenrgy - it is not thermodynamically spontaneous, meaning that you need to supply all of the energy needed to convert your reagent to the products, plus any inefficiencies of reaction, plus your systemic losses.
Now, you want to convert carbon dioxide back to a hydrocarbon fuel - again uphill against thermodynamics.
But, you need to collect your CO2 first - and that takes processing energy as well - first because at 400 ppm in air, you are trying to collect a very dilute species if you are using Direct Air Capture, and second, even if you use a technology such as amine stripping to remove the CO2 from the tailgas of a power plant or similar fired device, you still need to concentrate and compress the collected material.
Now, once you have completed carbon capture and the production of Green hydrogen, you introduce them into your high pressure catalytic chemical reactor, with a very complex separaotr to remove the desired fuel and recycle the unreacted syngas, and all of that takes energy - and you do not have the Green fuels to spare to provide it.
Wind and solar are low intensity, low energy density power sources, requiring lots of complex equipment to produce, and only work part of the time.
Hydro-electric power requires waterflows such as rivers where the combination of flow and elevation drop can produce enough power... damming up rivers, and using metals and concrete which also require high temperature energy intensive processes to produce.
Or, you can build more nuclear power plants.
Ethanol is now cheaper to produce than petroleum jet fuel, gasoline, and diesel.
The spot cash price of ethanol is $2.09 vs $2.54 for jet fuel.
While the ethanol could be used directly in jets and with its high oxygen content be very efficient above 10,000 feet, as long as the conversion of ethanol to chemically identical SAF did not cost more than $.45/gallon, cost would be a wash.
@@danafletcher2341 Those prices are only attained for ethanol with massive government subsidies in the USA - in other words, at the taxpayers' expense.
@@chemech The Federal subsidies for corn ethanol ended back in 2011.
The long-standing stated goal of the G7 Nations to end petroleum subsidies? Not so much.
@@danafletcher2341 The corn subsidy acts expired - and got replaced with other, newer subsidies... Some firms are only just now getting their ethanol projects started into design, based on subsidies that were passed into law in 2021.
Oil & Gas subsidies??? Yhose only exist in propaganda - the oil refining business is at almost zero projects active right now, as they cannot make enough money to offset the new punitive regulations and restrictions that were also imposed in 2021 and 22.
The engineering and construction firms that support the petrochemical industry are shifting over to take on renewable fuels projects now in order to keep the doors open.
Again, this is a complete inversion of the economics from the status quo of 2020, when those ethanol and other renewables projects could not qualify for financing.
@@chemech Corn ethanol which is called generation one biofuel has been subsidy free since 2011. There were no new ones made after the VEETC.
Cellulosic ethanol which is not made frail grains is called generation two had a subsidy over twice that of corn’s but it never materialized. One plant was started in Nevada, Iowa but never got off the ground.
Generation two ethanol subsidy expired in January 2022.
If I could post links, the DOE has a great web page of current and past alternative fuel subsidies.
If you have a problem with petroleum subsidies, don’t talk to me, take it up with the G7 Nations.
If you are talking about the CO2 pipelines, I think those are complete and utter folly and have nothing to do with the price of ethanol since 2011. I do not think they will get through all the landowners or that is my hope.
CO2 is a resource, not something to spend money and energy liquifying and pumping across the country only to inject and bury in the ground as trash.
I have a feeling that hydrogen is not the solution for airline fuel. Looking at the wider picture we already use about 90 million tons of hydrogen per year. Less than 5% is produced from electrolysis most is being produced from natural gas, oil and coal contributing to green house gas emissions. It makes much more sense to clean up the existing industry before even contemplating hydrogen for aviation.
Burning hydrogen in a jet engine will produce nitrous oxide and the amount produced will depend on the combustion temperature in the engine. The higher the temperature the higher the efficiency, but the more nitrous oxide. So to be clean fuel cells are a way to go, but given that you can manage weight and storage issues you have a heat issue. Hydrogen gets really hot when it expands from cryogenic liquid to gas so it needs cooling before going into a fuel cell, and the fuel cell gets hot too. More systems and weight required for cooling.
I suggest battery electric maybe the answer for short to medium haul aviation. It does require high energy to weight ratio batteries which we don’t yet have but there are promising developments and we are seeing batteries being produced near 500 watt hours per kilogram. I think you need about 11,000 watt hours per kilogram to be of equivalent energy density to hydrocarbon fuel. However, a lot of hydrocarbon fuel energy is wasted producing heat so a battery does not need to be that energy dense to be viable. I think anything above 500 watt hours per kilogram maybe getting into the right ball park. Lithium air battery tech can get to 11,000 watt hours per kilogram but I suspect that is a long way off if ever.
It should be clear that a light weight safe, rechargeable, high energy density battery is the most efficient way to power anything. We just need to develop that technology.
SpaceX is switching to liquid methane for the superheavy/starship system. They rejected hydrogen due to the difficulty of handling and producing the needed quantities to allow the very ambitious launch schedules they're aiming for.
The main reason, why CH4 is used for Starship besides beter handling than H2 as a fuel is that Mars atmoshpere is rich in CO2 and it is believed to be H20 underground. By combining CO2 and H2O you can make CH4 and O2 which means there is no need to bring fuel and oxidiser from Earth. I believe this way requires less energy than H2O electrolysis.
What about ethanol? It's slightly less energy dense than fossil-based fuels, but it is easy to store and pump. Can be produced by fermentation of agricultural waste.
GE has built ethanol jet turbine engines (dual fueled) in Brazil as an electric plant. Same turbine engines as the Boeing 747.
Above 10,000 feet the high oxygen content would become very efficient.
United Airlines is making chemically identical jet fuel from ethanol soon with a pilot plant in 2024 and full scale plant in 2028.
The spot cash price of ethanol is $2.09 and jet fuel is $2.54/gallon.
@@danafletcher2341 There's a difference in energy content, due to the ethanol containing an oxygen atom.
Another excellent video! And, you mentioned my home town of Moses Lake, Washington and the Grant County airport. Back in my earliest days of flying, Grant County International was the world training center for Japan Airlines 747 pilots and crews. Before that, actually WAY before that, it was Larson AFB which was closed down in 1966. Yes, that's not a typo, I was a mere 9 years old then. Anyway, fascinating stuff!
This is a great video. Thank you
6:43 i remember that video, it was really cool. I just watched the latest in Rolls Royce massive engine bigger than the GEN9X. Pass all in house tests in December.
There is a little difference between jetfuel and hydrogen. Put jetfuel in a cup and try to light it using a quick match. It will not burn. For hydrogen the smallest spark is enough to ignite it.
I vote for hydrocarbon gas combustion tests on medium to small size airliners. Liquid Hydrogen is very dangerous fuel and leaks everywhere. JP fuel is expensive but safer in liquid form. No airport fuel distribution system budget can afford conversion to liquid Hydrogen technology. Every passenger will remember the Hindenburg tragedy when looking at a pure hyadrogen tank fitted into the cargo bay of an airliner. JP fuel still wins. It can be used as jet turbine fuel and can stop a fire in liquid form (emergency fuel dumping). Hydrogen for fuel cells and hydrocarbon fuel (JP preferred) for combustión. Thanks.
Great report, Petter! I know a little about H2 fuels, and you've covered all the issues!
The hydrogen vent line isn't there "in case of a leak" - it is there because despite all efforts, thermal enery *will* creep into the tanks. If the tanks were sealed, this would heat up the hydrogen, which in turn would increase pressure and eventally rupture the tanks.
One way around this is to allow some of the hydrogen to literally boil off, carrying away that thermal energy and thus keeping the remainder of the hydrogen cold enough to remain liquid (think of how water in a boiling kettle stays at 100 °C even when sitting on a much hotter stove).
In normal operation it might be possible to feed this gaseous hydrogen to the engines; but when they're not running (or if the engine is designed to take the hydrogen in liquid form), it needs to go somewhere else - which is where the vent line comes in.
Simply put, it is an inexpensive cooling system for the tanks - either as the primary system or as a highly reliable back-up to some active system.
So what happens when u park the aircraft inside a hangar. U probably need more than just a vent on the aircraft to be sure that the hydrogen is converted to H2O or u will be unintentionally modifying the hanger’s roof. NASA learned the hard way with that on a space shuttle engine test stand. Absolutely need vents in the roof.
@@Mentaculus42 That will be a logistical problem indeed. You'll probably want to detank the airplane whenever you know you won't be using it for a while.
However, the vent line might also be designed to work as a flare stack in such situations, with the boiled-off H2 being burned harmlessly.
@@CLipka2373 I was wondering about a flare or some sort of catalytic oxidizer or maybe a fuel cell that could provide a little power to help with this issue.
What a pitty I cannot like more than once... I really like your way of presenting challenges to go green in such posiitve and exciting way. Great work !!!
I don't usually like videos, but I did on this one just for you.
Petter hit the nail on the head about the biggest problems with hydrogen fuel. Good job sir.
Another very good video!! I really like the concept and am sure the industry has worked out most of the issues regarding hydrogen's capacity to go boom, but my primary concern would be incorporating this new technology on a global scale. It would be a difficult, but not impossible task for most "first world" countries to take part in the development and eventual deployment of this technology. However, how would those countries that barely have the financial resources to satisfactorily maintain their current jet-fuelled fleets even consider making such a cost-prohibitive switch??
Hydrogen have no futur... 25% to 30% is lost when storing or transporting it.
@@Didier88600t really comes down to an economic issue. Besides, a lot of hydrogen will be transported via ammonia. If you actually want to learn about hydrogen’s future, watch the 10s of billions of $s going into the green ammonia industry.
Good review. You may look into "hydrogen storage in metal hydrides", because it is bonded to Mg compound the low pressure tank can store several time the same volume as H2 in a high-pressure tank and it is a very safe way to store H2. It looks promising for ground applications but I don't know of the weigh aspect, which would be a decisive factor for aviation application.
Metal hydrides have been studied for decades and always hit ghe same stumbling block - the transport mechanism (metal hydride) is prohibively expensive.
For stationary applications it's much cheaper to use other solutions (10% of the cost) as volume/mass aren't an issue and for transport applications you end up with a fuel tank costing significantly more than just using batteries that ALSO takes as long as (or longer than) batteries to refill (hydrides are slow release/slow to fill)
The emissions from aviation are more than just CO2. The air quality near airports is generally very poor. We’ll need a mix of electrical, gaseous and liquid fuels. It’s going to be very different from reliance we have on Jet A today.
Yep, that’s correct
And planes construction...
The answer is nuclear.
Not in the aircraft, mind you; unless we figure out cold fusion, putting any kind of nuclear power on an airline is going to add an unacceptable amount of weight (never mind safety concerns around fission fuels). But the cheap energy provided by abundant fission (and hopefully soon, fusion) will make the high energy demands of synthesizing hydrocarbons a smaller issue. Besides giving extra hydrocarbons to blend into the existing fuels, it'll also pull excess carbon dioxide out of the atmosphere (and possibly sea water) and reduce environmental pressure.
Any form of concentrated energy storage is dangerous, whether jet fuel, gasoline, hydrogen, or electrical batteries. If we could figure out how to accomplish work without energy storage, now THAT would change the game. Good vid!
LASERS 😅
Issue with liquid hydrogen is that it leaks. Liquid oxygen, especially when it forms by accident in labs is much more dangerous per se (just add something oxidazible, like organic fumes and kaboom), but it doesn't leak in storage.
A big disadvantage with hydrogen in aviation is that it's a chicken and the egg situation. Realistically you would need to have hydrogen fuel available at all large and medium hub airports in a particular region of the world before you can even begin to introduce hydrogen airliners. In the U.S. for example that is 65 airports. No airline will buy a plane that can only fly into 10 airports. But how many airports will install expensive cryogenic hydrogen fueling infrastructure when there are no hydrogen airliners. And what plane manufacturer will want to build a hydrogen airliner, even with subsidies, until most airports already have hydrogen. Eventually the problem can be solved, but because of the chicken and egg situation I think it will be difficult to get this started.
Regional airlines might seem like a good fit because they typically fly into fewer airports than the majors. But they also fly into smaller airports that are less likely to have hydrogen. They would have to juggle aircraft around on their routes depending on the type of fuel that each one uses. Larger long haul aircraft might do better because airports at major cities like Paris and New York are more likely to have hydrogen, and airlines could simply schedule their A350 sized hydrogen planes between airports that have hydrogen.
But another problem is diversions. Let's say all of 30 of the large hub airports in the U.S. have hydrogen. But that means if a hydrogen plane gets diverted its choices are very limited. If they get diverted to say Kansas City and there is no hydrogen facilities at that airport, then the plane will have to sit there until hydrogen is trucked in from several hundred miles away or more, depending on how close is the nearest cryogenic hydrogen production plant.
Biofuels can be much simpler, assuming that a particular aircraft can run on either biofuel or regular jet fuel. Then they can fly into any airport they want and use biofuel whenever it's available, and if it's not available that's no problem.
Would prefer helium. Would be much safer as you'd know by the captains voice if there is a dangerous leak 🤔
Doesn't burn as well tho 😀
😂
Super video!!! Thanks!
I just wanted to say I really appreciate your videos. Tackling current, important topics, high production value, clear, interesting, useful. No stupid „weird face on the cover reaction videos“. Thank You.
Yes, no stupid weird faces!😂
@@mapleextOn an ENTIRELY unrelated note, Noel Philips. 🤐
Great video! So few people seem to understand the importance of energy density, but the airlines will be a great proving ground for energy dense green tech. Hydrogen is and ought to be at the top of that list!
Compared to the number of people having gone up in flames from current aviation fuel and plane accidents, I think that it would be safer with hydrogen, which would tend to escape quickly in case of the tank being ruptured, instead of a huge fire for minutes or more.
Well there may be two outcomes:
1. H2 does not combust.
2. When there is right mixture ratio of H2 and O2 and right temperature it can make VERY spectacular explosion similar to that on Space Shuttle Challenger tragedy. Survivability in this instance would be nearly imposible compared to fire.
Well... At the extremely high pressures needed to store gaseous hydrogen densely, a tank rupture would (1) cause quite an explosion merely from the pressure differential being released, and (2) the rapid drop in pressure would freeze a lot of nearby things including people (think of what happens to the temp as you use up a can of compressed air, and multiply it by a thousand times). That's why LH2 rockets store the hydrogen cryogenically - it's less problematic than compressing it. Any high-density energy storage medium is dangerous, whether it's avgas, hydrogen, or batteries.
@@jackyse The Challenger disaster was very different, as it was carrying both hydrogen and oxygen, in the "right" proportions, meaning BOOM. A plane accident would not have such a huge supply of oxygen available for a major immediate explosion. Sure, a fire could start, but it would not "just so" get to the explosive mix, and the hydrogen would rise while mixing. Combustion would be more gradual with the arrival of oxygen, and lots of the fire would be some distance above. Still dangerous to passengers, just not BOOM.
Anyway, suggestions are that the astronauts on Challenger may very well have survived for some time, until crashing. Hard to guess if they were conscious or not. I hope not.
@@JohnnieHougaardNielsen And what about domestic use of gas stoves and reports of explosions? Haven`t heard about that?
@@JohnnieHougaardNielsen All gaseous fuels are inherently dangerous and more so as the equipment ages. If something happened on a liquid natural gas tanker ship in port, it would be like a nuke going off.
I love your videos Peter! The best from Oslo ! 🙂
Thank you team :-) for touching on yet another 'developing story', current affairs news ..vital to the industry.
Somehow to me, the 2035 or anywhere in my lifetime it getting more widely accepted than current fuels.. seems a bit far fetched.
Mainly because.. it seems like a matter of time.. when somehow nuclear fusion would be both compact enough to be made available on waterships, airships.. but also.. somehow sustainable for being incorporated to convert/use all those systems within standard long haul at-least aircraft.
(If not the passenger versions, then the freighter versions).
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Yes hydrogen storage without pressurisation or in liquefied stage might be a challenge.. but aviation industry would surely figure that one out in a safe, cost effective manner.
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However hydrogen being highly combustible and many things in aviation still being a 'oops, we missed that' or there was a human error, lack of adherence to protocol... would mean.. that any incidents or crashes involving direct use of hydrogen as a fuel.. may not end well
Nuclear fusion’s ability to ever supply energy at economic prices is so unlikely that it should be characterized as the fossil fuel industry’s way of distracting us from viable alternatives that are in front of us right now, but not exploited because of their massive propaganda effort against renewables.
Let’s ignore the vast challenges of making, storing, moving and managing cryogenic hydrogen and also let’s ignore the challenges of the huge venting losses associated with handling hydrogen at -253 degC. Incidentally, when said quickly -253 C sounds just like it’s cold but feasible right? In fact it is in fact VERY cold: like the nighttime side of Pluto sort of cold; air is a solid at -215 deg C sort of cold and NASA etc really struggle to manage it even for relatively infrequent space rocket flights, let alone routine aircraft fuelling. No, let’s ignore all of that and let’s just look at the fundamental energy requirements for hydrogen electrolysis and cryogenic liquefaction. For an airport like Heathrow the 24/7 electrical energy demand required to replace jet fuel with liquid hydrogen is around 8GW. So that’s rough;y 8 nuclear power stations required just to supply Heathrow with aviation fuel (and yes, likely nuclear rather than renewable as the power supply needs to be sustained). More power stations would be needed for UK’s other airports.
Then that same sort of supply infrastructure investment needs to be replicated for every other airport that you might want to fly to before you have an airline business.
Like you say, not easy even though folks are working on it.
If such abundant quantities of cheap electrical power is available in future, it may solve a lot of the issues to connect the hydrogen to carbon from the atmosphere such that a kerosene fuel is produced, thereby eliminating all the extra complication, including 100% aircraft fleet replacement.
Using hydrogen in an airship has never gone wrong before. I think it’s an excellent idea!
Watch the video to the end 😉
The Hindenburg fabric was doped with a compound that produced the spectacular flames.
@@danharold3087 solid rocket fuel
@@freeculture Sounds right. Thanks
But does SAF create less CO2 when burned. That’s the concern, not where it’s sourced from.
Oh, Petter! Is hydrogen really safe to use and store these days. Accidents happen, humans make mistakes. Is hydrogen a better option to carry in the case of an air accident, than fuel. Is it less or more flammable. Was that hydrogen we saw being emitted from the ill-fated Challenger flight? I shouldn't worry as I will never fly again, given my age. But why do I worry when you don't, Petter. Compressed hydrogen or no, once hydrogen is no longer contained, does it not act and react as hydrogen would? If their was a leak or explosion at an airport, at the fuel store, or on the runway, would it be easier or more problematic for rescue services to deal with. I know I'm probably asking stupid questions, but stupid or no, I look to be assured by your superior knowledge.
Forgive me and thank you.
Every time you say Hydrogen, people think of the Hindenburg!!! This will cause issues of Trust!
Also both Liquid Oxygen and Liquid Hydrogen expand something like 55,000 times when becoming a gas. Then when you're talking about ultra-high concentrations of Oxygen, anything Organic (cotton, wood, humans) and even some metals (once an ignition source occurs like a burst seal venting a large flame) will BURN!!! Add in the super-rapid expansion from liquid to gas and both O2 and H2 being present = BOOM!!!!!!!!!
Good report on a tricky subject.
I’ll stick with JetA
Then one day you'll be sitting on the ground watching all the hydrogen powered planes flying.
That’s ok.
Remember my dad.. he wanted a electric car for 15-20 years before they was available. He never got to experience it. Things takes time.
I'm not entirely sold that going to net zero for the aviation industry will be important. As it is the amount of green house gases emitted from the aviation industry is small compared to the major sources and I don't think flying is going to grow so rapidly that it EVER becomes a real issue. With the increases in fuel efficiency so far and what will come over the next 20 - 30 years I imagine that's going to be good enough, but I see a global economy where the typical person is tightening their belts a lot more than they are now, and even in countries where people keep wanting to say the typical person is going to be doing a lot better, I'm skeptical. You can look at China for instance and their lift has been an economic boom created by a lot of industry, but more and more their govt. upsets other govts (I don't care about who did what and why because it doesn't change the outcome) and industry is on a slow move out of China.
What's clear is that wealth is leaving the middle class and going to the upper class, around the world and that's going to mean a larger percentage of the global population traveling less. So I just don't see a boom in air travel and I don't see the need to spend billions of dollars trying to solve a problem that isn't big enough to worry about. If anything trying to move to hydrogen will make flying more expensive and shrink the customer base if the industry goes that way, making emissions so trivial no govt will car about it. Today it's about 5% of emissions. It's much easier to get that other 95% down to about 5 - 10% of what it is now than it is getting that 5% down to 1%.
And SAF is NOT a solution, because growing fuel is in NO WAY green. You do the research on it and it's not any better than fossil fuels but it makes farmers rich which is why large investors buy up so much land, that and collecting rents from the world.
I'm glad you mentioned the "emissions" issue with hydrogen: burning hydrogen creates water vapour which then acts as a significant green house gas even though you could claim green hydrogen is carbon zero and sustainable - those terms are a simplification of issues which hides the facts - burning hydrogen for planes should not be done as a result. Now a fuel cell can make liquid water and if its dumped at low altitude would just cause rain - so that would be not so bad. But one of the biggest arguments against green hydrogen is the very low round-trip efficiency in using it as an energy source - you use electricity to electrolyse water (18%-46% efficient) and then use a fuel cell to create power for the electric motors/turbines. When you think about that this approach is not much different to a battery - the only difference is the unchanging weight of a battery - a battery round-trip efficiency is several times that of green hydrogen/fuel cell - we just have to cope with weight. Meanwhile technology progress is reducing the weight problem because more and more energy dense batteries are being produced - the killer advantage of a battery is you do not need oxygen to run a battery, so much higher altitudes could be reached and as a result very much higher supersonic speeds achieved. Also even though a battery plane will expend more energy to get to high altitude, much of that energy could be re-cooped when reducing altitude by using the turbines to charge the battery as the plane falls (VTOL needed). Today's emphasis on hydrogen is more political than sensible - the reality is the oil companies want to produce grey or yellow hydrogen as a way of continuing their business as people steer away from carbon based energy - their excuse will be they'll do green hydrogen later and then never do more than small token amounts. I'd love you to do an episode examining battery solutions and their advantages over hydrogen.
Maybe a video can be done on the research being done on the “WET turbine engine principle” that deals with the condensation trail issue (water vapor is a green house gas) and can increase the engine efficiency.
“MTU and Pratt & Whitney presented an EU Clean Sky project where they are developing an advanced engine concept based on the Pratt & Whitney GTF. The project is called SWITCH, an acronym for Sustainable Water-Injecting Turbofan Comprising Hybrid-Electrics.”
AND:
Pratt & Whitney’s HySIITE (Hydrogen Steam Injected, Inter‐Cooled Turbine Engine) which achieve thermal efficiency greater than fuel cells.