This is remarkably hard to follow. The actual technology at play here is bicarbonate-formate redox; as the linked paper states:
>It is also clear that more integration between the disciplines of electrochemistry and heterogeneous catalysis is needed to overcome the challenges for advancing the HCO3−–HCO2− system as a feasible green alternative for storing and transporting energy.
The idea of storing energy by converting bicarbonate to formate has already occurred to me years ago and probably was thought of by thousands of other scientists, because formate is one of the most common hydrogen precursors used in practical chemistry. The storage density is low, but the materials are extremely cheap and stable. Unfortunately, the paper does not seem to be announcing a breakthrough, but tallying up the current progress — which just isn't there yet.
As long as the electrodes / membranes for the conversion to electricity are stable and cheap as well. There's a big downside with PEM electrodes requiring platinum and with their longevity and energy density relative to capex.
Thanks for linking the real article. It's an interesting read, especially that the Gibb's Free Energy for formate-bicarbonate is so low. Ammonia is about 20-40x higher!
Looks like they're using Pd/Pt for the best catalyzers... that's definitely not going to be scalable. Though there should be effective alternatives, but it's surprising how unsophisticated much of the research in this field can be.
I don't really have much understanding of chemistry. So possibly the most helpful part for me is the diagram with little trucks, the cost chart, and the paragraph below that says:
"The electrochemical regeneration is not optimized...If the cell voltage could be reduced to 2 V and the faradaic efficiency raised to 80%, the total cost of hydrogen would be nearly cut in half...if the regeneration and reaction could be performed at 8 M rather than 3 M concentration along with an improved process and discounted electricity...the cost of hydrogen could drop to just over $3 per kg...[which is] below the cost of on-site electrolysis with full-priced electricity"
Why formate? Can't you get hydrogen from any acid, because that's literally the definition of an acid? "If the cell voltage could be reduced" sounds super fishy to me; isn't that just a useless wish that the elements / molecules you're working with have different properties than they actually do? "If the regeneration and reaction could be performed at 8 M rather than 3 M concentration...", why can't they? Doesn't a reaction usually proceed faster in more concentrated solutions?
It seems like several breakthroughs that are needed, some of which possibly stretch the laws of physics. But once you have that. But even with those improvements, they still compare formate+discounted electricity to electrolysis+fullprice electricity? Isn't that doing an apples-to-oranges comparison, blatantly putting your thumb on the scale in favor of formate?
For that matter, what's wrong with electrolysis for making hydrogen for bulk energy storage? Isn't water electrolysis super well-understood, cheap, simple, scalable, as safe as anything involving bulk quantities of hydrogen gas can be, and only requires water and electricity for inputs?
>Why formate? Can't you get hydrogen from any acid, because that's literally the definition of an acid?
Formate releases hydrogen differently:
HCOOH >> H2 + CO2
Other acids need an electron donor to produce hydrogen. Formate reduces itself.
>"If the regeneration and reaction could be performed at 8 M rather than 3 M concentration...", why can't they?
You're getting a little over my head here, but I think there might be some solubility problems.
>"If the cell voltage could be reduced" sounds super fishy to me; isn't that just a useless wish that the elements / molecules you're working with have different properties than they actually do?
The standard electrode potential does create a minimum voltage, but usually there is considerable inefficiency.
I can't answer the other questions, except to mention that formate is very stable and easy to store.
Hydrogen is needed for all kinds of industrial processes, but it is best generated at the point of use as needed, as storage and transport is too problematic. If absoultely needed, the most obvious way to ship hydrogen is as methane.
Synthesis of methane from water-sourced hydrogen and atmosphere-sourced CO2 is at present a good deal more expensive than fossil natural gas, but that's a somewhat artificial situation: natural gas production is heavily subsidized and many of the costs are externalized to the public (see global warming, air and water pollution, etc.). However, once accomplished you can just feed this renewable methane into the existing natural gas infrastructure, and get the hydrogen back as needed from well-understood processes, i.e. steam-methane reforming.
> If absoultely needed, the most obvious way to ship hydrogen is as methane.
Methane has 2 problems: 1. it's a massive greenhouse gas if it leaks, 2. it requires CO2 to make, and in a decarbonized future that can only come from either biomass (limited) or DAC (expensive).
You would either want ammonia or methanol. Ammonia does not have any of these problems, but it's very toxic. Methanol has the CO2 problem as well, but it's a liquid, so it's easier to transport. Neither is perfect, but there are no perfect solutions.
Methane is the worst of all options. If you want a hydrocarbon, then usually methanol is what you want. And don't trust me on that, just look at what projects are actually planned out there. Plenty of green ammonia and green methanol projects, green methane is exotic at best, barely anyone wants to do that.
Ammonia is a greenhouse gas itself, and it tends to react with air creating various nitrous oxides, that are much more potent greenhouse gases than methane, very toxic, and create acid rain (after what it becomes fertilizer).
The best shipping option is probably just to face all the issues and ship the hydrogen. But storage is a different matter.
Ammonia is no greenhouse gas, it has a GWP of zero. Burning ammonia produces N2O, which is a potent greenhouse gas, and NOx, which is an air pollutant. But these can be taken care of by scrubbers, and are irrelevant if you ship ammonia for other uses. (I mean the biggest use case of hydrogen these days is making ammonia for fertilizers.)
It's not a greenhouse gas if you make it from atmospheric CO2, that's the whole point. Also, sending methane through a pipeline is pretty straightforward. Methanol is an option on the liquid side, but if you can make methanol from atmospheric CO2 and water, you can also make jet fuel, which will be needed as jet travel isn't really electrifiable.
That makes no sense. Methane has a global warming potential of around 28 over 100 years, meaning it causes 28x as much warming over that timeframe. It does not matter where the CO2 comes from.
What you likely mean is that when taking atmospheric CO2, burning methane does not cause additional CO2 emissions. However, that is orthogonal to the problem of methane itself as a greenhouse gas when it leaks (which by all experience it does regularly).
Methane is oxidized to CO2 in the atmosphere with a half-life of about 10 years, and if you're making it from atmospheric CO2 at high cost, you have strong incentives to use leakless-infrastructure to transport it - and hydrogen is more likely to have leak issues than methane, and it has a GWP issue as well:
> "It is, however, very likely that hydrogen is emitted throughout the value chain, but it is unclear – given lack of data – which components contribute most and least to emissions."
Depends on how you're slicing it. By the total flux of energy batteries may be able to handle 80% of the "energy traffic" over the course of a day by smoothing out day/night cycles.
However that last 25% needs to be stored over long periods where the cost is prohibitive to store in current battery systems.
There's many ways to judge what "80%" is. The batteries will cycle many times every week. They will have much more energy flowing through them in a year than the storage we need for dunkelflaute would.
Yes, in terms of amount of energy stored at full capacity, batteries would not get us to 80%. But those last 20% have reduced requirements for charge/discharge rates, effiency, cost/kWh, which makes many other solutions viable.
A system that can store 1000% more energy than what is possible with batteries could very well power the entire system. Thus eliminating the need for batteries for this purpose. It's always something that stuck out to me as an obvious point that few have noticed.
Batteries have reasonably high round trip efficiency ~80%, where many proposed long term storage options are much much lower.
If your storing nearly free power for 9 months then having 40% round trip efficiency may not actually be a problem. But it’s terrible for daily storage as you would need roughly twice as many solar panels etc.
You can build twice as many solar panels. It is making batteries that is problematic. Not to mention the argument supposes that the storage system must only output electricity, which is not necessarily the case.
Batteries really aren’t problematic. EV’s need more batteries than the grid and there’s plenty of raw materials to cover global EV’s needs on top of this grid batteries have more options because they didn’t need portability or a 25 year lifespan etc.
If your alternative now needs massive amounts of solar panels just to charge it then suddenly it’s vastly more expensive. Also, both batteries and solar panels are bottlenecked by production capacity, so no you can’t just snap your fingers and have twice as many panels.
Also, deploying any other system at scale means ramping up production of that.
Those sound like excuses. FYI, a lot of the alternatives are things like pumped hydro which isn't that inefficient. Many situations just need heat at the end, and therefore don't need pure electricity.
I am merely pointing out that the battery part seems like an unnecessary component.
There are zero viable alternatives when you start talking TWh.
That’s simply the reality and why there isn’t any long term grid storage, nothing is even close to viable when compared to batteries and extra generation.
Pumped hydro simply doesn’t scale. You can look at topographic maps and do some basic math but the vast quantities of water you would need simply don’t have enough locations to be viable. Worse, the fewer times you use that infrastructure the larger the payback you need when it’s actually in use.
Hydrogen is expensive, has terrible round trip efficiencies, dangerous to store, etc etc.
Now you're just lying. Pump hydro scales better than batteries, although there are geographic limitations. Compressed air and thermal also scale better than batteries while not having any geographic limitations. Hydrogen scales beyond every else in terms of quantity, and this becomes even more pronounced once you talk about hydrogen derivatives like ammonia.
And you're consistently ignoring the part about not everything needing electricity exclusively. Any sort of heat utilization or recapture massively increases efficiency for some of those ideas.
Individual pumped hydro locations scale well, there isn’t enough locations to make ~1,000 TW of pumped hydro thus it doesn’t scale.
Compressed air and thermal aren’t economically viable, which is why decades after introduction there isn’t large scale deployments of the stuff.
> Any sort of heat utilization or recapture massively increases efficiency for some of those ideas.
Low grade heat has minimal to zero economic value. This is why nuclear power plants need to build cooling towers etc rather than having something useful to do with all that heat energy. There’s some very niche utility, but it’s competing with other extremely cheap sources of heat like solar thermal which itself has barely catch on despite rapid payback periods.
You’re being very dishonest again, and are consistently portraying things in the worst light possible. An individual system of pump hydro can be built much larger than any realistic battery facility. There are enough viable locations that it will scale better than batteries. You need to let this go and stop BSing.
There was no need for compressed air or thermal energy storage until recently. In fact, there were no large scale battery energy storage systems until recently either. All of them are starting to happen.
Your point about low grade heat is entirely a red herring. It’s not even true as storage of low grade heat is valuable in a renewable energy world. But more importantly those energy storage can definitely store higher grades of heat. Especially if it is hot enough to drive a turbine, or used to that heat to make other systems more efficient. In large scale facilities, it is not meaningfully less efficient that batteries. So the conclusion is the same: there does not really need to be batteries for this purpose. You can eliminate them and save yourself the money. After all, you already admitted that you need those other systems anyways, so just have those other systems and not bother with batteries.
Most storage is short term, so the same battery can be re-used again and again by charging and discharging it, e.g. 365 solar peaks a year in sunny countries. Longer term storage would lock up the battery for longer, which given the cost of batteries, wouldn't make financial sense.
31 comments
[ 3.2 ms ] story [ 81.8 ms ] thread>It is also clear that more integration between the disciplines of electrochemistry and heterogeneous catalysis is needed to overcome the challenges for advancing the HCO3−–HCO2− system as a feasible green alternative for storing and transporting energy.
The idea of storing energy by converting bicarbonate to formate has already occurred to me years ago and probably was thought of by thousands of other scientists, because formate is one of the most common hydrogen precursors used in practical chemistry. The storage density is low, but the materials are extremely cheap and stable. Unfortunately, the paper does not seem to be announcing a breakthrough, but tallying up the current progress — which just isn't there yet.
https://pubs.rsc.org/en/content/articlelanding/2023/gc/d3gc0...
Looks like they're using Pd/Pt for the best catalyzers... that's definitely not going to be scalable. Though there should be effective alternatives, but it's surprising how unsophisticated much of the research in this field can be.
"The electrochemical regeneration is not optimized...If the cell voltage could be reduced to 2 V and the faradaic efficiency raised to 80%, the total cost of hydrogen would be nearly cut in half...if the regeneration and reaction could be performed at 8 M rather than 3 M concentration along with an improved process and discounted electricity...the cost of hydrogen could drop to just over $3 per kg...[which is] below the cost of on-site electrolysis with full-priced electricity"
Why formate? Can't you get hydrogen from any acid, because that's literally the definition of an acid? "If the cell voltage could be reduced" sounds super fishy to me; isn't that just a useless wish that the elements / molecules you're working with have different properties than they actually do? "If the regeneration and reaction could be performed at 8 M rather than 3 M concentration...", why can't they? Doesn't a reaction usually proceed faster in more concentrated solutions?
It seems like several breakthroughs that are needed, some of which possibly stretch the laws of physics. But once you have that. But even with those improvements, they still compare formate+discounted electricity to electrolysis+fullprice electricity? Isn't that doing an apples-to-oranges comparison, blatantly putting your thumb on the scale in favor of formate?
For that matter, what's wrong with electrolysis for making hydrogen for bulk energy storage? Isn't water electrolysis super well-understood, cheap, simple, scalable, as safe as anything involving bulk quantities of hydrogen gas can be, and only requires water and electricity for inputs?
Formate releases hydrogen differently:
HCOOH >> H2 + CO2
Other acids need an electron donor to produce hydrogen. Formate reduces itself.
>"If the regeneration and reaction could be performed at 8 M rather than 3 M concentration...", why can't they?
You're getting a little over my head here, but I think there might be some solubility problems.
>"If the cell voltage could be reduced" sounds super fishy to me; isn't that just a useless wish that the elements / molecules you're working with have different properties than they actually do?
The standard electrode potential does create a minimum voltage, but usually there is considerable inefficiency.
I can't answer the other questions, except to mention that formate is very stable and easy to store.
Synthesis of methane from water-sourced hydrogen and atmosphere-sourced CO2 is at present a good deal more expensive than fossil natural gas, but that's a somewhat artificial situation: natural gas production is heavily subsidized and many of the costs are externalized to the public (see global warming, air and water pollution, etc.). However, once accomplished you can just feed this renewable methane into the existing natural gas infrastructure, and get the hydrogen back as needed from well-understood processes, i.e. steam-methane reforming.
Methane has 2 problems: 1. it's a massive greenhouse gas if it leaks, 2. it requires CO2 to make, and in a decarbonized future that can only come from either biomass (limited) or DAC (expensive).
You would either want ammonia or methanol. Ammonia does not have any of these problems, but it's very toxic. Methanol has the CO2 problem as well, but it's a liquid, so it's easier to transport. Neither is perfect, but there are no perfect solutions.
Methane is the worst of all options. If you want a hydrocarbon, then usually methanol is what you want. And don't trust me on that, just look at what projects are actually planned out there. Plenty of green ammonia and green methanol projects, green methane is exotic at best, barely anyone wants to do that.
Ammonia is a greenhouse gas itself, and it tends to react with air creating various nitrous oxides, that are much more potent greenhouse gases than methane, very toxic, and create acid rain (after what it becomes fertilizer).
The best shipping option is probably just to face all the issues and ship the hydrogen. But storage is a different matter.
What you likely mean is that when taking atmospheric CO2, burning methane does not cause additional CO2 emissions. However, that is orthogonal to the problem of methane itself as a greenhouse gas when it leaks (which by all experience it does regularly).
https://acp.copernicus.org/articles/22/9349/2022/
> "It is, however, very likely that hydrogen is emitted throughout the value chain, but it is unclear – given lack of data – which components contribute most and least to emissions."
Why couldn't you just add 25% more batteries?
However that last 25% needs to be stored over long periods where the cost is prohibitive to store in current battery systems.
Yes, in terms of amount of energy stored at full capacity, batteries would not get us to 80%. But those last 20% have reduced requirements for charge/discharge rates, effiency, cost/kWh, which makes many other solutions viable.
If your storing nearly free power for 9 months then having 40% round trip efficiency may not actually be a problem. But it’s terrible for daily storage as you would need roughly twice as many solar panels etc.
If your alternative now needs massive amounts of solar panels just to charge it then suddenly it’s vastly more expensive. Also, both batteries and solar panels are bottlenecked by production capacity, so no you can’t just snap your fingers and have twice as many panels.
Also, deploying any other system at scale means ramping up production of that.
I am merely pointing out that the battery part seems like an unnecessary component.
That’s simply the reality and why there isn’t any long term grid storage, nothing is even close to viable when compared to batteries and extra generation.
Pumped hydro simply doesn’t scale. You can look at topographic maps and do some basic math but the vast quantities of water you would need simply don’t have enough locations to be viable. Worse, the fewer times you use that infrastructure the larger the payback you need when it’s actually in use.
Hydrogen is expensive, has terrible round trip efficiencies, dangerous to store, etc etc.
And you're consistently ignoring the part about not everything needing electricity exclusively. Any sort of heat utilization or recapture massively increases efficiency for some of those ideas.
Compressed air and thermal aren’t economically viable, which is why decades after introduction there isn’t large scale deployments of the stuff.
> Any sort of heat utilization or recapture massively increases efficiency for some of those ideas.
Low grade heat has minimal to zero economic value. This is why nuclear power plants need to build cooling towers etc rather than having something useful to do with all that heat energy. There’s some very niche utility, but it’s competing with other extremely cheap sources of heat like solar thermal which itself has barely catch on despite rapid payback periods.
There was no need for compressed air or thermal energy storage until recently. In fact, there were no large scale battery energy storage systems until recently either. All of them are starting to happen.
Your point about low grade heat is entirely a red herring. It’s not even true as storage of low grade heat is valuable in a renewable energy world. But more importantly those energy storage can definitely store higher grades of heat. Especially if it is hot enough to drive a turbine, or used to that heat to make other systems more efficient. In large scale facilities, it is not meaningfully less efficient that batteries. So the conclusion is the same: there does not really need to be batteries for this purpose. You can eliminate them and save yourself the money. After all, you already admitted that you need those other systems anyways, so just have those other systems and not bother with batteries.