Hydrogen as fuel

[jderimig]

The above company is developping the aircraft. Other companies will buy and operate it. If you want any of them to use green hydrogen, then tell them. Here's a start as to where to find green H2:

1. St. Gabriel Green Hydrogen Plant
2. Sauk Valley Green Hydrogen Plant
3. Kingsland Green Hydrogen Plant
4. Casa Grande Green Hydrogen Plant
5. Donaldsonville Green Hydrogen Project

https://www.airswift.com/blog/green-hydrogen-projects-usa
Some people act like they don't understand this, others really don't.

There is no green hydrogen. Round trip efficiency of hydrogen energy cycle is at best 50%, more like 25%. And that assumes you get the water with no energy expended. So you throw away half of your green electricity instead of sending it all to the grid to power all the lights, motors, air conditions and charging your EV at about 90% efficiency. So by electrolyzing H2 more fossil fuel is burned and emissions go UP. Green would be shuttering all the H2 generators.

 

[Funkworks]

There is no green hydrogen. Round trip efficiency of hydrogen energy cycle is at best 50%, more like 25%. And that assumes you get the water with no energy expended. So you throw away half of your green electricity instead of sending it all to the grid to power all the lights, motors, air conditions and charging your EV at about 90% efficiency. So by electrolyzing H2 more fossil fuel is burned and emissions go UP. Green would be shuttering all the H2 generators.

You brought it up and I found 5 US companies doing it for you but hey, type whatever you want. I bumped up this thread for a new aircraft and off you go diverting to electricity distribution.

https://www.hydrogen.energy.gov/
https://en.wikipedia.org/wiki/Green_hydrogen
A thread for comparing different energy sources for different applications (most efficient energy source for carrying an aicraft X miles) might be interesting. Let me know what you think. If you have a specific concern, maybe you could clarify it in there.

 

[kuririn]

U.S. Department of Energy Hydrogen Program : DOE Hydrogen Program

As John has pointed out on another thread, the Dept. of Energy has some of the most brilliant scientists in the world. Here is a draft of their clean hydrogen strategy and a roadmap to that goal:
https://www.hydrogen.energy.gov/pdfs/clean-hydrogen-strategy-roadmap.pdf

 

[speed]

"Using clean hydrogen can reduce U.S. emission approximately 10 percent by 2050 relative to 2005"
From that report. Sounds like a winning strategy to me! lol

 

[jderimig]

"Using clean hydrogen can reduce U.S. emission approximately 10 percent by 2050 relative to 2005"
From that report. Sounds like a winning strategy to me! lol

That's great news except that US ghg emissions have already dropped 10% since 2005. Based on that I am in total agreement with the above statement.

 

[speed]

That's great news except that US ghg emissions have already dropped 10% since 2005. Based on that I am in total agreement with the above statement.

That report is unbelievably optimistic. Unbelievable being the operative word. I wonder what China is doing to cut their emissions? India, Russia, South America and Africa too! Lots of folks in those countries. What happens when a first responder needs to use the jaws of life on a hydrogen powered car? Are all of these cars going to have the lines in the exact same spot, i sure hope so.

 

[speed]

I found this interesting:

Hydrogen-fueled cars sound squeaky clean. Why aren’t we all driving them?​

There’s virtually no pure hydrogen on Earth because it’s so reactive. Most hydrogen is made from methane [natural gas] in a process that produces carbon dioxide and other greenhouse gases. Hydrogen can also be made from water using electrolysis, but that requires electrical energy. To get that, we’re back to burning fossil fuels.

https://news.usc.edu/trojan-family/why-hydrogen-fuel-isnt-mainstream-as-fossil-fuel-alternative/

 

[kuririn]

I found this interesting:

If you read further down in the article you linked to, the author advocates using ICEs burning hydrogen instead of gasoline.

I wonder what China is doing to cut their emissions? India, Russia, South America and Africa too!

193 of 197 nations in the world have signed the Paris Agreement, including all those you named.
China is actually way ahead of the US in EV production and usage.

What happens when a first responder needs to use the jaws of life on a hydrogen powered car? Are all of these cars going to have the lines in the exact same spot,

A hydrogen fuel cell vehicle is not directly powered by hydrogen. It is powered by the electricity generated by the fuel cell which uses hydrogen. So there are no lines going from the hydrogen tank to a motor. As for any special hazards involved, they are addressed in training, just as a first responder is trained in handling EV crashes, and the special requirements involved. And leaking gasoline is also flammable, and four times as energy dense. Do first responders know where all the gas lines are on every ICE model?

 

[cls]

As for any special hazards involved, they are addressed in training, just as a first responder is trained in handling EV crashes, and the special requirements involved. And leaking gasoline is also flammable, and four times as energy dense. Do first responders know where all the gas lines are on every ICE model?

Hydrogen leaks can not be detected by smell, and hydrogen flame isn't visible to human eyes.

So, not comparable at all. F.

Hey all rocketeers, what was the biggest trouble with the SLS? Handling the hydrogen! Duh.

 

[kuririn]

Hey all rocketeers, what was the biggest trouble with the SLS? Handling the hydrogen! Duh.

Cryogenic, not compressed.
Not comparable at all. F.

 

[cls]

brought it up and I found 5 US companies doing it for you but hey, type whatever you want. I bumped up this thread for a new aircraft and off you go diverting to electricity distribution.

You fail to apprehend the larger picture.

There is no green hydrogen. Round trip efficiency of hydrogen energy cycle is at best 50%, more like 25%.

This is the point. H2 economy is a net loss, and a sop to fossil fuel companies.

 

[cls]

Cryogenic, not compressed.
Not comparable at all. F.

Not suitable for handling by ordinary people, half of whom have an IQ less than 100.

 

[kuririn]

Not suitable for handling by ordinary people, half of whom have an IQ less than 100.

Agree, Same for a can of gasoline.
Edit: And yet we have public hydrogen fueling stations.

 

[kuririn]

You fail to apprehend the larger picture.

Actually, I think we're quite apprehensive about the larger picture, if nothing (or not enough) is done.

 

[Funkworks]

You fail to apprehend the larger picture.

I'm not trying to apprehend a larger picture, so I guess you failed to understand that. I like hydrogen vehicles, and I mentionned reasons. Here's another one:

https://www.uforklift.com/warehouse-forklift/hydrogen-forklift/
If these have builders and buyers, then I'm in. If you're going for a larger picture, enjoy, but me, I'll stay right here, cozy and warm in the smaller picture.

Hey all rocketeers, what was the biggest trouble with the SLS? Handling the hydrogen! Duh.

Rocketeers know about the shuttles, Saturns, Arianes, and countless other H2 vehicles that were successful and continue to be.

 

[jderimig]

China is actually way ahead of the US in EV production and usage.

Yes and they will be mostly powered by coal.

27 February 2022 — Chinese local governments permitted a staggering 106 gigawatts of new coal power capacity in 2022, equivalent to 100 large coal-fired power plants[1] and the most since 2015. The amount of newly permitted capacity quadrupled from 2021.

https://globalenergymonitor.org/pre...ewly permitted capacity quadrupled from 2021.

 

[kuririn]

Yes and they will be mostly powered by coal.

It appears there is a dichotomy between national and provincial leaders in China:
https://e360.yale.edu/features/despite-pledges-to-cut-emissions-china-goes-on-a-coal-spree"Additionally, a struggle is underway between the coal sector and government forces pushing for a more rapid transition away from coal-fired power. In recent months, both the environment ministry and top Communist Party leadership reprimanded the National Energy Agency for approving too much coal-fired power too fast. President Xi delivered a widely publicized speech before the country’s top financial planners on March 16 in which he said the years leading up to 2025 would be critical to ensuring that China’s emissions peak by 2030. Many analysts saw this as a sign that the country’s leadership is unhappy with provincial and local government planners who have approved the increased coal-power rollout."

PS. Not unlike the divisions between some state and national leaders here, huh?
Really hard to get things done with so much divisiveness, isn't it?
Even really important stuff.

 

[Funkworks]

So as I was saying, the first H2 flight of a 40-passenger aircraft just happened and it's a wonderful technical achievement.

https://www.canarymedia.com/article...rplane-just-made-a-record-setting-test-flight

 

[cls]

Agree, Same for a can of gasoline.
Edit: And yet we have public hydrogen fueling stations.

No, not the same handling situations, did you read what I wrote?

 

[cls]

I'm not trying to apprehend a larger picture, so I guess you failed to understand that. I like hydrogen vehicles, and I mentionned reasons. Here's another one:

https://www.uforklift.com/warehouse-forklift/hydrogen-forklift/
If these have builders and buyers, then I'm in. If you're going for a larger picture, enjoy, but me, I'll stay right here, cozy and warm in the smaller picture.


Rocketeers know about the shuttles, Saturns, Arianes, and countless other H2 vehicles that were successful and continue to be.

There are good reasons to light LH2+LO2 on the ground, better reasons to light it in orbit. But look at the experience of the ground support, terrible for H2, everywhere

 

[cls]

I like hydrogen vehicles, and I mentionned reasons. Here's another one:

https://www.uforklift.com/warehouse-forklift/hydrogen-forklift/If these have builders and buyers, then I'm in.

You're in! Great! Which one are you going to buy?

Anyway, no fair moving the goal posts. We were talking about H2 in the larger economy. Specifically, transportation.

I agree there is probably some place (mines?) Where H2 makes sense. But it clearly pales in total energy cycle efficiency vs. batteries.

 

[kuririn]

No, not the same handling situations, did you read what I wrote?

Hey all rocketeers, what was the biggest trouble with the SLS? Handling the hydrogen! Duh.

Absolutely. Did you read what I wrote?
The SLS uses cryogenic liquid hydrogen, at over -423 deg. F.
Fuel cell vehicles uses compressed hydrogen at ambient temperature.
Big difference in handling characteristics.
To compare the two is misleading.
That's like saying steam and ice have the same handling characteristics because they're both water.
And if it was so dangerous then why are there hydrogen fueling stations open to the general public?
Duh.

 

[cls]

And if it was so dangerous then why are there hydrogen fueling stations open to the general public?
Duh.

There's a Latin phrase for that, not a good line of reason...

Many things are available to everyone that are not the best idea.

Thanks

 

[tfrielin]

Hydrogen has the highest possible specific impulse (which is impulse per unit weight) of any chemical rocket fuel simply because it is the lightest possible substance in the universe, and dividing total impulse by the smallest possible number for weight gives the biggest possible number for specific impulse. Having a high specific impulse means you are getting more impulse per unit weight of propellant, making it an excellent measure of efficiency.

However, hydrogen's efficiency comes at the cost of being extremely fluffy (a word I use in opposition to dense), which means a lot of the advantages of hydrogen get cancelled out by the large tanks required for hydrogen-fueled rockets. More non-propellant mass in your rocket is never helpful.

Despite this disadvantage, hydrogen is usually worth using for upper stages that don't require as much propellant to do their jobs. However, hydrogen is usually not a good choice for lower stages because the first stage is the biggest stage and using hydrogen makes that big stage even bigger.

Since the SLS was mandated to use leftover RS-25 engines from the space shuttle program, it was stuck using hydrogen fuel, which is why the core stage is so big. I haven't done the math myself, but I would bet that being saddled with this massive hydrogen-powered core stage goes a long way towards explaining why the SLS is not as capable as the Saturn V.

Totally on target, Antares.

The Shuttle and SLS purchased/overcame the shortcomings of the large (and, so heavy) hydrogen fuel tank by strapping on those BIG SRBs to get the stack through the lower atmosphere.

Saturn V did the same job with less efficient S-IC stage, powered by RP-1.

But the efficiency of the hydrogen-powered S-II and S-IVB stages more than made up for using the less (lower Isp) efficient first stage, thus the Saturn V's superior payload capability compared to SLS. You pay a high price for those tanks---the larger ones that LH2 require. And SRBs are heavy, too. so there's all that to subtract from the efficiency tradeoffs.

Required reading:
Liquid Hydrogen as a Propulsion Fuel by John Sloop. Available on-line at the NASA History Web site.
Also, for fun, google Project Suntan for the story of the USAF's attempt to develop a hydrogen-powered plane back in the '50s.
And, if you can find it, my article from Space World magazine entitled "The Liguid Hydrogen Club" Outdated, maybe (mid-'80s) but a good survey of the topic at the time.

 

[Funkworks]

You're in! Great! Which one are you going to buy?

Not sure what this spin is for.

Anyway, no fair moving the goal posts. We were talking about H2 in the larger economy. Specifically, transportation.

I've been talking about H2 aircrafts the whole time, and there are no goal posts to move. Although someone did move the discussion away from aircrafts to electricity distribution and whatnot. To minimize emissions in aviation, green H2, "green" here meaning H2 produced by renewable sources, appears to be an ideal fuel.

I agree there is probably some place (mines?) Where H2 makes sense. But it clearly pales in total energy cycle efficiency vs. batteries.

Batteries are heavy to carry at altitude over long distances, which is why H2 aircrafts are interesting.

I agree there is probably some place (mines?) Where H2 makes sense.

That is where I'd like to see this thread go: those places where H2 are a decent or better solution to some problem.

Namibia is well positionned to produce and export green hydrogen:

 

[jderimig]

Hydrogen is Big Oil's dream. Establish critical mass of hydrogen demand. Green energy will never be reliable enough to provide the required capacity. Creates much much higher demand for nat.gas sourced H2. Nat gas prices rise, oil companies get richer. If you want to invest in H2 buy XOM.

 

[Funkworks]

Many people do not want to increase emissions, and that is fine.

https://press.siemens-energy.com/gl...-develop-large-scale-electrolyzer-partnership
https://www.airliquide.com/group/pr...ean-production-large-scale-renewable-hydrogen

 

[cwbullet]

And if it was so dangerous then why are there hydrogen fueling stations open to the general public?
Duh.

Is that needed? No reason to insult.

 

[kuririn]

Is that needed? No reason to insult.

Hey all rocketeers, what was the biggest trouble with the SLS? Handling the hydrogen! Duh.

Does that apply equally to all sides?
Simply my response in kind.
But I agree, no need to stoop to that level.

 

[cwbullet]

Does that apply equally to all sides?
Simply my response in kind.
But I agree, no need to stoop to that level.

That is my point. Turn the other cheek. It was directed at all sides. Remember, the penalty in football is usually the reaction.