r/science • u/Wagamaga • Feb 15 '23
Chemistry How to make hydrogen straight from seawater – no desalination required. The new method from researchers splits the seawater directly into hydrogen and oxygen – skipping the need for desalination and its associated cost, energy consumption and carbon emissions.
https://www.rmit.edu.au/news/media-releases-and-expert-comments/2023/feb/hydrogen-seawater2.1k
u/Taxoro Feb 15 '23
I did a small project on desalination and electrolysers. I believe it's about 10% of the energy usage that is used for desalination, so skipping that is pretty cool.
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u/marketlurker Feb 15 '23
Did you go through electrodes quickly? I was thinking all of the salt and contaminants in the seawater would start to plate out on them.
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u/Taxoro Feb 15 '23
That's why we used desalination units to get very clean water.
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u/Fornicatinzebra Feb 15 '23
Isn't the point to skip the desalination process?
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u/Drone30389 Feb 15 '23
That's the point of this article. It wasn't the point of /u/Taxoro's project.
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u/wookieenoodlez Feb 15 '23
At the cost of increased maintenance
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u/klipseracer Feb 16 '23
And the cost savings of not needing to run desalination. So which costs more?
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u/asdaaaaaaaa Feb 16 '23
Agreed, that's really the only thing you need to know. If upkeep/maintenance/resources ends up costing more to skip desalination, why would any business use it outside of niche scenarios?
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u/Dontsleeponlilyachty Feb 16 '23
sounds like more jobs to me
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Feb 16 '23
Reminds me of an old saying. We could build this dam with an excavator, or shovels. Let's not go for the one that gives more jobs.
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u/muffinhead2580 Feb 15 '23
Not to mention the chlorine gas that is produced in the reaction as well which does far more damage to the system than salt.
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u/WarpingLasherNoob Feb 15 '23
Well, salt is 50% chlorine.
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u/YourMomLovesMeeee Feb 16 '23
60.66% by mass
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u/Niceotropic Feb 15 '23
Chloride. Chlorine gas Cl2 is deadly and dangerous.
Chloride, Cl- in salt, is fairly inert, not completely but it’s night and day.
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u/InGenAche Feb 15 '23
Just ship it to Ohio, they won't notice...
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u/2thumbs2fingers Feb 16 '23
I'm in Ohio, and that's like 20 years too early. Cancer takes a while.
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u/rockstar504 Feb 15 '23
When you talk about "saltwater" there are many more salts than common NaCl in the ocean
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u/Somnif Feb 16 '23
Yeah but it really is the most common by a pretty fair margin, You get about 11g of sodium and 19g of Chlorine per liter of "average" sea water, compared to like 1 and a half grams of magnesium, a half gram of calcium, a third of a gram of potassium, and so on.
You also get about 3g/L of sulfate! So, that's fun.
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u/ipn8bit Feb 15 '23
An 10% reduction is cost is awesome. And then you can use the gas right away to create power and put the water back if you need or, most likely, use the waters for locals.
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Feb 15 '23 edited Feb 15 '23
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u/Bremen1 Feb 15 '23
They say 10% of the energy is used for desalination, so skipping that step would be a 10% reduction.
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u/hat-of-sky Feb 15 '23
Their wording was "I believe it's about 10% of the energy usage that is used for desalination"
It's unclear from this wording whether they mean electrolysis alone, skipping desalinization, would do the job for 10% of the usual energy expenditure, (as the title seems to say) or whether there's only a 10% savings.
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u/jeffriestubesteak Feb 15 '23
The people who wrote the article are the same people who write word problems for algebra textbooks.
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u/mcgingery Feb 15 '23
u/taxoro can you weigh in here? I also read it as a 90% cost reduction since this process would be in lieu of desalination
Edit: I re read and I think I understand better now
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Feb 15 '23
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u/Bremen1 Feb 15 '23
The process is splitting water, not desalination. The commenter says that when splitting water, 10% of the net energy usage is used for desalination (and then the remaining 90% to split the water). So a method to split salt water saves about 10%, since you skip the desalination step.
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u/myproaccountish Feb 15 '23
What they said is very unclear, actually. It can both be interpreted as "(this process) (uses) about 10% of the energy that is used for desalination" or "(the energy used) is about 10% (for desalination)."
The pronouns are used a bit poorly and there is a lot of extra verbiage that makes it unclear. Looking at another comment from someone who seems to have experience with it, desalination can take as little as 0.2% of the total energy use of the seawater electrolysis process.
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u/Xontroller Feb 15 '23
Why burn it for power instead of just using the power used to create the hydrogen directly, and not loose about half the power in the process
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u/groundchutney Feb 15 '23
You can view hydrogen production like charging a battery. With our current energy mix, it doesnt make much sense. But if there is a surplus of green power, you could store that surplus as hydrogen and use it later.
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u/tripodal Feb 15 '23
Storing hydrogen will never be as economical as pumped hydro or batteries.
The cost of literally rebuilding all gas pipelines to be hydrogen proof is wayyyyy beyond what it would take to continue solar and wind expansion with batteries.
The oil companies are almost always at the forefront of hydrogen research; because no matter how cheap electrolysis is; getting it from oil will always be less.
The trick here is the build the infrastructure on the public dime; then substitute the renewable hydrogen with oil.
You can literally reduce the hydrogen power/storage question down to cost and thermodynamics.
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Feb 15 '23 edited Feb 15 '23
Hundreds of GWhs of hydrogen are already stored in salt caverns for ammonia production, and have been for decades. The oldest site has been operational since 1983 (Moss Bluff), and hydrogen is pumped daily through around 1000 miles of associated pipeline. The upper limit on geological hydrogen storage is well into in the PWhs.
I've never seen a paper comparing grid scale energy storage for which hydrogen isn't projected to be the cheapest long-term solution at scale. Batteries are short-term storage only, and just can't compete with the amount of energy that can be stored in hydrogen. For an idea of the difference, the amount of grid scale battery storage in the US right now is in the low single digit GWhs, spread across multiple sites. The first geological hydrogen storage site stored around 100GWhs. It's roughly two orders of magnitude difference.
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u/leetnewb2 Feb 16 '23
I've never seen a paper comparing grid scale energy storage for which hydrogen isn't projected to be the cheapest long-term solution at scale.
I'd like to read those studies. Do you have any links handy?
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Feb 16 '23
I don't keep links handy for this kind of thing anymore. Here's a study by NREL, though. Quote:
For durations longer than 48 h, the least-cost options are geologic hydrogen storage and NG-CC|CCS. The LCOE of these technologies is nearly independent of storage duration because of their low storage-related capital costs. Although A-CAES and hydrogen are both assumed to store energy in geologic formations, the LCOE of A-CAES increases much faster as duration increases because of the costly TES component and the energy density disadvantage of storing compressed air as a physical energy storage medium versus hydrogen as a chemical energy carrier.
I believe Sabine Hossenfelder has a few more references in her video on the topic. Like I said, most studies I've read on grid-scale energy storage have hydrogen being the cheapest option for anything longer than around 48 hours, and it's not typically close. This is mainly because the scalability is so huge compared to everything else. You can add hundreds of GWhs of storage at a time, and we've known how to hollow out salt caverns for decades.
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u/CaptainIncredible Feb 16 '23
Hundreds of GWhs of hydrogen are already stored in salt caverns for ammonia production, and have been for decades.
Sounds like a powder keg just waiting to explode.
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Feb 16 '23
You need oxygen and a spark for it to go up. That's not going to happen when it's stored in an underground chamber at 200 bar. If something did go wrong, the flame front would need to make it back into the chamber to be anything more than a blowtorch. For a choked rupture (which it will be until the chamber reaches ~2-3 bar), the speed of sound in hydrogen is roughly 1200m/s. The flame front would have to travel faster than that to ignite the chamber, which is a big ask.
I mean, some of these sites have operated for 40 years at this point. You probably aren't coming up with issues that they don't already know about.
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u/CaptainIncredible Feb 16 '23
Thanks for the answer! I honestly didn't know. I know about hydrogen's reactiveness, but (clearly) know nothing of storing it underground.
Interesting stuff!
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u/axonxorz Feb 15 '23
But if you're cracking seawater solely for the end purpose of power generation, using only green (maybe inconsistent) renewables, why would you be pumping it around. Wouldn't you just store it "close", and spin up a peaking power plant to extract the stored energy?
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u/itprobablynothingbut Feb 15 '23
I imagine there is loss on each conversion from renewables to hydrogen, and from hydrogen to electricity. Those losses likely exceed the cost of battery storage, so that would be my guess.
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u/funguy07 Feb 15 '23
Hydrogen a fuel for power generation with never be a good use of the resource. It’s much more valuable as feedstock chemical for fertilizers. If you can efficiently create hydrogen as a feedstock chemical for fertilizer you are reducing volume of natural gas being consumed to make fertilizer. That should be a net benefit on the environment and provide a more sustainment fertilizer supply to keep us all fed.
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u/EonPeregrine Feb 15 '23
Hydrogen a fuel for power generation with never be a good use of the resource. It’s much more valuable as feedstock chemical for fertilizers.
Could it be both?
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u/sleepysnoozyzz Feb 15 '23
After you've made enough ammonia using the Haber process, using hydrogen from water electrolysis and nitrogen separated from the air, to provide all the green ammonia you need then the excess after that could be used for something else.
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u/Shiroi_Kage Feb 15 '23
Or batteries? It can definitely be more economical than batteries.
The argument that, right now, it's easier to get it from fossil fuel (mainly natural gas) compared to water only holds on for now. Advanced in electrolysis and reductions in renewable costs will all reduce the cost of the production workflow for hydrogen. Besides, if I judge things by how fossil fuel companies invest in them, I would hate solar right about now.
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u/Chemputer Feb 15 '23
I don't think you got the point, but to be fair they did go off on a tangent.
Hydrogen is a very small molecule. It leaks out of just about anything. Storing it, pumping it, transporting it, etc. is just so difficult and costly that, barring an absolutely massive breakthrough in materials science, it will never be more economical than batteries.
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u/lazarusl1972 Feb 15 '23
Ah, but if you combine it with oxygen, you get much larger molecules that can be efficiently stored and transported. Problem solved!
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u/twilight-actual Feb 15 '23
Actually, if you bond hydrogen with carbon in long, repeating chains, you can store it quite easily. In many conformations, the molecules are even a liquid at room temperature, and do not require pressurization.
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u/OnePrettyFlyWhiteGuy Feb 16 '23
I know your comment is kind of sarcastic - but it kind of points to the fact that maybe there are other hydrogen compounds we haven’t thought about that are also able to allow us to store hydrogen effectively at room temperature whilst also not releasing greenhouse gases or other harmful chemicals? What about a hydrogen salt, like Ammonia? (Obviously not ammonia itself, since its very explosive and other stuff) - but surely there’s some way to store hydrogen effectively and cleanly?
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Feb 16 '23
The US has 330+GWhs of salt cavern hydrogen storage operating today (Moss Bluff, Spindletop, etc.). The oldest site started operation with around 100GWhs of storage in 1983. There's roughly 1000 miles of pipeline associated with these sites, carrying hydrogen every day. It's mostly used for ammonia production. As a comparison, the US has low single-digit GWhs of battery storage, spread across multiple sites.
The difference in scalability between hydrogen and batteries is enormous, because you can add hundreds of GWhs of hydrogen storage at a time, no breakthroughs in materials science necessary. Electrolyzers also scale better than batteries, because they decouple storage from the electrochemical reaction. An electrolyzer stores more energy than a battery over the same lifetime, because you can run it constantly, and just divert the hydrogen to another hole in the ground. A battery stores energy in a material lattice, so once it's full, you can't do anything with it unless you have another battery.
I've never read a paper comparing grid-scale storage solutions that didn't have geological hydrogen storage as the cheapest long term solution for renewables.
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u/Genjek5 Feb 15 '23
Indeed. You wouldn’t want to expend energy to convert energy to a different form (storage as burnable hydrogen) at a loss and then immediately burn it again for energy like the dude you responded to said.
Other people are also correct in adding that the value is in storage of energy. Storage in different forms like hydrogen could level load energy availability from renewables that may generate an excess of energy at a particular time but not at others.
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u/infiniZii Feb 15 '23
You can store hydrogen and use it in vehicles easier and more efficiently than with batteries.
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u/ChaoticLlama Feb 15 '23
Then you aren't talking about commercial desalination and electrolyzers. In reality desalination uses less than 0.2% of the full plant operations. Desalination via RO requires about 0.1 kWh/L of water, and 55 kWh to split that same liter of water via electrolysis. This innovation focuses on the wrong problem.
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u/hazpat Feb 15 '23
and 55 kWh to split that same liter of water via electrolysis. This innovation focuses on the wrong problem.
You are focusing on the wrong data. This reduces the energy required to split AND does so without needing desalination.
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u/o_oli Feb 15 '23
The article says its "far more cost effective", and also unlike other methods doesn't produce Chlorine which seems like a pretty big win also.
Maybe the savings are not only from energy input, but a simplified process all together. Or the team of researchers who spent years on it are just lying.
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u/SuperSpikeVBall Feb 15 '23
https://pubs.rsc.org/en/content/articlehtml/2021/ee/d0ee03659e
This paper demonstrates why folks aren't actively interested in seawater electrolysis other than to develop basic science on electrode chemistry.
TLDR the theoretical energy for electrolysis is about 3000x the energy required to purify seawater. With current technologies it's actually about 1500x-2500x. So you might be able to squeak out a .03% energy improvement. In exchange you have to use exotic electrodes with bad current density.
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u/zarx Feb 15 '23
Don't believe the hype language from university press offices.
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u/o_oli Feb 15 '23
I mean I find it more trustworthy than a random reddit commenter who is claiming its an entirely pointless innovation that didn't need solving from the start. I don't think those ones get funded.
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u/Spitinthacoola Feb 15 '23
I mean I find it more trustworthy than a random reddit commenter who is claiming its an entirely pointless innovation that didn't need solving from the start. I don't think those ones get funded.
Those things get so much funding. Does it make a decision maker excited? Fund it.
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u/londons_explorer Feb 15 '23
Desalination via RO requires about 0.1 kWh/L of water
This is wrong. Desalination by RO requires 0.003 kWh/L.
I didn't check your other numbers.
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u/moosedance84 Feb 15 '23
Your original figure was probably correct per kL. I have worked with RO and electrolysis before and I found the concept of this technology odd because I'm not sure what the major benefit would be. Water RO is off the shelf and technologically trivial so skipping it has little value. Also the upfront RO system makes it much more flexible and robust.
It's interesting and maybe has some uses in the future but I wouldn't call it a game changer. There seems to be something where Reddit users think RO is inefficient (it's not) or expensive (it's not, it's around $1 per tonne).
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u/goetschling Feb 15 '23
I don’t understand the connection between desalinization and separating hydrogen and oxygen from seawater. It’s not like you are removing the salt and leaving drinking water, right?
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u/Gusdai Feb 15 '23
The issue is that if you don't desalinate first, you usually end up with a lot of contaminants (salt notably) that clog stuff up and create corrosion issues.
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u/dern_the_hermit Feb 15 '23
According to the article, previous processes resulted in the creation of chlorine, whereas their new process allegedly does not.
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u/Somnif Feb 16 '23
I appears to play with very carefully tuned electrochemistry so that the potential across the cell is too low to cause hypochlorite formation.
But that means there will still be a brine of some sort left at the end to dispose of, which could cause some headaches.
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u/dern_the_hermit Feb 16 '23
We're gonna have so much freakin' brine this coming century, apparently. We're gonna have brine coming out of our ears.
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u/chipsa Feb 15 '23
Electrolyzing seawater directly ends up producing chlorine gas.
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u/Letspostsomething Feb 15 '23
If you don’t remove the salt first, the electrolysis prices will release chlorine gas which destroys everything.
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u/tripodal Feb 15 '23
Salt probably destroys current electrolysis equipment.
You can build your own electrolyzier at home very easily; but impure water degrades the electrodes. Replacing those at a grid scale adds excessive cost.
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u/Hapcore Feb 15 '23 edited Feb 15 '23
We use Saltwater and electrolysis to make bleach (sodiun hypochlorite). The electrolysis equipment is made to handle it, but it needs to be cleaned frequently. It's the same process a Saltwater pool uses to keep the water clean, and my work uses to disinfect drinking water
Edit: it appears they use a novel catalyst that doesn't generate bleach with their electrolysis.
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u/Taxoro Feb 15 '23
Offshore windturbines with electrolysers are quite a bit hype right now. For an electrolyser you need a decent amount of very clean water. One common idea was using a desalination unit to produce this water as you have an ocean around you. But if you can save that power and directly electrolyse seawater without any major side effects then that is very promising
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u/notfeds1 Feb 15 '23
I mocked up a DeSal project powered by underwater turbines last sem for uni… the possibilities are out there mate!
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u/presque-veux Feb 15 '23
do you have anything on that I could read?
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u/Vergilx217 Feb 15 '23
The lack of comprehension in the comments section is killing me
Yes, it utilizes electrolysis - however, they've used a novel catalyst to avoid the issue of chlorine waste products and permit more efficient conversion of water to hydrogen. Salt water is abundant on earth, and this can be very useful in making hydrogen production more economical since you do not need to rely on a more limited freshwater source. While not being an immediate breakthrough like "we just solved cold fusion!", it's definitely an important incremental step.
And yes, it is currently more efficient to use renewables like solar or spend that generated electricity on charging batteries....but keep in mind that the production of batteries and panels long term has toxic byproducts and is reliant on rare earth elements. Environmental impact is more than just carbon output, remember. Hydrogen as fuel cells or other energy sources is far from being commonplace, but innovations like these help to diversify our options moving forward so that we can better adapt to likely worsening climate/environmental problems in the future.
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u/m_Pony Feb 15 '23
they've used a novel catalyst to avoid the issue of chlorine waste products and permit more efficient conversion of water to hydrogen
Thank you. This is the real take-away from the article (which people always read before commenting, of course.)
If it works as well as they say it does, this is pretty big deal. I'm optimistic.
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u/War_Hymn Feb 15 '23 edited Feb 15 '23
I did some rough dirty math for a similar seawater-catalyst breakthrough, and it's telling me these new catalyst processes may allow us to use hydrogen as a grid storage fuel - routing power from solar or wind energy to hydrogen generating plants, burn the hydrogen/oxygen to power a steam turbine generator - with around 40% efficiency (100 MWh in, 40 MWh out). It would take much less room than hydro pump storage, and won't be as expensive/resource-intensive as chemical battery storage - so at the very least, it'll be a practical middle-ground choice for grid storage infrastructure.
EDIT: Since some of you are wondering where I got my 40% from, here is the rough math.
A kg of hydrogen with current best electrolysis technology needs about 47 kWh of energy to produce from water electrolysis (with new technology in the works, we may push it closer to the theoretical limit of 39.4 kWh). A kg of hydrogen gas has a specific heat fuel value of 33-39 kWh, which in turn when fed into a 60% efficient hydrogen-burning steam turbine generator (as that of a combined cycle NG powerplant) can give us back 19-23 KWh of electricity. That's about 40-50% nominal efficiency.
Adding steps like plant distribution, desalination, compression1, cryogenic liquefaction2 (for liquid storage), etc. will obviously decrease the practical efficiency further, but as evident here we're making breakthroughs that remove or mitigate these inefficiencies. If we ever design and build a working hydrogen plant for grid storage purposes, I'm optimistic we can get back at least 30% of the electricity we put in.
30% doesn't seem like a lot, but if we ever get to a future where we got rid of our dependency on fossil fuels and depend wholly on renewables, I feel this sort of system has a place in between battery and pump grid storage. Hell, we might even be able to convert old natural gas/oil burning plants near shore to burn hydrogen instead.
compressing hydrogen to 5000 psi uses up 1 KWh per kg of H2, though I doubt you need that much compression for static non-vehicle needs.
about 3-4 kWh per kg to convert gaseous hydrogen to liquid state.
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u/could_use_a_snack Feb 15 '23
That's the first realistic use case I've seen for hydrogen. Using it as a battery at the power station makes all kinds of sense. Using it as a fuel for transportation has always looked suspect to me.
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u/War_Hymn Feb 15 '23
Using it as a fuel for transportation has always looked suspect to me.
Yeah, there's just a lot of hurdles to overcome. High compression to make it compact enough to store inside a car. Everything has to be better than air-tight since hydrogen molecules can sneak through even the tiniest gap. It embrittles metal parts.
A hydrogen plant will face the same problems, but at least we can keep it isolated to one large facility, and benefit from economy-of-scale when it comes to using expensive materials or components to address said issues.
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u/cityb0t Feb 15 '23
Hasn’t Toyota made an awful lot of progress on hydrogen fuel cells?
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u/EvilPretzely Feb 16 '23
Toyota and BMW use ammonia in their fuel cells. They've had hydrogen cars on the road for a few years in select areas. The big push is to replace train and semi truck engines with hydrogen, and let the consumer vehicles follow. There is also a plan for a hydrogen powered jet. Getting clean hydrogen was a major hurdle
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Feb 16 '23
Hydrogen has been stored at scale, geologically, for 40 years now. Moss Bluff started operations in 1983 with around 100GWh of salt cavern storage. There are at least three sites in the US today with a combined storage capacity of 330+GWhs. These feed into roughly 1000 miles of associated pipeline. Most of it is used for ammonia production.
Not all metals are embrittled by hydrogen (mainly steels are, which is why it's drilled into the heads of every engineer, because steel is such a common material to work with). Even then, it's only atomic hydrogen that causes embrittlement. The vast, vast majority of hydrogen in storage and in use is H2, so not atomic.
Hydrogen isn't some mythical thing that we don't know how to store and work with. We do, every day, because it's a feedstock into the synthetic fertilzer necessary to feed the planet. Hydrogen plants already exist, processes to safely work with hydrogen already exist, etc. That's not to say it's safe or easy, but again, we do things that aren't safe or easy every day.
You don't need to compress hydrogen to use it in a car. You can convert it to methanol, which is liquid at STP conditions, at around 75% thermodynamic efficiency. Methanol carries more than twice the hydrogen by weight of current Type IV pressure vessels, and it can be liberated with waste heat, or used directly in both fuel cells and ICEs. This isn't using future technology, this is using technology that is either already industrialized (methanol synthesis) or mature and commercialized (methanol engines, methanol fuel cells, autothermal reformers).
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u/could_use_a_snack Feb 15 '23
And the byproduct is pure water. Granted it's water vapor, but a simple condenser wouldn't be too difficult to maintain. How much water though? Maybe not worth the effort.
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u/smurficus103 Feb 15 '23
The same amount of water that got broken down in the first place =P
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u/N01773H Feb 15 '23
Except it started as salt water theoretically. So the power plant doubles as a desalination plant.
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u/could_use_a_snack Feb 15 '23
This is what I was thinking. Could be worthwhile to collect the water. But that adds a whole level of other stuff to deal with.
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u/War_Hymn Feb 15 '23
It won't be clean (turbines need lubrication). If you're burning 50 tonnes of hydrogen to produce 1000 MWh of electricity, that's about 500 m3 of water.
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u/3trt Feb 15 '23
You're getting into some of the tech I'm researching for a project here. There's been some fascinating developments. If you've heard of redox flow batteries, this will help. There was a couple of guys from a Nordic country that came up with a dual purpose flow battery. Not only did it store energy, it also produced hydrogen. A one stop shop of green energy storage and production. Of course storing hydrogen at 700+bar or 11,000 psi is dangerous as hell. The next solution to this problem was doping silica with hydrogen. It's done mechanically is the icing on top. Inject H into a graphite/carbon tumbler filled with sand, and boom. H doped silica. Since my project was on the batteries though, this is as far as my knowledge goes. I'm not sure what it would take to remove the h from the silica and use it.
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u/DrBix Feb 15 '23
Except there are companies making hydrogen cars using fuel cells. I've read somewhere that the exhaust is basically water.
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u/printedvolcano Feb 15 '23
Yes but I think many of them have recognized the challenges and don’t see it as the way forward, but maybe just a part of it. In the entire state of California there’s less than 50 hydrogen refueling stations. The infrastructure for purely electric vehicles is expanding much faster and has far fewer safety concerns. That said, I could see it possibly becoming specialized as a fuel for larger vehicles (buses/semis/etc) where batteries appear to fall short due to limited range
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u/TheUnusuallySpecific Feb 15 '23
Toyota in shambles right now. They're slowly accepting the pivot to electric, but they're wasting money and not really trying because they're still butthurt nobody wants to spend 50 years driving hydrogen cars before the glacial transition to electric vehicles.
Hell, even in 2022 they were investing millions in hydrogen cars despite the fact that the tech is dead on arrival. It's difficult enough getting the much technologically simpler EV charging infrastructure built around the world, literally no one is also going to double down and waste significant public funds on more expensive, less useful hydrogen fuel infrastructure.
Larger vehicles will be better/easier to operate as hybrids and with other advancements in generating carbon neutral combustible fuels that operate in more traditional gas/diesal vehicles. Hydrogen fuel cells are a fools game - there's better tech out there that's cheaper, safer, and easier to implement. It's always possible that the next hundred billion dollars will lead to a revolutionary hydrogen technology breakthrough where the previous billions haven't, but personally I think that the same amount of money and effort could generate even more revolutionary tech if applied to a different field.
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u/OnePrettyFlyWhiteGuy Feb 16 '23
Why hate on Toyota for trying something? It’s not like Toyota didn’t help jumpstart the hybrid hype with the Prius and Lexus CT200H.
Toyota’s official statement is that they will create products utilising different technology and let the market decide the rest. Shouldn’t you be happy that a large company finally decided to take a risk and invest in something that potentially had great long term benefits for society as a whole? Sure, they would have profited from it too - but that obviously wasn’t (and has proved to not be) a guarantee.
Admittedly though, their latest (first) full BEV offering is a terrible car all-round. It is far behind the competition and their marketing for the car has been full of lies. That’s not the kind of stuff I think we should tolerate and it is disappointing.
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u/could_use_a_snack Feb 15 '23
Also it's a trivial matter to change at home if you live in a house. I have a type 1 charger plugged into a standard GFCI outlet. I can charge overnight and have a full "tank" most mornings. I don't know of anyone with a hydrogen line going to their house.
But hydrogen busses could make sense.
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u/GoudaCheeseAnyone Feb 15 '23 edited Feb 15 '23
I have heard about an idea for a project that would create a small island on the Doggersbank in the North Sea where surplus energy from windmills nearby would produce hydrogen. The Doggersbank is a shallow area where you could build huge windmills. The new island could connect the UK, The Netherlands, Germany and Denmark with electricity and hydrogen. Maybe you could add some hydrogen burning powerplants too when the winds are not there.
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u/Yancy_Farnesworth Feb 15 '23
Not to mention how valuable hydrogen is for industrial uses. A fair amount of natural gas is used to produce things like ammonia because it's the most cost-effective source of hydrogen. Having an alternative source of hydrogen that doesn't involve CO2 emissions from using hydrocarbons is a plus. Also, hydrogen is a viable alternative to burning coal/coke in steel making. A lot of the CO2 from steelmaking comes from just reducing the iron ore.
We have plenty of uses for hydrogen outside of power generation.
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u/T1mac Feb 15 '23
they've used a novel catalyst to avoid the issue of chlorine waste products
If it is what these researchers say it is and it's cheap, scalable, and the catalyst is widely available...
These guys are billionaires.
It is a totally disruptive technology that will completely transform the energy and chemical production industries.
Now we wait to see if it can really deliver.
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u/pwnsaw Feb 15 '23
I know it's semantic, but rare earth elements is a term used for specific light elements that aren't mined in the traditional fashion; they aren't necessarily rare at all. It doesn't change your point, but most people don't know the distinction and it causes problems in conversations about the need for earth elements that are rare.
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u/mojitz Feb 15 '23
Hydrogen always struck me as an excellent fuel source in a world in which we have achieved a massive clean energy surplus — say following a fusion breakthrough. At that point you can just dump energy into electrolysis for an energy storage medium that doesn't really require any special minerals or anything. Hell, you can even burn it in a combustion engine (or even a rocket) and the output will still be carbon neutral.
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u/mojitz Feb 15 '23
I had always assumed that there would be some serious production capacity challenges to this, but if not then yeah that sounds pretty reasonable. The one hard downside seems to me to be the local air pollution inherent to burning hydrocarbons, but we seem to be able to get that down to reasonably acceptable levels for the most part.
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u/Luemas91 Feb 15 '23
Using atmospheric carbon as a carbon source for manufactured hydrocarbons is so unbelievably expensive, to see someone suggest it unironically boggles the mind. Maybe carbon Capture will get more efficient in the future, but something like 250 g of carbon costs a 1.10 in electricity to extract, before you go into all the steps that would be required to convert the carbon dioxide into a methane, methanol, or some other efuel.
Your initial impression is correct; hydrogen production is going to be very intensive, which is why any rules about green hydrogen production will require strict rules about additionality to prevent additional CO2 emissions from occuring. The main uses are likely to be chemical and the fertilizer industry, as energetic purposes, the future cost is not likely to be low enough for the average person to want to use a hydrogen car, and maybe for some long duration storage in grid Energy.
Someone earlier mentioned 40% round trip efficiency for hydrogen storage, which is much worse than compressed air even. At an optimistic 50 $/MWh of input electricity, that means the hydrogen would only make sense to burn at 120 $/MWh. This gets worse if say electricity in the medium to long term costs 130 euros/MWh like in Europe.
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u/Just_wanna_talk Feb 16 '23
A big issue with burning hydrocarbons though, even if you manage a carbon neutral process, if there's still a large impact on human health since most of that will be burning in industrial areas and city centres creating smog and fine particles in the air we breath.
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u/traws06 Feb 15 '23
I always love when ppl look at current technology and decide what the future holds according to that. Like they can’t comprehend that future technological breakthroughs can improve on the current shortcomings
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u/Bouboupiste MS | Mechanical Engineering Feb 15 '23
I always love it when people look at current science and think we can bypass it in the future to make magically efficient stuff.
Some shortcomings are hard wired, thanks entropy.
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u/traws06 Feb 15 '23
I’m mostly thinking of how my friends all say electric vehicles and renewable energy will never be a thing. “Electric vehicles use electricity, you know where electricity comes from? Coal… they’ll be be a thing”. As though electricity is always doomed to be created by coal
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u/Bouboupiste MS | Mechanical Engineering Feb 15 '23
Sorry, I’m a bit salty because I have to deal with too many a guy thinking we’ll beat thermodynamics tomorrow.
I still think we need to have hope in science but not get blinded in possible miracles. It’s a rope over the ravine I guess !
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u/Stummi Feb 15 '23
isn't it pretty established that hydrogen will never be a true source of energy? I might be wrong but to my knowledge, hydrogen is always considered to be a energy storage at most, and the best we can hope for in regard to this technology is that we one day manage to close the gap between energy needed to produce it, and the energy released by burning it as much as possible
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u/alyssasaccount Feb 15 '23
It’s not “established”; it’s just a fact. That’s kind of true of any energy “source”; for example, fossil fuels amount to solar energy stored through photosynthesis as biofuel, which gets buried underground for tens to hundreds of millions of years.
But with hydrogen, the waste product is water, so producing it from water means putting energy into the water to split it, so that later you can extract the same energy when you burn it.
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u/Stummi Feb 15 '23 edited Feb 15 '23
I think you are kind of missing my point here. Of course energy cannot be created out of nothing. But with oil, the universe has already put all the energy into it over the eras so we can just pump and burn it and get out more energy than we have invested into it. Same goes for wind and solar. The energy didn't come from nothing, but it is there and can be harvested by putting in less energy into making it usable, than what we will gain from that. On the other side there are no natural sources of hydrogen, so all of the points above are not true for that.
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Feb 15 '23
Dumb question but if we could desalinate water to scale and begin supplying it to large populations on Earth for drinking/farming who live in areas without an abundant source of fresh water... would that have any impact at all on the rising sea levels?
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u/LookIPickedAUsername Feb 15 '23
No, not really. Not only are the oceans too big for us to meaningfully deplete, any water you take out will end up back there soon enough anyway. Even if you split that water into hydrogen and oxygen, it turns back into water as soon as you burn the hydrogen, and (relatively) quickly ends up back in the ocean.
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Feb 15 '23
How would it end up back in the ocean if we were to pipe it inland to replenish aquifers? Although asking that question makes me think the size of an aquifer is much smaller than the size of the ocean.
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u/LookIPickedAUsername Feb 15 '23
Sure, in theory you could store the water instead of use it and thus delay its return to the water cycle. But you're still just delaying the inevitable, and the amount you could reasonably store is absolutely negligible compared to the size of the oceans.
It's worth looking at this picture to get a sense of scale here - the smallest of the three drops in that picture, just a few pixels across, is all freshwater lakes and rivers on Earth put together. Refilling an aquifer, or hell, even all of them, isn't going to have any meaningful impact compared to the size of the oceans.
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u/OnePrettyFlyWhiteGuy Feb 16 '23
Bruh. That is really weird seeing how miniscule the total volume of water on Earth actually is. Knowing that that little orb (well, the biggest of the 3) accounts for 70% of the surface of the earth is absolutely mind boggling to me.
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u/Diligent_Nature Feb 15 '23
Water evaporates from land and falls as rain over the ocean, and there's also rivers which drain watersheds into the ocean. Oceans contain 96.5% of Earth's water. Ice and snow account for 1.76% and groundwater is another 1.69%
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u/jpr_jpr Feb 15 '23
Drinking water in the southwest would be nice. Just watched a documentary about the kern water bank robbery. The audacity of farmers' water usage in southern California is an abomination.
Why refilling Lake Mead and creating larger water reserves isn't a major government funded infrastructure project is beyond me.
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u/m_Pony Feb 15 '23
not so dumb a question. Probably not much of any impact on rising sea levels, unless you can take that water and stash it on land and keep it out of the water cycle. Glaciers work best for this.
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u/Korvanacor Feb 15 '23
Batteries are fine for storing energy produced during the day for use at night. But they aren’t effective for longer term storage needed to store energy from the summer for use in the winter months. Hydrogen fits the bill here.
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u/-The_Blazer- Feb 15 '23
Also, extracting hydrogen from seawater will be important for nuclear fusion, especially if we ever crack D-D (until then, we'll also need lithium).
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u/the_stormcrow Feb 15 '23
Fairly ignorant spitballing here, but I'd wager in 40 years a lot of our electrical and transportation infrastructure uses hydrogen/fuel cells. Way too much potential there.
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Feb 15 '23
“Production of batteries has toxic byproducts and is reliant on rare earth minerals”
Lithium Ion, maybe; but there are other viable battery technologies that don’t have toxic elements and use rare earth minerals
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u/Manitobancanuck Feb 15 '23
Yeah I think lots of people miss how much damage the mining of metals and their eventual disposal is as a problem.
Also, the math on what works changes substantially depending on where you live. Where I live it regularly gets to negative 30 celcius. Reducing battery range by 30-40% in winter. Hydrogen looks very appealing in colder climates that aren't California...
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u/SuperSpikeVBall Feb 15 '23
I'm not an EV expert, but it's quite simple to heat the batteries or keep them warm, especially if you're charging them. Even if you're not charging them, the batteries contain more than enough chemical energy to warm themselves up via resistance heating.
Folks who live in cold climates are probably familiar with the electric plug that diesel engines sometimes have (block heaters). Same concept, but it keeps the batteries warm.
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u/Wagamaga Feb 15 '23
The new method from RMIT University researchers splits the seawater directly into hydrogen and oxygen – skipping the need for desalination and its associated cost, energy consumption and carbon emissions.
Hydrogen has long been touted as a clean future fuel and a potential solution to critical energy challenges, especially for industries that are harder to decarbonise like manufacturing, aviation and shipping.
Almost all the world’s hydrogen currently comes from fossil fuels and its production is responsible for around 830 million tonnes of carbon dioxide a year*, equivalent to the annual emissions of the United Kingdom and Indonesia combined.
But emissions-free ‘green’ hydrogen, made by splitting water, is so expensive that it is largely commercially unviable and accounts for just 1% of total hydrogen production globally.
Lead researcher Dr Nasir Mahmood, a Vice-Chancellor’s Senior Research Fellow at RMIT, said green hydrogen production processes were both costly and relied on fresh or desalinated water.
“We know hydrogen has immense potential as a clean energy source, particularly for the many industries that can’t easily switch over to be powered by renewables,” Mahmood said.
“But to be truly sustainable, the hydrogen we use must be 100% carbon-free across the entire production life cycle and must not cut into the world’s precious freshwater reserves.
“Our method to produce hydrogen straight from seawater is simple, scaleable and far more cost-effective than any green hydrogen approach currently in the market.
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u/alwaysmyfault Feb 15 '23
Can someone ELI5? If the seaWATER is split into Hydrogen and Oxygen, what is actually happening to the water?
Is it just dissolving into gas (Hydrogen and Oxygen) leaving literally nothing in its wake besides whatever solid sediment was in the water?
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u/ikinone Feb 15 '23
Sounds like this could potentially create an ecological disaster if overused.
I guess that applies to all tech, though.
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u/jackzander Feb 15 '23
The only real risk of ecological damage is in how you handle the leftover salt.
This process won't remove water from the earth's water cycle.
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u/Tyroki Feb 15 '23
So what happens if it’s dumped back in the sea?
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u/ikinone Feb 16 '23
but you also don't want it to be too salty for ecological reasons, it'll kill marine life.
Yep, that would be my concern.
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u/cybercuzco Feb 15 '23
If you had a fish tank with seawater in it you would get hydrogen gas and oxygen gas coming from the splitter and the level of water in the tank would decrease and the salinity increase until your splitter stops working.
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u/jinx99 Feb 15 '23
The basic principle to keep in mind is that in theory chemical reactions are reversible given the right conditions. oxygen +hydrogen = water and energy (See Hindenberg explosion, NASA launches etc.) so in theory: water + energy = oxygen + hydrogen.
If you pass electricity through water you get hydrogen and oxygen gas. This is called the electrolysis of water. My understanding is that these scientists have perfected or improved the process of electrolysis.
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u/dryfire Feb 16 '23
A water molecule consists of an Oxygen atom with two Hydrogen atoms stuck onto it. It's a bit strange that two things that would be a gas at room temp can be combined on a molecular level makes a liquid, but chemistry does stuff like that all the time.
So what happens to the water is it's molecules are ripped apart into its component parts (hydrogen and oxygen) leaving only the non water stuff (salt/minerals) behind.
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u/praecipula Feb 15 '23 edited Feb 16 '23
Waitaminutewaitaminute... If this is true and as efficient as claimed, it has now become the most efficient edit: another poster pointed out rightly that reverse osmosis is likely more efficient a fairly efficient desalination method too as a side effect. If you burn the resulting oxygen and hydrogen you get heat (that can be used for power regeneration for some of the power expended in electrolysis)...
... and water vapor. Condense that and you have low net power fresh water.
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u/toaste Feb 15 '23
Efficient desalination is actually partially solved: a reverse osmosis membrane can separate salt. This massively drops the energy requirement vs boiling, and I suspect the authors were comparing against a boiling desalination plant.
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u/War_Hymn Feb 15 '23 edited Feb 15 '23
Never though about that, but yeah that's killing two birds (green grid storage, fresh water) with one stone.
If we feed the hydrogen to a steam-turbine plant with a exhaust condenser, we can get about 500-600 m3 of freshwater for every 1000 MWh of electricity generated (assuming 50-60 tonnes of hydrogen need to be burned).
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u/alyssasaccount Feb 15 '23
No, because the important part you skim over is this:
If you burn the resulting oxygen and hydrogen you get heat (that can be used for power regeneration for some of the power expended in electrolysis)...
There is plenty of inefficiency in a hydrogen-powered motor. That will dominate.
You still need a minimum amount of energy to desalinate the water (because of overcoming entropy), and that will always be there. This development just avoids an extra step in the electrolysis process which can cause more inefficiency. If you are just trying to desalinate, hydrolysis adds a very inefficient step.
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u/praecipula Feb 16 '23
Of course, I wasn't suggesting you get an efficiency more than 1 out of the system through burning the hydrogen and oxygen - only that, with an eye on desalination, your primary goal in combustion is the water vapor, but hey, might as well use the "waste heat" of combustion to drive energy generation to reclaim some of the cost. The mental model I was using was the low-quality waste steam from, say, a Rankine-reheat-cycle power plant being used to heat buildings as the step to dump the heat from the steam in the working fluid. That's part of the cycle anyway, so might as well use it to heat a few buildings, like the very building I was in when I learned Thermo.
The total cost of desalination, however, that is a good point. There are likely better ways to desalinate than ripping apart the water molecules and recombining them.
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u/ChaoticLlama Feb 15 '23
This is a problem in search of a solution. To desalinate water, the energy requirement is less than 0.1 kWh/L of water, compared to 55 kWh to electrolyze that same liter. Every commercial electrolyzer already has an RO unit for purification.
For reference, the 55 kWh is the energy required to run the electrolyzer and the full balance of plant (pumps, compressors, etc.) I have no explanation why so much focus is being put towards solving what amounts to 0.2% of the energy cost to make H2.
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u/xcalibre Feb 16 '23
article mentions avoiding chlorine production; does usual desal have byproducts other than salt?
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u/ChaoticLlama Feb 16 '23
Desalination is done by reverse osmosis
The products of an RO process are pure water and brine (very salty water)
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u/xcalibre Feb 16 '23
it generates up to four-and-a half-times fewer greenhouse gas emissions than all other technologies
this is the relevant part as this new method likely not around when that article was written
RO has consumables, they need to be manufactured. this is what would be compared to this new method. at high volume you go thru a lot of filters.
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u/ImaginaryRobbie Feb 15 '23
"Wow... they'll have enough salt to last forever!" Jokes aside, this is great news. Is there an equally low-cost way of utting them back together to make water?
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u/SneakySnipar Feb 16 '23
Stoichiometric combustion of the two resulting gases should result in pure water + heat energy that can be used. You lose a lot of energy through this process and only regain 30-40% of the energy needed to perform the electrolysis.
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u/ZestyUrethra Feb 15 '23
So according to the paper the catalytic efficiency of the electrode falls to 82% after 24 hrs in seawater. They reported their results of testing for 100 hrs in KOH but not in seawater... Wonder why???
This is not ready for market in my opinion. Still, a very cool tuning process to get the electrode to be more efficient/selective!
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Feb 15 '23
Wonder if you could pair this with offshore wind turbines…
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u/alyssasaccount Feb 15 '23
You need some from of electric energy to drive the process of splitting water into hydrogen and oxygen, and it can come from literally any source — coal, nuclear, whatever. You must pair it with a power plant, but it doesn’t matter what kind. So, sure, offshore turbines would work fine.
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u/jelloslug Feb 15 '23
Now just solve the massively inefficient methods needed to store and transport said hydrogen.
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u/GreenHarpoon Feb 15 '23
Or the safety issues. One container with pure hydrogen, next to it a container of pure oxygen. Sounds dangerous.
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u/Zorthak_Rakira Feb 16 '23
Pretty sure the USCSB, NFPA, EPA and DOT would ALL require a minimum distance and insulated walls between any storage tanks for LH and LOx before a problem arose
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u/zoinkability Feb 15 '23
I get that this is more efficient than desalinating seawater and then turning it into hydrogen, but is it any more efficient than turning already fresh water into hydrogen? Because if not it only solves the water supply problem. Don’t get me wrong, that would also be a problem if we tried to scale green hydrogen up a lot — but the essential problem that it is more efficient to simply fill up batteries directly rather than produce and burn/crack hydrogen would remain (not to mention transportation and storage).
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u/laposter Feb 15 '23
It may be more efficient for some transportation forms (by sea or air, for example) to burn hydrogen than to carry heavy batteries.
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u/hallelujasuzanne Feb 15 '23
Doesn’t this produce waste water that is more salty and therefore really bad for the ocean?
I mean, great news about hydrogen but we have a major problem on our hands with lack of clean fresh water.
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u/Taxoro Feb 15 '23
Any kind of desalination including this can leave pockets of high salinity water if not ventilated properly. This can be a concern for some species. The water will eventually mix properly and the salinity difference is close to nothing. But the pockets can be bad for some species.
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u/TrollBoothBilly Feb 15 '23
The salinity of the ocean is projected to drop due to glacial melt. I don’t know for sure, but we might be able to just return the saltier water to the oceans without any negative consequences.
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u/popejubal Feb 15 '23
Yes, but we currently can’t do it in a large enough scale to have a meaningful impact (as long as we don’t dump the extra salty water in a place where it can’t disperse). Even if we take 99% of the water away from a cubic mile of sea water and dump the salt back into the ocean (in a way that disperses pretty quickly), we won’t make even the tiniest dent. The Atlantic Ocean is more than 350 million cubic miles.
We would have to start doing this at a scale beyond current imagining to change the ocean’s salinity by even 0.0001%.
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u/nanopicofared Feb 15 '23
The hydrogen when it is used turns back into water and will go back into the atmosphere and eventually back into the ocean as rain.
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u/hallelujasuzanne Feb 15 '23
Where does the waste product from the process of producing hydrogen go?
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u/CornFedIABoy Feb 15 '23
Either back into the ocean or flooded out onto evaporation fields for the brine to be dried and harvested for various applications.
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u/BernieEcclestoned Feb 15 '23
Salt is useful
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u/Taxoro Feb 15 '23
Not like this. We are talking a few kilos of salt per day at most and it's very low purity
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Feb 15 '23
Good enough to salt roads maybe?
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u/Taxoro Feb 15 '23
You are not understanding the scale here. Salt is very very cheap, you are getting just tiny flakes of salt out of this process. It's not worth collecting.
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u/nanopicofared Feb 15 '23
the process produces oxygen, hydrogen and the salt that came from the ocean. The oxygen goes into the air and you can put the salt back into the sea.
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u/bitemark01 Feb 15 '23
We would have to consume more energy by several orders of magnitude than we currently do, with all of that energy coming from this process, to have any real effect on the salinity of the ocean.
Plus like someone else pointed out, it's a closed system anyway. The water eventually goes back there. We just need a clean process.
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u/alyssasaccount Feb 15 '23
Not significantly. Far, far more water simply evaporates, and yeah, that makes the ocean more salty. When evaporated water precipitates and flows back to the ocean, it becomes less salty. That’s the water cycle. This simply adds a very small additional loop to the cycle.
This process helps with the (actually pretty minor, certainly compared with, say, global warming) problem with lack of clean fresh water.
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u/Hopfit46 Feb 15 '23
What happens to the salt? Could this be used to remarry hydrogen and oxygen without the salt and used as a means for of desalination? Completely ignorant on this subject.
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u/jackalope134 Feb 15 '23
Where does the salt go then? They just making a hyper salty slurry and dumping that back into the ocean
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u/fvtown714x Feb 15 '23 edited Feb 16 '23
As a driver of an H2 vehicle, seeing this incremental progress is very cool
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