7 ms·

Seawater split to produce green hydrogen

59 points by tech2 4y ago

refuse 4y ago
Maybe one day we'll generate hydrogen with floating renewables in the ocean and just fill up a tanker to bring it to shore. It would make hydrogen a very attractive option for energy storage and transportation.
- phkahler 4y ago
  Hydrogen is a terribly dangerous thing to keep around for fuel. I've been in garages where fuel cell vehicles were being developed alongside EVs. They had hydrogen detectors and alarms. In case of leaks, evacuate. It has a very wide range of concentration where it will not just burn but explode. You don't want this in your neighbors garage.
  - refuse 4y ago
    It'd be great in a renewables-based grid for energy storage and transport. It could be carefully controlled and monitored because of the partial centralization. I'm not sure it'll ever make much sense for vehicles unless you could increase the density so it's stored as a slush without needing a high-pressure or an ultra low-temp holding tank.
    - bobthepanda 4y ago
      Right now, for planes and ships, it’s either hydrogen or syngas, because batteries are too heavy.
      - deleted 4y ago
        [deleted]
    - dahfizz 4y ago
      You can't just put hydrogen in a tank like you can with i.e. propane. It's a real pain to deal with, and I don't think grid scale hydrogen will ever work out. It would make more sense to use the hydrogen to synthesize methane, and then use that for grid scale storage and generation. This would be carbon neutral.
      - gadflyinyoureye 4y ago
        These are the types of conversations we need. So many people crap on hydrogen, but you can use it in a variety of ways. We can run cars on methane or convert it to ethanol. This makes converting our current fleet of vehicles cheaper and more realistic than converting to an all EV future. Even if we really, really wanted to move to EV, we can convert the existing fleet to carbon neutral ethanol for the next 50 years while slowly introducing EVs. Electrocatalytic oxidation of methane to ethanol via NiO/Ni interface - https://www.sciencedirect.com/science/article/abs/pii/S0926337320303039 https://www.sciencedirect.com/science/article/abs/pii/S09263...
  - beambot 4y ago
    Lesser-known, but there are solid-state hydrogen storage options that compare favorably to liquid storage (energetically, volumetrically, and inherently temperature & time stable). Best example is storing hydrogen in an aluminum matrix -- Aluminum Hydride, aka Alane. Companies like FuelX are commercializing. https://en.wikipedia.org/wiki/Aluminium_hydride https://en.wikipedia.org/wiki/Aluminium_hydride https://fuelx.tech/ https://fuelx.tech/
  - MisterBastahrd 4y ago
    What if we had a process to stabilize it? Say, mix it with carbon somehow....
  - contravariant 4y ago
    I mean it's not as if oil based fuels are good in that regard either.
WithinReason 4y ago
We have split natural seawater into oxygen and hydrogen with nearly 100 per cent efficiency What % efficiency does "nearly 100% efficiency" mean in this context?
- phkahler 4y ago
  Seems like a good first step in desalination.
  - pixl97 4y ago
    Seems more like a way to increase salination. Instead to me it sounds like a way to take solar and convert it into a hydrogen storage battery.
    - gadflyinyoureye 4y ago
      That is exactly what it does. This is a good thing. We can convert it into a fuel that can power vehicles and infrastructure. Yes, hydrogen is a scary element. Yes, hydrogen is hard to store. However, with water it is an abundant fuel source that should allow competition in conveyance and grid scale storage.
- tech2 4y ago
  I'd wondered the same, but even with that question hanging I think the outcome of being able to electrolyse sea water directly was interesting.
- andrewflnr 4y ago
  I read it as with exactly the same number of joules of electricity as the enthalpy of formation of the water they electrolyze (not sure about the terminology, it's been a while since I took chemistry). Basically the electricity supplies exactly enough energy to pop off the hydrogens.
- marcosdumay 4y ago
  The paper is being widely discussed everywhere. I didn't get it (paywalled), but it seems the high efficiency claim means that way more than 95% of the electrical current goes into electrolysis. Overall, the most important thing is that this thing is cheap. Everything else you read around just means it's equal or not much worse than the usual electrodes.
tarotuser 4y ago
There is no such thing as "Green hydrogen", other than the facade of oil companies that created that term to allay climate change fears. And we even have a term for this - Greenwashing. https://theecologist.org/2020/dec/18/hydrogen-hoax https://theecologist.org/2020/dec/18/hydrogen-hoax
- refuse 4y ago
  I'd say overall that hydrogen is an attractive proposition because once you have the infra for it, you can substitute whatever color of hydrogen you want. The trick will be making sure we can easily replace gray hydrogen in the future for green.
- thinkcontext 4y ago
  Millions of tons of hydrogen will be necessary for fertilizer production and other industrial processes for the foreseeable future. If this hydrogen is produced using electricity from no carbon sources, what would your objections be? What do oil companies have to do with hydrogen not derived from any of their products?
  - LarryMullins 4y ago
    Both things are true. Green hydrogen is necessary for green fertilizer production, but green hydrogen for energy production is still a scam.
    - skedaddle 4y ago
      There's no way to ship solar or hydro energy. And for shipping everything else -- how would you power a boat from India to the US? Or a plane? Hydrogen remains the only green (ish) game in town for these needs.
      - _0w8t 4y ago
        Methanol produced using green energy is much better alternative to hydrogen. It is vastly easier to handle and store.
Animats 4y ago
Another electrolyzer. It runs on unpurified seawater. But for how long? Where does the salt go? What is throughput like? How do they keep the thing from crudding up? And what happened with the last five promoted articles for new electrolyzers?
- andrewflnr 4y ago
  Don't know about the rest, but the salt can probably just stay dissolved. Their feedstock is cheap, costing a bit of pump electricity at worse, so I assume they can turn just a little bit of it into gas and toss the rest overboard.
  - samtho 4y ago
    You will quickly reach a max saturation unless you are letting water simply run through it. Regardless, the act of running water with impurities through any medium will result in deposits.
    - andrewflnr 4y ago
      Just letting it run through, or otherwise cycling it really quickly and cheaply, does seem possible to me. I'd be interested to know if there are any fundamental reasons you can't let it flow, like if water moving past the electrodes decreases efficiency or something. You would at least need to watch out for the current taking away your product. Deposits, yeah, but that alone doesn't sound like a showstopper. This is far from the first engineering application to use seawater, there are probably ideas out there that they can borrow.
- nibbleshifter 4y ago
  I've always wondered how they prevent all the salts from reacting. Or what they do with side products. If you run electricity through salty water, you tend to get a whole bunch of interesting chemistry happening. There are products you can buy that perform electrolysis on water with a small bit of salt to make bleach (sodium hypochlorite). If you bung in a shitload of salt, you eventually get sodium chlorate, or perchlorate forming, depending on the amount of amps you chuck in. You also get chlorine coming off, etc... You can kinda limit or control this with membranes, but with seawater you have a fuckload of side reactions that are going to happen.
andrewflnr 4y ago
From the abstract of the linked Nature article[0]: > This is achieved by introducing a Lewis acid layer (for example, Cr2O3) on transition metal oxide catalysts to dynamically split water molecules and capture hydroxyl anions. Such in situ generated local alkalinity facilitates the kinetics of both electrode reactions and avoids chloride attack and precipitate formation on the electrodes. For all the hype about "untreated seawater", I have to assume they're at least running it through a mesh to get the larger contaminants out. [0] https://www.nature.com/articles/s41560-023-01195-x https://www.nature.com/articles/s41560-023-01195-x
ajb 4y ago
Where are we going to use this hydrogen, that it would be cheaper than just using electricity directly? Lots of people in the UK use methane gas for heating. This is cheaper than heating with electricity (using standard electric heaters). There is talk of replacing the boilers with ones that can run off hydrogen. But even if the hydrogen is generated at 100% efficiency, surely it can be no cheaper than using the electricity directly, and since it won't be 100% efficient, it must be more expensive. And that's without taking into account the gain from using heat pumps, as opposed to directly creating heat. The other main use of gas is to create electricity! So where will this hydrogen be used?
- deleted 4y ago
  [deleted]
- ben_w 4y ago
  Between about 2000 and 2010 I kept seeing people say "well actually hydrogen isn't a power source it's a just a storage mechanism", since about 2010 I keep seeing people say "oh we can't possibly get to 100% renewables, storage isn't a solved problem". And back in the 80s and 90s, the US was regularly making 3.5 GWh hydrogen tanks fly hypersonic while attached to strong enough pumps that it could've powered an entire medium-sized European country for the 500 seconds it took to empty the tank, and they didn't bother to make them reusable. So yeah, I recon it will be used for heating and power. Not 100% sure because it has competition from batteries, pumped hydro, and a global power grid, but it's certainly viable and the competition will take time.
  - arghnoname 4y ago
    Despite the many challenges, I like hydrogen as part of the solution to this stuff. It's easy to produce with commonly available inputs. If we had efficient central energy generation, it's a way of making that energy transportable. When burned (or used in a fuel cell) at the point of use, it burns clean. I suspect the fears about its volatility are manageable. All concentrated forms of energy are dangerous. The issues with containing it and improving its density, I'm not sure. I'm glad we're not just 100% going with batteries. With all of these technologies there's a lot of ??? between here and panacea. I just wish this attitude I see that this is an easy problem and we're going to invent our way out of the energy situation in a few years are a bit glib. The benefits of traditional energy forms are immense. The externalities can no longer be ignored, but we have an immense challenge to get even near parity in a general way. I think we'd do better to more soberly assess the situation. Just to be clear, I'm agreeing with you, but there's a lot of untold story in how we get to the "it will be used for heating and power" bit.
CharlesW 4y ago
Submission from yesterday (86 comments as I type this): https://news.ycombinator.com/item?id=34635111 https://news.ycombinator.com/item?id=34635111
indymike 4y ago
Can we please stop adding colors to elements? It's silly and very awful marketing. I'm pretty sure that last I looked, hydrogen is transparent in gas form.
- nautilius 4y ago
  So are there strange quarks?
- AtlasBarfed 4y ago
  Well, the proper color for anything hydrogen is "shadow" because all mass market placement of "hydrogen" is the oil industry trying to delay the onset of EVs and alternative energy. Don't get me wrong, there is legitimate scientific aspects to green/blue/black classification, but those don't matter, because what is being discussed here is in the fantasy land of news media. Anything "green" or "blue" in hydrogen is something far off in the future and they will use fossil fuels in the "short" run. Almost like, it is an "aspirational" green power source. Green, as in, someday theoretically it can be green. For SPECIFIC industrial use cases, I welcome hydrogen as a possible step off of fossil fuels, you know, someday. Fertilizer, steel, etc. And I like the discussion of reusing existing natural gas turbines and other equipment but... anyway, don't get your hopes up. They tipped their hand with the "100%" figure. Hey guys, look, we violated the basic laws of thermodynamics! That's why the reporting on hydrogen is so hair-pulling, everything is smoke and mirrors and obfuscation and fake numbers and miracle technologies, so even where there is legitimate potential and uses, I completely distrust it. I mean, I have to go to goddamn reddit to get a discussion of the "100%" figure: https://www.reddit.com/r/science/comments/10rvo8x/comment/j6y00ni/?utm_source=share&utm_medium=web2x&context=3 https://www.reddit.com/r/science/comments/10rvo8x/comment/j6... 100% is for Faradaic efficiency. "Faradaic efficiency only looks at the efficiency of charge transfer and is not the same as the energy conversion efficiency. The latter is usually meant when speaking of "efficiency" of hydrogen production and it will likely still be ~60% for this new process. Fucking ridiculous. TLDR The title is highly misleading." Fuck your latest "magic hydrogen technology" of the day.

59 points by tech2 4y ago

Maybe one day we'll generate hydrogen with floating renewables in the ocean and just fill up a tanker to bring it to shore. It would make hydrogen a very attractive option for energy storage and transportation.

phkahler 4y ago
Hydrogen is a terribly dangerous thing to keep around for fuel. I've been in garages where fuel cell vehicles were being developed alongside EVs. They had hydrogen detectors and alarms. In case of leaks, evacuate. It has a very wide range of concentration where it will not just burn but explode. You don't want this in your neighbors garage.
- refuse 4y ago
  It'd be great in a renewables-based grid for energy storage and transport. It could be carefully controlled and monitored because of the partial centralization. I'm not sure it'll ever make much sense for vehicles unless you could increase the density so it's stored as a slush without needing a high-pressure or an ultra low-temp holding tank.
  - bobthepanda 4y ago
    Right now, for planes and ships, it’s either hydrogen or syngas, because batteries are too heavy.
    - deleted 4y ago
      [deleted]
  - dahfizz 4y ago
    You can't just put hydrogen in a tank like you can with i.e. propane. It's a real pain to deal with, and I don't think grid scale hydrogen will ever work out. It would make more sense to use the hydrogen to synthesize methane, and then use that for grid scale storage and generation. This would be carbon neutral.
    - gadflyinyoureye 4y ago
      These are the types of conversations we need. So many people crap on hydrogen, but you can use it in a variety of ways. We can run cars on methane or convert it to ethanol. This makes converting our current fleet of vehicles cheaper and more realistic than converting to an all EV future. Even if we really, really wanted to move to EV, we can convert the existing fleet to carbon neutral ethanol for the next 50 years while slowly introducing EVs. Electrocatalytic oxidation of methane to ethanol via NiO/Ni interface - https://www.sciencedirect.com/science/article/abs/pii/S0926337320303039 https://www.sciencedirect.com/science/article/abs/pii/S09263...
- beambot 4y ago
  Lesser-known, but there are solid-state hydrogen storage options that compare favorably to liquid storage (energetically, volumetrically, and inherently temperature & time stable). Best example is storing hydrogen in an aluminum matrix -- Aluminum Hydride, aka Alane. Companies like FuelX are commercializing. https://en.wikipedia.org/wiki/Aluminium_hydride https://en.wikipedia.org/wiki/Aluminium_hydride https://fuelx.tech/ https://fuelx.tech/
- MisterBastahrd 4y ago
  What if we had a process to stabilize it? Say, mix it with carbon somehow....
- contravariant 4y ago
  I mean it's not as if oil based fuels are good in that regard either.

WithinReason 4y ago

We have split natural seawater into oxygen and hydrogen with nearly 100 per cent efficiency What % efficiency does "nearly 100% efficiency" mean in this context?

phkahler 4y ago
Seems like a good first step in desalination.
- pixl97 4y ago
  Seems more like a way to increase salination. Instead to me it sounds like a way to take solar and convert it into a hydrogen storage battery.
  - gadflyinyoureye 4y ago
    That is exactly what it does. This is a good thing. We can convert it into a fuel that can power vehicles and infrastructure. Yes, hydrogen is a scary element. Yes, hydrogen is hard to store. However, with water it is an abundant fuel source that should allow competition in conveyance and grid scale storage.
tech2 4y ago
I'd wondered the same, but even with that question hanging I think the outcome of being able to electrolyse sea water directly was interesting.
andrewflnr 4y ago
I read it as with exactly the same number of joules of electricity as the enthalpy of formation of the water they electrolyze (not sure about the terminology, it's been a while since I took chemistry). Basically the electricity supplies exactly enough energy to pop off the hydrogens.
marcosdumay 4y ago
The paper is being widely discussed everywhere. I didn't get it (paywalled), but it seems the high efficiency claim means that way more than 95% of the electrical current goes into electrolysis. Overall, the most important thing is that this thing is cheap. Everything else you read around just means it's equal or not much worse than the usual electrodes.

tarotuser 4y ago

There is no such thing as "Green hydrogen", other than the facade of oil companies that created that term to allay climate change fears. And we even have a term for this - Greenwashing. https://theecologist.org/2020/dec/18/hydrogen-hoax https://theecologist.org/2020/dec/18/hydrogen-hoax

refuse 4y ago
I'd say overall that hydrogen is an attractive proposition because once you have the infra for it, you can substitute whatever color of hydrogen you want. The trick will be making sure we can easily replace gray hydrogen in the future for green.
thinkcontext 4y ago
Millions of tons of hydrogen will be necessary for fertilizer production and other industrial processes for the foreseeable future. If this hydrogen is produced using electricity from no carbon sources, what would your objections be? What do oil companies have to do with hydrogen not derived from any of their products?
- LarryMullins 4y ago
  Both things are true. Green hydrogen is necessary for green fertilizer production, but green hydrogen for energy production is still a scam.
  - skedaddle 4y ago
    There's no way to ship solar or hydro energy. And for shipping everything else -- how would you power a boat from India to the US? Or a plane? Hydrogen remains the only green (ish) game in town for these needs.
    - _0w8t 4y ago
      Methanol produced using green energy is much better alternative to hydrogen. It is vastly easier to handle and store.

Animats 4y ago

Another electrolyzer. It runs on unpurified seawater. But for how long? Where does the salt go? What is throughput like? How do they keep the thing from crudding up? And what happened with the last five promoted articles for new electrolyzers?

andrewflnr 4y ago
Don't know about the rest, but the salt can probably just stay dissolved. Their feedstock is cheap, costing a bit of pump electricity at worse, so I assume they can turn just a little bit of it into gas and toss the rest overboard.
- samtho 4y ago
  You will quickly reach a max saturation unless you are letting water simply run through it. Regardless, the act of running water with impurities through any medium will result in deposits.
  - andrewflnr 4y ago
    Just letting it run through, or otherwise cycling it really quickly and cheaply, does seem possible to me. I'd be interested to know if there are any fundamental reasons you can't let it flow, like if water moving past the electrodes decreases efficiency or something. You would at least need to watch out for the current taking away your product. Deposits, yeah, but that alone doesn't sound like a showstopper. This is far from the first engineering application to use seawater, there are probably ideas out there that they can borrow.
nibbleshifter 4y ago
I've always wondered how they prevent all the salts from reacting. Or what they do with side products. If you run electricity through salty water, you tend to get a whole bunch of interesting chemistry happening. There are products you can buy that perform electrolysis on water with a small bit of salt to make bleach (sodium hypochlorite). If you bung in a shitload of salt, you eventually get sodium chlorate, or perchlorate forming, depending on the amount of amps you chuck in. You also get chlorine coming off, etc... You can kinda limit or control this with membranes, but with seawater you have a fuckload of side reactions that are going to happen.

andrewflnr 4y ago

From the abstract of the linked Nature article[0]: > This is achieved by introducing a Lewis acid layer (for example, Cr2O3) on transition metal oxide catalysts to dynamically split water molecules and capture hydroxyl anions. Such in situ generated local alkalinity facilitates the kinetics of both electrode reactions and avoids chloride attack and precipitate formation on the electrodes. For all the hype about "untreated seawater", I have to assume they're at least running it through a mesh to get the larger contaminants out. [0] https://www.nature.com/articles/s41560-023-01195-x https://www.nature.com/articles/s41560-023-01195-x

ajb 4y ago

Where are we going to use this hydrogen, that it would be cheaper than just using electricity directly? Lots of people in the UK use methane gas for heating. This is cheaper than heating with electricity (using standard electric heaters). There is talk of replacing the boilers with ones that can run off hydrogen. But even if the hydrogen is generated at 100% efficiency, surely it can be no cheaper than using the electricity directly, and since it won't be 100% efficient, it must be more expensive. And that's without taking into account the gain from using heat pumps, as opposed to directly creating heat. The other main use of gas is to create electricity! So where will this hydrogen be used?

deleted 4y ago
[deleted]
ben_w 4y ago
Between about 2000 and 2010 I kept seeing people say "well actually hydrogen isn't a power source it's a just a storage mechanism", since about 2010 I keep seeing people say "oh we can't possibly get to 100% renewables, storage isn't a solved problem". And back in the 80s and 90s, the US was regularly making 3.5 GWh hydrogen tanks fly hypersonic while attached to strong enough pumps that it could've powered an entire medium-sized European country for the 500 seconds it took to empty the tank, and they didn't bother to make them reusable. So yeah, I recon it will be used for heating and power. Not 100% sure because it has competition from batteries, pumped hydro, and a global power grid, but it's certainly viable and the competition will take time.
- arghnoname 4y ago
  Despite the many challenges, I like hydrogen as part of the solution to this stuff. It's easy to produce with commonly available inputs. If we had efficient central energy generation, it's a way of making that energy transportable. When burned (or used in a fuel cell) at the point of use, it burns clean. I suspect the fears about its volatility are manageable. All concentrated forms of energy are dangerous. The issues with containing it and improving its density, I'm not sure. I'm glad we're not just 100% going with batteries. With all of these technologies there's a lot of ??? between here and panacea. I just wish this attitude I see that this is an easy problem and we're going to invent our way out of the energy situation in a few years are a bit glib. The benefits of traditional energy forms are immense. The externalities can no longer be ignored, but we have an immense challenge to get even near parity in a general way. I think we'd do better to more soberly assess the situation. Just to be clear, I'm agreeing with you, but there's a lot of untold story in how we get to the "it will be used for heating and power" bit.

CharlesW 4y ago

Submission from yesterday (86 comments as I type this): https://news.ycombinator.com/item?id=34635111 https://news.ycombinator.com/item?id=34635111

indymike 4y ago

Can we please stop adding colors to elements? It's silly and very awful marketing. I'm pretty sure that last I looked, hydrogen is transparent in gas form.

nautilius 4y ago
So are there strange quarks?
AtlasBarfed 4y ago
Well, the proper color for anything hydrogen is "shadow" because all mass market placement of "hydrogen" is the oil industry trying to delay the onset of EVs and alternative energy. Don't get me wrong, there is legitimate scientific aspects to green/blue/black classification, but those don't matter, because what is being discussed here is in the fantasy land of news media. Anything "green" or "blue" in hydrogen is something far off in the future and they will use fossil fuels in the "short" run. Almost like, it is an "aspirational" green power source. Green, as in, someday theoretically it can be green. For SPECIFIC industrial use cases, I welcome hydrogen as a possible step off of fossil fuels, you know, someday. Fertilizer, steel, etc. And I like the discussion of reusing existing natural gas turbines and other equipment but... anyway, don't get your hopes up. They tipped their hand with the "100%" figure. Hey guys, look, we violated the basic laws of thermodynamics! That's why the reporting on hydrogen is so hair-pulling, everything is smoke and mirrors and obfuscation and fake numbers and miracle technologies, so even where there is legitimate potential and uses, I completely distrust it. I mean, I have to go to goddamn reddit to get a discussion of the "100%" figure: https://www.reddit.com/r/science/comments/10rvo8x/comment/j6y00ni/?utm_source=share&utm_medium=web2x&context=3 https://www.reddit.com/r/science/comments/10rvo8x/comment/j6... 100% is for Faradaic efficiency. "Faradaic efficiency only looks at the efficiency of charge transfer and is not the same as the energy conversion efficiency. The latter is usually meant when speaking of "efficiency" of hydrogen production and it will likely still be ~60% for this new process. Fucking ridiculous. TLDR The title is highly misleading." Fuck your latest "magic hydrogen technology" of the day.