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- Hacker News
- A problem I'd have with seawater electrolysis is production of undesirable chlorine compounds: hypochlorite or elemental chlorine.
Or maybe there are uses for these? Releasing chlorine (diluted!) into the atmosphere might be a way to accelerate the scrubbing out of methane. Chlorine is photolysed by sunlight into chlorine atoms, which immediately react with methane.
by pfdietz - Unfortunately, some products of methane-chlorine reaction are much less desirable than methane.by nyeah
- If we're talking seawater already, why not dilute it with seawater down near the ocean floor and have it react with some rocks or something? Why put chlorine gas directly into the atmosphere?by NortySpock
- Don't they also react also with about anything else ? I would be a bit worried what else "gets eaten" if something as reactive as chlorine is released into the atmosphere on a wider scale.by m4rtink
- "The same research program previously produced anti-COVID-19 stainless steel in 2021"
WTF is "anti-COVID-19 stainless steel" I wonder.
Edit: Turns out it's a high-copper alloy that has antiviral properties.
by SoftTalker - While interesting is this ever going to be actually needed? Unless hydrogen is going to be used in a decentralised fashion, which seems unlikely, water can simply be saved from recombining hydrogen and oxygen. So you only ever need a finite amount of water.
Plus there's also futures where harvesting salt / lithium from seawater leaves clean ish water as a by product, or a future where when it's sunny, just boil water to evaporate it with nearly free solar, then electrolyse it. And you'd need near free electricity to make this economic.
by benj111 - Is there any progress being made on cars so they are less susceptible to rust? In my country that's the main reason why vehicles are scrapped, engines can be repaired easily enough, but when various suspension parts are corroded and need replacing it's not worth fixing anymore.
As I understand one of the reasons against using materials like stainless steel or other alloys for cars is that is is harder to work with, but most new cars today are written off - rather than being repaired - after even minor accidents, so that doesn't really seem like it's a realistic concern.
by lucaspiller - This is basically a solved problem. Saturn used plastic body panels on cars for a while. These cars had some painted metal parts that were protected by the plastic, and would never rust, because painted metal only rusts after the paint is compromised. Saturn went bankrupt and no one has been doing this. I suspect that it is really bad for a car company's bottom line because it lets people keep their car instead of buying a new one.
Also, you can coat your car underbody in an oil based coating 1-2x a year, and it won't rust. Its just an annoying chore that most people don't want to even think about.
by simulator5g - Stayed a few times in a place exposed to constant breeze from a tropical Pacific coast beach, and learned that stainless steel doesn't really last very long there. Everything stainless steel-based (fixtures, fridges, handles) rusts in a few years. I'd bet there's a market for upscale alloysby inasio
- Depends on the alloy. Just a guess, you had 304 stainless which will rust fairly easily in saltwater. 316 would last longer. Also it can be tricky to retain the corrosion resistance when welding stainless, your part might corrode first at weld points.
https://www.nemaco.com/blogs/304-vs-316-stainless-steel-diff...
by annoyingnoob - Making hydrogen from seawater is not an actual problem that needs solving.
The problem with hydrogen electrolysis is its energy requirements to split water. The energy requirements for the desalination of water before that is a rounding error. It's not worth the hassle to develop electrolyzers that can deal with seawater.
by hannob - Desalination is not the only application of seawater electrolysis.by nickff
- I truly do not understand the fixation with hydrogen as a fuel. Compressing H2 to store it requires around half of the total energy that you can expect to get from its final application. Add in production losses and the difficulty in storage and handing, its always much worse than batteries.
I can see the argument for use in industrial processes like steel manufacturing as a reducing agent, but not as a power source.
by briandw - > I truly do not understand the fixation with hydrogen as a fuel
Not everything is about "muh EV".
There is a reason that countries that have built significant Solar PV and Wind Turbine manufacturing capacity like China, Germany, SK, Japan, and India have also been investing in H2.
H2 as an energy market helps subsidize additional H2 usecases such as Ammonia/NH3 production for fertilizers (this has become critical due to the ongoing Iran War), steelmaking via H2 direct reduced/sponge iron, and (for China and India) coal gasification.
Additionally, REEs and critical minerals have increasingly become a bottleneck so additional options is good to have depending on the country, which is a major reason Japan heavily invested in hydrogen along with sodium solid state battery R&D.
And finally, the brutal truth is no major country actually cares about climate change - they care about energy security. Most larger countries have the ability to afford the externalities that arise from climate change, the three largest CO2 emitters in the world (China, US, India) are seeing CO2 emissions rise (mind you at a reduced rate, but still unsustainable from a climate change perspective), and in China and India's case continue to leverage coal as an energy security tool especially after the Iran War supply chain crisis highlighted the criticality of coal gasification for the fertilizers and agriculture.
by alephnerd - I truly do not understand the fixation with trying to use batteries in applications that really need a fuel.
- It's basically a battery. It's not a power source, it's energy storage. If the energy is cheap enough (e.g. solar) inefficiencies don't matter as much.by SoftTalker
- with hydrogenotrophs you can create food (all amino acids) from solar hydrogen, supposedly about 10% more efficiently, this could return a lot of arable land for wilding, solar farms, housing, ...
Imagine dividing farmland by 10x by feeding hydrogenotrophs with solar H2.
by DoctorOetker - I seem to remember Iceland was looking hard into hydrogen for their fishing fleets. They have to import Diesel fuel but they've got geothermal running out of their ears.
I haven't checked to see how that went, but it sounded like the perfect test case for hydrogen's viability.
by spauldo - I think the best argument for hydrogen is for automobiles. Existing cars can be converted to use it, doesn't spray pollution all over the city, and can be refilled quickly unlike a battery.by dec0dedab0de
- Well green hydrogen is also a necessity if you want to make carbon-neutral synthetic hydrocarbon fuels.by fisherjeff
- In a lot of places in the world, the marginal cost of electricity is zero, if your capital costs are low enough to only purchase when there is excess wind.
The cost of batteries for long-term storage is still prohibitively high. In contrast, large hydrogen (or methanol, etc further products) are relatively cheap to store.
Those two things put together is pretty much it. There is massive room for additional wind capacity in northern europe (and solar in north africa, etc). In order for constructing that additional capacity to make any sense, there needs to be more demand that can idle for ~2/3rds of the time, and make economic sense to run a third of the time. In these conditions, the roundtrip efficiency is an entirely uninteresting statistic, and the capital cost of capacity is what matters.
by Tuna-Fish - The "cannot be explained" headline is a bit much, but the underlying result is genuinely interestingby SwtCyber
- So apart from the clickbait, the reason why this is interesting is because it's a limiter for the often cited idea of clean green hydrogen from electrolyis. The current use of titanium and precious metals is, obviously, really expensive, so it's uneconomical to build something that only runs on "spare" electricity.by pjc50
- Yes, although I'd still want to see how much of total delivered hydrogen cost this actually movesby SwtCyber
- I don't think the efficiency or longevity of electrolysis equipment is the limiting factor...
The limiting factor is that natural gas is very cheap and cracking it to make blue hydrogen is really easy at scale, and gives off CO2 which is useful for injection into wells to increase production. That sets a price ceiling of hydrogen.
At the other end of the scale, there are batteries to store 'free' electricity and resell later. That sets a floor price of electricity.
Between the floor price of the input and ceiling price of the output, there is no room for electrolysis, even at 100% efficiency, unless government policies mandate it or restrict batteries or blue hydrogen.
- This would be great for other use cases too like climbing bolts and anchors in coastal areas. Lots of areas are switching to titanium glue-ins which are expensive, but I wonder if this could enable more affordable option. A climber recently died in Greece after multiple bolts failed: https://gripped.com/news/rock-climber-dies-in-kalymnos-after...by lukeinator42
- 3 10mm bolts failing simultaneously after two decades (on direct it seems) is unexpected! If it were an installation problem, I can’t imagine it would take that long and that they’d all go at the same time. Ditto for corrosion… people take victory whips all the time.by kansface
- Good point, not only is titanium expensive but the glue-in part is tricky to get right as the glue has to completely surround the bolt. Not only that, but early efforts at titanium rebolting sometimes didn’t use glue at all. In Thailand, I pulled out some titanium bolts with my fingers because they weren’t glued in.by cgh
- Very interesting. Highly corrosion resistant "unconventional" steels have become somewhat popular in cutlery, with steels like LC200N, H1/H2, and MagnaCut. LC200N and H1/H2 in particular can be left in body of water uncoated/unpainted and come back in a year and they'll be fine. Obviously that's a different setting than electrified seawater for hydrogen production, though. So much cool materials science happening!by asa400
- I'm not at all convinced that the highly corrosion resistant knife/tool steels you mention are actually especially high on the corrosion resistance scale -- I think they may just be excellent for a tool steel.
If you look at the knifesteelnerds article on H1 (https://knifesteelnerds.com/2019/06/24/h1-steel-how-it-works...), you'll find that it's an austentitic alloy (which is highly unusual for any sort of tool steel), and that it seems like it's likely a somewhat less corrosion resistant than usual variant on steels like 301 or 304. And the rather common stainless alloy used for non-tool applications where high levels of corrosion resistance is 316, which is more corrosion resistant than 304.
In any case, this new alloy is weird -- it seems like it specifically has excellent resistance to electrochemical corrosion when it is used as an anode, which is not what people usually use stainless steel for :)
by amluto