Researchers generate hydrogen more efficiently from water | Hacker News Reader

Researchers generate hydrogen more efficiently from water

phys.org

183 pointswglb131 comments

Technically this is about evolving oxygen gas from water more than it is about the hydrogen end of the electrocatalytic reaction. Since this is a cathode (2H+ + 2e- -> H2 gas) vs. anode process (2H2O -> 4H+ + 4e- + O2) linked up by a wire to close the circuit, you have two chemical processes to manage. The oxygen-evolving one tends to be slower, i.e. rate limiting. For an overview:

https://sci-hub.se/10.1039/c9cs00607a

Song, et al. (2020). "A review on fundamentals for designing oxygen evolution electrocatalysts." Chemical Society Reviews.

>"Therefore, the OER is the key process that governs the overall efficiency of electrochemical water splitting. To date, IrO2 and RuO2 have been state-of-the-art OER catalysts. However, both of them are made of precious metals and the cost is high. Therefore, it is imperative to seek low-cost alternative materials that can effectively reduce the kinetic limitation of OER and improve the efficiency of water splitting."

So, they discovered that the catalyst used at the OER end has some light-activation property, which is pretty interesting, i.e. they discovered a kind of photovoltaic electrocatalyst. Whether it will prove to be industrially useful is anyone's guess. There are similar systems but they're not very practical (i.e. they require high-energy UV):

https://physicsworld.com/a/light-activated-catalysts-make-ne...

As far as hydrogen-from-water tech, again it has three plausible large-scale cleantech industrial uses: ammonia from atmospheric N2, reduction of iron ore to sponge iron, and methane (and plausibly jet fuel) production from atmospheric CO2.

Hydrogen has numerous uses. Petroleum refineries produce and consume hydrogen in numerous places, if they find they are steam reforming they could use green hydrogen instead, together with storing waste Carbon dioxide to green operations.

Even if we quit refining oil from the ground we will still be doing chemistry like petrochemisty with other feedstocks.

If you can figure out how to get the carbon feedstock from the atmosphere at scale, why would anyone bother with refining a mixed muck coming out of the ground? What we call 'petrochemistry' today will be called 'aero-hydro-chemistry' tomorrow.

I’ve looked into the chemistry you’d use to turn a carbonaceous asteroid into useful products such as plastic films or material for a biosphere and the old C1 chemistry (manufactured gas and PVC from acetlyene) and the new stuff for utilization of CO2 turns out to be very relevant.

For instance you are going to get CO2 as a waste product and you will not throw it away because it is precious so you will add energy to recycle it. You might just get O2 from processing of metals and stones, burn the carbon and feed the CO2 into some system for further processing. The difference with earth is you have 24 hour sunlight and the anility to concentrate it with weightless mirrors.

There really is very, very little carbon in the atmosphere, famously ~410 ppm. (Yes, that little bit is enough to absorb significantly more heat from the sun).

So, whatever capture system you use, you'd need to move a lot of air through in order to produce a small amount of something like liquid hydrocarbon fuel.

It will require thousands of times more air, by mass. Since the output fuel product is hundreds of times more dense, it would require a crazy large volume of air to extract the carbon necessary to fill a fuel tank.

A corn field combined with a methanol fermentation and distillation facility is an example of a machine that does that. Very large.

The advantage of attempting it mechanically is that you might use less water and less fixed nitrogen. Water consumption is directly linked to how plants absorb CO₂ from the atmosphere, see https://ripe.illinois.edu/blog/difference-between-c3-and-c4-...

Plants pull 100 gigatons of carbon out of the atmosphere every year and convert it to biomass (essentially, oxy-ammonia-hydrocarbons like sugars, proteins, fats, etc.). Humans pull about 6 gigatons of carbon out of the ground each year and pump it into the atmosphere.

The reason this cycle doesn't exhaust the atmospheric pool, of course, is that animals and fungi (more the latter) break down biomass into CO2 and release it back into the atmosphere.

That's not what I'd call 'very very little carbon'.

On a planetary atmosphere level? It’s still tiny.

Literally .0441%

Getting anything at that concentration out is… generally not easy.

Doable! But not easy.

That it’s chemically low reactivity makes it even harder.

Plants have spent billions of years evolving to do it, and from an energy perspective aren’t very efficient at it.

Unless we want to burn even more oil trying to power the process or just make a tiny dent in it, we’ll need to not only figure out a somewhat efficient way to do it, but also figure out how to generate a massive amount of power without burning oil to power it.

For even more perspective, human breath can be easily composed of somewhere between 20,000 ppm and 40,000 ppm, and tens of thousands greater than that with enough energy expenditure. (I know this because I've actually measured this myself with research grade NDIR CO2 sensors)

441 ppm can be "a lot" depending on the gas and the expected effect. You don't want to breathe in 441 ppm of chlorine gas. But CO2 being fairly non-reactive makes 441 ppm of it relatively minuscule in contrast to the other predominant atmospheric gases. It's also nowhere near enough to cause outright catastrophe.

441 ppm CO2 turns out to be quite close to enough to cause global catastrophe.

Eventually. But no one is going to keel over dead due to suffocation today because of global CO2 concentration, which is ‘outright’.

Pretty sure global minimum temperatures above 100F would also count as ‘outright’.

There are already places where being without a cooling method other than sweating would be fatal, at least one day of the year.

In many more places, crops are failing.

People necessarily leaving these places will need to go where other people already are.

That happened before too, and has been (at lower frequency) for all of recorded history, near as we can tell. As noted, not an outright catastrophe right now.

The discussion is about avoiding it becoming one, and relative impacts. Humanity isn’t going to be dead tomorrow because of this, but may be in more pain in a decade or two, and longer term even more so.

Regional collapses have happened. This will be the first global collapse.

If it happens, it will be much earlier than you hope, as millions, then tens of millions, then hundreds of millions force their way across borders, and fascist governments ride that into power and then start a global thermonuclear war. The refugees will only be fleeing crop failure and increasingly murderous kleptocratic government.

It is already starting. Lots of governments are flirting with dictatorship, and many have got there already. US and Brazil have drawn back a hairsbreadth from the brink, but for how long?

You might want to slow down and breath a little.

I favorited that comment. When I feel anxious about something, I’ll read it again and realize anxiety can always be worse.

Just like the people who were entering the Capitol about 20 months ago.

It is a fact that almost half the US voting population is ready and willing to vote in somebody who would arrange never to leave office. Numerous billionaires support that outcome.

I'm not saying that you're wrong (or right). There is a LOT of scary stuff going on right now, for a lot of people.

I'm just asking you to slow down a bit, and take care of how you are now.

Otherwise, you'll never get to the point of any of the other stuff mattering anyway - and likely make it a lot worse for yourself in the meantime.

Really? Thanks an amazing claim! I'm sure you can provide us some evidence to support this.

Multiple Megatonnes of many different materials are mined at much lower concentration, and that requires digging up rocks. CO2 has many properties that make it fairly easy to select for.

We've already figured out that last part, it's called putting a few tens of square km of solar panels and heliostats (don't need it all to be electricity) in egypt or bolivia. A square metre nets you enough energy for a few tonnes per year in realistic current tech. This will never stem the tide if we don't go to net zero first, but reversing the damage in a century is doable by covering one medium sized desert.

Sounds easy and we’ve got it all worked out at scale. Problem solved then?

Maybe. Just maybe there's a middle ground between something being unfathomably difficult and impossible because big number bad, and being trivial?

There are lots of potential avenues for stuffing the genie back in the bottle with a small fraction of the energy we got out of releasing it. All that's lacking is the political will to hold the fossil fuel industry accountable, stop them doing more damage, and confiscate the proceeds of their crimes to start undoing the damage.

This last part isn't helped by reactionaries constantly screaming 'big number mean impossible' and 'der entropy'. Almost as if the goal of such discourse is to prevent solutions.

Who are you talking to exactly?

I never said anything of the sort, nor did anyone else near as I can tell?

You were concern trolling to try to shit on the best plan we have for a planet that remains habitable by vaguely gesturing about how hard it is with no context.

Then you sullenly implied I was saying it was trivial when I contextualised the actual scale involved.

This is part of the standard reactionary fud playbook.

Now you're playing the victim and trying to imply that's never what you meant.

Literally completely false.

You might want to re-read the thread and actually follow the site rules this time?

Feel free to read my prior comments if you want to see how completely false your perception seems to be of my motivations too.

My point is this takes time and treasure, and it isn’t yet solved - and incremental improvement helps, because if we were to try to actually do things at scale with our current level of knowledge, we lack the infrastructure to do so without burning more oil.

Which will slowly change over the next couple decades and centuries, but not without a lot of fallout first due to the speed of change.

I looked at your previous comments and retract my accusation. Apologies.

Most of the time when someone mentions CO2 air concentration it's as a prelude to pushing CCS or some vague idea about producing 100s of kW of energy per person using nuclear abundanceand I pattern matched a little preemptively.

This doesn't excuse your rhetoric about it not being urgent though. The damage may take effect later, but it is being done right now.

Thanks for acknowledging that, it isn’t easy.

You might want to recheck again though on that urgency claim. I never said that either.

To recap some discussions in other threads, what I’m pointing out is due to the sheer size of the problem, this will take decades to centuries to get under control (if the models are right, barring some truly revolutionary technology), no matter what.

Depending on the level of force used, it can and likely will lead to large scale war, which burns even more oil based on the way military operations are run now (and for the foreseeable future).

Even if we did things at the urgency level of the Manhattan project with infinite resources - unless we burned more oil. Even then, probably.

This is a heavily overloaded train that has been building up speed for 150+ years.

As to if any individual should be panicking or calm about this is up to them, but I personally find panic to put someone in a place where they are easily misled and results in bad and poorly thought out decisions which can often make it worse.

Which tends to be why folks go to fascism when they’re overloaded and scared, IMO.

As to if this discussion is useful or not? I don’t know. But I figured I’d throw it out there.

You mean ethanol, right? I don't think it's produced by fermentation, at least not without a secondary process that removes the other hydrocarbon.

That aside, yes, plant biomass to alcohol is a carbon-neutral tech that has already existed for a really long time. Let plants take carbon out of the atmosphere, ferment the starches and sugars into fuel alcohol, feed the remaining cellulose to animals, burn the fuel, eat the animals, and return most (but not all!) of the carbon back to where it came from. It's really an incredible process, but obviously its existence is a threat to the oil industry. If you've ever noticed the propaganda that ethanol is bad for engines and worse for the environment, well, just follow the money.

It takes a very great deal of hydrocarbon fuel to produce the ethanol going into our engines. When EVs displace gasohol-burning cars, the ag production, 30% of the maize crop, can go back to feeding people (or, more likely, feeding chickens); and we may hope the fuel used will be synthetics from atmospheric feedstocks.

Brazil's sugar cane operations seem to produce more fuel than the process consumes.

D'oh! Yes, ethanol. Thanks for the correction!

But there are CO₂-rich exhausts in chemical plants and power plants, with concentrations well above 50%. This is where the capture could work efficiently. These likely produce a sizable portion of the carbon dioxide surplus.

Capturing carbon from a jet engine will remain problematic, or slow. Maybe we should just grow more trees, extract solid carbon from them (by burning or otherwise), and bury it in old coal mines.

Even more efficient than carbon capture from power plant exhaust?

not pulling the carbon out of the ground and burning it to begin with

It makes zero sense economically to expend a huge amount of energy to pull the carbon out of power plant exhaust and do something with it, when we can generate the energy without releasing the co2 in the first place.

You have to do something to the existing power plants, before you build out enough solar, wind, batteries, and nuclear. It capture is cheaper then rebuilding the plant, it may make sense to run it until the end of its planned service life.

Certain things produce CO₂ as a part of non-power-generating chemical processes, like steelmaking, or producing cement for concrete. If the CO₂ can be captured economically, it would be a great win; there are few known remotely viable alternatives.

You're forgetting all the lifecycle emissions and the whole 'if capture is cheaper' part given that running a coal plant without CCS is more expensive than replacing it with new solar panels in many areas already.

> It makes zero sense economically to expend a huge amount of energy to pull the carbon out of power plant exhaust and do something with it, when we can generate the energy without releasing the co2 in the first place.

It kind of makes sense, if energy is cheap enough. If we have surplus energy, we can remove enough CO2 from the atmosphere to stop or even revert climate change. If we can desalinate water with that surplus energy, we can even use that extracted carbon to increase the amount of biomass on the surface.

Both climate change and fresh water supply are solvable with abundant cheap energy.

This comment is inaccurate, the way CO2 traps heat isn't from the sun, but the thermal black body radiation from the surface.

Do you have a link to something where I can read more about this?

Home furnaces burn a lot of natural gas and put the water in the sewer and the CO2 in the air. I wonder how much tweaking the sewer system would need to start acting as a CO2 return system also. If it were a closed loop system you could at least be carbon neutral, and stockpiling methane for the winter is easier than stockpiling electricity.

I think the upgrade to far, far more efficient heat pumps would be small compared to the cost of that...

Direct carbon capture makes sense whenever you have a high concentration of CO₂ emissions. The most obvious are cases where you can get pure carbon, not CO₂. Other times, it might be also worth capturing the CO₂ from something burning. Direct carbon capture from the air will probably be the most expensive solution, but it is still doable. You figure that eventually it will be subsidized.

The other problem with carbon capture (if you could overcome the low concentration issue somehow) is that the result of the tragedy of the commons isn't just "oops the temperature went up by 2°", it's "oops we killed off all plant life on Earth simultaneously and now nearly every living thing on Earth will be dead within a few years".

It took centuries to increase atmospheric CO2 to problematic level.

If we are so lucky as to have to worry about overcorrection, I'm confident we'll be able to find the 'off' switch to whatever solution in time.

It would be good if there was some sort of indication of how much more efficient the process is. Is it a 5% improvement or a 50% improvement?

Well, it's a typical hydrogen news story.

So while there is a lot of potential in hydrogen, a LOT of legitimate and useful use cases, and likely some real fundamental science in the article, the hyping of hydrogen is a desperate astroturfing campaign by oil/gas/nuclear to stave off EVs and wind/solar/battery which is eating their lunch in raw economics.

Thus the lack of real numbers intentional. Hydrogen production isn't efficient compared to grid transport and battery/hydro storage, because water is a very stable molecule and splitting it will fundamentally take a fair degree of energy and thermodynamic/heat loss/entropy.

I understand the oil/gas industry produces hydrogen from methane. But why would nuclear care whether their electricity is used for electrolysis or battery EVs?

Gen 4 Nuclear could use sulfur-iodine or other thermochemistry to make hydrogen directly rather than spinning a turbine and doing electrolysis.

There was recent news on this calling it purple hydrogen or something silly.

We're so far away from having sufficient green (or green adjacent) hydrogen supply to cover existing industrial uses that it's pointless even considering it for transportation.

If anything, cheap electrolysis is a deadly threat to nuclear. Green hydrogen solves the last remaining problems for a 100% renewable grid (the rare dark/calm periods and seasonal leveling.) Cheap electrolysers mean nuclear is defenseless against much lower LCoE renewables.

nuclear sees themselves as a provider of heat/electricity for industrial hydrogen generation.

I didn't say it made sense, but it might give them gravitas for subsidies to keep them afloat. Political calculus is totally different than economics or logic.

Why the issue with nuclear ?

Doubly so because the same oil and gas industry has spent quite a bit of money over the years to spread anti-nuclear hysteria, including covert support of environmental groups such as the Sierra Club. The effects can be seen now in EU, where gas has been labeled "green", while nuclear isn't.

https://www.forbes.com/sites/kensilverstein/2016/07/13/are-f...

This link provides a breakdown (be aware that is from an explicitly pro-nuclear group):

https://www.ans.org/news/article-930/sierra-club-natural-gas...

The oil and gas industry has tremendous incentive to expose nuclear. It's still the only game in town for truly replacing them.

Yup :)

> The effects can be seen now in EU, where gas has been labeled "green", while nuclear isn't.

Gas plants have been labeled a transition technology on the path to a fully renewable grid, because they are cheap, fast to construct and can serve as peaker plants burning biogas. While they are currently burning fossil fuels, the emissions are way lower than for other fossil fuel plants - per each kWh produced, less CO2 gets emitted, and particulate emissions are additionally way lower.

In contrast, nuclear plants take an extremely long time to plan and build - the EPR design took almost two decades alone for building it in Olkiluouto and almost as much in Flamanville. Add to that the many years of bureaucracy in obtaining permits, purchasing land and other activities, and suddenly you're looking at 25+ years until the plant is operational, and dozens of billions of euros in sunk cost.

The future is many things, but certainly not nuclear fission!

Renewables will still require some form of long-term utility energy storage though. Hydrogen seems like it could be a useful medium for that - batteries have gotten a lot better, but it's not clear that they'll become cheap enough when everything else wants batteries as well. Pumped hydro can only be installed in so many places (not to mention the tremendous environmental impact of building it).

Hydrocarbons for energy storage are and will stay way more efficient and safe than pure hydrogen or batteries.

Using synthetic hydrocarbons for energy storage will always cost more than storing hydrogen underground, or bonded to nitrogen as ammonia.

There will be reasons to synthesize hydrocarbons, but energy storage won't be among them.

This comment doesn't quite make sense. A hydrogen cell is still just a battery with a different name and those vehicles would still be EVs, no?

I believe the name is hydrogen fuel cell. It takes hydrogen as a fuel and generates electricity like a battery, instead of combusting it like a typical gas powered motor

The output of a hydrogen fuel cell is water, so it is a fairly sustainable loop if you can capture the water and generate hydrogen from it. But you need an efficient process to convert water into hydrogen

That fuel cell is more like an engine than a battery. You have to get O2 into it, get waste heat out (harder than the engine because the temperature is lower), keep it from drowning in the water it makes, etc.

It is hard to see the fuel cell EV competing with a battery EV.

Yes, but they have very different characteristics. You can't just plug a hydrogen car into the grid and charge it anywhere, so the overnight charges that EV owners are accustomed to go away. The hydrogen fuel cells tend to be large and heavy, so they don't save weight and also lose luggage capacity relative to an EV of similar size.

And without great advances in hydrogen production, they tend to cost more to operate than gasoline powered vehicles.

The one perk is faster fillups for road trips or lacking infrastructure. Most EV owners wouldn't switch just for that.

>the hyping of hydrogen is a desperate astroturfing campaign by oil/gas/nuclear to stave off EVs and wind/solar/battery which is eating their lunch in raw economics

Meanwhile, in reality, gas (not sure why you lumped in nuclear but others have already called you out on it) are providing the lion's share of reliable power generation and will continue to do so for decades. Even after 2050, you'll still need gas-fired generation to provide a backup to intermitten generation from wind/solar, which WILL need it, a lesson that California has yet to learn.

As for oil, it's an incredibly dense form of energy which can be stored in a tin can. Even with battery storage wind/solar will never have that ability.

Tired of HN's need to put ideology over real economics.

> Well, it's a typical hydrogen news story.

Yeah, if you combined all the published results on generating hydrogen from water, you'd have perpetual motion. Search with Google for "hydrogen from water breakthrough":

* Revolutionary technique to generate hydrogen

* A breakthrough method uses solar energy to produce hydrogen

* Israeli scientists make breakthrough on producing 'green' hydrogen fuel

* CRUCIAL BREAKTHROUGH IN HYDROGEN ENERGY

* Australian Lab Turns Hydrogen Into Green Energy With Secret

* UCSC Makes Green Hydrogen Breakthrough

* New breakthrough in the study of hydrogen production by

* A new way to generate hydrogen fuel from seawater (Stanford)

* SunHydrogen has developed a breakthrough technology to produce renewable hydrogen using sunlight and any source of water.

* HyTech Power may have solved hydrogen, one of the hardest ...

* Universal Hydrogen's decarbonizing technology is coming to

These go back years.

The difference is that there is serious interest in 2022 in green hydrogen to replace hydrogen from methane steam reforming or the shift gas reaction and coal.

Having a "serious interest" and earnestly wanting it this time doesn't change the fundamental fact that you need a lot of power to crack water apart. There's simply no way around that, all improvements found will be marginal at best.

I wish somebody would do a very simple roundtrip calculation for each of these 'breakthroughs' and publish it.

all i want to know is the efficiency, cost & power density these on consumption side so I can decide which applications this works best in. on the production side same thing except for power density. the fact that its incredibly hard to find these numbers makes me think that these are mostly puff pieces for hydrogen before BEV eats their lunch.

green/blue/gray hydrogen is mostly BS.

The main interest now is not for ‘dispatchable energy’ but for industrial uses of hydrogen, metallurgy, etc. There is a lot of competition for energy storage such as conventional batteries, vanadium flow batteries, compressed air, pumped hydro, etc. I think fuel cell cars have been dead since Tesla made attractive BEV cars.

why would I care about hydrogen when I have a perfectly good electrical system ready in hand. hydrogen's main selling point is energy density, which makes is good on paper for 'mobile' applications. if you forgo that than there are plenty of good energy carries like NG/gasoline or electricity which round-trip much better in efficiency terms.

I am not sure if there is a sudden step up in industrial uses of H. on face value this looks more like groundwork for some upcoming fossil greenwashing subsidy that uses hydrogen to justify public funds.

I'm not sure you understood this: "The main interest now is not for ‘dispatchable energy’ but for industrial uses of hydrogen, metallurgy, etc."

He's not talking about hydrogen as a store of energy. He's talking about hydrogen to be used in industrial processes that require hydrogen input. Energy density has nothing to do with it, and the superiority of NG/gas/electic for carrying energy isn't relevant.

> I am not sure if there is a sudden step up in industrial uses of H

Step up? There is existing demand for hydrogen which this would, presumably, be more efficient at meeting. If they're not meeting that demand for hydrogen by cracking water apart, they'll do it by cracking natural gas apart instead.

Look up Paul Martin on linkedin for a thorough examination of H2 as a fuel, including round-trip efficiency.

thanks for the suggestion. This is exactly what I needed: https://www.linkedin.com/pulse/distilled-thoughts-hydrogen-p...

esp the efficiency chart about 1/3rd way in lays it bare.

You're welcome!

> I wish somebody would do a very simple roundtrip calculation for each of these 'breakthroughs' and publish it.

Yeah. Commercial electrolyzers are about 70% efficient right now. So only 30% headroom is available for improvement. There are people with prototypes that claim 95%. It's apparently possible to beat 70% without much trouble, but overall costs go up. If you search for "electrolyzer efficiency" you find discussions of equipment size, cost, durability, water quality requirements, and purity of the output gases. That's apparently a bigger issue in practice than electrical efficiency. The breakthrough story industry wants is "we built a big one, it cost half as much to build, it runs on tap water, and it's self-cleaning."

When you electrolyze water, the dissolved solids have to come out somewhere. Or you have to start with highly purified water, which means a big water processing operation and more operating cost.

The amount of energy to crack water is already only a small multiple of what you get back when you get the products back together.

The improvements are in the cost of equipment per unit output capacity, and the production rate per unit volume of said equipment. Improvements are cumulative.

Airports, steel mills, and ammonia synthesizers will need to produce huge amounts of H2, soon, so reductions are important.

Exactly the same thing can be said about battery and solar technologies.

But eventually research does reach a point where they make a difference to ordinary end users.

Right, but also things like electricity was harnessed a mere 100 years or so after its discovery -- so it might take another 100 years before it's practical.

The other problem is that we have an infrastructure built up for electricity today. This is not the case for H2. It's not that we can't make it, but, electricity is far cheaper to transfer across a continent than H2.

Your comment has an air to it which makes you sound no different than the same dogmatists you seek to discredit.

Framing the raw economics of renewables as superior to fossil fuels is wrong in many ways, mainly due to the narrowmindedness of viewing it through the lens of just energy. Do your views encompass the the vast network of global production tied to fossil fuel derived goods and processes?

No one should view it as a competition between fossil fuels and renewables. Phasing out fossil fuels has huge implications beyond energy production and if you're not at least attempting to model the "raw economics" to include things like plastics, fertilizers, etc., you're doing a disservice to achieving a sustainable future.

The fossil fuel industry certainly sees it as a competition, and they're playing for a very different goal of preserving profits at pretty much any cost - including broad social costs. Trying to play that off as "no competition between fossil fuels and renewables" seems very naive at best.

I do think it is an interesting question on "phaseout" of fossil fuels as a carbon emitting energy consumable, vs a feedstock for various chemical processes, like fertilizer production. But the fossil fuel industry very much does not want to go from a centralized role in energy vs a smaller role in chem feedstocks.

Hydrogen is needed to do chemistry and is a possible path to make metals. Fuel cells for cars don’t look like a good idea compared to battery EVs, but they might find a niche.

Notice how solar mppt controllers (or wind turbine controllers with dump load resistors) are lacking a "hydrogen electrolysis" load connector for excess?

Enough trickles make a flood (butterfly effect scaled), but on the same token, its like converting a pretty yard into an edible organic yielding space.

Diversification is now offering a lot more options that do not have toxic byproducts.

Just using excess capacity from solar transforms local hydrogen harvesting into a boost to many local economies (emptied/harvested weekly/monthly/quarterly to power local infra for example using an onsite storage cylinder and scheduling similar to trash pickup).

The sardine can neighborhoods cannot gaudy retrofit any of it, but an energy shed 50ft from a residence with new construction makes the applicable opportunities more than a pipe dream. They have to relocate the fire-hazard solar panels to a ground array anyways for reasonable insurance rates and right-sizing options for expandability as the technology progresses.

Wealth breeds health :)

>Hydrogen production isn't efficient compared to grid transport and battery/hydro storage

Electrolytic hydrogen production and consumption is not efficient. Mostly because of the consumption end of the equation (~50%, fuel-cell) rather than the production (~70-80%, electrolysis). But nuclear-driven thermochemical hydrogen production is currently being developed, and can theoretically exceed the thermal->electric conversion efficiency of the nuclear power plant:

https://www.sciencedirect.com/science/article/pii/S095965262...

https://www.sciencedirect.com/science/article/pii/S036031992...

For applications where energy is used for incineration, direct chemical use of hydrogen, or when power-to-weight efficiency is critical, it has some potential: we are really comparing thermal->electric->thermal with thermal->hydrogen->thermal in that case. Such applications account for a decent fraction of total energy use.

>campaign by oil/gas/nuclear

Oil and gas companies have always worked against nuclear. There's no association there.

Nowadays coal companies promote nukes, because a new nuke started means at least a decade of continued coal sales.

They know coal is doomed, so the best they can do is put off the inevitable. Solar, wind, or tidal would start displacing coal almost immediately. The nuke, furthermore, costs so much it eats budget that could have been spent on displacing much more coal than the nuke will when it is finally turned on.

> Nowadays coal companies promote nukes

Is there any source for this information?

Not if they are careful enough.

Passenger vehicles account for about 16% of greenhouse gas emissions. Electric power is another 25%. The rest is industry, commercial & residential, agriculture, and other forms of transportation. It is these areas of the economy which will need hydrogen.

You'll probably die of old age before there is even a whisper of a battery powered passenger plane the scale of a 787. But you may live to see a hydrogen powered passenger plane.

Once LH2 airframes start being delivered, displacement of kerosene airframes will happen very fast, probably limited mainly by production capacity of synthetic hydrogen. The changeover will certainly have started by 2040.

> the hyping of hydrogen is a desperate astroturfing campaign by oil/gas/nuclear

I'm not sure why it would be an astroturf. This really reads like an institution that is promoting the work they are doing and they are trying their best to make a newsworthy story. The second they add in words like "thermodynamics" and "entropy", or add anything boring like actual science, they are no longer newsworthy. Nothing to see here, just (over-hyped) marketing.

Many experts disagree with you, hydrogen may play a role in clean energy grid scale distribution due to existing pipeline capital.

> "This drop in performance, nobody has ever noticed it before, because no one has ever done the experiment in the dark," said Assoc. Prof. Xue.

How many modern discoveries like this can be accounted for somewhat sloppy experimental procedure? Sometimes there is not enough chaos in science, just messing around can open up crazy avenues of research.

Love it! Table top physics is still alive and kicking. We need more people doing more outlandish (seemingly) things.

Probably at lots of other labs their equipment worked in the dark, and they didn't try adding light.

>Aspartame was discovered in 1965 by James M. Schlatter, [...] He discovered its sweet taste when he licked his finger, which had become contaminated with aspartame, to lift up a piece of paper.

There are legitimate use cases for hydrogen. Trains are a good example - electrification of medium to long distances (through tough terrain) is prohibitively expensive, as is battery usage for the whole journey.

Trains require a lot of energy to get started (where batteries work well), but then a relatively small trickle of power is needed: hydrogen fills this niche. Big companies are investing billions into this right now.

Maybe we could power the trains along the rail, or in catenary above? Add a very small battery to power it maneuvering around the rail yard?

How do you restart the train after stopping in the middle of nowhere ?

hydrogen generators?

Trains are a silly use case for hydrogen. Electric trains have been used and viable for approximately 100 years. The only problem is how expensive it is to electrify thousands of miles of tracks.

That problem is now gone, batteries can be used to bridge gaps in the catenary wires.

Think mountain passes or similarly difficult terrain. Or lower volume cargo trains, like into and out of industrial areas in the north. Catenary networks not only take a lot of money to set up, the maintenance is huge - especially in rough terrain or over long distances!

ed: Not saying that all trains should be hydrogen, there just are use cases for some when we're talking zero-emission.

Power cables are an attractive theft target, many places.

An extra insulated car filled with lightweight LH2 would not appreciably increase the cost of operating a train.

Liquified ammonia under low pressure might be more practical, if safety worries don't dominate. We already move tanks of ammonia on trains. And much worse.

Liquid green hydrogen costs an order of magnitude more than electricity, and always will since it's created from electricity and uses electricity for liquification. It definitely will appreciably increase the cost of operating a train.

The weight of one extra car will increase the operating cost of a 100-car train by 1%, give or take a bit. Using cheap hydrogen instead of expensive kerosene may save much more than that. Moving light hydrogen instead of heavy kerosene may save more than that.

If the electricity could be delivered directly to the train, the energy used would be cheaper, but installing (and replacing "shrinkage" of) many thousands of miles of "third rail" would cost a lot.

The hydrogen is not yet cheaper than the kerosene, but costs on that side are falling fast.

You don't need thousands of miles of third rails or catenary wires. Just a ~mile every ~hundred, and a battery on the locomotive.

That is an interesting alternative.

You need a battery that tolerates many many cycles, and being charged at 100x its usual discharge rate. Maybe a molten CaSb battery, from Ambri.

I guess if all the cars can be wired to take in power, you just need a short stretch of 3rd rail at each charge point, say 60 m, not 1600. If each car has its own battery and drive motors, they don't need to be wired together. Relative charge rate goes to 10,000x, but the grid load stays the same.

It's cheaper to just electrify the gaps. His views are fundamentally nonsensical and shows that he hadn't really thought about the problem. Hydrogen trains are for remote tracks, sometimes thousands of miles of unelectrified rail. If you can't justify ever electrifying those tracks, then hydrogen trains are the obvious answer.

Ammonia trains might be a better answer.

For tracks that cannot justify the cost of electrification, you will want hydrogen trains. Battery trains make the least sense, since it is easier to electrify those short gaps than to buy an entire new class of locomotives.

Electrification of existing lines and even new high speed lines are both much cheaper than the cars and fuel they can replace.

Wouldn't large container ships and trains be the perfect candidates for electrification? Create some sea can sized batteries that can easily be loaded on to and off of the train/ship. The infrastructure already exists for loading them, and they are used to carrying sea cans already. As I understand, ships are huge carbon emitters so if you could load a dozen sea can sized batteries, perhaps it could power it across the Atlantic (or maybe it would take a 1000 sized batteries, which would make it impractical).

Hydrogen makes a great way to store excess energy produced by wind and/or solar farms too.

Efficiency isn't even particularly important - in many cases farms can produce too much power for grids to absorb so you just convert it to hydrogen and use in those rare times you don't have solar or wind power for longer than batteries can absorb.

Actually, it's pretty inefficient as a storage solution. There are far better storage systems that loose far less energy.

Efficiency is important if the input (energy) is not free. That's why hydrogen based transport is a non starter because it costs about 3-5x the amount of energy.

The other problem with hydrogen is that both storing and transporting it are hard problems. A lot of it just boils off. It takes up a lot of space. Compressing it to 600bar takes up a lot of energy and requires some heavy duty equipment. Etc. Most hydrogen that is currently produced is used on site and not stored/transported.

> Efficiency is important if the input (energy) is not free.

This is the point - with some solar/wind farms the energy is free (ie, the grid price is negative).

It can be efficiently stored in metal hydride, e.g. Ti hydride, at low pressure.

> Food companies use hydrogen gas to turn unsaturated oils and fats into saturated ones, which give us margarine and butter.

Hydrogen is not used in the production of butter

> Long-touted as a sustainable fuel, hydrogen fuel produces no emissions as it burns upon reacting with oxygen—no ignition is needed, making it a cleaner and greener fuel source. It is also easier to store, making it more reliable than solar-powered batteries.

no ignition is needed? Easier to store?

has to be intentional. It easy to be half wrong, if you're 100% wrong it's as hard as being 100% right!

Sounds similar to photosynthesis. Light+Water is converted into chemical energy. Interesting that lights boost hydrogen conversion in a similar fashion.

Nature article:

https://www.nature.com/articles/s41586-022-05296-7

From the article supplement:

In typical electrolyzer stacks, it is difficult to trigger light-induced COM due to the limited penetration of light. Recently, Zhang et. al. developed a redox decoupled water splitting device which can facilitate the COM mechanism in electrolyzer stacks. It enables the decoupling of HER and OER from the electrodes to spatially separated catalyst bed reactions via a pair of redox mediators. Oxygen evolution for this redox decoupled water splitting device occurs at the oxygen evolution tank, which can be made of transparent material. This option of choosing transparent material for the construction of the oxygen evolution tank implies the possibility of actualizing our proposed COM in this redox decoupled water splitting device. Furthermore, the electrocatalyst powders can be directly dispersed in the electrolyte without the need to coat on a substrate. This can then enable the effective utilization of light by the catalyst, and the photon can then be used to effectively trigger COM. Thus, based on these considerations, the proposed COM can be actualized in this redox coupled water-splitting technology.

There isn't a way to harvest the light in sonoluminescence, yet.

https://en.wikipedia.org/wiki/Sonoluminescence

‘No ignition is needed’ is wrong. It doesn’t take much to ignite hydrogen but you do need a spark. You can always find a spark in an industrial environment so you can count on the Centaur blowing up in the Space Shuttle bay or the hydrogen bubble in a nuclear meltdown causing an over pressure event if not a consequential explosion.

Sounds a little like the plot from Chain Reaction (1996).[1]

[1] https://en.wikipedia.org/wiki/Chain_Reaction_(1996_film)

Is there any chemical way to store hydrogen in a car without pressurizing it? Driving around with a pressurized tank of combustible gas doesn't sound fun.

Liquid fuel can be created from carbon dioxide and hydrogen.

https://www.nationalgeographic.com/science/article/carbon-en...

It can be stored as metal hydrides. Hydrogen atoms can penetrate he crystal lattice of certain metals to form a metal hydride, usually a very fine powder. These are stable at pressures a little higher than earth's normal atmospheric pressure.

Fraunhofer are doing this thing: https://en.wikipedia.org/wiki/Powerpaste

So long as the energy which can be produced from the hydrogen is less than the energy which is required to extract it, these scientists are safe.

What makes electrolysis expensive is a whole bunch of secondary details. Impurities in the water foul the catalyst, or steal power for side reactions that may contaminate the product or the water. The best catalysts are expensive metals that you would like not to erode and be carried away.

After you get the hydrogen atoms separated from the oxygen, the oxygen atoms bond to become O2 molecules, releasing heat uselessly, and will later need to separated again (other oxygen, of course) when you burn the hydrogen, consuming much of the released energy; and likewise for hydrogen molecules.

The recent story about using water vapor as the feedstock might signal a solution to the impurities and erosion problems that introduces new problems to solve before it can be used.

Efficiency of the process is becoming unimportant as the cost of solar and wind-generated energy continues rapidly down, making other things like the cost of equipment and the volume of production more important.

The frequent reports on improvements to electrolysis indicate not hype, but research cumulatively improving an important process, just as improvements in production techniques drove and still drive down the cost of solar panels.

According to Wikipedia existing electrolysis systems are between 70-100% efficient. It's not fundamentally difficult to do (when I was a kid I made a "rechargable bomb" that would fill a balloon with hydrogen+oxygen and blow it up) but if you are doing it at scale you are going to be very concerned about capital cost and energy efficiency so there is room for improvement.

The important number when using hydrogen to carry energy is the round-trip efficiency. It has been hard to improve the efficiency of the energy-releasing side. We are fortunate that the number's importance is declining.

I don’t think the main interest is energy storage today, I think it is to replace other sources of hydrogen in industrial processes. Hydrogen as a fuel to say cook food or run a power producing turbine competes with many other energy sources and carriers but for industrial purposes there is often no alternative or the alternative is carbon heavy. (E.g. carbon monoxide is used to reduce iron in a blast furnace, hydrogen is substitutable for CO for many metallurgical functions.)

As cost to produce falls, it will be used in more places. Ways to store and transport energy will be among those.

LH2 is very attractive as aircraft fuel.

But I take your point: for other uses, the production efficiency counts more. Conversion to raw heat is pretty good, losing only what it takes to split the H2 and the O2, and then whatever of that heat you fail to direct to the end use, e.g. the steam that rises past the sides of your saucepan.

It competes with heat pumps for space heat, particularly given that air source heat pumps have gotten a lot better in 20 years. 20 years ago the word was that you needed a ground source heat pump in upstate NY but today air source heat pumps are completely practical.

Mine works down to a remarkably low temperature, but at that temperature is able to extract much less heat than the house needs to stay warm at that outside temperature. So I still burn a noticeable amount of propane, in bursts.

A fuel cell driving a heat pump is an interesting notion. The "waste heat" from the fuel cell is not wasted, here. If half the contained energy drives the heat pump at, say, 3x, you get 1.5x vs just burning it.

The extra expense of the fuel cell and heat pump seem hard to justify unless you have other uses for them. This is to say that hydrogen for home heating is unlikely to be important.

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