r/Futurology • u/[deleted] • Feb 16 '23
Environment How to make hydrogen straight from seawater – no desalination required
https://www.rmit.edu.au/news/media-releases-and-expert-comments/2023/feb/hydrogen-seawater7
u/No-Owl9201 Feb 16 '23
Sounds like a step in the right direction, I'm sure solar and wind will in time provide the bulk of the World's energy but hydrogen has a part to play in shifting energy and got back up to other systems.
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u/bremidon Feb 16 '23
hydrogen has a part to play in shifting energy and got back up to other systems.
Hydrogen does not provide energy. Hydrogen stores energy. It does not compete with solar or wind, but with batteries.
Right now, it's hard to see where hydrogen would fit in. It needs another 20 years of maturation before we can even really start asking the question seriously.
Even if this lab approach was 100% ready to go to the next stage (it's not), then we would be looking at 5 years of pilot plant production at least, followed by another 5 years of getting a production plant up and *then* we could start talking about rolling this out over another 5 years. So 15 years, assuming that this is ready to leave the lab tomorrow. Which it is not. It also assumes that nothing really bad happens when they try to get it through the pilot plant stage, which happens pretty often.
Source: my father did this sort of thing for a living.
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u/VitaminPb Feb 17 '23
Don’t I seem to remember these exact same arguments being made about solar in the 1970’s, 1980’s, and 1990’s?
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u/bremidon Feb 17 '23
Well, yes. Because they were true.
My argument is that they need about 20 years before being ready. If I take 1985 as a midpoint from your range, it took about 25 years (to 2010) before it became cheap enough and powerful enough to really start being a serious alternative.
So we can check back in 2048 and see how hydrogen is getting on :)
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u/goodsam2 Feb 17 '23
Solar has plunged to be super cheap and is already the cheapest energy source ever and it's still falling in price...
Wind is as well.
Batteries have been on a similar curve but are mostly for intra-day demand shifts. Moving cheap solar to the night.
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u/WeLiveInAnOceanOfGas Feb 16 '23
This would be fantastic if true. The other claims are that this method:
-Uses a relatively cheap catalyst, both to make and run (low power usage)
-doesnt produce carbon dioxide or chlorine
-can be used at room temperatures
This, along with using abundant seawater, would address most of the downsides of current hydrogen production.
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Feb 16 '23
Researchers have developed a cheaper and more energy-efficient way to make hydrogen directly from seawater, in a critical step towards a truly viable green hydrogen industry.
[...]
“The biggest hurdle with using seawater is the chlorine, which can be produced as a by-product. If we were to meet the world’s hydrogen needs without solving this issue first, we’d produce 240 million tons per year of chlorine each year – which is three to four times what the world needs in chlorine. There’s no point replacing hydrogen made by fossil fuels with hydrogen production that could be damaging our environment in a different way,” Mahmood said.
“Our process not only omits carbon dioxide, but also has no chlorine production.”
Their process makes hydrogen from seawater via direct electrolysis. There does not need to be a desalination step. That's because their method does not release chlorine. As a result, this is cheaper and more environmentally friendly than past attempts at seawater electrolysis. A cheap and environmentally friendly way of making green hydrogen will be a major benefit to society and will avoid causing shortages of fresh water.
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u/Hammer_beats_paper Feb 16 '23
Now can this be technology be combined with water desalination plants to create a self sustaining system?
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u/giospez Feb 16 '23
I'm sure I'm missing something, but since I was a child I remember experimenting with hydrolysis, using salt water (adding regular kitchen salt to tap water, the salt was needed to conduct electricity), a battery and two electrodes, and producing H2 and O2 in two separate chambers. Therefore, in my deep ignorance, I don't see the breakthrough here. Just get some seawater, lower two electrodes in it, add DC current, and get your H2. There may be some advances in tweaking the electrodes' shapes and materials to make the process more efficient (i.e. more H2 obtained per KWH of electricity), but the basic science has been out there for literally a century or more
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u/crisbeebacon Feb 16 '23
Salt is Sodium and Chlorine. A second reaction in this salty aqueous solution occurs that results in the release of CL2 Chlorine gas which is not good.
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u/st4nkyFatTirebluntz Feb 16 '23
Leaving aside the issue of what to do with all that toxic gas, you also lose energy efficiency to the unwanted reaction chain, AND it corrodes your electrodes, so it's really screwed on 3 fronts.
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u/giospez Feb 16 '23
Thank you. After reading your response I spent some time reading and learning. Obviously more complicated than I thought. Now I feel embarrassed...
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Feb 16 '23
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u/WeLiveInAnOceanOfGas Feb 16 '23
Yes, the water is broken apart and is no longer there leaving nothing but salt etc. behind (at least that's what this method claims). Oxygen is much heavier than hydrogen so it's relatively easy to separate the gasses and collect at that point.
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u/FuturologyBot Feb 16 '23
The following submission statement was provided by /u/Hypx:
Their process makes hydrogen from seawater via direct electrolysis. There does not need to be a desalination step. That's because their method does not release chlorine. As a result, this is cheaper and more environmentally friendly than past attempts at seawater electrolysis. A cheap and environmentally friendly way of making green hydrogen will be a major benefit to society and will avoid causing shortages of fresh water.
Please reply to OP's comment here: https://old.reddit.com/r/Futurology/comments/113i2z4/how_to_make_hydrogen_straight_from_seawater_no/j8qctc7/