Hydrogen fuel could revolutionize airlines - Los Angeles Times

[TLoraine]

Samantha Masunaga of Los Angeles Times has written an article looking at hydrogen fuel....

Hydrogen fuel could revolutionize airlines. Here’s how that could look

Global airline travel has grown over the decades, and with it, so have the industry’s carbon emissions.

Not everyone has the time to use more eco-friendly travel methods, like Swedish climate activist Greta Thunberg’s famous two-week voyage last year across the Atlantic Ocean on a zero-emissions sailboat.

But can the airline industry shrink its carbon footprint, which currently makes up 3% of all U.S. greenhouse gas emissions? The answer hinges on development of alternative fuels.

Last month, European aircraft maker Airbus announced it would evaluate three concept planes, each of which would be primarily powered by hydrogen. The goal is to figure out an aircraft design and manufacturing process so the hydrogen plane could potentially enter commercial service by 2035.

“Alternative fuels are the key to unlocking air transportation emissions,” said Megan Ryerson, the University of Pennsylvania’s UPS chair of transportation and an associate professor of city and regional planning and electrical and systems engineering. “Without them, we either have to stop flying or make drastic cuts in other sectors.”

There’s a lot researchers like about hydrogen. For one, it’s incredibly energy dense — more so than jet fuel, and much more than current battery technology. It’s also plentiful and burns cleanly, producing no carbon dioxide or carbon monoxide.

“Hydrogen is an amazing fuel,” said Gozdem Kilaz, an associate professor at Purdue University’s school of engineering technology. “It is theoretically a wonderful fuel option.”

But there are technical and logistical challenges that need to be resolved.

As demonstrated by the 1937 Hindenburg airship disaster, the fuel is extremely flammable. And figuring out where in the plane to put it requires a brand-new aircraft design. Hydrogen is a gas at room temperature, so to store the fuel as a liquid — which takes up less space — hydrogen tanks would have to be more sturdy and high-pressure than those that hold traditional jet fuel. Such tanks would be too heavy to fit in a plane’s wings, where jet fuel is currently stored.

That means other parts of the aircraft will probably be repurposed for storage, said Amanda Simpson, vice president for research and technology at Airbus Americas.

The other major issue: a lack of infrastructure. Unlike with jet fuel, there are no established pipelines or facilities at airports where planes could fill up. Creating that infrastructure would be expensive and would probably require buy-in from governments and industry players across the globe.

If single-aisle passenger planes worldwide were to run on hydrogen, airlines would buy about $320 billion of the fuel per year, said Paul Eremenko, chief executive of fuel logistics firm Universal Hydrogen Co. That’s a lot, he said, but it still doesn’t necessarily justify building out such an expensive infrastructure system.

That’s where his company would step in. Universal Hydrogen, which plans to establish headquarters in Los Angeles, is developing a type of capsule technology that would enable either liquefied or gaseous hydrogen to be shipped using the existing freight shipping system and delivered to airports to fuel up planes.

Eremenko described the company’s business model as similar to that of companies that make Keurig or Nespresso drink pods. The company doesn’t want to produce hydrogen or build fleets of hydrogen-fueled planes. Rather, it wants to license the capsule technology and connect those two ends of the hydrogen supply chain.

The start-up plans to begin service with regional airlines in 2024 and has so far focused on design of the supply system and some prototyping. It does not yet have confirmed supply contracts.

Over the next year, Universal Hydrogen plans to do a full-scale demonstration of its capsules and work on its aircraft conversion kit, which would help airlines convert their planes to run on hydrogen. The company plans to offer to subsidize the conversion in exchange for a long-term contract, said Eremenko, who previously worked at Airbus and aerospace conglomerate United Technologies.

“We are relying just on the sheer economics of hydrogen,” he said. “The reception from the operators has been very positive.”

On the manufacturing side, the challenge is to figure out how hydrogen best powers a plane.

In one of Airbus’ concepts, a plane with a turbofan engine would be powered by hydrogen fuel and be able to carry 120 to 200 passengers for more than 2,300 miles. In another idea, more suitable for short-range trips, a turboprop engine powered by hydrogen would be used.

Airbus’ investment to develop a hydrogen aircraft will be “sizable,” Simpson said. Although Airbus hasn’t tabulated an exact cost, Simpson said it could be in the millions of dollars. Engines are a big part of the investment, but so are the systems for handling fuel and getting it aboard an aircraft. Investments would also be made by governments, research institutes and industry players around the world, Simpson said.

The company plans to spend the next five years focused on technology development before reaching the design and manufacturing stage.

Airbus is also looking at the potential emissions from burning hydrogen.

Water vapor is one. But there also could be a “trace amount” of atmosphere-warming nitrous oxide, Simpson said, though it would be “extremely small” compared with the amount from conventional jet fuel propulsion.

The final decision on whether a hydrogen plane is ready for commercial service will “come down to the economics and the supportability and, quite frankly, our customer interest,” Simpson said. “Showing the technology is feasible and that it’s economical is key.”

Hydrogen is just one option Airbus is considering. The company is also looking at hybrid hydrogen-electric planes and all-electric planes. It has made some inroads on the all-electric front: In 2015, a two-seat Airbus electric plane crossed the English Channel.

But experts say limitations in battery technology make electric planes less feasible for conventional air travel. The most important consideration for a plane is weight, and without a major breakthrough in battery technology, jet fuel is still lighter and provides more energy.

Another option is biojet — that is, a subset of biofuels that mimics the behavior of conventional jet fuel.

Unlike with hydrogen or electrification, biojet could be used in current planes largely as they are, without requiring any engine changes or major shakeups to fuel infrastructure.

“The burden of switching over doesn’t lie with the airline industry,” said Tonghun Lee, a professor in the department of mechanical science and engineering at the University of Illinois at Urbana- Champaign who researches alternative clean fuels. “That’s why I think it’s a more feasible solution.”

But biojet is expensive. And burning it still spews carbon into the air, though its net carbon emissions are lower because the first step in producing the fuel is to grow organic matter, such as plants, that absorb carbon dioxide.

It also can’t stand alone yet. ASTM, an international standards organization, has approved only blends — biojet mixed with conventional jet fuel — in order to meet performance requirements and safety concerns. Even the highest-percentage blend is only half biojet.

More collaboration between government, businesses and academia would be needed to effectively produce biojet in mass quantities in the future, Purdue’s Kilaz said.

While these fuels are developed, airlines will have to decide whether they will adopt them. After all, many are reeling from a steep loss in revenue caused by the COVID-19 pandemic, and buying new aircraft is a pricey proposition, especially if airlines have older aircraft in storage.

“Airlines aren’t necessarily motivated by the environment,” said Ryerson of the University of Pennsylvania. “If making profit and reducing their greenhouse gas emissions works together, they will invest in reducing greenhouse gas emissions. But if those two things are not tied, they will favor making a profit.”

[PEI_3721]

Airbus view:-

https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html

https://www.airbus.com/newsroom/stories/these-new-Airbus-concept-aircraft-have-one-thing-in-common.html

https://www.airbus.com/newsroom/news/en/2020/10/hydrogen-fuel-cell-cross-industry-collaboration-potential-for-aviation.html

[Dan Dare]

I spent most of my life convinced that the clean-burn of Hydrogen had to be the future of our automotive and aviation needs: right up until I l recently learned about how difficult it can be to contain it and that in gaseous form it is so buoyant that it can escape our atmosphere. I can see Greta's grandchildren protesting our missing water as all the Hydrogen has disappeared in to space.

[Pugilistic Animus]

Absolutely not!

[KingAir1978]

Ok let me just put the elephant back in the room, because it seems to be missed... HOW do we get the hydrogen?! Ow that's right; we electrolyse H2O. Ah ok, simple. How do we get enough electricity for that? I know what, let's burn coal...

[Momoe]

Hydrogen obtained by electrolysis of water isn't particularly efficient, Hydrogen production (https://www.hindawi.com/journals/cpis/2013/690627/) has moved on considerably. Granted, it still requires energy but that could be provided by green/nuclear electricity, thus not contributing additional CO2.
Also the newer methods 'crack' higher end fossil fuels, which is a win-win, oil industry keeps producing, raw materials for plastics/petro-chemical industry readily available and CO2 reduced dramatically.

[Less Hair]

Hydrogen use means nuclear energy use given the amount of electrical power needed to generate it. There is not enough "green" energy to generate all the hydrogen needed. There is no free lunch.

[TURIN]

Methane. Thats the future.

https://www.wired.co.uk/article/spacex-raptor-engine-starship

[ATC Watcher]

There are a lot of Elephants in the rooms right now regarding new forms of energy to replace fossil fuels . The largest is indeed how to "produce" those alternative energies ,Nuclear fusion reactors are being mentioned to give the necessary electricity , but its technology is not yet mature and their environmental impact is only Zero when they work correctly.:E So Greta has still some future ..
Another elephant for the future electrical transpiration future system we are told is coming ( whether aircraft or cars) is the cost of the batteries re-loading . Not only the Kw needed , but also the cost of setting up the recharge stations in sufficient numbers everywhere including the cabling / transportation required. This infrastructure will have a huge cost that will have to be passed on to the user..

[lomapaseo]

Sounds like Perpetual motion. What fuels the inefficient manufacture of another fuel? That's where the trades should be.

The cleanest way is back to wind power or to pipe volcanic gasses to the manufacture of fuel

[Momoe]

Less hair,

Re-read my post re "green/Nuclear energy", I'm not saying that nuclear energy is green (That's another debate), it's non CO2 producing which is the point. By using fossil fuels without having to burn them to create energy, we keep an entire industry sector running, plastics don't grow on trees unfortunately.

Free lunch is still on the table

[ericoides]

Whatever they come up with, as well as being carbon neutral, it must satisfy two criteria:

No, or little, noise.
No contrails, such as currently disfigure our skies like some sort of careless straight-line graffiti.

[tartare]

Isn't the problem that it can't be condensed enough to a volume to carry in a conventional airframe, due to pressure, temperature requirements?

[Ascend Charlie]

Take Jurassic Park's dinosaurs, bury them for a million years, there's your oil. Simples.

[George Glass]

Yawn.
Hydrogen as a fuel has been proposed for over a hundred years.
It hasn’t worked for over a hundred years for the same reasons.
It will only work if fossil fuels are priced out of the market by a carbon tax.

[Momoe]

Tartare,

Hydrogen is relatively energy dense, about 3 times Jet A-1, problem is it's the lightest element and even in liquid form under pressure, it's about 4 times the volume of the same amount of Jet A-1.

This would mean larger fuselages as more efficient to have large tanks in fuselage, larger wetted area but less weight, wings would need a redesign as without fuel tanks, a stronger, more rigid structure is required. Double bubble fuselage might work just fine.

[tartare]

Good luck.
Some very smart people have tried and abandoned hydrogen fueled designs...
https://en.wikipedia.org/wiki/Lockheed_CL-400_Suntan

Skip past the ads - this is quite an informative video on Suntan:
https://www.youtube.com/watch?v=UzIS5KSG7Uk

[Less Hair]

This is where we are.
https://youtu.be/pz5IG88g50w
https://www.youtube.com/watch?v=ZtZCubRfIyU
The soviets tested some converted Tu-154 with one engine on hydrogen as well.

[Uplinker]

.............This would mean larger fuselages as more efficient to have large tanks in fuselage, larger wetted area but less weight, wings would need a redesign as without fuel tanks, a stronger, more rigid structure is required. Double bubble fuselage might work just fine.

As you allude to, empty wings are not ideal, since if the fuel was contained within the fuselage, stronger wing spars would be required to support that fuel weight. Maybe put pax baggage in the wings ?!! :)

A solution for a hydrogen tank equipped aircraft might be the 'flying wing' blended body type?

I have to say though, I feel nervous about having large highly pressurised tanks anywhere on an airliner.

[Deltasierra010]

Hydrogen is not “energy dense” liquid hydrogen needs 5 times the volume to match jet fuel, moreover it needs to be compressed and refrigerated, less of a problem at 30,000 ft but critical on the ground, we are highly unlikely to see airliners fueled by hydrogen. Although it would be possible to fill the hold with hydrogen cylinders and carry less paying cargo. For road vehicles battery electric is the technology developing now, are we really expecting a separate distribution system for hydrogen to be rolled out nationwide, although it may have applications in specific places.

[tdracer]

Hydrogen is not “energy dense” liquid hydrogen needs 5 times the volume to match jet fuel, moreover it needs to be compressed and refrigerated, less of a problem at 30,000 ft but critical on the ground, we are highly unlikely to see airliners fueled by hydrogen.
Yea, I laughed when I saw that little 'energy dense' tidbit in the article (apparently there is a reason we don't let reporters design aircraft). Yes it's light, but you need many times more volume. To be even remotely viable, the H2 tanks need to be spherical or cylindrical - so you're not going to be carrying it the wing. Worse, even though it's light relative to Jet A, you're still going to need a lot of it to go very far, so you need to store it near the aircraft CG to maintain acceptable trim as it burns off. So what you're going to end up with is a massive H2 tank in the middle of the fuselage - which needs to have fail-safe segregation from passengers and crew. So what you're apt to end up with is passenger/cargo space in the front and rear, with a massive fuel tank in between. At best, a complete re-think of aircraft design and layout.
Biofuel (probably based on algae) is a far more viable long-term solution than H2 - with the added advantage that it would work with today's aircraft...

[Deltasierra010]

Hydrogen fuels can be reformed into many different fuels, for Aviation weight and volume are critical, when land transport is fully non fossil fueled liquid fuels will still be used for Aviation, unless some yet unknown technology is discovered. Safety is a different matter, it is not possible to segregate passengers and compressed fuel in an airline, any fault would destroy the whole thing so either you accept that risk or forget it.

Limited range light aircraft have possibilities either Battery powered or Fuel Cell electric, wether that is within the price range of recreational pilots is another matter

[jolihokistix]

@tdracer, "...with a massive fuel tank in between".

Could that not be two medium-sized tanks, or even four little 'uns? Granted that you waste space between the cylinders, and you face interchangeability problems.

[Check Airman]

Whatever they come up with, as well as being carbon neutral, it must satisfy two criteria:

No, or little, noise.
No contrails, such as currently disfigure our skies like some sort of careless straight-line graffiti.



I can’t tell if this is serious or satire.

[Momoe]

By energy dense, I'm referring to the potential energy per kg compared to Jet A-1, this is not related to volume.

Relative energy densities (https://en.wikipedia.org/wiki/Energy_density#/media/File:Energy_density.svg)

[Deltasierra010]

By energy dense, I'm referring to the potential energy per kg compared to Jet A-1, this is not related to volume.

Relative energy densities (https://en.wikipedia.org/wiki/Energy_density#/media/File:Energy_density.svg)

The only density that matters is how much volume of fuel you need to travel a given distance, a heavy fuel like gasoline is 5 times more efficient than liquid hydrogen. In any moving vehicle that is important, if it’s a static installation, no problem you can pump it along a pipeline uncompressed.
But then there would be no point, you could have used the electricity directly, or store it in batteries, current technology is moving that way, not hydrogen. We need a quantum leap in technology for hydrogen to be more efficient.

[Less Hair]

We need a quantum leap in battery technology before any big commercial airplane can fly with electrical battery power. This view is undisputed within the industry and this is the reason why big manufacturers look elsewhere likte at hydrogen.

[Deltasierra010]

Battery power is out for large long range jets, it’s going to be hydrogen based that’s for sure but not compressed gas, the technology we have now has been around for many decades we need something new, that’s for batteries as well as hydrogen

[infrequentflyer789]

So what you're going to end up with is a massive H2 tank in the middle of the fuselage - which needs to have fail-safe segregation from passengers and crew.

Or you could put strap a really big, uncompressed H2 tank on top. Would add massive drag, so speeds would be limited, but on the other hand it would provide lift. Might take longer to get from A to B but given the need for 14 days quarantine at B anyway, there may be les of a rush in future. Add emergency H2 (or Jet A1) tanks somewhere, say in the wings :-), and an ejection mechanism for the "tank" and you've got that fail-safe segregation.

Biofuel (probably based on algae) is a far more viable long-term solution than H2 - with the added advantage that it would work with today's aircraft...

Or synthetic fuel produced from carbon capture by chemical process. Definitely the easier way to go, utilising all existing infrastructure, if such a process (or algae) can be found and scaled up. That is the bet that is being hedged with H2 R&D.

[flypaddy]

One major advantage that hydrogen has over batteries is that you are not carrying the full weight of the reactants around with you. You carry the hydrogen (which gets consumed throughout the flight) but you don’t need to carry the oxygen as it is in the air through which you fly. A battery must carry all reactants throughout the flight and what’s more, will weigh just as much on landing.

Over a decade ago I was lectured on the exciting possibility of storing hydrogen in a “carbon sponge” which went some way to alleviating the fears of explosion of hydrogen tanks in a car accident. I haven’t since heard much on this technology!

[Less Hair]

With a battery aircraft every landing is overweight.

[jolihokistix]

Not if you take off from a hilltop aerodrome using a ground-based battery-powered catapult, and release used batteries along the way, which then self-glide to collection points.

[TURIN]

Not if you take off from a hilltop aerodrome using a ground-based battery-powered catapult, and release used batteries along the way, which then self-glide to collection points.
The Electron Rocket does this very cool 'hot battery swap' with it's second stage. The turbo pumps are electrically driven, powered by Li-Po batteries. When the first two batteries are exhausted, it automatically switches to the third battery and jettisons the first two. At the moment they burn up on reentry but recovery and re-use is not impossible.
About 33 minutes into this video.

https://m.youtube.com/watch?v=_6SxcO-fHEU

[Vessbot]

The turbo pumps are electrically driven

​​​​​​In other words, "the pumps" ;)

[tdracer]

Over a decade ago I was lectured on the exciting possibility of storing hydrogen in a “carbon sponge” which went some way to alleviating the fears of explosion of hydrogen tanks in a car accident. I haven’t since heard much on this technology!
The problem with the 'sponge' technology that absorbs H2, then releases it slowly is that it's heavy - even for an automotive application. The one I looked at (many years ago) - a 'sponge' that could hold enough H2 to equate to a ~20 gallon fuel tank weighed nearly two tons. Troublesome for an auto - non-starter for an aircraft.

Something I didn't mention previously - liquid H2 has another problem: The cryogenic temperatures involved are very hard on the materials used. This means a massive maintenance burden to keep the system working properly and safely. Rocket engines and the associated hardware (pumps, etc.) only operate for minutes, then are either discarded or rebuilt before they are used again - not a practical solution for an aircraft that is expected to operate eight or more hours a day, every day, for years...

[FakePilot]

So if you put AI and hydrogen together, which revolutionizes which?

[Ex Cargo Clown]

Methane. Thats the future.

https://www.wired.co.uk/article/spacex-raptor-engine-starship

Pretty sure combusting methane creates CO2

[tdracer]

Pretty sure combusting methane creates CO2
However if you manufacture the methane using CO2 from the atmosphere, it can be carbon neutral (depending on the source of the energy used in the process). Same basic theory as biofuels.

Being 'carbon neutral' doesn't have to mean moving away from hydrocarbon fuels - it just means you need to re-think how you source them.
Given the inefficiencies inherent in using H2 as fuel, I remain far from convinced it's a better solution than 'manufacturing' hydrocarbon fuels.

[Deltasierra010]

Whatever the fuel of the future for air transport is it wont be liquid hydrogen, far too dangerous, technically difficult and expensive. Maybe Ethanol or some other liquid synthetic fuel but that is way in the future, as land transport moves to electric there will be ample fossil fuel for aviation for at least 50 yrs and probably way into the next century.
Until there is a quantum leap in hydrogen technology it will remain the holy grail of energy.

[radiosutch]

They may have to take out the chemtrails tanks to fit the H2 tanks.

[TURIN]

​​​​​​In other words, "the pumps" ;)

Er, yes, quite. 😁

But you know what rocketeer are like. Turbo pump sounds so much more exotic.

[Ex Cargo Clown]

Been a while since I studied chemistry, but you can create H2 from CO2 and CH4. However this isn't so simple. H2 as the H2 produced has a nasty habit of reacting with the CO2 at low energies. Good for power stations etc,not so good as a fuel source. At a push (although I've never seen it) I'm guessing you could use Sabatier reaction conditions. and end up with CH4 but use a load of CO2 in the process. Not very efficient though.

[ericoides]

I can’t tell if this is serious or satire.
Why on earth not? It's self-evident to all but the plane-crazy that aeroplanes make an unpleasant noise and mess up the sky with their exhausts. Take a walk in the "World Heritage Site" that is the British Lake District one day. You go for peace, quiet and tremendous views, and return having experienced the continuous daily racket of the Manchester to Glasgow, Paris to New York etc etc flights and the azure sky criss-crossed with numerous trails. Not ideal, although doubtless the people off on their jollies abroad will have a great time, perhaps in turn having their own peace and quiet ruined by the thunder overhead. And so it goes, man handing on misery to man. Planes may have ther good points too, but the noise and the sky-graffiti should be, and in the case of the noise, are being, addressed.

[Ex Cargo Clown]

Why on earth not? It's self-evident to all but the plane-crazy that aeroplanes make an unpleasant noise and mess up the sky with their exhausts. Take a walk in the "World Heritage Site" that is the British Lake District one day. You go for peace, quiet and tremendous views, and return having experienced the continuous daily racket of the Manchester to Glasgow, Paris to New York etc etc flights and the azure sky criss-crossed with numerous trails. Not ideal, although doubtless the people off on their jollies abroad will have a great time, perhaps in turn having their own peace and quiet ruined by the thunder overhead. And so it goes, man handing on misery to man. Planes may have ther good points too, but the noise and the sky-graffiti should be, and in the case of the noise, are being, addressed.

Is this a wind-up? What us unpleasant about an aircraft noise? I find lawnmowers far more annoying, shall we ban them? Oh, and if you can hear Paris - NYC departures in the Lake Ditrict, you mut have bloody good hearing. It would be so quiet (if audible at all). Do ticking clocks 100 yards away annoy you as well.

[Rocchi]

xxxxxxxxxx

[FakePilot]

Who cares how much volume is used by the hydrogen? The lift of the hydrogen easily overcomes the weight of the any structure needed to contain it.

[tonytales]

Fake Pilot
No lift from hydrogen in its liquid form. If you use gaseous hydrogen as the fuel, you couldn't store enough to fly any distance, energy density is too low.

[Rocchi]

I withdraw....

[Ex Cargo Clown]

Gaseous hydrogen = airship and not very fast. No wings required.

Someone please close this thread. It's been invaded by loonies.

Personally I'd go for tractor beams, never mind discussing why hydrocarbon fuels have a vastly higher energy density than H2.

[jolihokistix]

Can someone quickly comment on the proposed (re)use of CO2 in making aviation fuel?
https://www3.nhk.or.jp/nhkworld/en/news/20201202_27/

Major Japanese air carrier All Nippon Airways will begin developing fuel made from carbon dioxide in cooperation with several other firms.
The group, including Toshiba, Toyo Engineering and Idemitsu Kosan, aims to put the new fuel into practical use in the latter half of the 2020s. The group plans to produce the fuel by chemically treating CO2 emitted from factories and other sources through technologies owned by Toshiba and Toyo Engineering.
The developers will work to clear several challenges. They include fuel quality and profitability, and whether the fuel can be produced and supplied steadily. ANA started passenger flights using fuel made from food waste in November. The company says the CO2-derived fuel is expected to be able to reduce net emissions further. The aviation industry is in a difficult position on environmental issues, especially in Europe, as aircraft produce more CO2 emissions than trains and other transportation means.

Air carriers are rushing to take action as CO2 emission restrictions on international flights will be introduced next year.

And last year discussed in the BBC
https://www.bbc.com/news/business-49725741#:~:text=Based%20at%20the%20airport%2C%20it,be%20tra nsformed%20into%20jet%20fuel.​​​​​​​

[Checkboard]

It's either a cynical PR exercise, or (more worrying) some idiot has scammed a politician/business person without any idea of science.

Plant a tree - much more efficient way to take CO2 out of the air. Trees are solar-powered CO2 capture machines.

If you're going to make CH2-polymer fuels from CO2 then you have to put in as much energy into that process as burning the fuel gives you for the reverse reaction. It's called the law of conservation of energy. In that sense, liquid fuel is just a "battery" for energy - oil is years of solar energy, stored in CH2 bonds.

If you're going to "make" fuel from CO2 - where is the energy you're going to need to do that coming from? The local coal powerplant? That's on top of the energy cost of collecting the CO2 in the first place, when it only makes up 0.04% of the atmosphere. (So, if you have a 100% efficient collection process, getting a ton of CO2 will need you to pass 2500 tons of air through your collector - and those pumps and whatnot are lost cost - you haven't even started trying to reduce the CO2 to hydrocarbon fuel yet.)

[jolihokistix]

And the (cold) reality pours in. Thank you!

[Peter47]

Carbon capture may be the next big thing although it might double the energy cost for fossil fuel plants. It could be that a power station would pay you to capture the CO2 (although unless the facility was burning biomass the exercise would not be carbon neutral once the jet fuel was burnt). Its like cryogenic storage of hydrogen, very useful as a demonstration exercise but certainly not practicable in the short term. If you want to make fuel from CO2 I would grow seaweed and work out how to convert that to jet fuel - although the work so far hasn't been that successful, there could be a breakthrough in the future.

[Rivet gun]

Maybe there could be a synergy between nuclear energy, cement production and aviation.

Build a small modular reactor (such as Moltex) on the same site as cement works.
Reactor provides heat for the cement making process as well as producing hydrogen from water.
CO2 is captured from the cement making process and combined with the hydrogen to make liquid hydrocarbon fuel for long haul aviation.

CO2 is emitted when the fuel is burnt, but...
Cement is made into concrete structures which absorb CO2 during their lifetime.

[ThreeThreeMike]

Why on earth not? It's self-evident to all but the plane-crazy that aeroplanes make an unpleasant noise and mess up the sky with their exhausts. Take a walk in the "World Heritage Site" that is the British Lake District one day. You go for peace, quiet and tremendous views, and return having experienced the continuous daily racket of the Manchester to Glasgow, Paris to New York etc etc flights and the azure sky criss-crossed with numerous trails. Not ideal, although doubtless the people off on their jollies abroad will have a great time, perhaps in turn having their own peace and quiet ruined by the thunder overhead. And so it goes, man handing on misery to man. Planes may have ther good points too, but the noise and the sky-graffiti should be, and in the case of the noise, are being, addressed.


Your objection about the aesthetics of contrails brings to mind the obvious eventual result of "carbon free" electricity production using wind turbines, solar farms, and battery storage.

The physical installations needed to provide replacement for power that is now produced with fossil fuels will eventually cover practically every ridgeline, prairie, and desert on earth. The adoption of nuclear powered generation would provide an alternative whose footprint would compare favorably with current fossil fueled powerplants, but that is, of course, out of the question.

It appears that so far this has not occurred to the proponents of green energy production.
​​​​​​​

[tdracer]

If you're going to "make" fuel from CO2 - where is the energy you're going to need to do that coming from? The local coal powerplant? That's on top of the energy cost of collecting the CO2 in the first place, when it only makes up 0.04% of the atmosphere. (So, if you have a 100% efficient collection process, getting a ton of CO2 will need you to pass 2500 tons of air through your collector - and those pumps and whatnot are lost cost - you haven't even started trying to reduce the CO2 to hydrocarbon fuel yet.)

The idea of 'making' hydrocarbon fuels is not new (think of the synthetic petroleum the Germans used during WW II) - although the rational is changed. The Germans used coal to make petroleum - the new plan is to make petroleum from CO2 and hydrogen using excess electricity. It won't be cheap, and it's dependent on a plentiful supply of 'green' electricity, but it's far from pie in the sky. One of the problems with most 'green' electrical production is that it isn't consistent (solar) or reliably predictable (wind), meaning sometimes you're going to have large surpluses or large shortages. Using those periods of large surplus to manufacture hydrocarbon type fuels is one way to balance out the peaks and valleys.

Personally I think bio (algae) based hydrocarbon fuels are the future of aviation, but assuming we can create large scale 'green' electrical electrical generation, manufacturing hydrocarbon fuels is certainly a viable option.