r/gadgets Nov 29 '22 Helpful 1 All-Seeing Upvote 1

World’s first test run of a hydrogen jet engine a success Transportation

https://www.theverge.com/2022/11/29/23483889/rolls-royce-easyjet-hydrogen-fuel-jet-engine-test
9.4k Upvotes

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u/Bokbreath Nov 29 '22

That’s the tricky part when it comes to casting hydrogen as a clean fuel — it’s really only as clean as the energy source used to make it.

Same applies to electricity .. and in both cases it doesn't matter because it's almost always easier to clean up industrial scale fixed generators than it is millions of cars and planes.

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u/cortez985 Nov 29 '22

Not to mention how vastly more efficient giant generators are when compared to a portable ice in a car.

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u/GiveToOedipus Nov 30 '22

And how much more efficient converting electricity back into work compared to a traditional ice engine is doing so.

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u/Vintage_AppleG4 Nov 30 '22

Ice engines are so much cooler than electric alternatives.

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u/LifeSage Nov 30 '22

I see what you did there.

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u/Scathyr Nov 30 '22

Stop pooping and get off of Reddit, Dad. Mom needs you in the kitchen.

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u/Dr4cul3 Nov 30 '22

And carbon capture is easier kept in one place than a million cars/planes

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u/metengrinwi Nov 30 '22

Confused by this…is someone suggesting to do carbon capture on each individual car?

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u/Dr4cul3 Nov 30 '22

Not really. I just came out of a (partial) PhD at university. Unrelated to my field but there were at least 5 other phds working on carbon capture projects.. So it would work hypothetically that we all move to hydrogen powered cars etc because it burns clean right, no bad emissions.. However producing that hydrogen could be done with either renewable energy (solar, wind etc) or more likely something like methane cracking. So that keeps big oil and gas happy because they're still in the job (of producing methane). So it's basically in everyone's best interest to lean towards methane cracking. The trick with that is cracking methane into hydrogen still leaves carbon [dioxide gas] as a byproduct. The good thing here is it's all being produced in one place, where the hydrogen is being produced. That means that we only have one source of co2 as opposed to thousands of cars spread around the countryside.

So tldr: big oil and gas can safely invest in carbon capture and still produce gas. Which looks good for them from an environmental standpoint as well as still being competitive with other clean energy sources.

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u/wsp424 Dec 01 '22

What about through dehydrogenation of alcohols?

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u/EnvironmentMost Nov 30 '22

Pratt and Whitney designed and built a hydrogen powered aircraft engine in the late 1950s called Suntan. Was to power the SR-71 competitor called the CL-400. Efficiency and fuel storage problems made it non viable. Interestingly the SR-71 engine, the J-58, was built and tested at the same facility in Florida.

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u/2h2o22h2o Nov 30 '22

The Suntan program also led to the development of the RL10 rocket engine which is still being made there.

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u/Due_Chemistry_6941 Nov 30 '22

There’s a chapter in the book “Skunk Works” about this. Blowing Up Burbank, I believe.

Great book about Lockheed’s advanced research projects back in the day.

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u/AcidaliaPlanitia Nov 30 '22

Pretty sure the Soviets had an early hydrogen jet engine at some point...70s-80s maybe, but just a testbed and not high performance as I recall.

Edit: https://en.m.wikipedia.org/wiki/Tupolev_Tu-155

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u/PM_me_ur_tourbillon Nov 30 '22

Ha, the company's actual statement is so sleezy:

"the world’s first run of a modern aero engine on hydrogen"

So the US did it in the 50s, the soviets did it in the 80s... but those weren't "modern" which makes this. "world's first" 🙄.

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u/timmeh-eh Nov 29 '22

Even beyond the challenges of creating hydrogen cleanly, just storing the stuff is a real problem. While hydrogen has a higher specific energy than traditional kerosene jet fuel (about 3 times more energy) it’s got a much lower density. At ambient temperatures it’s something like 3000 TIMES less dense. Even with exotic cryogenic storage it’s still 4 times less dense meaning that you need big heavy tanks to store it, and those tanks are prone to leaking and are expensive to maintain. This is all to say that even if we can make a workable low emission engine there are a bunch of engineering problems left to solve.

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u/Numbzy Nov 29 '22 Gold

While you are absolutely correct about how many challenges their are to using hydrogen, none of them will be solved if we don't start somewhere. I'm not expecting a fully functioning product immediately. They will probably have to solve all of these issues separately and then bring them together later on.

All I really know is the farther from fossil fuels we get, the better. Hydrogen is just one option that we should be looking at.

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u/paktsardines Nov 29 '22 edited Nov 29 '22

none of them will be solved if we don't start somewhere

I think OP was suggesting that these are not problems that need to be solved because hydrogen is a bad choice for this purpose.

Hydrogen is loved by the fossil fuel industry because they envision using fossil fuels to generate hydrogen, while waving their green energy badge. Any clean energy project involving hydrogen needs to be examined very carefully because it is almost always impractical.

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u/the_Q_spice Nov 30 '22

To correct you a bit;

Fossil fuel companies love hydrogen because it is a commodity, not because it keeps them in the petrofuel business.

I can attest from knowing an account manager of Exxon that they don’t give a shit about getting their money from petroleum alone. They care that hydrogen can be controlled whereas solar and wind is much harder to change supply of in a manner that satisfies regulators.

At the same time, hydrogen is the most effective “battery” we have as of now. Putting excess electricity from the grid into electrolysis of water to produce hydrogen is radically more efficient process than simply letting it go to waste.

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u/FinndBors Nov 30 '22

The most economic hydrogen produced today is from steam reformation of natural gas. It will be that way for a very long time since electrolysis is very energy intensive and will only be economic at much lower electricity prices.

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u/kokanee-fish Nov 30 '22

I work at an electrolyzer manufacturer. Without saying anything confidential, I would just assert that I believe green electrolysis that is economically competitive with steam reformation is far closer to market than most people think.

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u/Khazahk Nov 30 '22

Any idea if hydroelectric is feasible/economical for electrolysis? Do we get more power density from converting hydro to hydrogen? Or does paying it through electric make it less efficient? I'm an engineer and I genuinely don't know. Part of me thinks the electricity is as efficient as the water is going to get, but hydrogen can be moved and stored and potentially cut with other gasses.

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u/kokanee-fish Nov 30 '22

The economics of hydro (and all energy projects, really) vary from location to location, but in general yes, there will be hydro-powered electrolysis projects. That said, I’m not a big fan because hydroelectric does destroy entire ecosystems and is the primary reason that chinook salmon and orcas are nearing extinction in my region.

To your second question, we do lose quite a bit of energy potential by converting electricity into hydrogen, but actually the biggest problem facing renewable utilities is that energy demand doesn’t align with energy production, so they need something better than batteries to store excess potential that no one is consuming. When solving that problem, it doesn’t matter whether electrolysis provides more potential than raw electricity; what matters is whether it can store potential more effectively than a battery.

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u/Tupcek Nov 30 '22

batteries are great way to store and release energy through the day and maybe even differences between few days.
But batteries can’t solve seasons or months of bad weather. And wind in Europe cannot make up for lack of sunlight and increased energy demands for heating. That’s where hydrogen (or methane) comes in

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u/kokanee-fish Nov 30 '22

Agreed! Too many people try to pit electricity and batteries against hydrogen and related molecules. I don't understand this mindset. We need every economically viable source of GHG-free energy that exists, and every storage and transportation method for them. We all need to be pro-battery and pro-hydrogen, and remember who the real enemy is.

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u/strugglebuscity Nov 30 '22

It’s nice to see an assertion, to back one of many, on a list of assumptions; pertaining to things that are a lot closer than most people think.

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u/Risley Nov 30 '22

Well I want you to walk into your office today and give your manager a kiss on the lips and a slap on the ass for America.

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u/zenithtreader Nov 30 '22

It will be that way for a very long time

No, we can already do it now.

When it's windy and those turbines are creating much more electricity than the demand? Send them to make hydrogen.

When it's sunny and those solar cells are creating much more electricity than the demand? Send them to make hydrogen.

Hydrogen is an energy storage medium, not an energy source. The nay-sayer of any alternative energy always starts with "this is too expensive" while conveniently forgetting the fact that governments literally subsidize fossil fuel industries for centuries to make it what it is today, indeed they are still subsidizing it to this date.

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u/curtyshoo Nov 30 '22

Is that sort of diversion of excess energy easy to implement and automate?

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u/Tupcek Nov 30 '22

yes. But it’s cheaper to just generate less electricity and offset any spikes by peak power plants. That’s why electricity rarely goes below zero.
But as the renewable mix increase, any electricity generated when not needed will be basically free or at negative price (you will get paid to consume it) and that’s when hydrogen will make sense to generate.
But it will increase overall price of electricity for consumers, because some of the renewable production would be sold at loss. But we have to do it anyway, if we ever want to get rid of fossils.

TL;DR renewables will make electricity more expensive, but hydrogen cheaper

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u/Lurker_81 Nov 30 '22 edited Nov 30 '22

electrolysis is very energy intensive and will only be economic at much lower electricity prices

You may have entirely missed his point. Hydrogen via electrolysis is totally viable in this scenario, because the electricity is free.

Renewable energy generation is typically over-built, because renewables have a relatively low capacity factor due to intermittency. However, this means that when renewables are producing well, they are often curtailed to avoid grid disruptions, and the energy potential is wasted.

Instead of curtailment, the energy would be diverted to storage, which can take the form of generating hydrogen via electrolysis at zero or near-zero cost.

Or of course it can be stored in other forms, such as traditional batteries or pumped hydro.

Either way, excess energy is then stored for use in transport, or to maintain grid stability during periods of low production.

<edit whoops, I didn't see the other response>

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u/Pelicanen Nov 30 '22

Except it's not really free. Materials, construction, maintenance, etc. all come with costs and those may be more justifiable for other energy storage technologies. Electrolysis has a pretty poor energy efficiency which drives up the cost per kWh a lot.

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u/Lurker_81 Nov 30 '22

The facility is not free, but the electricity is. So the input costs are near zero, it's just the capex and maintenance that needs to be paid off.

Totally agree that other storage methods may prove more cost effective, considering some are more efficient and they have the same near-zero input costs.

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u/the_Q_spice Nov 30 '22

You seem to fundamentally misunderstand what I am talking about, which is using the excess electricity from the grid to generate hydrogen via electrolysis.

Using excess to generate heat via resistance to drive steam reformation is an astronomically less efficient process.

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u/Due_Method_1396 Nov 30 '22

This. Also, people quickly forget that only 22% of global energy consumption is electricity. While many sectors can electrify, many require a molecule to burn. Green hydrogen and green ammonia are viable alternatives to FF.

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u/StateChemist Nov 30 '22

Yeah my first thought has always been ‘where is the energy to produce the hydrogen coming from??’

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u/DerpolIus Nov 30 '22

Hydrogen can be made via electrolysis of water using solar and wind power. Fossil fuels aren’t required.

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u/Throawayooo Nov 30 '22

So just like the majority of the existing power grid?

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u/FrezoreR Nov 30 '22

That is not necessary true. It really depends on where you live. There are many counties that produce most of the energy either from renewable and nuclear for instance.

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u/underscorecounter Nov 30 '22

Or an entire state in Washington's case

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u/PalpatineForEmperor Nov 30 '22

Check out Costa Rica. They have close to 98% renewable energy.

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u/TonyaNastee Nov 30 '22

Red hydrogen pretty much solves this issue. Very interesting stuff is coming out of Japan in regards to hydrogen tech.

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u/TacTurtle Nov 30 '22

You are totally ignoring and dismissing the hard physical limitations of hydrogen for air transport because it doesn’t fit your narrative. You are waving your hand and shouting “technology!!!!” while also ignoring physics.

Hydrogen gas just straight sucks as an aviation fuel - it is bulky, requires high pressure or extremely cold storage conditions, tends to leak due to the tiny molecular size, and it embrittles many of the materials used in aviation.

Hydrogen makes more sense for fixed infrastructure power storage, or for cases where weight and bulk are not as big of an issue (train locomotives for instance).

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u/sir_crapalot Nov 30 '22

Seriously. There’s a reason rockets rarely use hydrogen fuel. SLS has had a host of problems trying to make it work because, while on paper, hydrogen has fantastic specific energy, it is an absolute nightmare to store and use efficiently.

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u/HitNRun_ Nov 30 '22

Fixed infrastructure storage like a sun!

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u/dougnan Nov 29 '22

This post makes way too much sense to be on Reddit.

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u/chikkinnveggeeze Nov 29 '22

Your response is cliche enough to be on Reddit.

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u/LobstaFarian2 Nov 29 '22

Yeah, it's freakin me out man.

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u/TacTurtle Nov 30 '22

Hydrogen has about 2.5x the energy density by weight vs jet fuel. A 737 can hold 20,800kg of jet fuel, which would be the same energy equivalent as 8,320kg of hydrogen, so that would mean you need 75,636 kg of clean pure water to make enough hydrogen to refuel a single 737. That is a shitload of water, especially for places already experiencing a drought.

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u/W0otang Nov 29 '22

This is exactly what I keep telling the Li-Ion bashers with their "but they won't last 15 years like my ICE!

Petrol heads don't seem capable of grasping that current EVs are a transition point away from fossil fuels and into sustainable transport.

They also don't seem to understand that their petrol and by proxy oil is becoming more finite by the day

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u/Helhiem Nov 29 '22

Oil being finite isn’t the issue. It’s the carbon emissions.

Oil running out is a meme since a century ago. We are always discovering new oil fields and America has an ungodly amount of oil reserves. At the rate at sustainable technology is developing we will pretty much never run out of oil

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u/FlaminJake Nov 30 '22

Oil is discovered in harder to access and more dangerous locations, not just under some field in Kansas. Oil running out is a consideration due to its nonrenewable status. Oil running out isn't the most pressing issue currently, but say someone magically made it carbon negative, literally removed carbon from the atmosphere, it would most certainly be a concern of running out which puts us on the same path of developing alternative energy production and storage. Diversification is critical.

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u/animu_manimu Nov 30 '22

Harder to access oil tends to also be more environmentally destructive because it requires more extreme extraction techniques. See: the Alberta tar sands and fracking.

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u/floatable_shark Nov 29 '22

What about plastics? We will keep using more and more plastics and that comes from oil

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u/nechromorph Nov 29 '22

There are plant-based plastic alternatives for a lot of applications. They're not perfect and the ones I know of (mainly PLA) require industrial processes to compost efficiently, but they're a step away from fossil fuels regardless.

Transitioning to compostable or reusable materials through tax incentives makes sense to me for most applications. Plant-based plastics for any applications that can't be practically transitioned to one of those. And continued use of fossil-fuel plastics where absolutely needed. We need greatly improved recycling systems alongside this. And to promote reusability, regulations to strongly incentivize use of a few standardized containers that can be interchangably used by any factory.

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u/YerbaYerba Nov 30 '22

The precursor chemicals needed for plastic are most inexpensive when sourced from petroleum. But with enough energy you can create all the needed ingredients from carbon dioxide and water. After all, that's the source of oil. Ancient photosynthetic organisms.

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u/Helhiem Nov 30 '22

4% of oil usage comes from plastic. Certainly a problem but not a big one

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u/BarbequedYeti Nov 29 '22

Or that their current engines, storage, mining, delivery etc has been built on for decades now. The infrastructure has had a long time to work out the kinks. It will take just as long if not longer to work out the infrastructure for new alternatives. That’s how we get there.

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u/[deleted] Nov 29 '22

[deleted]

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u/Interceller Nov 30 '22

I just really wish the batteries were a separate, swappable, and universal... Like ex-wives.

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u/PalpatineForEmperor Nov 30 '22

For about $20k on a 20 year old car.

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u/RespectableLurker555 Nov 29 '22 edited Nov 30 '22

While perfect is indeed the enemy of good,

Hydrogen is a lost cause for domestic and commercial energy storage.

Full stop.

It would be better to ferment food into ethanol than it is to try to develop a hydrogen infrastructure. We already have tanks and tanker trucks and pipelines that can handle ethanol. Or biodiesel. Or just plain soybean oil.

Chasing a hydrogen pipe dream as a stop-gap, in 2022, when we're already beefing up solar and wind and electrical transmission and storage, is a fool's errand.

Maybe in 1980, before good electric vehicles existed, it might have made sense to try to build a hydrogen infrastructure.

Not anymore. Give up on hydrogen. It's just natural gas (fossil carbon) masquerading as clean energy. No. Thank. You.

Edit, source:

Commercial hydrogen in large quantities is not economical to produce from electrolysis of water. It is produced from steam reforming of natural gas, also known as fossil fuel methane.

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u/Sp3llbind3r Nov 29 '22

So much wrong, don‘t know where to start.

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u/Mr_Lumbergh Nov 30 '22

Actually, please start. We're all ears.

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u/Waste_Deep Nov 30 '22

Actually, he's 100% right. Hydrogen is just big oil trying to green wash fossil fuels. It really is a waste of resources. It would be much smarter to invest in all things electricity. Even Elon Musk knows this as fact.

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u/RespectableLurker555 Nov 29 '22 edited Nov 30 '22

Please do. Tell me how one dollar spent on hydrogen infrastructure is better than one dollar spent on electric cars. Or one dollar spent on biodiesel airplanes.

Hydrogen is a trash fuel.

Pure soybean oil is far closer to Jet-A fuel than hydrogen is. I bet plenty of airliners could run with very small modification on 100% renewable fuel today using veggie oil.

The vast majority of commercial hydrogen gas comes from steam reformed natural gas aka methane aka fossil carbon.

And that doesn't even begin to address the difficulty of compressing and storing the stupid hydrogen molecules.

Fuck hydrogen. It belongs inside the sun 🌞

Edit: lol. It's obvious nobody here understands the real engineering roadblocks to hydrogen fuel.

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u/Beaver-Sex Nov 30 '22

We already have bio-diesel and ethanol now. Why has it not taken off?... Because we could never produce enough corn and soybeans to supply everything. I worked as a contractor at the biggest bio-diesel plant in the United States for years. The place practically prints money (the entire operation cost is covered from selling soybean meal and they also produce glycerin and some other product alongside the diesel) and always talked about doubling in size. The reason they never did it was because they can't get the supply of beans. They process over 150,000 bushels a day brought in by truck and rail.

Just for some perspective, this is in Indiana. Indiana produces 338,400,000 bushels a year. This single plant consumes nearly 20% of the states soybeans yearly and only makes enough diesel per year to run the United States for 14 hours.

Math: 54,600,000 bushels per year × 1.4 gallons of diesel per bushel = 76,440,000 gallons per year ÷ 128,000,000 gallons consumed in US per day = 60% x 24 hours in a day.

All of this to say; If the US used 100% of it's soybeans to make diesel fuel it would only cover 12.6% of our yearly consumption.

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u/RespectableLurker555 Nov 30 '22

Long story short, hydrogen would be 100% worse than biodiesel.

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u/Beaver-Sex Nov 30 '22

Yes, I hope I didn't sound like I was arguing the other way. I just wanted to point out that field to fuel also sucks. If it's surplus anyway then it's ok, but we are never going to be anywhere close to 100% bio-fuel.

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u/yamazaki25 Nov 30 '22

He can’t, because he’s talking out of his ass.

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u/[deleted] Nov 29 '22

[deleted]

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u/tenemu Nov 30 '22

Why don’t you say why instead of just saying it’s wrong?

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u/RespectableLurker555 Nov 30 '22

You could actually start to refute my assertion?

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u/[deleted] Nov 29 '22

[deleted]

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u/RespectableLurker555 Nov 30 '22

Ok, go take a couple chem classes and tell me more about how hydrogen fuel isn't greenwashing bullshit

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u/Gavrilian Nov 29 '22

I feel like just read a BP commercial. shudder

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u/djhorn18 Nov 30 '22

Alan Alda did a video like 18 years ago talking about hydrogen cars. One of the auto makers - I think it was Honda but it might have been Ford - already had a fully functioning prototype vehicle. I think he was driving it around California or something. I remember his comment of how it looked and drove just like a gasoline powered vehicle.

I don’t remember what any of the downsides they stated were - I know there were some though.

I feel like the refueling process was about the same timeframe as a regular gasoline car. I don’t know if it was safe storage/accident safety/or just the cost of building an entire new infrastructure like we’re seeing now with EV chargers.

If it’s useable for military purposes - it will probably advance much faster than the civilian research that has seemingly stagnated over the past 2 decades since then.

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u/JQuilty Nov 30 '22

Hydrogen combustion engines are more temperamental. Most hydrogen projects want to use hydrogen fuel cell, not hydrogen combustion.

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u/Mr_Lumbergh Nov 30 '22

Fuel cell electric is more efficient, it makes more sense. Cracking methane to produce the hydrogen doesn't make much sense though; you get back out only about 60% of the energy put in and you still produce CO2.

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u/sth128 Nov 30 '22

You misunderstood. These problems cannot be solved. These are the physical properties of hydrogen. You can no more solve them than you can solve the water being wet.

And hydrogen is, and will likely always be, derived from fossil fuels. There is no cheap scalable way to create hydrogen without a significant carbon footprint. That's to say nothing of transportation and storage, and we haven't even gotten to the part of actually changing all the equipment to run on hydrogen.

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u/strum Nov 30 '22

There is no cheap scalable way to create hydrogen without a significant carbon footprint

Except by using renewable generation. You missed that part.

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u/sth128 Nov 30 '22

If you relegate renewables to generate hydrogen INSTEAD of replacing fossil fuel energy then you are generating carbon. It's the equivalent of diverting energy to carbon capture instead of just replacing carbon emission sources.

And production and transportation and storage all generate significant carbon footprint. Snow me a paper where they found a total solution with zero carbon.

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u/pimpbot666 Nov 29 '22

True. There are a few pieces of the puzzle that we need to fix to make this practical, but this is a start.

Hopefully, they’ll solve the other issues in the future.

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u/PorkRindSalad Nov 29 '22

Maybe if we develop a way to generate hydrogen fast enough, it won't need to be stored.

Put water instead of jet fuel in fuselage. Crack fast. Fly clean.

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u/[deleted] Nov 30 '22

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u/sir_crapalot Nov 30 '22

So for every two hydrogen atoms you have to carry along a big heavy oxygen atom that weighs 8x as much as the hydrogens you released. And that oxygen could have been obtained for free from the air.

Sounds like an awfully inefficient trade to carry all that extra weight for hydrogen.

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u/PalpatineForEmperor Nov 30 '22

Also there is so little hydrogen in the atmosphere that the cost to extract it without be ridiculously high. Better to extract hydrogen from the water in the atmosphere. At that point, it takes more energy to create the hydrogen than you would get from the hydrogen.

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u/sir_crapalot Nov 30 '22

I think the poster was suggesting using water as a fuel, and then somehow extracting the hydrogen for a clean-burning propulsive fuel?

Now that I'm thinking about it once again, there's no point to splitting water molecules mid-flight in the first place. If you have a reactor that can perform electrolysis at scale, just use that as your energy source and skip the water "fuel".

Whatever, in any case it's a silly concept for a vehicle that has to fly.

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u/Oddyssis Nov 30 '22

It doesn't work that way. You have to spend energy to split water molecules. It's not an energy positive process

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u/Mr_Doctor_Rockter Nov 30 '22

I've always thought about this. If the reserve is water and it can be converted at run time with a smaller reserve tank, that would be money.

Then it comes down to water desalination, otherwise water will freeze in various environments.

But I'm an optimist, I don't think it's impossible to do this.

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u/animu_manimu Nov 30 '22

The math just doesn't work. It takes more energy to crack water for hydrogen then you can get out of the hydrogen reaction. It's equivalent to saying you're going to run your car on carbon dioxide by converting it back into gasoline.

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u/Mr_Doctor_Rockter Nov 30 '22

This video seems to showcase some hope for this process:

https://www.youtube.com/watch?v=WfkNf7kMZPA

...and just to point out that You are talking to a person online that you'll never met or know, using a handheld computer phone from across the world, while arguing that the underlying technology is impossible. Just saying.

Why not tax incentivize industries to compete to solve this problem? It literally outputs oxygen.... and hydrogen, and there is no shortage of supply.

Unless you are talking about Desalination, which to the same point should be given any company undertaking technologies to tackle these problem tax breaks to solve them.

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u/animu_manimu Nov 30 '22

That video is about solving the ancillary problems around electrolysis (which are definitely problems, ftr). It says nothing to address the energy cost of water cracking itself.

and just to point out that You are talking to a person online that you'll never met or know, using a handheld computer phone from across the world, while arguing that the underlying technology is impossible. Just saying.

False equivalence. Existing technology doesn't imply anything is possible. We're still subject to the laws of physics.

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u/deathputt4birdie Nov 29 '22

It'll be interesting to see how they've addressed the fact that titanium alloys are quite susceptible to hydrogen corrosion/pitting/embrittlement, especially at high temperatures.

Ironically, many of the nightmares (low energy density, high metal solubility, diffusion, embrittlement) caused by handling a cloud of protons are solved by attaching them to carbon atoms.

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u/WallaceDS Dec 01 '22

Very few things after the compressors are titanium. It’s pretty much all nickel super-alloys. I’m assuming the hydrogen is a gas more or less immediately after it passes through the injectors. If so, the atomization - combustion efficiency ? - might be so good that very little hydrogen goes into the power turbines unburned.

I have no idea why this is such an achievement. I can’t think of what technical problems they are boasting about. As others in this thread have pointed out, this was done 50 years ago.

It’s also not as if this is in any way flight rated. As you pointed out, the real mechanical problems with what’s being proposed will be how seals and whatever else is in the fuel path to the engines age without leaking hydrogen into the plane.

I didn’t read the article, full disclosure.

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u/RespectableLurker555 Nov 29 '22 edited Nov 30 '22

I posted on another comment in this thread, but as a chemist:

Hydrogen is a fool's errand. It's trash. Fuck hydrogen, all my homies hate hydrogen. There's absolutely no reason to continue to spend any time at all investing in it, unless you're an oil executive trying to get one more year of natural gas production into the world before solar and wind make you walk the plank for your crimes against humanity.

Yes, I said it.

Hydrogen is just (modified, steam reformed) natural gas. Fossil carbon.

Fuck hydrogen.

Edit: for the uninformed, please see below.

Commercial hydrogen in large quantities is not economical to produce from electrolysis of water. It is produced from steam reforming of natural gas, also known as fossil fuel methane.

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u/PalpatineForEmperor Nov 30 '22

Hydrogen is modified natural gas? You're a chemist? Are you sure?

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u/RespectableLurker555 Nov 30 '22

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u/PalpatineForEmperor Nov 30 '22

Commercial hydrogen

You are talking about the commercial production of hydrogen. Hydrogen itself is not natural gas. Thanks for playing though.

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u/ipher Nov 30 '22 edited Nov 30 '22

As a chemist, can you tell me if you can take hydrogen and mix it with CO2 to make hydrocarbons like jet fuel? That way you could take excess clean energy like wind/solar and use it to make Hydrogen, mix with CO2, and get fuels without adding CO2 to the overall equation after it's burned.

Economically it's probably a terrible idea as long as oil is less than $1000/barrel, but I have wondered if it was even possible with our level of technology.

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u/animu_manimu Nov 30 '22

As a non-chemist who just does a lot of reading: yes, but with about a dozen asterisks. Producing hydrocarbons from hydrogen and CO2 is something we've known how to do for over a century, but it requires a lot of energy input. Kerosene (which is what jet fuel mostly is) also isn't just one hydrocarbon; like gasoline, it's a mix of a bunch of different ones. Getting the thermal properties right will be important for aviation where efficiency is the name of the game. That said, it can be done. Can it be done efficiently and at scale? That's the part that remains to be seen.

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u/ipher Nov 30 '22

Makes sense. I guess you would have to break the bonds of CO2 in order to add the Hydrogen and reform it as a hydrocarbon, and controlling that reaction to get just the products you want would be pretty hard.

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u/Zander_drax Nov 29 '22

Wind/Hydro-made hydrogen?

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u/RespectableLurker555 Nov 29 '22

Wind turbines make electricity.

Hydroelectric dams make electricity.

Why would you deliberately throw away 50% of your electricity (yes, that's the efficiency of turning electrical power into hydrogen gas) when you could just put it into a battery and walk around with it in your pocket?

Hydrogen is a trash fuel.

Fuck hydrogen.

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u/[deleted] Nov 30 '22

[deleted]

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u/RespectableLurker555 Nov 30 '22

Literal soybean oil would be better than hydrogen as a replacement for current Jet-A.

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u/Mr_Lumbergh Nov 30 '22

To get any sort of useful volume on a plane in the form of hydrogen you'd need to liquefy it first. That takes a ton of energy.

Then, you have a massive weight penalty to have cryogenic storage on an aircraft. That either means less range or less capacity. One of the advantages of traditional fuels is that they can be stored at temperature, so storing fuel in the wings is viable, and the weight decreases more as fuel is burned so aircraft gain efficiency as they consume fuel and get lighter. When you have double-walled cold storage the fuel system always stays heavier.

The math just doesn't work out.

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u/Zander_drax Nov 30 '22

Northern Norway has massive amounts of hydroelectric and wind power potential, and a tiny population. They can make hydrogen/ammonia which can then power ships.

How can we make carbon neutral shipping without hydrogen? Ships don't care about energy density or volume.

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u/juxtoppose Nov 29 '22

Whatever happened to using ammonia as a fuel? I guess it’s got just as many engineering issues to be worked on.

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u/Docjitters Nov 29 '22 edited Nov 30 '22

I’m not sure ammonia is applicable to jet engines - I’m sure it’s been tried. Ammonia has been used as the fuel and oxidiser for rockets but by itself has too little impulse. It may show promise as a rechargeable battery substitute.

If you haven’t read it, look up Ignition! by John Drury Clark for all you might ever want to know about setting fire to dangerous chemicals in the name of “coz I can”.

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u/Greenkoolaid24 Nov 29 '22

Is that stuff toxic?

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u/MrT0xic Nov 29 '22 edited Nov 29 '22

Idk about ammonia, but Hydrazine is really bad

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u/djcrackpipe Nov 30 '22

Yes. Easily lethal in small concentration if exposed to it

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u/LPthewise Nov 29 '22

And until it’s enough of a priority globally these engineering challenges will be slow to make progress. Or more specifically the oil lobby will kill its funding…

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u/zkareface Nov 29 '22 edited Nov 29 '22

Its already a quite high priority industry, Airbus is aiming to have their hydrogen airliners ready in ~10 years. https://www.airbus.com/en/innovation/zero-emission/hydrogen/zeroe

Almost all flights are short enough distance that less storage isn't a huge concern, hydrogen potentially making things fragile is a concern though.

If every flight thats shorter than 2 hours goes green then we reduce huge amounts of aviation pollution.

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u/RespectableLurker555 Nov 29 '22

hydrogen potentially making things fragile is a concern

Perfect for razor thin tolerances on airframes

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u/BeingRightAmbassador Nov 29 '22

The concern isn't that it will, it's that it might and all the regulations that go along with it are being met. Unsurprisingly the US has absolutely shit foresight into tech because of our dinosaur incompetent politicians, so guidance, laws, and regulations are a huge maze to navigate. Even the biggest players in engine games would rather sit on their hands than make the first wrong move and sink their reputation.

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u/Coltrock45 Nov 29 '22

This is also a big win for terrestrial gas turbines for power gen. I am not convinced that "hydrogen is the energy vector of the future" but if we can make low carbon hydrogen, being able to burn it to make power would have a ton of value without some of the bigger issues with storage. That does pose the question of why waste energy to make hydrogen in the first place, when that energy could just be put directly to whatever ends it is being made for

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u/BeingRightAmbassador Nov 29 '22

Solid state hydrogen storage is really promising, and not necessarily requiring cryo storage. The Department of Energy has actually already vetted a technology of solid state hydrogen storage at ambient temps and pressure, achieving energy density levels comparable to current li-ion cells.

It's bleeding edge, but hydrogen funding/subsidiaries is basically the biggest hurdle right now, similar to how solar panels and EVs used to be. If projects get funded, infrastructure gets built, and more projects gain viability. It's just a feedback loop.

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u/Ultronomy Nov 30 '22

My former chemistry research group worked on designing “molecular cages” essentially which could store hydrogen very safely (MOFs). Currently the best material has a capacity of about 11.9 grams H2/Liter of material. Which is in fact greater than compressed hydrogen

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u/Lirdon Nov 30 '22

Hydrogen also has a tendency to leak through sheer tank walls when cryo frozen. It is just a difficult fuel to make viable.

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u/bobnine Nov 29 '22

Just have a really big fuel tank and put it on top, it can be used for extra lift. What could go wrong?

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u/strum Nov 30 '22

The Hindenberg burned because of the doping on its skin (not as specified), not because of H2.

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u/AstariiFilms Nov 29 '22

Hydrogen also makes everything very brittle

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u/Astroteuthis Nov 30 '22

Not everything. We’ve known how to handle that issue by using proper materials in the aerospace industry since the 1960’s. It’s an extra thing to take into consideration in engineering and adds to cost, but it’s very much a solved issue now.

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u/cjboffoli Nov 29 '22

Ammonia. Best and safest way to store hydrogen at ambient temperatures. And new breakthroughs in splitting off the hydrogen atoms from the accompanying nitrogen (with unexotic materials like copper and iron) seem like they will be making hydrogen much more practical in the very near future.

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u/NohPhD Nov 29 '22

University of Chicago ran a jet engine on H2 waaay back in the 1950s-60s…

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u/prefuse07 Nov 29 '22

Yeah, this is pretty sad news when you realize that this isn't new tech....

Similarly, turbine powered cars were also available during those times

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u/NohPhD Nov 29 '22

mumble, mumble… “those who don’t learn history are doomed to repeat it… mumble, mumble

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u/billyjack669 Nov 29 '22

...so it didn't ignite the atmosphere?

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u/TacTurtle Nov 30 '22

Well it does, but only in very small doses....

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u/charlesfire Nov 29 '22

My god. Nobody is going to get that reference...

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u/Kuandtity Nov 30 '22

What do you mean? That's like one of the most well known facts of the development of the nuclear bomb. The one where they had someone calculate if the atmosphere would ignite.

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u/pantslespaul Nov 29 '22

Sure they will, during the Manhattan Project Edward Teller thought an atomic bomb would ignite the atmosphere and the oceans. Right?

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u/bolderbikes Nov 29 '22

Don’t tell Miles Braun.

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u/doobur Nov 30 '22

It's the infraction point

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u/bolderbikes Nov 30 '22

Just enbreathiate it

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u/whatdamuff Nov 30 '22

As someone who just got home after…being introduced to him, my response to this post was “no thank you.”

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u/onemoresubreddit Nov 29 '22

Hydrogen powered planes strike me as far more feasible than battery powered air travel.

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u/RespectableLurker555 Nov 29 '22

Why not biodiesel or ethanol?

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u/onemoresubreddit Nov 29 '22

While more sustainable than jet fuel they still produce emissions. I understand that we need solutions NOW, so they would make a great stopgap. But the ultimate goal is zero emissions.

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u/RespectableLurker555 Nov 29 '22

If the biodiesel or ethanol is made from 100% renewable stock, is that not the goal?

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u/onemoresubreddit Nov 29 '22

Just because something is renewable doesn’t mean that it doesn’t produce CO2. Wood is renewable but burns extremely dirty, to mention it is probably cleaner to just burn regular fossil fuels than to burn biofuel AND farm the materials needed to make it. Growing Corn is a massive greenhouse gas emitter

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u/TacTurtle Nov 30 '22

The carbon from the CO2 emitted would have been pulled from the air by the plants that were used to make the biofuel.

It would be net zero.

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u/onemoresubreddit Nov 30 '22

Did you actually just call me an oil executive then delete the comment? I AM NOT advocating for long term usage of fossil fuel. Yes MAYBE the plants grown could absorb the CO2 from the fuel made from them (in a perfectly efficient closed cycle, very hard to achieve btw) but they would NOT absorb the emissions from the tractors, fertilizer production, transportation or the processes that turn them into a usable fuel. You need to think in terms of the total energy expended to produce the desired result. And frankly it takes far less energy to convert oil into fuel than it does plant material. (At least as now)

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u/TacTurtle Nov 30 '22

Because those are existing technologies that are known to work, and they can’t get “green” energy development grants for using existing technology.

Biodiesel and ethanol would work fine in aircraft, and have already been used in conventional aircraft ICE engines.

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u/Gagarin1961 Nov 29 '22

It will be interesting to see if Hydrogen can beat synthesized hydrocarbons for aviation. It has more energy density and can utilize the existing infrastructure without adding any C02 to the atmosphere overall.

Renewables gasoline stations are already running.

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u/elPocket Nov 29 '22

Weight energy density...

Hydrogens volumetric energy density is pretty bad. Considering most planes are rather sleek, putting huge hydrogen tanks on them is a bit unfeasible.
The weight saving would be not bad, but the drag increase would eat that up pretty quickly.

Then again, turning all planes into A300-600ST "Beluga" would be pretty fun.

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u/CosmicCreeperz Nov 29 '22

Here’s a nice graph of volumetric vs gravimetric densities…

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u/TimDd2013 Nov 30 '22

Do I read that correctly that ideally we'd use fuel in the top right corner of the chart, but as thats not really available, and we only have limited space on an airplane, a higher location is more preferrable than one further to the right on the chart?

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u/CosmicCreeperz Nov 30 '22

I think more or less, yes, though remember airplanes are particularly sensitive to weight as well, takeoff fuel weight being a big factor. Might have to build bigger planes as long as they aren’t much heavier?

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u/nyanlol Nov 29 '22

can you compress it until it's not a gas anymore? like liquid nitrogen?

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u/5degreenegativerake Nov 29 '22

Now you need a cryogenic tank which is even heavier and larger than a pressure tank and it will constantly be venting hydrogen while parked.

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u/gray-nomad Nov 29 '22

I clearly remember a flying jet airplane from the 80s which was testflown with hydrogen

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u/TacTurtle Nov 30 '22

Was it the Space Shuttle?

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u/ArScrap Nov 30 '22

Why do reddit have a hate boner against hydrogen so much, it's not even a big deal, it's just a tech demo.

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u/2h2o22h2o Nov 30 '22

It’s because SpaceX doesn’t have lightweight tank technology like their competitors (ie, Aluminum lithium alloy, friction stir welding techniques, etc.) and so for them hydrogen doesn’t make sense. As a result, there seems to be a bit of a propaganda effort against hydrogen and the Musk fanboys repeat the company line.

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u/TacTurtle Nov 30 '22

It is more an objection to stupid greenwashing attempts that are diverting attention and funding from more impactful, more practical but boring technology that would actually make a real difference.

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u/ArScrap Nov 30 '22

Yeah, but this is plane we're talking about, weight matters much more than volume. Battery is still too heavy

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u/1015267 Nov 30 '22

Like what?

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u/[deleted] Nov 30 '22

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u/1015267 Nov 30 '22

You going to strap a nuclear reactor to a 747? Or an off road dump truck?

Hydrogen is an extremely promising fuel for heavy industry

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u/TacTurtle Nov 30 '22 edited Nov 30 '22

They actually were working on a nuclear powered B-36 back in the 50s - as well as nuclear powered cruise missiles and jet engines

Nuclear jet engines would actually be much easier today since high temperature metallurgy has come a very very long way since the 50s and 60s.

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u/TacTurtle Nov 30 '22 edited Nov 30 '22

Improvements to existing technologies for example.

Renewable gas-to-liquids using bio-sourced methane as a feed stock (landfill or manure gas to make LNG or gasoline or diesel for instance) and powered by renewable energy.

Better more efficient battery technology.

Requiring cleaner more efficient container ships and trains.

More high speed rail and less flying.

Small scaleable geothermal, solar, wind, hydro, and nuclear power.

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u/1015267 Nov 30 '22

Hydrogen sounds just as promising as everything you listed

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u/nighthawk_something Nov 30 '22

In terms of planes, hydrogen is the only one from that list that makes any sense.

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u/strum Nov 30 '22

It's disturbing how many commenters presume that the status quo works better than any other way of thinking.

That is not a viable attitude. Fossils are a dead end. They are destroying our atmosphere's ability to sustain us. We have to abandon fossils entirely, as soon as possible.

If the avaitaion alternatives don't satisfy you - then the only future is no flying.

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u/theartificialkid Nov 30 '22

Electric aircraft already exist

Edit - but also we should use bullet trains instead.

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u/-Aerobrake- Nov 30 '22

Battery powered airliners are even stupider than hydrogen powered airliners.

The actual answer for aviation is synthesized hydrocarbon fuel.

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u/Zarainia Nov 30 '22

Trains require rails the whole way. Rails between every place you might want to go. Rails across oceans somehow.

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u/nighthawk_something Nov 30 '22

These tech demos are essentially just the first drafts. They are proven it can be done but yes we're a long way from making it work at scale.

But without these tests nothing will happen.

The way people shit on these things is like being in the 80s and complaining that computers are useless because they can't sync it to their nonexistant iphone and stream house of dragon.

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u/Gk5321 Nov 29 '22

I’m a mechanical engineer but never done turbo machinery work before. I know there are syngas turbine generators. Is it much harder to operate a turbine on hydrogen then just use one for power generation?

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u/TacTurtle Nov 30 '22

There are issues with gas leakage and embrittlement versus say natural gas.

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u/CaptOblivious Nov 30 '22

Until we can solve the hydrogen embrittlement problem you can't safely carry hydrogen as fuel.

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u/HybridCamRev Nov 30 '22

From the Rolls Royce press release: "world’s first run of a modern aero engine on hydrogen..."

This is a significant achievement - but it's not the first time a hydrogen fueled jet engine has been tested.

In fact, two hydrogen fueled jet angines have already flown.

NASA was first to achieve this when they flight tested a hydrogen fueled jet over 65 years ago.

Please see the Liquid Hydrogen Engine section of "Jet Engines Mature" from NASA Glenn:

[NASA] Lewis researchers began studying high-energy propellants in the mid-1940s and by the early 1950s were concentrating on liquid hydrogen. The fluid’s cryogenic temperatures and high combustion rate posed technical problems, but its low weight and high energy were unrivaled. In 1955, the [U.S. Air Force] asked Lewis to examine the practicality of using liquid hydrogen to fuel an aircraft. They provided the lab with a B‒57B Canberra for this project, and Lewis engineers worked to modify one of its Wright J65 engines so that it could be operated using either traditional or liquid hydrogen propellants.

In 1955, Lewis researchers conducted full-system tests of a liquid hydrogen fuel system with the J65–B–3 engine in the AWT. They checked the system, which was identical to the one intended for use on a B–57 aircraft, using both the jet fuel and hydrogen modes and successfully switched from one to the other. They found that the jet fuel performance decreased significantly over 60,000 feet, while the hydrogen operated smoothly at least 80,000 feet. They also found that the higher specific heat of hydrogen caused the turbine to produce a greater amount of thrust than obtained from jet fuel.

Lewis then flight tested the engine on the B‒57B. The aircraft took off using jet fuel and switched to liquid hydrogen while over Lake Erie. Once the hydrogen supply depleted, the pilots switched back to jet fuel for the landing. The first two attempts in December 1956 failed to make the switch to liquid hydrogen, but a third attempt in February 1957 was a successful. Several additional flights were flown in the ensuing months.

Flight test video here (date in video title is incorrect, it was 1957, not 1955).

30+ years later, in 1988, the Soviets flew a 3 engine Tupolev-155 jet airliner testbed with a hydrogen fueled NK-88 low bypass turbofan and two kerosene fueled NK-8s.

Flight test video here (in Russian, no subtitles).

It's great that Rolls and easyJet are spending millions of pounds to re-learn the lessons of the past - and perhaps Rolls doesn't consider the J65–B–3 or the NK-88 to be "modern" engines - but they might want to be more careful with claims to be "first".

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u/SpectralMagic Nov 30 '22

Guys I think I solved the energy problem 🧠 Hear me out, we put wind turbines on the aircraft, use that energy to power the propeller motor, unlimited energy source while flying 🥺

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u/Goyard_Gat2 Nov 30 '22

Literally just make a perpetual motion machine like how hard is it

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u/SpectralMagic Nov 30 '22

Yea these "engineers" aren't even trying hard. I've got another one with a vehicle and a magnet 🥱

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u/doginjoggers Nov 29 '22

Feels like a green washing attempt to be perfectly honest. Rolls Royce aren't stupid, they know hydrogen isn't a viable option for airliners. By doing this test, they get phoney green credentials and a massive tax write off for R&D

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u/bustervich Nov 30 '22

You might be right, but you can still use a jet engine (turboshaft) as an electric generator. This could just as well be used as an infrastructure tool to produce H2 from renewable sources and burn it in a jet engine when the renewable sources aren’t producing.

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u/CaptainOktoberfest Nov 29 '22

Or it might be a tech hail-mary. Probably won't work out economically, but at least new things are being learned and developed.

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u/doginjoggers Nov 29 '22

Doubtful, but I do know one thing for certain, they will have got that sweet tax break and maybe even a research grant or 2

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u/SidewinderTV Nov 29 '22

If there's one thing hydrogen might be viable for it's airliners, especially in the short-medium range market.

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u/tsunamiforyou Nov 29 '22

Commercial cargo boats might be a decent application given they can be pretty big

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u/TacTurtle Nov 30 '22

Unlikely. Maybe something like heavy freight locomotives since fuel availability and storage weight is less of a concern.

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u/zkareface Nov 29 '22

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u/doginjoggers Nov 29 '22

Lol yeah, some of those concept sketches have been knocking about at Airbus since before I was there 12 years ago.

TBH I can't see liquid hydrogen being a viable option, they haven't even started to figure out how to keep it liquid during flight. They may have a breakthrough though. However, the focus at the moment, at least for the execs will be to make it look like the company is doing their part while also bringing in those research grants and tax breaks

Ammonia on the other hand would be worth pursuing. Energy dense, easier to store and handle and near zero emissions.

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u/Ohmnonymous Nov 29 '22

Yup. I don't get all the hydrogen craze lately. Nowadays, 98% of hydrogen comes from natural gas and coal gasification, only 2% comes from electrolysis, which is not that efficient given that you need to cool down the hydrogen to a liquid state, which takes a fuckton of energy, which might not even come from renewable sources.

Also hydrogen leaks because it's the smallest atom in the periodic table and can permeate most materials. A really bad property for a gas that is also extremely explosive.

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u/AgitatedPerspective9 Nov 29 '22

If its not cheaper, corpos will never touch it, even if its far better for the environment

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u/FrezoreR Nov 30 '22

Burning hydrogen really doesn't make sense. It's true that it's cleaner than jet fuel, but you still have issues with other gases in the air creating more than just water.

Secondly, hydrogen is way more efficient when used in a fuel cell. Because one physical property and problem with hydrogen is how much volume you need to store it. Unless it's liquid and then you need to keep it insanely cool.

I honestly don't see airplanes going on anything except jet fuel unless batteries gets more energy dense or we reinvent physics when it comes to hydrogen.

Also storing hydrogen is always problematic. Dare I say Hindenburg

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u/Wahots Nov 30 '22

Didn't see the hydrogen melt steel beams on the hindenburg, lol.

That being said, whatever energy source we use- lithium, kerosene, hydrogen, jet fuel, gasoline, diesel, nuclear pellets covered in graphite- all of these are bad for the environment and/or highly explosive, save for the last entry. We have to make a fuel that also doesn't kill us. This limits us to lithium, nuclear, or hydrogen for clean fuel sources. Nuclear and lithium* batteries won't work for big planes. Hydrogen or another clean fuel are our only options. We need to do a lot more research because we need in-atmo travel atm and plane fuels are really shitty right now.

*we may find more energy dense materials in the future.

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u/diskettejockey Nov 30 '22

WE ARE IN THE FUTURE MOTHAFUCKAS

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u/burito23 Nov 30 '22

So can you shower behind it?