> “Places that have excess energy could make iron, and others can buy it. This way, you could commodify renewable energy so it can be globally distributed without the need for transmission lines. Metals can solve a big problem in the renewable energy transition: long-duration energy storage.”
My gut feeling is that transmission lines would still be cheaper. That being said long-term storage seems to be the value proposition here.
In my corner of the world coal is still frequently used to heat homes during winter. A single house uses around 4-6 tonnes of the stuff each season. This heap of coal takes a significant amount of space.
If my back of the napkin calculations are correct, the energy equivalent in iron dust would be half the volume. Of course there's the issue of weight - about 5x that of coal, but perhaps the cost of moving all that iron could be somewhat mitigated by having a rust reprocessing plant in the neighbourhood.
> My gut feeling is that transmission lines would still be cheaper
Transmission lines are great for moving electricity, but only if there's demand for that electricity _right now_. Otherwise, you have to store it - which is a problem, because battery tech right now isn't great (or rather, it's not good enough for grid-scale requirements) . This iron powder could be thought of as a "battery". It might be harder to move than compared to a transmission line, but it's _stored_ energy and can be redeemed at a later time.
> or rather, it’s not good enough for grid-scale requirements
I disagree with this point. LFP batteries are cheap, high density, and have huge cycle life. The big drawback of LFPs is manufacturing is just starting to ramp up on them. That is, they aren’t available.
LFPs just came out of patent protection last year and you are already starting to see them everywhere. The biggest problem with LFPs today is demand is outstripping supply.
Is that still true? Aren't there a number of very successful grid battery installations now? And given the steady decline in battery costs, it ought to just get better and better.
But isn’t that the point of transmission lines - match supply and demand? Given a large enough region, there is going to be a place where renewable electricity can be produced. Case in point being offshore wind turbines where there are almost always strong winds to spin these. Moving this electricity to where it is consumed is a huge issue though. Existing power grids were created with centralised power stations in mind, which are usually located close to where the electricity will be needed.
You can use those transmission lines to move the energy to a facility where it would then be stored.
In fact, you have to use some sort of transmission lines to get energy to those locations, otherwise you have no way to get energy to or from them. Even if they have local power generation, you still have to use transmission lines to get that power out.
Iceland has absurd amounts of spare energy. So they bring in ships full of bauxite and refine it into aluminum blocks then load it back on the ship. Aluminum is refined by electrolysis, so it’s a perfect way to export their excess electricity.
That’s stocking btw that it takes 4 tons of coal per year per house. That’s an absurd amount.
It's not that absurd. One ton of coal produces ~25 million BTUs. That's about the same output as a cord of oak or hickory, which weigh about 2 tons per cord. And most people that heat their home exclusively by burning wood use about 5-6 cords per year.
I'm a serious PITA about recycling aluminum. I have this mental image of vast quantities of bauxite and energy being tossed out whenever an aluminum container (or bit of foil) is not recycled. But I don't have any firm numbers.
Pipelines of liquid or gaseous fuels is pretty much always going to be the cheapest solution for energy transmission. This fact will inevitably lead to people investing in some kind of green chemical. If not hydrogen, then likely something made from hydrogen like ammonia or methanol.
It's not actually clear if transmission lines are cheaper. Ships and trains can carry a lot of mass. For an energy dense fuel, this can be cheaper. Then again, this idea needs you to carry things in both directions, both the iron and the iron oxide. That may doom this idea to being too expensive.
How many posts about hydrogen being the best and only hope have you made here?
I can’t recall it all now, but my understanding was that if you take the entire chain from production to storage to consumption of hydrogen, it’s pretty much an unworkable engineering problem. “The closest thing to a vacuum, other than a vacuum” was one memorable quote. Happy to be shown to be wrong.
So the cut off between them is that if you use this for more than about four (/eight) months, the grid was cheaper.
That said, while I personally love the idea of a global grid, geopolitics rather than technical merit is likely to be the dominant constraint for any solution, as everything[0] is cheap enough that cost doesn't matter.
Also, possibly still useful for shipping? Possibly? I assume they'd prefer synthetic oil, but I don't claim any real knowledge, that's just my uninformed guess.
[0] Well, almost everything — concrete-based gravity batteries produce too much CO2 so they're expensive with current production methods just in a non-monetary sense, and antimatter production is so inefficient it's not viable, but those are the only two exceptions I know about.
I suppose it's not more complicated than an LPG system in a car, which fires up on gasoline and switches to gas only after warm-up.
My Uber today was a Corolla hybrid and at one point I heard the telltale clunk of the LPG system engaging. Apparently you can have that on a hybrid as well.
The demand for natural gas is probably minuscule compared to the total heat output of a burning cycle. Also, thanks to the war in Ukraine, demand for natural gas might decline in the long term if European countries switch to alternative, hopefully greener, energy sources.
Transmission is expensive if you're running a line to somewhere without a lot of demand. Something like this could be a relevant solution for anything in remote locations.
> 0.3% of the Iron-oxide becomes nanoparticles which cannot be converted back into Iron.
At that rate, 50% of the initial iron will be gone in 333 cycles of iron -> iron oxide -> iron.
This a hard type of energy source to reason about:
1. It's not a pure fuel and acts like a battery most of the time, but it's also not renewable
2. Iron is extremely abundant on Earth, but it requires mining and processing to extract
3. Iron oxide in nanoparticle size would likely be a pollutant and hazardous to human health, not something that will break down quickly and harmlessly.
The high fuel density and low explosiveness may make it a good use case in some niches, but I imagine it's actually more scalable and healthy to burn jet fuel and reproduce it from renewable powered carbon capture, where density is needed.
> The nanoparticles are not emitted in the atmosphere but captured in a HEPA filter.
If that's true, your point #3 is moot. And if the nano particles can be captured by a filter, maybe we could design filters specifically for iron oxide nano particles that would allow the nano particles to be extracted
> but I imagine it's actually more scalable and healthy to burn jet fuel and reproduce it from renewable powered carbon capture, where density is needed.
You're saying capture carbon from CO2 and turn it into kerosene? I tried googling around and everywhere I look it seems like this is currently way more difficult than renewable iron fuel (https://www.planet.veolia.com/en/how-produce-kerosene-co2).
Cherry-picking the fuel for jets example makes sense, since somehow we don´t expect aviation to transition completely to airscrews.
As for the disposal of HEPA filteres loaded with air-stable inorganics, that still is pollution, only the kind of waste you store safely, and if not give people cancer, but highly localized so.
The nanoparticles can't be converted back to iron in this process, but they can still be turned back into iron by other processes. No system is truly closed loop, but this is more closed loop than any other energy-to-fuel system.
You need to extract the feedstocks for any energy-to-fuel system. Iron is cheap and simple to extract, compared to say carbon from the atmosphere.
The nanoparticles do not get released to the environment. Emissions from burning carbon based fuels also include pollutants that are hazardous to human health.
To a first approximation, Earth is a big ball of iron, so losing 50% of the iron in 333 cycles doesn't seem like that big a deal. Getting more iron is an energy issue rather than an availability issue.
I'm also somewhat concerned about the nanoparticle's effect on living things. It is likely that it is only a question of local exposure, as in general once they get out they should still rust in some relatively short period of time, and as Earth is the aforementioned big ball of iron, a bit of rust in the environment is quite unlikely to hurt anything because if it could hurt a thing that thing would already be dead, but locally nanoparticles would be something weird and I could see breathing them could be problematic. It is also entirely possible that it is safe up to surprisingly absurd levels too (your body is familiar with iron, and while there are toxic doses of iron you're not getting to them with nanoparticle exposure any time soon), it would just be something that would need some study.
> once they get out they should still rust in some relatively short period of time
Nanoparticles of iron oxide are already rust.
There is certainly some inorganic phenomenon that will turn it into normal, aggregated rust. It probably requires water and some time.
But those particles sound like the kind of thing that will stay for years on the atmosphere, and contaminate every living thing. And yeah, they are probably safe in some surprisingly large amount, so whatever direction it goes, we will only know after we start doing it.
Is iron oxide magnetic in nanoparticle size? Because if it is, then we can probably very efficiently filter it before releasing it into the atmosphere.
Even if it isn't we are very good at filtering materials from exhaust gasses. Something like a wet electrostatic precipitator is probably overkill, but would do the job without having to care about magnetic properties.
Might be possible to create a completely closed system to address the loss?
I am more concerned/confused by the fact that they use hydrogen to reduce the iron. That seems like a very convoluted process, why not use the hydrogen generate heat instead? Yes, it has much lower density, but it has advantages to make up for it, for instance the fact that you don't need to worry about evaporation, leakage, filters, all that at all.
Hydrogen is devilishly hard to transport and store. Hydrogen packs a lot of energy per gram, but the density is so low. You need a huge tank if you compress it as a gas, you can liquefy it but the density is still not great, it takes a lot of energy, and you have to deal with this:
freshly liquefied hydrogen contains a lot of stored energy in that form which will be released over time and cause quite a bit to vaporize, for long term storage you have to release that energy.
Thus people have looked at all sorts of schemes for storing hydrogen such as absorbing it in metals like palladium, metal hydrides, chemical carriers such as ammonia, methane, etc.
Sounds like one of the least efficient energy storage ideas I've heard in a long time, I wonder how this is getting funded? Hmm, let's check to see who is behind this...the founding professor https://www.tue.nl/en/research/researchers/philip-de-goey/ is a fellow/awardee of the Combustion Institute, gets funding from ERC, etc. OK, so I guess all that European taxpayer money won't spend itself, and if you have a hammer blah blah nails...
They're a bit further along (scaling up from low-volume production, some installs in the wild) with a different approach to the use of iron (flow batteries).
ESS should not be mentioned except as an example of how prone the green news cycle is to fraud. As I detailed last year, their claims are highly dubious:
(previously I misspelled the last name of Sri Narayanan as "Narayan", for which I belatedly apologize)
And that prediction was substantiated when they were subject to a class-action shareholder lawsuit in February involving a fabricated customer which was actually a subsidiary:
Yes, this is a strange approach. Separate iron from iron oxide, which is energy intensive. That's what blast furnaces did, or do, and it's a messy and energy-intensive process. Burn iron to get heat and iron oxide. Repeat.
Are there numbers on the energy efficiency and costs of this process? This seems very strange. Batteries are above 90% round-trip efficiency now. This has to be lower.
Iron is not widely available in nature as a ready-to-use element, it must be processed into elemental iron, which takes a lot of energy as input. Therefore this can't be really considered as fuel, more like energy storage. You still need fossil fuels or nuclear power to turn iron ores into iron, then you have iron available for the process described in the article.
I'm not criticizing the process, but it's not accurate to call it "fuel" like it could be the solution to replacing fossil fuels.
"If these problems can be overcome, you could use renewable electricity to produce iron, store it as long as necessary, transport it there and then burn it for power when needed, says Bergthorson. “Places that have excess energy could make iron, and others can buy it. This way, you could commodify renewable energy so it can be globally distributed without the need for transmission lines. Metals can solve a big problem in the renewable energy transition: long-duration energy storage.”"
Sure you could use renewables to make iron. But that thought process also extends to other methods too. You could use renewables to make other non renewable fuels.
This is actually the same principle as BTC. High volume cheap electricity is used to process random numbers and the value is stored as BTC allowing it to be freely transferred once first mined.
The green economics of this need some serious consideration as i'd be really aware if you can reprocess it and get a second reaction for less energy than it cost you to turn the rust back into free iron metal.
If a power plant has sufficient store of Iron, with a complete cycle, from burning iron to recovering iron, then it is no longer a consumable.
I can imagine a solar plant, making iron in the day and burning it in the night and essentially act as a base load plant, the holy grail of renewable energy.
Yeah but it pretty much requires that producing the fuel requires less energy than the fuel provides, otherwise itd be like trading a quarter for a dime.
But also don't underestimate how huge it would be if we could store energy efficiently as elemental iron. E.g., produce it using solar, burn it for grid energy. Of course that depends on the efficiency of the whole process.
> “You can think of iron fuel as a clean, recyclable coal,” says Bergthorson.
I was under the impression that basically all naturally found iron is in the form of iron oxide. Which means you first have to put in energy to reduce it to pure iron, to then burn it and turn it back to iron oxide. That's much closer to what a battery does, or hydrogen, than it is to coal.
I imagine it's still useful in many applications since hydrogen is a pain to store and transport.
I learned that stainless steel burns the hard way. You can use stainless steel scrubby pads as a heat sink to vaporize DMT in a contraption called "the machine". Naively, I thought steel wool would work instead of the scrubby pad. It doesn't. The fibers are too small and it ignites--pretty much exactly the opposite of what you want in a vape.
Iron/steel production is one of the largest individual sources of co2 emissions and uses a lot of energy.
And then to just burn it back into iron ore for energy - At best you'll only get back the energy you expended to refine it in the first place.
Assuming they are burning scrap, it would surely be better to melt it down and recycle it as steel.
As energy storage, it may well have more energy per liter than gasoline, but it weighs many times more. There are surely better options - even in the same category, eg aluminium?
Fortunately, iron oxide can be reduced using hydrogen. In the article, they conclude that the system cost of shipping iron and iron oxide back and forth from an electrolysis facility (presumably from renewables) is lower than using hydrogen directly as a fuel.
And just like articles about hydrogen, no mention of the extraction/distribution supply chains needed or the costs/emissions involved. Nope, just focus on our fancy (ZERO EMISSION) generator and ignore how the inputs are actually produced.
It has the energy density of coal, only unlike coal it requires both mines as well as smelters/processing facilities to produce the iron powder. So this can only work if we build out twice the infrastructure that coal currently enjoys, with all the costs and emissions therein.
I'm so tired of breathless scientific reporting of "breakthroughs" that ignores any and all economic context. Or, like this article, treats it as a side issue to be addressed with literally one sentence.
It is not an energy source.
It is a (battery) energy storage solution that can scale. Meant to support renewables use at night/ low sun/low wind periods.
And not on hourly scale like normal batteries but on year scale on plant level.
Like in an energy plant. That during the day when there Is surpluses they generate iron powder from ironoxide and cheap electricity. And when there is no surplus they burn the iron powder to irononoxid. And they can both be stored at unlimited scale on a heap.
The problem is that that is the same idea that people are proposing with hydrogen energy storage systems. The difference is that hydrogen works a lot like natural gas. You can pipe it and fire up gas turbines with it. It is also useful as a chemical feedstock in many industrial processes. You can also use it to power vehicles, something that you probably can't with this idea.
So in other words, this is a really crappy version of something that already exists. I guess there are three takeaways to be had:
1) We still need large scale energy storage and it simply cannot just be a pile of batteries. It really needs to be a chemical system and it really has to be able to burn.
2) But that always takes you down one road: Hydrogen or something made from hydrogen. That's the only class of chemicals that really works and doesn't involve carbon. This causes a lot of conflict since it is definitely not many people's favored energy storage idea. And since so much FUD has been flung around for so long because of that, many people have become convinced that this inevitability is actually impossible.
3) So you usually end up with two alternative ideas: Something crazy like burning metals. I've heard of burning boron too BTW. This particular proposal is a continuation of that way of thinking. Probably they are all DOA ideas. And the other is something akin to linking all of the grids across world together with vast numbers of HVDC lines. But this too is crazy, especially once you realize the sheer cost and complexity of it all. Not to mention you are still wasting oodles of energy since you have minimal energy storage.
So eventually we end up in this cycle of one crazy idea being proposed after another, and nothing of importance actually being achieved.
We are already using the most economically viable option. The trouble is that it's not sustainable long term. The solution then will not be the most economical one.
Right, but from an emissions standpoint this is a bad idea too. You not going to create an emission-free iron mine/processing supply chain any time soon. This just moves the emissions up the chain and would take decades to build out. It might be just as bad as coal in terms of emissions at the end of the day, and marginally better at best.
Solar, Wind, more/better batteries and nuclear are our best paths forward if we want to take the immediate action we need to take. If crap like this gets traction we'll just have a greenwashed future where all the coal and natural gas plants will be gone, but global emissions will still be high and power will be many times more expensive. Maybe then people will start to do math.
Back when I was in college the Environmental Science majors were a joke because the chemistry classes they took senior year were the same classes the Chemical Engineers took freshman year. I thought my university just had a crappy environmental science program, but after reading a number of articles like this one I'm thinking it might be a more pervasive issue.
The second most economically viable option is basically going to be hydrogen in some way. Either made from renewables or nuclear power, possible natural sources if they exist in quantity. That is why you hear about it so much.
But this fact causes large scale confusion on all sides. For those invested in the existing system, this is a threat. But for those who think it will be some other kind of green technology, this means admitting they were betting on the wrong horse the whole time.
> We are already using the most economically viable option.
Arguably we always are doing that, by definition. Investment is spending money on current non-optimal returns in exchange for much greater returns later.
If an investment had guaranteed success; if it had no flaws, then it would already have been made. There is nothing flawless in this world - not you or me, not Facebook or Messi, not oil or iron or renewables or nuclear.
Not really economically viable unless you narrowly focus on profits. For total direct and external costs (i.e. total societal costs) it's already nonviable.
This is another Aluminium Air battery, same concept different metal. None of them considers splitting water is energy intensive and inefficient. Another hydrogen fool cell category fuel imo.
Who cares if it's energy intensive or inefficient if our other option for using the energy is to run it through a big resistor or to not produce it in the first place? This is a tool for repeatedly storing and releasing excess energy from power plants that can't control their output in response to grid conditions. Let's supposed for the sake of argument that battery banks were prohibitively expensive in some applications, and that hydroelectric storage was too damaging to the local environment. In those cases, your only option is to either dissipate any excess energy or to not produce it in the first place.
What this does, then, is provide you an alternative storage medium that is relatively inert until you want to use it. And it provides you a simple self-sustatining scalable chemical reaction that can be started by supplying some initial heat and then goes on to produce even more heat steadily and continuously until you run out of fuel.
Why don't you try to do a Fermi estimate before voicing your concerns? Maybe things are not so bad.
Steel is one of the few materials that humans produce in quantities exceeding one gigaton per year (the other ones are coal, oil, natural gas, concrete, and 4 agricultural crops, sugar cane, corn, rice and wheat).
A lot of steel is recycled. It depends how you count, but between 60% and 90% of steel is recycled. Still, a lot of steel is produced out of iron ore each year.
Currently to make a ton of steel out of ore we emit about 2.2 tons of CO2, including upstream emissions[1, page 26]. If we make it from scrap steel, we only emit about 0.4 tons of CO2. It is projected that by 2050, both emissions will go to 0.1 tons CO2-equivalent per ton of steel.
The article mentions an energy density of 11.3 kWh per liter. Iron has a density of about 7.9 kg/l so, we're talking about 1.4 kWh per kilogram. From the article, we learn that the way the energy will be extracted from the iron powder is via burning in a regular thermal power plant. Good power plants now have efficiency of up to 64%, but let's says with the new fuel, they'll just produce 50%. The charging part will probably be more efficient, but let's say the round trip will be only 20% efficient. So what? This could still turn out to be much more economically efficient than hydrogen, or any other alternatives. If you want, we can do some estimates there too, but your concern was about emissions, not about profitability.
Let's focus on emissions. Each time you burn one ton of iron powder, you generate (assuming 50% efficiency) about 0.7 MWh of electricity. In the US, on average, in order to produce that much electricity, you emit about 0.5 tons of CO2-equivalent, according to the EPA. If you charge and burn one ton of iron only 5 times, you come out ahead. But you will charge and burn it hundreds if not thousands of times. It's just iron, it's not a battery that degrades over time. It's iron powder, after each round trip, it's iron powder again.
Each ton of iron powder can potentially reduce emissions by thousands of tons of CO2 equivalent. Each year all of humanity emits about 50 gigatons of CO2 equivalent, gross. The planet absorbs about half of that. A fraction of a gigaton of iron powder could help us get rid of all of our emissions.
This thing here could be a revolution. Until now, I thought that our only economic way to store long time or transport long distance electricity is hydrogen. Iron powder solves so many problems with hydrogen.
Feel free to criticize it, but don't simply be dismissive. Bring information to the table, so everyone here can appreciate it was worth their time reading your comment.
Readit News
My gut feeling is that transmission lines would still be cheaper. That being said long-term storage seems to be the value proposition here.
In my corner of the world coal is still frequently used to heat homes during winter. A single house uses around 4-6 tonnes of the stuff each season. This heap of coal takes a significant amount of space.
If my back of the napkin calculations are correct, the energy equivalent in iron dust would be half the volume. Of course there's the issue of weight - about 5x that of coal, but perhaps the cost of moving all that iron could be somewhat mitigated by having a rust reprocessing plant in the neighbourhood.
Transmission lines are great for moving electricity, but only if there's demand for that electricity _right now_. Otherwise, you have to store it - which is a problem, because battery tech right now isn't great (or rather, it's not good enough for grid-scale requirements) . This iron powder could be thought of as a "battery". It might be harder to move than compared to a transmission line, but it's _stored_ energy and can be redeemed at a later time.
I disagree with this point. LFP batteries are cheap, high density, and have huge cycle life. The big drawback of LFPs is manufacturing is just starting to ramp up on them. That is, they aren’t available.
LFPs just came out of patent protection last year and you are already starting to see them everywhere. The biggest problem with LFPs today is demand is outstripping supply.
Is that still true? Aren't there a number of very successful grid battery installations now? And given the steady decline in battery costs, it ought to just get better and better.
In fact, you have to use some sort of transmission lines to get energy to those locations, otherwise you have no way to get energy to or from them. Even if they have local power generation, you still have to use transmission lines to get that power out.
That’s stocking btw that it takes 4 tons of coal per year per house. That’s an absurd amount.
It's not actually clear if transmission lines are cheaper. Ships and trains can carry a lot of mass. For an energy dense fuel, this can be cheaper. Then again, this idea needs you to carry things in both directions, both the iron and the iron oxide. That may doom this idea to being too expensive.
I can’t recall it all now, but my understanding was that if you take the entire chain from production to storage to consumption of hydrogen, it’s pretty much an unworkable engineering problem. “The closest thing to a vacuum, other than a vacuum” was one memorable quote. Happy to be shown to be wrong.
Article says energy density of 11.3 kWh/litre.
WolframAlpha says using that for all global electricity for a day is 33e9 kg iron: http://www.wolframalpha.com/input/?i=2%20TW%20%2A%201%20day%...
Some estimates I did a while back and then wrote up nicely with ChatGPT said a global power grid would use about x100 that much iron: https://github.com/BenWheatley/Studies-of-AI/blob/main/Globa...
So the cut off between them is that if you use this for more than about four (/eight) months, the grid was cheaper.
That said, while I personally love the idea of a global grid, geopolitics rather than technical merit is likely to be the dominant constraint for any solution, as everything[0] is cheap enough that cost doesn't matter.
Also, possibly still useful for shipping? Possibly? I assume they'd prefer synthetic oil, but I don't claim any real knowledge, that's just my uninformed guess.
[0] Well, almost everything — concrete-based gravity batteries produce too much CO2 so they're expensive with current production methods just in a non-monetary sense, and antimatter production is so inefficient it's not viable, but those are the only two exceptions I know about.
You will also need a very specialized furnace, and supplies of CH4.
My Uber today was a Corolla hybrid and at one point I heard the telltale clunk of the LPG system engaging. Apparently you can have that on a hybrid as well.
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Iron is not a good solution for moving energy because it is so heavy. Aluminium would be a much better solution.
See interesting chart of energy densities by weight and volume.
https://en.wikipedia.org/wiki/Energy_density#/media/File:Ene...
At that rate, 50% of the initial iron will be gone in 333 cycles of iron -> iron oxide -> iron.
This a hard type of energy source to reason about:
1. It's not a pure fuel and acts like a battery most of the time, but it's also not renewable
2. Iron is extremely abundant on Earth, but it requires mining and processing to extract
3. Iron oxide in nanoparticle size would likely be a pollutant and hazardous to human health, not something that will break down quickly and harmlessly.
The high fuel density and low explosiveness may make it a good use case in some niches, but I imagine it's actually more scalable and healthy to burn jet fuel and reproduce it from renewable powered carbon capture, where density is needed.
If that's true, your point #3 is moot. And if the nano particles can be captured by a filter, maybe we could design filters specifically for iron oxide nano particles that would allow the nano particles to be extracted
> but I imagine it's actually more scalable and healthy to burn jet fuel and reproduce it from renewable powered carbon capture, where density is needed.
You're saying capture carbon from CO2 and turn it into kerosene? I tried googling around and everywhere I look it seems like this is currently way more difficult than renewable iron fuel (https://www.planet.veolia.com/en/how-produce-kerosene-co2).
As for the disposal of HEPA filteres loaded with air-stable inorganics, that still is pollution, only the kind of waste you store safely, and if not give people cancer, but highly localized so.
You need to extract the feedstocks for any energy-to-fuel system. Iron is cheap and simple to extract, compared to say carbon from the atmosphere.
The nanoparticles do not get released to the environment. Emissions from burning carbon based fuels also include pollutants that are hazardous to human health.
Which do get released into the environment in quite large quantities!
I'm also somewhat concerned about the nanoparticle's effect on living things. It is likely that it is only a question of local exposure, as in general once they get out they should still rust in some relatively short period of time, and as Earth is the aforementioned big ball of iron, a bit of rust in the environment is quite unlikely to hurt anything because if it could hurt a thing that thing would already be dead, but locally nanoparticles would be something weird and I could see breathing them could be problematic. It is also entirely possible that it is safe up to surprisingly absurd levels too (your body is familiar with iron, and while there are toxic doses of iron you're not getting to them with nanoparticle exposure any time soon), it would just be something that would need some study.
Nanoparticles of iron oxide are already rust.
There is certainly some inorganic phenomenon that will turn it into normal, aggregated rust. It probably requires water and some time.
But those particles sound like the kind of thing that will stay for years on the atmosphere, and contaminate every living thing. And yeah, they are probably safe in some surprisingly large amount, so whatever direction it goes, we will only know after we start doing it.
No it's not.
Inside the crust both Si and Al are more common.
There is plenty of Fe, which is all in oxide form. Mining and processing required.
Where does the Iron go??? It's not like Fission or Fusion is happening, right?!
This is a totally useless thing to say unless you have secret technology for core mining.
I am more concerned/confused by the fact that they use hydrogen to reduce the iron. That seems like a very convoluted process, why not use the hydrogen generate heat instead? Yes, it has much lower density, but it has advantages to make up for it, for instance the fact that you don't need to worry about evaporation, leakage, filters, all that at all.
https://en.wikipedia.org/wiki/Spin_isomers_of_hydrogen
freshly liquefied hydrogen contains a lot of stored energy in that form which will be released over time and cause quite a bit to vaporize, for long term storage you have to release that energy.
Thus people have looked at all sorts of schemes for storing hydrogen such as absorbing it in metals like palladium, metal hydrides, chemical carriers such as ammonia, methane, etc.
Meanwhile, stationary class (i.e. relatively poor energy density) iron air batteries are making commercial progress. https://pv-magazine-usa.com/2023/06/12/form-energy-to-deploy...
Also seems worth mentioning ESS. https://essinc.com/
They're a bit further along (scaling up from low-volume production, some installs in the wild) with a different approach to the use of iron (flow batteries).
https://news.ycombinator.com/item?id=31430227
(previously I misspelled the last name of Sri Narayanan as "Narayan", for which I belatedly apologize)
And that prediction was substantiated when they were subject to a class-action shareholder lawsuit in February involving a fabricated customer which was actually a subsidiary:
https://www.bloomberg.com/press-releases/2023-03-10/the-law-...
The other shoe has yet to drop, but I suggest that any battery company without publications should be considered with appropriate salinity.
Are there numbers on the energy efficiency and costs of this process? This seems very strange. Batteries are above 90% round-trip efficiency now. This has to be lower.
The entry for iron in the link below is also higher than the iron energy density reported in the parent link (11/3 kWh/L).
https://onlinelibrary.wiley.com/doi/full/10.1002/ente.202000...
Of course, aluminum used in this way is the classic thermite reaction; I conjecture that the iron reaction is also.
https://en.wikipedia.org/wiki/Thermite
I'm not criticizing the process, but it's not accurate to call it "fuel" like it could be the solution to replacing fossil fuels.
"If these problems can be overcome, you could use renewable electricity to produce iron, store it as long as necessary, transport it there and then burn it for power when needed, says Bergthorson. “Places that have excess energy could make iron, and others can buy it. This way, you could commodify renewable energy so it can be globally distributed without the need for transmission lines. Metals can solve a big problem in the renewable energy transition: long-duration energy storage.”"
Why not just skip the middleman? Use renewables?
The green economics of this need some serious consideration as i'd be really aware if you can reprocess it and get a second reaction for less energy than it cost you to turn the rust back into free iron metal.
I can imagine a solar plant, making iron in the day and burning it in the night and essentially act as a base load plant, the holy grail of renewable energy.
I was under the impression that basically all naturally found iron is in the form of iron oxide. Which means you first have to put in energy to reduce it to pure iron, to then burn it and turn it back to iron oxide. That's much closer to what a battery does, or hydrogen, than it is to coal.
I imagine it's still useful in many applications since hydrogen is a pain to store and transport.
And the article doesn't even hint at any way to do this using renewable energy. Which makes me suspect that no such process exists.
https://www.youtube.com/watch?v=NMJtieqVUc4
I hosted this. Getting permission from the Building department to have fire indoors was lotsa fun.
I learned that stainless steel burns the hard way. You can use stainless steel scrubby pads as a heat sink to vaporize DMT in a contraption called "the machine". Naively, I thought steel wool would work instead of the scrubby pad. It doesn't. The fibers are too small and it ignites--pretty much exactly the opposite of what you want in a vape.
Iron/steel production is one of the largest individual sources of co2 emissions and uses a lot of energy.
And then to just burn it back into iron ore for energy - At best you'll only get back the energy you expended to refine it in the first place.
Assuming they are burning scrap, it would surely be better to melt it down and recycle it as steel.
As energy storage, it may well have more energy per liter than gasoline, but it weighs many times more. There are surely better options - even in the same category, eg aluminium?
Fortunately, iron oxide can be reduced using hydrogen. In the article, they conclude that the system cost of shipping iron and iron oxide back and forth from an electrolysis facility (presumably from renewables) is lower than using hydrogen directly as a fuel.
It has the energy density of coal, only unlike coal it requires both mines as well as smelters/processing facilities to produce the iron powder. So this can only work if we build out twice the infrastructure that coal currently enjoys, with all the costs and emissions therein.
I'm so tired of breathless scientific reporting of "breakthroughs" that ignores any and all economic context. Or, like this article, treats it as a side issue to be addressed with literally one sentence.
Like in an energy plant. That during the day when there Is surpluses they generate iron powder from ironoxide and cheap electricity. And when there is no surplus they burn the iron powder to irononoxid. And they can both be stored at unlimited scale on a heap.
So in other words, this is a really crappy version of something that already exists. I guess there are three takeaways to be had:
1) We still need large scale energy storage and it simply cannot just be a pile of batteries. It really needs to be a chemical system and it really has to be able to burn.
2) But that always takes you down one road: Hydrogen or something made from hydrogen. That's the only class of chemicals that really works and doesn't involve carbon. This causes a lot of conflict since it is definitely not many people's favored energy storage idea. And since so much FUD has been flung around for so long because of that, many people have become convinced that this inevitability is actually impossible.
3) So you usually end up with two alternative ideas: Something crazy like burning metals. I've heard of burning boron too BTW. This particular proposal is a continuation of that way of thinking. Probably they are all DOA ideas. And the other is something akin to linking all of the grids across world together with vast numbers of HVDC lines. But this too is crazy, especially once you realize the sheer cost and complexity of it all. Not to mention you are still wasting oodles of energy since you have minimal energy storage.
So eventually we end up in this cycle of one crazy idea being proposed after another, and nothing of importance actually being achieved.
Solar, Wind, more/better batteries and nuclear are our best paths forward if we want to take the immediate action we need to take. If crap like this gets traction we'll just have a greenwashed future where all the coal and natural gas plants will be gone, but global emissions will still be high and power will be many times more expensive. Maybe then people will start to do math.
Back when I was in college the Environmental Science majors were a joke because the chemistry classes they took senior year were the same classes the Chemical Engineers took freshman year. I thought my university just had a crappy environmental science program, but after reading a number of articles like this one I'm thinking it might be a more pervasive issue.
But this fact causes large scale confusion on all sides. For those invested in the existing system, this is a threat. But for those who think it will be some other kind of green technology, this means admitting they were betting on the wrong horse the whole time.
Arguably we always are doing that, by definition. Investment is spending money on current non-optimal returns in exchange for much greater returns later.
If an investment had guaranteed success; if it had no flaws, then it would already have been made. There is nothing flawless in this world - not you or me, not Facebook or Messi, not oil or iron or renewables or nuclear.
What this does, then, is provide you an alternative storage medium that is relatively inert until you want to use it. And it provides you a simple self-sustatining scalable chemical reaction that can be started by supplying some initial heat and then goes on to produce even more heat steadily and continuously until you run out of fuel.
Why don't you try to do a Fermi estimate before voicing your concerns? Maybe things are not so bad.
Steel is one of the few materials that humans produce in quantities exceeding one gigaton per year (the other ones are coal, oil, natural gas, concrete, and 4 agricultural crops, sugar cane, corn, rice and wheat).
A lot of steel is recycled. It depends how you count, but between 60% and 90% of steel is recycled. Still, a lot of steel is produced out of iron ore each year.
Currently to make a ton of steel out of ore we emit about 2.2 tons of CO2, including upstream emissions[1, page 26]. If we make it from scrap steel, we only emit about 0.4 tons of CO2. It is projected that by 2050, both emissions will go to 0.1 tons CO2-equivalent per ton of steel.
The article mentions an energy density of 11.3 kWh per liter. Iron has a density of about 7.9 kg/l so, we're talking about 1.4 kWh per kilogram. From the article, we learn that the way the energy will be extracted from the iron powder is via burning in a regular thermal power plant. Good power plants now have efficiency of up to 64%, but let's says with the new fuel, they'll just produce 50%. The charging part will probably be more efficient, but let's say the round trip will be only 20% efficient. So what? This could still turn out to be much more economically efficient than hydrogen, or any other alternatives. If you want, we can do some estimates there too, but your concern was about emissions, not about profitability.
Let's focus on emissions. Each time you burn one ton of iron powder, you generate (assuming 50% efficiency) about 0.7 MWh of electricity. In the US, on average, in order to produce that much electricity, you emit about 0.5 tons of CO2-equivalent, according to the EPA. If you charge and burn one ton of iron only 5 times, you come out ahead. But you will charge and burn it hundreds if not thousands of times. It's just iron, it's not a battery that degrades over time. It's iron powder, after each round trip, it's iron powder again.
Each ton of iron powder can potentially reduce emissions by thousands of tons of CO2 equivalent. Each year all of humanity emits about 50 gigatons of CO2 equivalent, gross. The planet absorbs about half of that. A fraction of a gigaton of iron powder could help us get rid of all of our emissions.
This thing here could be a revolution. Until now, I thought that our only economic way to store long time or transport long distance electricity is hydrogen. Iron powder solves so many problems with hydrogen.
Feel free to criticize it, but don't simply be dismissive. Bring information to the table, so everyone here can appreciate it was worth their time reading your comment.
[1] https://rmi.org/wp-content/uploads/2022/09/steel_emissions_r...
[2] https://www.epa.gov/energy/greenhouse-gases-equivalencies-ca...