> “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.
This is specifically what I'm talking about. Because of some weird patent agreements, manufacturing of LFPs have been confined to China and they've not really been producing a large enough number of them to fill the role of grid storage (at least outside of china). [1]
I can't see Lithium batteries of ANY kind ultimately being used for grid scale storage, beyond the initial pilot batteries we have going up now.
Current worldwide lithium production is at 3% of what it needs to be to electrify every car, which is a use case that has strict weight requirements. Ramping up lithium production by a factor of 30 is a big deal, and that's before we use any of it for grid storage!
Grid batteries are static so weight is not a concern, using the chemistry whose main advantage is weight for this purpose is a waste of resources. Heavy battery chemistries have largely been ignored because traditionally batteries have always been for mobile purposes, so we can expect an even better learning curve from low energy density but cheap battery technologies such as iron-air.
If we're using renewables, we need seasonal shifting, so cycle life doesn't matter at one cycle per year.
You could build nuclear to supply your winter power, but then you're overbuilt for summer and don't need any renewable. Or you could store heat directly in the ground like that Alberta pilot project, heat collectors on the roofs all summer drive the heat underground, pump it back out all winter.
Or our current plan, pretend to be "green" by spending money on solar while increasing coal usage and no feasible plan to replace space heating.
We don't need seasonal storage. The sun still shines in the winter, unless you're in the Arctic circle. We can use over building, production diversity, interconnection and short term storage instead. Or just use natgas peakers for the last 1% and call a 99% solution good enough.
If we had reasonably priced seasonal storage we'd use it, but we don't need it.
In winter cloudy conditions solar PV produces 10-15% power. Assuming some hydro storage, that's 4x overbuild. Not cost effective.
Europe all gets winter at the same time. If you've got a cold snap for three weeks with low wind, the only plan is reliance on massive fossil fuel backup. The cost of keeping that capacity for only using a week a year isn't priced into solar either.
The CO2-intensity of electricity generation in France stood at around 57 CO2/kWh in 2020 (source: Statista). In Germany, the electricity mix at the same time had a CO2-intensity of 366g CO2/kWh, which was more than six times higher
> Depends on the latitude and these numbers seem to be for very high ones close to the polar circles.
No, those values are far from polar circle. I'm guessing closer to central Europe, since for example in Finland the PV produces 0% during the winter months.
10-15% would be insane to get here, but there simply isn't any energy in the sun (and closer to the polar circle you get - there's no sun at all during winter) and the panels are often covered in snow in any case. And I'm not even talking about cloudy days now, but "sunny" ones.
March/October are already approaching those 10-15% levels. Nov-Feb is closer to 0% in most of the Finland.
> The cost of keeping that capacity for only using a week a year isn't priced into solar either.
Keeping gas power plants around for backup power isn’t all that expensive since fuel accounts for two thirds of their cost of generation.
Offshore wind is far more expensive than onshore wind and solar but even so costs about a third of new nuclear power, with strike prices in the UK of £37/MWh vs £106/MWh for Hinckley Point C. Maybe keeping gas backup adds another £15/MWh to that but it still works out at half the cost of nuclear.
By building more France will probably get nuclear costs down some, but even so will struggle to be competitive with renewables and backup.
> But yeah Germany's approach is really working!
Germany’s approach of keeping coal plants around while closing existing nuclear is extremely dumb.
> Or just use natgas peakers for the last 1% and call a 99% solution good enough.
Sadly, no. Given how long the CO2 stays in the air, anything less than 99.9% over all emissions from all nations — and that also includes cement and iron chemistry leading directly to CO2, cattle biochemistry leading directly to methane, etc. — then we're not pushing hard enough.
Natural gas is great as a way to buy time, but we can't let it be more than a rounding error in the ultimate ensemble… well, not unless there's corresponding CO2 capture.
They’re cheap enough for EV’s, but the big number here is you can get 10,000+ charge/discharge cycles. Predictions are near term ~2c/kWh grid storage looks realistic which completely changes the economics of the electricity grid. (As in whatever you pay for the electricity to charge the batteries you need to charge 2 more cents/kWh at discharge to break even.)
Pair with renewables and not only is nuclear and coal looking obsolete but even natural gas is uneconomical at current prices. Of course the economy reacts as you start to bring this stuff online which means wholesale natural gas prices could fall quite a bit etc. You also need enough wind/solar/hydro to actually charge the batteries, but that doesn’t seem to be an issue either.
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.
Batteries are amazing for short term supply / grid stabilization. They can supply massive current on very short notice. But the cost per kilowatt hour is still painfully high if we're talking about more than a handful of hours. Fortunately, it's still headed downward.
There are successful grid battery installations, but as far as I know, there are no grid-scale battery installations. Existing installations have really small capacity, and are only used for things like demand smoothing. The only energy storage solution deployed at scale is pumped hydro storage.
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.
Yes, but transmission lines can only go so far, and you still lack the ability to arbitrage over time instead of just spatially. E.g. from a solar power POV, it's night everywhere in a given region at the same time.
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.
Methanol is a pretty decent storage medium for hydrogen, and can be made more efficiently than LH2. It actually stores more hydrogen than LH2 on a volumetric basis, and you can crack it at fairly low temperatures, so a hydrogen economy is probably going to happen regardless, it just won't be in the form of transporting gaseous hydrogen. We need methanol to make solvents and polymers, and to power cargo ships. We need ammonia for fertilizer. These two vectors will probably be the way we create and move hydrogen around. Methanol will probably pick up an additional use case as a fuel for trucks and cars, since alcohols are what you typically resort to for ICEs in the absence of fossil fuels, and methanol is both the simplest to make, and a very good fuel in its own right.
Hydrogen itself is more likely to be used to store energy in salt caverns, which is a proven technology for decades now. Aside from storage for the above use cases, it's a workable fuel for gas turbines for backup power.
This seems like the most likely outcome in my opinion.
Because it is instrumental to solving to climate change. The better question is why are people unwilling to take the problem seriously?
Your understanding is the result of years of FUD against it. People really need to understand that they have been lied to repeatedly on this subject. If you have a basic grasp of engineering, you should understanding that it is literally made by running electricity through water. It is an incredible simple idea that you can even do at home. And since hydrogen is already being used in a vast number of industrial and chemical processes, it should be clear that there could not be any fundamental technical challenges that haven’t been solved.
Well, many years ago before I switched to software, I was an engineer in real life! Putting on the old dusty engineering cap, I have to say that your explanation there is so underwhelming as to make it hard to take you seriously. The information I have read on this has not been FUD. It’s been careful analysis by actual engineers with experience in the field. Something being “technically possible” is completely different to something being “economically feasible”. Sorry, if you want to make an argument, you’re going to have to do better than that.
Well even engineers can have seriously incorrect understanding of an issue, especially if it is many years out of date.
You’re argument seems to be based around economically feasibility, not technical issues, right? So then you will also agree that if green hydrogen radically dropped in cost, then you will agree that it will become a viable solution? Furthermore there will be subsidies going on, that will accelerate the process.
In fact, the problem might be that a combination of subsidies and cost reductions will drive the price to below $0/kg, causing market confusion:
That would be an interesting outcome and it will be interest to see how it ends up. But nevertheless, super-cheap green hydrogen should quickly refute the major arguments used against it. It is a process that mirrors what happened to wind and solar energy. They too have years of FUD followed by many skeptics who denied the possibility of cheap renewable energy. But that skepticism simply fell apart because basic economics overrule outdated opinions.
> You’re argument seems to be based around economically feasibility, not technical issues, right?
Economic feasibility due to engineering problems. Just because something can be done in a lab does not mean it can be done at scale. As an example, Musk with his stupid hyper-loop. Sure it is technically possible to evacuate a tube and send a vehicle through it at high speeds. It will never be economically feasible, however. Sometimes the engineers just have to say “not going to work” to an otherwise cool idea.
It’s not the cost of hydrogen production. It’s the engineering problems that pervade the rest of the handling, storage and distribution of hydrogen that look to be insurmountable.
> Economic feasibility due to engineering problems.
The question then becomes, who's actually saying this? It's certainly not real engineers. In fact, real engineers have pointed out that it is much cheaper to distribute hydrogen than electricity:
>BRINK: How do you move the hydrogen from the solar farms?
> AD VAN WIJK: By pipeline. That’s the interesting thing: It is about 10 times cheaper to transport energy by a hydrogen pipeline than by an electric cable. That makes it possible to transport electricity very cheaply from somewhere like North Africa to the demand centers in Europe, for example.
And all of this is happening under the auspices of effectively free hydrogen due to a combination of subsidies and cost reduction. This should really raise the question of how any of the alternative ideas are going to compete with this, not how whether this idea can work.
> The question then becomes, who's actually saying this? It's certainly not real engineers. In fact, real engineers have pointed out that it is much cheaper to distribute hydrogen than electricity:
If you actually take off the “hopium” goggles and critically evaluate the problems, I think the truth is the hydrogen solution is not only unsolved it also probably can’t be solved.
Paul Martin is not a valid authority on this. He is a known anti-hydrogen skeptic and had made many nonsensical claims about hydrogen. The most notable is perhaps his limited understanding of how fuel cells work, and his claim that fuel cells can never dramatically exceed the efficiency of diesel engines.
This is false, as fuel cells are electrochemical systems that do not follow Carnot's theorem. Which is to say that it is fully possible to build a fuel cell that greatly exceeds the efficiency of diesel engines.
Not to mention that most of his claims are from some years ago, and are becoming obsolete even if they were true. He has not commented on (AFAIK) about the effects of subsidies nor admitted that costs are dropping rapidly. He just sounds like another anti-renewable skeptic similar to those that criticized wind and solar.
It's worth mentioning that all of them are similar in a way: Old, retired or nearly retired, and usually coming from in the fossil fuel industry. And yes, Martin is from the fossil fuel industry, and has no experience with hydrogen beyond its existence as a feedstock for oil refining. He has never had any experience with modern hydrogen-related facilities, equipment and concepts.
Engineers that actually do have experiences with those area do not agree with Paul Martin. So there are alternative viewpoints from knowledgeable people. You can look at recent statements by BMW and Bosch, including what their engineers have said. They are clearly believers of the idea:
Your argument is now “older people are stupid?”. The information is old and irrelevant? The article I linked was from this year.
I just picked a critical engineer at random, but I can see I’m wasting my time here. You are clearly not any kind of expert. I am clearly not any kind of expert. This is just devolving into nothingness, and I’ll leave it here.
You are clearly misrepresenting my point. Your authority is not really an authority for a bunch of reasons. One of which is how he is basically a retired petroleum engineer with very little understanding of the modern state of hydrogen. And yes, this usually implies an old person, something Arthur C. Clarke noticed in one of his writings about elderly scientists. And while your link is from this year, he's been saying the same thing for many years now without change. In fact, the only recent change in tone is his exacerbation, as billions of dollars are being invested anyways and he is upset about that.
You are not picking a critical engineer at random. You picking basically one of the very few credible critics, and they're all basically known to the community. The rest of the engineering community in this sector are certainly not as skeptical. In fact, you completely ignored my link about engineers that are doing real work in this area.
I asked previous about "who's actually saying this?" to the question of engineers that doubt hydrogen. And that question is still relevant, because outside of a tiny minority of scientists and engineers, most of whom are outdated and poorly informed, the rest are just armchair experts and random celebrities.
So the point is that you are simply wrong about your understanding of the issue. The intellectual community fully accepts the possibility of hydrogen as a widespread fuel and a way to solve climate change.
> So the point is that you are simply wrong about your understanding of the issue. The intellectual community fully accepts the possibility of hydrogen as a widespread fuel and a way to solve climate change.
That is terribly naive and wishful thinking, I’m afraid.
For even the smallest-scale industrial applications, hydrogen is almost invariably produced on-site, near or within the manufacturing cell consuming it. Even if Linde charged nothing at all for hydrogen, electrolysis would still win: no 10kpsi (good lord) tank, no inevitable 1% loss per month of high-pressure hydrogen, no extra insurance premium.
If you’d dealt with hydrogen in industry, you might appreciate the problems with it. The static electric discharge from fingertip to ground required to ignite hydrogen is barely perceptible, and a ridiculously low atmospheric hydrogen concentration will burn with a very hot flame invisible in daylight.
The proposition of the public driving high-pressure hydrogen tanks around is brain-damaged. If you want fuel, you should make methanol from your hydrogen - for the same reasons that, if you want hydrogen, you already produce it from water or natural gas or propane.
Hydrogen has been an excellent topic for boastful press releases by car companies, corrupt nations, and fossil fuel producers murderously determined to continue the status quo indefinitely. It’s ideal for that, because there’s no danger of practicality.
Then you are repeating the same mistake as the other person: Who is your source? All of the stuff you said, which engineer or scientist is actually saying those things? And no, some well-known critic like Paul Martin doesn't count. Those are outmoded and outdated people, and are totally clueless about recent developments in the field.
In reality, you are just repeating the claims of some random armchair expert. These days, those seem to be usually battery car fanatics. Though you still see the occasional pro-biofuel or pro-fossil fuel guy. Either way, it is coming from a totally unqualified person.
A membrane-based seawater electrolyser for hydrogen generation (2022)
Here we propose a direct seawater electrolysis method for hydrogen production that radically addresses the side-reaction and corrosion problems.
A demonstration system was stably operated at a current density of 250 milliamperes per square centimetre for over 3,200 hours under practical application conditions without failure.
This strategy realizes efficient, size-flexible and scalable direct seawater electrolysis in a way similar to freshwater splitting without a notable increase in operation cost, and has high potential for practical application.
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.
Iron is abundant on Earth, including within the crust, where it's the fourth most abundant element (after Oxygen, silicon, and aluminium), roughly 5% by mass. And yes, considerably more prevalent in the core. Iron and oxygen account for roughly 32% of Earth's total mass, each, the largest proportion of any element.
There's even a fair bit of it flowing though your veins and arteries right now.
And yes, the major ore deposits are old. Most are BIFs (banded iron formations), and date to 1 bya or 3.5 bya, laid down by early oceanic algae for the most part.
Sometimes it's more than fine to allow a slight exaggeration to pass without litigating it to death.
Let's be reasonable here, mantle and nucleus iron don't matter to this analysis.
Crust iron is all oxide. Fe at 5% average. In some locations obviously more concentrated up to 90% ore. Not all sites are viable for mining, and this is very important to understand. Just because there is plenty of iron out there doesn't mean all of it is commercial grade.
This means energy input to turn iron oxide into iron, which the article claims could be used as fuel and/or long term energy storage.
-Fuel I don't believe for a second.
-Energy storage it's a maybe. It needs to commercially beat plenty of options. Which to me seems unlikely since the path still includes heat and steam engine which would incurr at a cicle loss of at least 50%. And this being conservative etc. Would mean a steam engine operated in a very narrow power band - which would mean a baselevel powerplant not a peaker powerplant. And didn't yet consider other possible losses, as for one, the Fe degradation over time. Energy cycles that count on heat and engine are wasteful. Could this waste be compensated by a much cheaper capex and/or opex relative to Li or similar batteries? That's a big Maybe.
I myself want to believe there is a solution to renewables intermittency. But on this one in particular, I'm quite bearish for the reasons above.
The proposal is clearly for energy storage, not as a primary energy source.
To that extent, it resembles other synfuel concepts. The principle difference being that iron-as-energy-storage entails reduction rather than synthesis, in the chemical sense, for hydrocarbon synfuels.
There's a lot to be said for options which provide long-term, "shelf-stable", environmentally-benign, high-volume energy storage with convenient storage, handling, and utilisation characteristics. I've looked with interest on petroleum-analogue hydrocarbon synthesis (Fisher-Tropf) and alcohol (Sabattier) processes for some years. Both have long (multi-decadal, approaching a century) of established use. Yes, the overall process is lossy (as little as 15% net energy recovery), but there are applications for which there are very few alternatives: powered heavier-than-air flight, marine transport, mobile use, off-grid primary or back-up power systems, heating, and industrial applications.
I think I'd made abundantly clear that the abundance question is pedantry.
The challenge of using synthesized chemicals for energy storage exists for quite some time indeed. For aviation and marine there may be no other option outside of synthetic fuels, I agree.
Can this scale up? Or is this a small scale only solution?
Transportation. How much energy would a truck be able to move? How does it compare to a tank truck? Weight is absolutely relevant here.
Also, production. Consider that reducing iron is measured by millions of tons per year per plant, and right now, it's done burning it with plain old coal.
Seems very odd to me the subtitle of the news is 'carbon free fuel'. That alone is a massive bullshit indicator, but I digress.
How something that may have a 10% global energy recovery efficiency could beat a pure redox power storage solution? This question has been avoided so far.
Germany and South Africa have both operated coal-to-liquids (Fisher-Tropsch) at industrial scale. Germany during WWII, South Africa from the 1940s or 1950s onwards (I'm not certain if it's still in process). Both nations had ample coal reserves but little petroleum.
I became aware of the prospect of synthesis from captured CO2 + hydrogen (from electrolysis) from a US Naval Research Lab study around 2015. Those papers had ... misleadingly-truncated citations, dating back only to the 1990s. It turns out that hydrocarbon synfuels were first proposed in the 1960s, by M. King Hubbert and studied at Brookhaven National Labs and M.I.T.
Google had an X Project devoted to the idea as well, though ran into insurmountable cost barriers.
Scaling seems to be a major concern, though the process does work at experimental scales, and produces usable fuel. It seems worth continued research based on the potential advantages, even if costs remain higher than fossil fuels. (The USNRL research suggested "competitive" costs, particularly for in situ military fuel generation, notably in aircraft carrier task groups which have ample supplies of nuclear energy, but need fuel for aircraft.)
Battery storage has numerous limitations: low energy density by both volume and weight, and the fact that whilst fuel burns off during flight (and accounts for 50% or more of take-off weight), batteries don't. In the case of metal-air batteries (iron and aluminium have both been proposed), as the redox reaction progresses, the battery gains mass as oxygen from the atmosphere is bonded to it. This poses problems for flight, and even ground-based transport tends not to work well with batteries at large scale.
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.
Not sure why this is dead, but AFAIK magnetism in iron and steel is dependent on "domains" of iron molecules that are aligned in a crystal structure so the magnetic effect isn't just scattered to all directions. That's why some kinds of stainless steel aren't magnetic - the adulturant elements break up the crystal structure. In this case I think the question would be whether these particles are big enough to form a "domain" and become magnetic.
And if iron(III) oxide is near the melting point, it's unlikely to be magnetic and may not even be paramagnetic. This would be an interesting lab experiment: heat a sample to 1500 C exactly and test for paramagnetic properties.
Unfortunately, you're mistaken. In practice, iron(iii) oxide is barely paramagnetic and the particles are likely well above the Curie point and possibly at the melting point.
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.
Sodium would be a much better proposition. With NaOH, you can create a closed cycle. The electrolysis of NaOH is the well known Castner process, a consumable metal anode fuel cell with sodium is also well known (expired Patent: US3730776A by Lockheed) More details and overlap with other approaches: https://orgpad.com/s/5BfLP-cxj-7
Sodium has higher energy density (3.5 kWh/L) than liquid hydrogen, there is no energy needed to store it and no catalyst is needed for the fuel cell because sodium is so reactive with water. The fuel cell is rather easy to construct (I know somebody, who has done it in a garage).
NaOH solution is very caustic but also neutralizes well naturally without long term effects at least in comparison to crude oil that seems to be the better proposition. And of course sodium is everywhere, where NaCl - table salt is.
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.
I think this is likely more of an energy storage project, rather than an energy production one (which seems to be the stance the article takes).
At grid-level, battery tech is challenging, requiring technologies like pumped storage that require particular environments (e.g. damming a river) and can't really be transported.
If this works out you could use excess solar during the day to deoxidize the rust produced, and then run the iron reactor overnight, or on cloudy, windless days.
Well, if you can burn it to produce energy + spent fuel
and then put back energy in the spent fuel to make new fuel again
then you have really a battery. That's how li-ion batteries work. The issue is the efficiency: how much of the energy you used to recharge the "battery" (iron) is going to be available when you discharge (burn) it
Non-rechargeable batteries are also consuming a fuel. The products just stay in the same enclosed container. Same with rechargable batteries, just that there the process is easily reversible.
It is a bit of a fuzzy distinction. Batteries are typically simple chemical reactions that cause electrons to move around. But viewed from the outside a hydrogen fuel cell behaves the same; so why not call this one a battery too (especially since the process is reversible).
A useful distinction seems to be that batteries are solid state and don't use high process heat, else something would be seriously wrong. Of course, the underlying reactions are probably very similar if you look at them with a chemist's eye.
Well, it ties into the storage issue that we see with renewable. We still need energy when there is no wind at night. Burning iron at night and regenerating during the day could be a solution.
It needs to prove that it can be competitive with the other methods (compressed air, li-ion batteries, flow batteries, molten salts, flywheels...).
> It needs to prove that it can be competitive with the other methods.
I think the one thing is that iron storage would be a potential long term form of storage, while all those other methods that you mentioned are really short term, designed primarily just to deal with the daily peaks and troughs of renewable production, but not as much the "it's been completely overcast for 3 weeks" problem. The only other form of storage I'm aware of that is also long term like that is pumped water storage, and that is obviously very geographically limited.
If using Fe why not iron batteries? Keep the redox, remove the energy from the system via eletrical current instead of low efficiency heat, boiler and steam engine combo.
Great point. Fe batteries are very new so I'm not aware of the cost/benefit or if Fe batteries still slowly discharge over time, but yeah in both cases you're just oxidizing iron, so why not take the more direct route to generate electrical current directly.
Here’s an out of the box thought. Can we wrap the globe in undersea cables or does transmission losses kill the idea? Reason being that time zones and hemispheres make the “renewable is not always on” problem go away. It’s always on somewhere, so if there was a global grid you don’t really need storage?
They mention that with hydrogen. It's cheaper to produce hydrogen but much harder to transport it. Fortunately, hydrogen can reduce iron oxide, which turns out to be a great complement. Their analysis is that the system cost of burning iron and renewing it at electrolysis plants is lower cost (and safer) than using hydrogen directly.
Because renewables are intermittent and unevenly located. This could potentially solve those problems.
There could be a space for it. Or maybe batteries will just always be better. Depends on the full costs of each and the use case. Burning fuel to make electricity is pretty inefficient, but burning fuel for heat compares better.
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.
There's a pretty big difference between BTC and a burnable fuel. It is not possible to turn BTC back into electricity directly, it is only possible to turn it into electricity by first turning it into money, which then buys more electricity (from any, renewable or non renewable) power source. You can't ship someone a container of memory sticks containing BTC and then they get power out of them without burning more fuel or building more solar panels/other renewables. The much better comparison would be hydrogen, which can be produced using readily available water and renewable electricity, shipped, then burned. The difference is that hydrogen doesn't really produce much in the way of by products when burned.
The maniacs who claimed that something had a price on a market and cost to create claim that this means value was created.
From an ecological perspective, nonsense. Economically, somewhat sound.
Misappropriated rare resources cause destroyed nature for the reason that capitalism said it was sound.
Every joule can only be spent once, but and as long as there is no moral coercion, there is a profit to be made from pillaging it from the supply.
Not sure I agree, on one hand you have actual, physical potential energy, on the other hand you have numbers on a computer that could become worthless depending on unpredictable economic factors.
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.
Then the issue is with the chemical engineers, who haven't learned the waste, counterproductiveness and foolishess of dismissing other ideas, viewpoints and people. It's a vicious cycle - it greatly limits their ability to learn what they don't already believe, or deal with challenges to their ideas. The only solution is to give no validity to such dismissals.
I was taught that, in part, by a fed-up engineering professor.
Actually rejecting someone's perspective because they lack expertise in the thing they claim to be an expert in is a pretty smart thing to do. Particularly if you can explain why their perspective is wrong because you are in fact an expert and have superior knowledge.
I would hope Environmental Scientists, who are purportedly concerned with things like ocean acidity, pollution, atmospheric makeup, etc would have the chemical knowledge necessary to understand what they're looking at. Apparently whoever designed their curriculum at my almamater thought it was unnecessary.
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.
Is iron oxide really that much more volumous than iron? In terms of capturing the iron oxide, why couldn’t this be run in a sealed container with a valve that allows oxygen in? This doesn’t work for hydrocarbons because the volume of CO2 is orders of magnitude greater than the volume of fuel, but does iron oxide have the same issue?
Requiring natural gas to work makes me a bit skeptical. They don't indicate how significant the nat gas component is, but if prices are low, it will be much simpler and cheaper to just use the gas itself.
“it’s more efficient to produce iron from hydrogen gas than to produce liquid hydrogen. So iron powder as fuel is more expensive than gaseous hydrogen but cheaper to produce and move across the oceans than liquid hydrogen.”
He's saying liquid hydrogen, but I gotta wonder if the the real story here is an attempt to deal with moving the energy in natural gas, since the liquified natural gas story is so shitty (expensive facilities, etc.) and pipelines are politically and logistically difficult.
I would not be surprised to see this turned into a "burn/process natural gas (in North America etc) to produce the iron 'fuel'. Ship the iron by train or boat & skip building pipelines and tankers and LNG facilities." Which gets us no further on the climate change front, but answers certain current European (esp German) ... political / economic ... problems.
Interesting, one benefit of such infrastructure would be that it could transition smoothly to using renewables. I believe it's possible to extract "Grey" hydrogen from LPG so it might not require burning, though it'd still release co2.
Similar proposals have been made previously, particularly for boron, which has ten times the energy density of iron, and yet similar low combustibility:
At that rate, there should be an encyclopedia dedicated to all projects that can be described as greenwashing.
I think it's a new strategy to "drown the fish", by flooding the media with "green" technologies just to pretend to say "we heard you, we are going to change the world with green new things" only to save more time until everybody realize each of those new projects are just not viable. The air travel sector seems to be rife with this.
Who could have guessed that snake oil could work in something as serious as the energy sector, I'm really surprised it's getting so low.
I'm going to be brutally honest, but you even hear people from first world countries playing the poverty card when you tell them they should stop driving alone in a 1 ton vehicle, and it seems sobriety and de-growth will have to convince those people that fossil fuels are a privilege, not a right.
I can bet that we are going to see people sabotaging cars, gas stations and refineries pretty soon if nothing is done. Greta Thunberg will be 25 soon and a whole generation will not tolerate more lies.
It's another "use energy/hydrogen to create a fuel" technology.
This one creates a very inconvenient fuel: iron powder. It can't be efficiently piped, and it needs some very strange technology to make it burn in controlled conditions. And you cannot use it for gas turbines or piston-based engines.
At this point, if you have hydrogen, you can just use it to produce methane that has none of these problems. Or maybe ammonia if we ever get catalysts working at mild conditions.
1 ton vehicles would actually be an improvement on the status quo, at least in the U.S. where a "small" car is usually more like 3,000 to 4,000 pounds.
Also, if self driving becomes wide-spread and successful, we're going to start seeing a lot of zero-occupant cars on the road, most likely bringing the average vehicle occupancy below 1.
While it's very true that greenwashing is a thing, bans on fossil fuels are not the right approach. You need sin taxes that account for the cost of the externalities instead. A CO2 tax is sensible, "degrowth" is a horrific thing that will kill billions.
Done correctly, degrowth need not lead to billions of deaths. We desperately need to restructure our economic systems and societies to account for the reality that infinite economic growth on a finite world is not possible, realistic or desirable. If we do so, we can minimize the bleeding.
If we fail to, billions will die on hothouse Earth regardless.
So it’s gone from burning non-renewable sources like gas and oil to burning… iron.
This feels like a poor stop-gap that will turn into a long term solution one day instead of focussing on nuclear fusion/fission, solar, wind, beaming energy from space, etc.
I had to lookup a German word for this: Weltschmerz.
> Weltschmerz literally means 'world pain' and refers to a sense of world-weariness.
Seems like a niche technology, useful if you're sitting on tons of scrap iron for example. I recall some proposals for using this in long-distance cargo shipping instead of very dirty (and fossil-sourced) bunker fuel, but even there synthetic diesel or methane from atmospheric CO2 + water might be the more versatile solution (and the overall mass of the iron required for say, a trans-Pacific journey is an issue). See:
> "A disadvantage of iron as a fuel for ships is the relatively high specific mass of iron powder and the increase in the weight of the iron oxide that is produced during combustion. As a result, a ship will lie deeper and deeper during the voyage."
They seem to have a prototype in the works c. 2030.
>"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.”"
first off.... WTF? Transporting iron is cheaper than transmission lines? I call BS.
If they require Hydrogen to complete the loop, you're going to create a lot of CO2 in the process. 4% of H is produced using renewables today: https://rmi.org/the-truth-about-hydrogen/
If I remember correctly, the process of recycling iron oxide into iron involves carbon monoxide and results in carbon dioxide, so, I’m not sure this would be as carbon neutral as they claim.
There are other ways of course, but this is only for storage and recycling uses a lot of energy.
I’m talking about turning the iron oxide back into iron that can be burned. That usually uses carbon monoxide (mixed with hydrogen) to capture the oxygen atoms out of the iron oxide.
Form Energy is a bit light on details, but it looks like they are using a water based electrolyte, add oxygen, get electric power and rust when discharging, then add electric power and get iron and oxygen when charging.
The project mentioned here is setting the iron powder on fire and need to use a steam turbine to get electric power out of it. So different tech.
> Our first commercial product is an iron-air battery capable of storing electricity for 100 hours at system costs competitive with legacy power plants.
> you could use renewable electricity to produce iron
Is there a known process to do this? At the moment most iron production is using coal.
Edit: Also, what about nitrogen oxides? Almost any combustion with air produces them to some degree and they are harmful pollutants. The article never mentions them.
I don't really understand why iron is being considered over aluminum. Is aluminum production from ore too complex compared to iron? I would have to imagine burning metallic aluminum produces much more energy per gram.
Aluminium production is complex and might be less efficient per kilogram than iron production. Also, compared to iron there are no known processes to employ hydrogen, which can be had from green-ish sources, in aluminium production.
Aluminum definitely oxidizes extremely well. Most of the aluminum you come in constant with is oxidized intentionally (anodizing).
It’s just a ridiculously expensive metal to make.
Look up how much alumina is minded all over the world, how it’s shipped to Iceland for processing because of their cheap geothermal electricity, then shipped to China to processing, then shipped back around the world to final destination. It’s crazy.
The elephant in the room are, as always, nitrous oxides (NOx).
Whenever you burn something in a nitrogen atmosphere, NOx are created. They contribute to acid rain and the formation of smog, and are a trigger for asthma.
While certainly being an issue, they are a far smaller problem than emissions of greenhouse gases by fossil power sources. It is a greenhouse gas itself, but most human emissions come from agriculture. Moreover, there are technologies to reduce the emission of NOx'es from burning processes.
it could be, but like other posters have mentioned, it takes a lot of energy to mine and refine the iron so it'd be in a usable state.
I think it's easiest to think of iron as another energy storage medium that could ease the peaks of renewable energy, by taking excess renewable energy to generate the iron, and oxidizing the iron for energy generation during peak demand periods with low renewable generation
Comparing petrol with iron based on volume rather than weight seems highly misleading. I’m assuming that actual energy density is much worse with iron right?
It really depends, principally on what your extant constraints are.
For some applications, mass is a critical concern (e.g., powered aircraft). For others, it's volume, say, powerplant + fuel stores aboard a marine vessel.
As I'm understanding this proposal, the iron is largely recycled, so transport of iron is relatively minimised. The concern is how much iron is required on site, and what the plant-sizing characteristics are given that.
Though of course, in any public communication of novel research and technological proposals, there's a significant amount of PR, spin, and narrative-spinning, so it's fair to be skeptical.
I assume they are using renewable energy to reduce naturally-occurring iron oxide.
When the iron is burnt are they going to do with pure oxygen? Otherwise they'll get pollutants like nitrogen dioxide, possibly ozone. And the 0.5% not burnt will also become a pollutant unless carefully removed in some smokestack scrubber.
Or is this 'burning' to occur some kind of iron fuel cell? How would they liquidize the iron which is quite heavy?
Lastly, iron is heavy. Moving reduced iron could be expensive and dangerous.
Still, if sufficiently close to the renewable source this could provide much needed load leveling for intermittent sources.
The article assumes the viability of a hydrogen-driven process to reduce the iron. The intention is to establish a circular economy of reducing iron oxidized by burning it in the proposed fashion.
The byproducts from burning iron are no more noxious than burning fossil fuels, possibly less so. Filtration technologies exist as well.
Of course this technology would have to compete with other technologies to make use of excess renewable energy, like liquid hydrogen storage and transport (which it has several advantages over), iron-based battery technologies, or green-produced carbon-based fuels. I guess it makes the most sense in applications where heat instead of electricity is required.
> Of course this technology would have to compete with other technologies to make use of excess renewable energy, like liquid hydrogen storage and transport (which it has several advantages over), iron-based battery technologies, or green-produced carbon-based fuels. I guess it makes the most sense in applications where heat instead of electricity is required.
I'm going to come out and say those competing technologies are vastly more plausible and viable.
There is no shortage of iron, while this is another way to make usage of abundant renewable energy. Especially when at the destination actually heat is required. Apart from that, neither wind turbines nor more transmission lines help with the problem of making excess energy available for future use.
Using electricity to run a heat pump will beat combustion in efficiency, and that only becomes way more true when the energy source starts as electricity being sunk into creating a synthetic fuel.
While that is probably true, the problem still exists that renewables produce a lot of electricity when there is not enough demand for it. Iron combustion is a solution for that problem.
> Iron oxide can also be reduced to iron using hydrogen
> Altiro gets around this problem by adding a little natural gas
This is transparently just green washing from the fossil fuel industry. There is no way that this will be an efficient energy storage mechanism and it definitely won't be carbon neutral. Developing cost-effective methods to produce steel from iron ore without the use of coke (coal) is important, but if you want to do that just do that.
The natural gas is used to help starting and stabilizing the flame. Actual use of natural gas is probably negligible to the total output of the process.
I used to be very excited about the iron cycle when the first news about that brewery appeared. But these days I wonder how useful it really is, as an energy store? Won't it start oxidating at room temperature unless kept in inert atmosphere? And if that's a requirement, is it really that much less trouble than plain H2 or some gaseous or liquid intermediate?
Sure, but liquids and gases are routinely handled in vessels with a maintenance interval of "never" on the inside, I'm not so sure that could be transferred to a powder. But this might be my lack of knowledge of existing processes in "powdery industries" speaking, if those are solved problems there I would not know.
Your mention of gasoline evaporating made me realize that some of the iron oxidating is probably not all that bad, just make sure that there's no ventilation continuously swapping in fresh air. I guess I'm looking forward to the next iron age!
There's the kinetics of oxygen transport into a big pile of iron powder. If that's not good enough, you can always transport it in a closed container with a block of dry ice. You don't even have to seal it, just change the chemical potential of O2 in Fe.
Doesn't this seem like we are just going to use up iron supplies.
Iron would then become a used up commodity and drive up prices.
Just like when Corn was used for ethanol, the side effect was driving up corn prices, and raising food prices.
This could use up Iron, and then impact a ton of stuff.
EDIT
Missed this:
"This can later be reduced—that is, the oxygen can be stripped away—back into iron powder. “You can think of iron fuel as a clean, recyclable coal,” says Bergthorson."
Iron is one of the most abundant elements on earth, but also we aren't going to be burning it like we do fuels now. Instead we would produce pure iron using green power and oxidize it back to it's natural state for energy in a cycle.
Imagine loading an iron rod into your car, driving for a while, and then when you get into the gas station you dump a pile of rust off and buy a fresh iron bar.
* Kids playing with iron filings sounds a lot safer than kids playing with gasoline. "Don't leave your magnets in the fuel tank; it clogs up the lines!"
* The gasoline party scene in Zoolander would need to be reconsidered.
Imagine thinking that a material stars can't use for fuel is one that makes sense as a "renewable energy source." These idiots need to go back and take undergraduate thermodynamics.
You can't extract energy from iron by nuclear fusion, which is how stars "burn" fuel, but this is a chemical process, Fe + O2 => (some Fe&O compound) + energy.
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.