this post was submitted on 14 Apr 2024
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658
How is the hydrogen made? (slrpnk.net)
submitted 5 months ago by [email protected] to c/[email protected]
97 comments fedilink hide all child comments
 

cross-posted from: https://slrpnk.net/post/8569504

How is the hydrogen made?

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[–] [email protected] 2 points 5 months ago (2 children)

Are those CO2 emissions? I don't get where the CO2 comes from.

I know this is an animation, but it shows pretty well, how hydrogen is made from natural gas. No CO2 emissions. And using the hydrogen should produce H2O.

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

[–] [email protected] 30 points 5 months ago (3 children)

In reverse order:

1 - it needs to be tranported

2 - it needs to compressed and cooled, in order to transport it. You need to cool it down around 1700 degrees, because:

3 - methane pyrolysis is done at around 1500 degrees C, getting something that hot isn't free.

4 - methane isn't the only component in natural gas, so you need to seperate out all the impurities.

5 - methane is a very strong contributor to global warming, so any natural gas leak from the drill to the factory adds co2equivalent.

6 - you need to extract natural gas from the ground and transport it, which takes energy.

[–] [email protected] 10 points 5 months ago

Plus the big one is that my taking the hydrogen off of the methane, you're left with carbon. And that carbon is usually reacted with oxygen to make carbon dioxide during the refining process. So for every two liters of hydrogen you make, you'd make a liter of CO2.

[–] [email protected] 6 points 5 months ago

And we're not doing so well on the gas leak part...

https://youtu.be/K2oL4SFwkkw?si=Kn-uO64U4X5B_szD

[–] [email protected] 2 points 5 months ago (1 children)

So what is the best solution, in your opinion?

[–] [email protected] 29 points 5 months ago (3 children)

Hydrogen isn't a solution at all. Literally anything is better than using hydrogen from methane, even shovelling coal into steam engines produces less CO2 equivalent.

So, "don't do that, it makes things worse".

I don't think I should have to produce an answer to one of the main problems facing Western society to be able to point out that hydrogen is mostly natural gas under an asbestos bedsheet.

[–] [email protected] 5 points 5 months ago

It could make sense for planes, where batteries are just too heavy. But you'd need to weigh it against things like synthetic electrically produced kerosene or biodiesel.

[–] [email protected] 1 points 5 months ago (1 children)

How about hydrogen from water? Yeah, you need high amounts of electricity to get it, but, as one example, if it's used in ICE engines, isn't that significantly cleaner than petrol? And a lot less damaging than making lithium batteries? Once burned, wouldn't it just react with oxygen to then form water vapour? And then, if it's making water, that's a self-sufficient cycle?

I feel like hydrogen can potentially be a very good solution, but the technology needs to catch up massively. I mean, scientists are getting to on nuclear fusion reactors, and their yield seems a lot better than everything else. Even fission reactors.

Also, I had this thought the other day, and yes, it's extremely futuristic, with the right people in charge thought, but mining gas planets for the hydrogen. We'll more than likely never inhabit those ones or use them for much, so we might as well use them for something, at least. At least before Dyson swarms become a thing.

[–] [email protected] 5 points 5 months ago

Using excess green energy to produce hydrogen is a great option, but those events are pretty rare, and it doesn't produce very much, compared to pyrolysis of natural gas. Using regular electricity isn't very smart, since you're burning hydrocarbons to create hydrogen from water, when you could just get them from the hydrocarbons, so that's even less efficient.

[–] [email protected] -4 points 5 months ago* (last edited 5 months ago) (1 children)

Should keep doing what we've been doing?

WTF is people against asking questions?

[–] [email protected] 12 points 5 months ago (1 children)

Obviously not. But switching to something new and worse also clearly isn't the solution.

[–] [email protected] 9 points 5 months ago (1 children)

I think the issue is where the energy to heat the reaction vessel comes from. The video shows green sources, but that isn't the only way to do it. The thing is, this is ultimately an energy storage tech rather than an energy generation tech. You need excess capacity to make it work, and if that means you have to make up for a shortful with conventional generators elsewhere, you aren't actually saving anything.

I don't know if the previous poster is right of course, but the planet is an almost closed system, and there really is no such thing as a free lunch when it comes to energy.

[–] [email protected] 3 points 5 months ago (1 children)

The ultimate idea afaik is to build huge renewable energy power plants (for example solar energy in deserts) to generate it there, and then transport it through pipelines to wherever you need it.

[–] [email protected] 4 points 5 months ago

The only logical way to use it is as fuel for heavy transport if it's produced in the same place that said transport refuels. We can't keep petrol in pipelines, how do people think we'll keep hydrogen in them?