[HN Gopher] Iron Cycle based energy storage and generation
___________________________________________________________________
Iron Cycle based energy storage and generation
Author : jacquesm
Score : 106 points
Date : 2022-04-13 12:49 UTC (10 hours ago)
(HTM) web link (teamsolid.org)
(TXT) w3m dump (teamsolid.org)
| jpm_sd wrote:
| Seems like Form Energy has come up with a better method, also
| iron-based but no combustion.
|
| https://formenergy.com/technology/
| somethoughts wrote:
| Interesting lecture from one of the co-founders of Form Energy
|
| The Future of Energy Storage - Professor Yet-Ming Chiang, MIT
|
| https://www.youtube.com/watch?v=E76q-9q7ZDg
|
| Professor Yet-Ming Chiang, one of the world's most prominent
| researchers in energy storage, will give a personal perspective
| on some of the challenges and opportunities for better and
| cheaper energy storage. From a historical perspective, battery
| performance has improved steadily, but now the divergent needs
| for batteries in high energy density applications such as EVs
| (and, coming soon, electric aviation), and those for grid
| storage, which emphasizes ultra-low cost and earth-abundant
| materials, are becoming clear.
|
| He will give examples of emerging innovations that may address
| these different needs, including solid-state and other
| batteries that use alkali metal electrodes, and approaches that
| make use of the most widely available electroactive elements.
|
| Battery technologies are notoriously difficult to scale given
| high technology risk and high development costs. Yet-Ming will
| share some of the unique lessons learned at startups he has co-
| founded, including A123, 24M, and most recently Form Energy.
| jacquesm wrote:
| A123 went bankrupt:
|
| https://en.wikipedia.org/wiki/A123_Systems
| somethoughts wrote:
| Georgia Power explores multiday battery project with Form
| Energy
|
| https://www.spglobal.com/marketintelligence/en/news-
| insights...
| AndrewDucker wrote:
| What's their efficiency? I can't find anything on their site.
| otherotherchris wrote:
| They claim ~65% round trip currently and think they can
| improve to 75%. Not great, but polysilicon solar panels are
| cheap cheap cheap so charging efficiency doesn't matter much.
|
| It's being sold as a complementary solution to more efficient
| LFP cells (for evening peak shifting), and as an alternative
| to pumped hydro and peaking gas turbines.
| Cthulhu_ wrote:
| That's just it, 65 - 75% efficiency is still a lot better
| than having it wasted or end up on the market at negative
| value for power wasters like crypto farms and Facebook
| datacenters to just use up.
| cinntaile wrote:
| It's better for crypto farms and Facebook datacenters to
| use the energy instead, the efficiency is higher. If it
| would be wasted then it would be worse than this
| solution.
| ncmncm wrote:
| The efficiency of crypto farms and Facebook is zero if
| not negative: energy in, dystopia out.
|
| It would be better to waste the energy than to let them
| have it for free.
| cinntaile wrote:
| That's ideology, I'm talking about physics.
| AndrewDucker wrote:
| That's great. I hope they can scale it up and mass-
| manufacture it.
| otherotherchris wrote:
| Pretty much every iron chemistry has failed to reach
| market. I reckon they're probably just blowing smoke.
|
| I really want them to succeed for the sake of the planet,
| but it's another "revolutionary new battery just five
| years away" story.
| jacquesm wrote:
| They're one step ahead of the vaporware stuff you
| normally read about in that they are already operating at
| a scale worth noticing (no long lab level power but 100's
| of KW) and they are about to scale up to 5MW which will
| be a very important proof point if it can be done
| economically and reliably enough.
| philipkglass wrote:
| They're still shipping small volumes but ESS Inc. has at
| least delivered some of their iron-based flow batteries:
|
| https://essinc.com/
| andrewmutz wrote:
| I completely agree about efficiency. For managing solar's
| "duck curve", efficiency is less important than cost.
|
| As solar gets cheaper and cheaper, the ability to mitigate
| efficiency loss by just increasing the size of the solar
| installation gets easier and easier.
| jacquesm wrote:
| And HVDC lines coupling areas far away from each other
| can help to deal with overcast and even offset some of
| the day/night cycle.
| lkxijlewlf wrote:
| Not to poo-poo this, but that video sure made it sound "perfect".
|
| I think we need a number of different solutions. Solar takes up
| vast real estate and isn't very efficient, wind - we bury how
| many thousands of 747 size blades in the ground each year that
| won't break down? Surely, that's not sustainable. Nuclear needs
| to be on the table, too.
| foxyv wrote:
| > we bury how many thousands of 747 size blades in the ground
| each year that won't break down?
|
| This is worth worrying about, however landfill is one of the
| most plentiful non-renewable resources we have. These blades
| are completely non-toxic and can be buried safely so it is one
| of the least worrying problems about wind. The most damage that
| wind causes is destruction of ecosystems and excessive land
| use. Even that is pretty minor compared to other power
| generation methods. Wind is pretty awesome. (Also, yay
| nuclear!)
| intrepidhero wrote:
| I agree with you. But I learned yesterday that Seimens has a
| process where they completely recycle carbon fiber turbine
| blades. I had no idea that was even possible. If it works out
| that's pretty neat.
|
| https://www.siemensgamesa.com/newsroom/2021/09/launch-world-...
| Cthulhu_ wrote:
| I saw a video about that ('used up' wind power blades),
| honestly it sounded like anti-renewable propaganda and I'm sure
| the problem was hugely overstated. I'd rather have
| fiberglass/carbon/whatever but inert and harmless blades stored
| somewhere than CO2 and other shit in the air, or coal slag
| dumped wherever, or nuclear waste.
|
| Just grind them down and put them in landfill or whatever, it's
| fine.
| guerby wrote:
| I read somewhere that even if we max out on wind turbine, the
| flow of blades to landfill would be about 1% of the current
| flow of comparable materiels from recreationnal boating.
|
| https://www.theguardian.com/environment/2020/aug/06/nautical...
|
| As mentionned by other the fact that we talk about "waste" from
| wind turbine is likely due to fossil companies funding media
| campaigns about it.
| originalvichy wrote:
| It's highly likely it's for that reason. Almost all fossil
| alternatives get these "silver bullet" counter-arguments that
| don't survive basic tests.
|
| Example: ICE cars vs. Electric: electric cars need more
| resources to create and thus use more CO2 in reality!
|
| Simple truth: initial energy cost might be high but battery-
| electric cars catch ICE cars in resource friendliness after
| only few years.
|
| They just had to find one for wind turbines that was better
| than "they are an eyesore".
| imtringued wrote:
| I don't know why but people don't seem to understand that
| expending all energy upfront can actually be a benefit
| assuming you don't throw the car away for ridiculous
| reasons. In economics capital is often considered to be
| stored labor.
|
| In practice storing labor is a very difficult or maybe even
| impossible thing, so the ability to store additional labor
| in the form of physical capital is very useful. Lots of
| people want to retire early. They want to work a lot in
| their youth and then relax instead of working until they
| die. If you get an ICE car right before your retirement,
| you are dependent on a lot of young people running the
| infrastructure necessary for that car. Meanwhile with EVs
| that infrastructure is a lot less labor intensive so a
| demographic decline isn't that bad. All the work was done
| before demographics got worse.
|
| Now try doing the same with food. You can drive a car for
| 20 years off a wind turbine that lasts 20 years but you
| can't store food for 20 years. You are reliant on young
| workers who will take care of you.
| jacquesm wrote:
| And that bird thing too... very boring these non-arguments.
| imtringued wrote:
| Have you ever thought about much much carbon we would have to
| bury if we wanted to properly dispose of the CO2 we emit? It
| would go way beyond wind turbine blades.
| dayofthedaleks wrote:
| Maybe this is how Russia goes green-ish, assuming Magnetigorsk
| isnt tapped out.
| bdamm wrote:
| Russia will be one of the last to go green.
| throwaway432412 wrote:
| Another approach is iron-air batteries: https://formenergy.com/
|
| Fuel has other valuable properties, though. I hope both of these
| can help soften our landing.
| usrusr wrote:
| Apparently the same org that was discussed in 2020, nice to see
| them going on.
|
| https://news.ycombinator.com/item?id=24996153
|
| What I do wonder is how well the storage part really scales: what
| would be the most economical way to keep large energy stockpiles
| in that shape safe from, well, getting a little rusty over time?
| jacquesm wrote:
| They're scaling up to 5MW now:
|
| https://www.nu.nl/economie/6194949/nutsbedrijf-veolia-gaat-e...
| (dutch)
| ISL wrote:
| I perpetually dream of systems like this where a process might be
| undertaken in locations that require HVAC systems that can make
| use of the waste heat.
|
| Whether with iron or some other energy-consumptive process,
| imagine if a municipal truck rolls up to your house with a bucket
| of rust and picks up your bucket of iron. You roll the bucket of
| rust into a receptacle in your furnace and through the winter,
| slowly process rust back to iron as you heat your home with the
| waste heat.
|
| You're happy, because your heating costs are offset by the sale
| of processed iron. We're happy, because someone somewhere isn't
| consuming even more energy just to create processed iron _and_
| you 're probably able to process iron at a lower cost, reducing
| the price of processed iron.
|
| Depending on the process, the thermodynamics may or may not
| pencil out, but it's a dream I keep contemplating. The key
| requirement is that the process be dead-simple, hard to game, and
| very energy-intensive.
| dragontamer wrote:
| > I perpetually dream of systems like this where a process
| might be undertaken in locations that require HVAC systems that
| can make use of the waste heat.
|
| Cities are the solution there. Waste-heat from power-plants is
| ~200F (just under boiling), because the water needs to be steam
| to efficiently move a turbine. The 200F waste-water is no
| longer useful at turning the generators, but its still useful
| to pump around the city and warm up homes.
|
| ----------
|
| IBM was playing around with waste-heat systems to increase the
| efficiency of solar panels. Solar Panels lose efficiency above
| 140F, which is pretty common because the sun heats up the solar
| panels. By running water through the panels and dropping the
| temperature down a bit, you end up with say, 130F water and
| 130F panels (increasing panel efficiency, but now you gotta
| deal with 130F water).
|
| The 130F water is waste heat, but unlike New York City
| steamworks, its in a hot location that won't be able to use the
| waste-heat in a useful manner. Unfortunately, I don't think
| this is high enough temperature to be used for this chemical-
| iron process...
|
| ---------
|
| That being said: Iron Fuel itself is something I haven't
| considered personally. But the chemical process sounds quite
| similar to Hydrogen Fuel / Syngas. Iron being a solid sounds
| like its easier to move around and store, but Hydrogen has
| pumping benefits (ex: hydrogen pipelines).
|
| Chemical energy storage methodologies seem useful. There's all
| sorts of low-grade waste heat (130F to 200F), that's really
| difficult to figure out how to use. Anything, even if its like
| 30% or 40% efficient, will be better than the 0% efficient
| "Waste" that we do right now.
| starlust2 wrote:
| I've wondered whether you could pump heat from a solar panel
| into a swimming pool.
|
| I've seen systems where heat from A/C is used to heat
| swimming pools. Mostly just needs an extra exchanger on the
| A/C coolant line that transfers the heat to the pool water.
| You generally run both system at the same time when it's hot
| out. (assuming you are fortunate enough to have a pool)
| ncmncm wrote:
| People have tried running water to cool solar panels. It is a
| bad fit. Plumbing is a source of trouble; the more fittings
| involved, the worse it gets.
|
| Somebody is selling plastic frames you attach your panels to,
| to blow air through to cool the panels and claim the excess
| heat. Air ducting makes less trouble than plumbing does. The
| air can go through a heat exchanger attached to a heat pump
| to concentrate it.
|
| Keeping the panels cool increases their efficiency enough to
| pay for the fan and heat pump, and makes them degrade much
| more slowly; and, you get the heat if you want it.
| jacquesm wrote:
| I worked for a bit on a solar powered Stirling engine to drive
| a refrigeration cycle for HVAC, the idea being that when the
| sun is shining you need your AC the most and you get all the
| power in the world to run it directly proportional to how much
| the sun is shining. So it doesn't need any further control
| circuitry, sun shines, pump runs. No electricity involved.
| mountainboy wrote:
| that sounds cool. did you get it working?
|
| Stirling engines are quite tricky to get right, as I
| understand it. And that sounds like you'd need a good sized
| one, not a toy.
| jacquesm wrote:
| The basics, yes. A direct solar->Stirling path using a
| stationary engine and tracking mirrors worked very well,
| the next trick to figure out would have been to arrange for
| the mechanics and to scale it up a bit.
|
| It's quite magical to see sunlight turned into motion
| without any intermediary.
| thatcherc wrote:
| Would this be in a scenario where homes are producing more
| electricity than they need, and using the extra to reduce iron
| oxide? With solar getting cheaper and cheaper, definitely a
| possibility.
|
| A system more similar to what we have in New England would be
| the opposite of what you describe: a truck drops off a load of
| fresh (elemental) iron, and it's oxidized over the winter to
| heat the house. Then, in the spring, someone comes back and
| removes all the rust for recycling. This plan would allow iron
| to replace a lot of propane and heating oil if the energy
| densities work out.
| thinkcontext wrote:
| > Would this be in a scenario where homes are producing more
| electricity than they need, and using the extra to reduce
| iron oxide?
|
| There's no need for this to be done at a home, since the home
| is on the grid.
| dragontamer wrote:
| > A system more similar to what we have in New England would
| be the opposite of what you describe: a truck drops off a
| load of fresh (elemental) iron, and it's oxidized over the
| winter to heat the house. Then, in the spring, someone comes
| back and removes all the rust for recycling. This plan would
| allow iron to replace a lot of propane and heating oil if the
| energy densities work out.
|
| I have severe doubts that iron has as much energy density as
| methane or propane.
|
| I also doubt that Iron is as easy to carry around as methane
| pipelines.
| foxyv wrote:
| > I have severe doubts that iron has as much energy density
| as methane or propane.
|
| The heat of reaction of elemental iron oxidizing to rust is
| about 1648kJ per 4 moles Iron. Propane burning is about
| 2220kJ per mole. Also, Iron atoms are heavier than
| molecules of propane (55.8g/mol vs 44.1g/mol). This means
| that propane has an energy density of about 50 joules/gram
| while Iron has about 7 Joules/gram. So no, not very energy
| dense on a per kilogram basis.
|
| However, energy density is only relevant to cost of
| transportation. If elemental iron is stupid cheap compared
| to methane due to taxation of external costs associated
| with emitting carbon dioxide, then the additional cost to
| transport it would be less relevant. In addition, since it
| is renewable, the cost could be reduced further. But yeah,
| we are a long way from that since methane and propane are
| very cheap right now.
| dragontamer wrote:
| > then the additional cost to transport it would be less
| relevant
|
| I mean, if weight is the only issue, then maybe don't
| transport it ever?
|
| Its not like we try to "transport" the Bath County Pumped
| hydro station around (aka: the largest battery in the
| USA). We just let it sit in one location and convert from
| electricity (usually nuclear at night) into energy-
| storage (pump water uphill), and then convert it back
| later (release the water during daytime peak-electricity
| usage).
|
| ---------
|
| If the energy "needs to be transported", then convert the
| energy into another form (Ethanol fuel? Syngas Kerosene?
| ). Each conversion loses efficiency of course, but if
| Iron is cheap enough to use as "energy storage", then it
| can be our "energy storage of last resort", since any
| storage is better than waste. (IE: Never turn off your
| solar panels. We always have "something" to dump our
| excess electricity into)
| foxyv wrote:
| I was thinking on a residential basis where you would buy
| and recycle the iron powder. But yes, in a large
| commercial heat storage facility you would not need to
| transport the iron at all. Pretty cool!
| londons_explore wrote:
| Or... Just install systems that don't have waste heat, like
| heat pumps.
|
| Anytime you hear 'use waste heat for X', the thermodynamically
| more efficient version uses a heat pump. And with time, the
| thermodynamically more efficient version will also be the
| economically more efficient version.
| xyzzyz wrote:
| There are no heat pump systems that could supply high grade
| heat for many (if not most) practical industrial processes
| done in large scales. You can't use heat pumps to burn
| clinker. You can't use them to heat aluminum for extrusion.
| You probably can't even practically use it for dryers in
| paper mills. The technology you are asking for simply does
| not exist. This is not to say that it _cannot_ exist, but
| it's silly to say that it's "just" an issue of installing
| heat pumps.
| fulafel wrote:
| Waste heat and heat pumps are not mutually exclusive. For
| example a data center may use heat pumps for cooling, and
| that exhaust heat is used along with more heat pumps to heat
| water in district heating circuits. There are lots of these
| in Europe.
| danhor wrote:
| Wouldn't plugging into district heating be a simple way to
| harness the thermal energy?
| imtringued wrote:
| Are you sure this is a good idea? Why not implement district
| heating? You can use solar collectors during sunny months and
| bridge winter with iron energy storage. Those solar collectors
| free up solar panels which means surplus electricity can be
| turned into iron instead.
| rob_c wrote:
| ...or gravimetric pump batteries to store energy which don't rely
| on complex high-temp furnaces to be maintained... nah that'd be
| daft
| jacquesm wrote:
| There are parties trying that as well, both by pumping 'uphill'
| as well as by using underground storage, there are also parties
| that are trying to do this with moving weights (but I don't
| think that will come to anything at scale).
| ncmncm wrote:
| Yeah, the cranes and weights thing is the dumbest idea I have
| encountered lately.
|
| Using deep underground cavities to drain water into, and pump
| back out of, extends pumped hydro to a lot more places than
| are usually assumed suitable. And, it multiplies the energy
| stored up a hill if you can drain the water to somewhere
| deep.
|
| The most surprising method I have enountered is deep-ocean
| pumped storage. This doesn't need a pipe, just a tank
| anchored down deep with a pump/turbine at the bottom. You
| charge it by pumping the water out, leaving water vapor, and
| get the energy back by letting the water back in. The only
| connection to shore is the wire. The amount of energy you can
| store in a 30-meter diameter tank under 300m of water is
| amazingly large. The tank does need to be very strong to hold
| back the pressure.
| jacquesm wrote:
| You could use two different fluids with different
| densities, lose a bit on the efficiency but far lighter
| construction.
| Udo wrote:
| I _know_ I 'm missing something obvious here, can someone close
| to this tech help me out? What problem does this solve? For
| reference, I'd like to compare this to a hydrogen cycle, which is
| apparently already a subsystem of the proposed process used to
| reduce the spent iron. I went to the "Why iron?" section of the
| web page and got the following points:
|
| ' _CO2 free_ ' - H2 cycle systems are also CO2 free
|
| ' _Compact_ ' - the energy density of iron is already pretty low
| and the proposed machinery also doesn't seem very compact.
| _Maybe_ storing uncompressed H2 would be somewhat inconvenient
| depending on your location, but you can always compress it. And
| if you need longer term storage, you can actually make
| hydrocarbons from it, although that wouldn 't technically be CO2
| free (only CO2 neutral if you use captured carbon)
|
| ' _Cost-effective_ ' - this system seems way more expensive, per
| kWh and in absolute terms, than gaseous cycle concepts.
|
| ' _Easy to store and transport_ ' - the iron is certainly not
| easy to transport, nor is the machinery using or recycling it. It
| _is_ easy to store safely, just not efficiently.
|
| ' _Scalable_ ' - while iron is abundant on Earth, most of our
| iron is actually at inaccessible depths, so we're stuck with
| traditional mining. If you think iron is cheap, you haven't tried
| to use it as a building material recently. Cheap and abundant
| metals would be calcium or potassium. Even cheaper, again: H2.
|
| ' _Safe_ ' / ' _Commodity_ ' - true, but how relevant are these,
| really?
| bdamm wrote:
| H2 is most certainly not CO2 free. It is quite energy intensive
| to produce it, and currently is produced from oil & gas
| products. The cleaner alternative is to use clean electricity
| to produce it from water; but if you're going to do that, it
| turns out that just using the electricity is almost always more
| efficient.
| Udo wrote:
| Any of these criticisms you levy against H2 would by
| extension also apply to iron, only more so.
|
| _> It is quite energy intensive to produce it_
|
| We're talking about a cycle that is supposed to store and
| release energy. "Quite energy intensive to produce" would be
| a plus in this context. It would matter though if it was
| inefficient to produce, which is not the case. On top of all
| that, H2 _is actually_ a part of the proposed iron cycle
| system.
|
| _> and currently is produced from oil & gas products_
|
| It would obviously not be produced from oil and gas products
| in the case we're discussing here. If you're going to have an
| H2 cycle, it makes zero sense not to start with water.
|
| _> but if you 're going to do that, it turns out that just
| using the electricity is almost always more efficient._
|
| As far as I'm aware, the iron cycle system also does not
| claim to _produce_ energy in order to compete with solar or
| wind. It claims to be a good and portable storage solution.
| Thermodynamics absolutely assures that _any_ such system will
| always be less efficient than using the electricity right
| away. It is absolutely ridiculous to use an argument of
| inefficiency against an H2 cycle system _while speaking in
| favor of an even more complex other cycle system_!
| jacquesm wrote:
| The big advantage afaict is that storing hydrogen for a long
| time inevitably leads to losses so you can't for instance do
| seasonal offset with it, and using hydrogen at grid scale for
| combustion is tricky whereas using metal as a fuel should be
| very scalable. The true test will be the economics.
| PaulHoule wrote:
| There is 'chemical looping combustion' where you reduce the iron
| separately from burning it but in the same facility.
| jacquesm wrote:
| This is pretty much that.
| andy_ppp wrote:
| I just don't get all of these different new mechanisms for
| storing energy when we can create methane at about 60% efficiency
| now (and already have infrastructure to be able to use methane).
| Can someone explain why if the issue is building up the
| renewables and will to do it why we don't just make a start on
| infrastructure (wind, solar, nuclear + gas generation for old
| power stations) for this now?
| guerrilla wrote:
| I can't answer your question but like green hydrogen I'd guess
| there are practical reasons.. but my question is wouldn't that
| just contribute to greenhouse gasses?
| dibujante wrote:
| If you create it out of atmospheric carbon then it's carbon-
| neutral. I don't know if that's what they're proposing,
| though.
| loudmax wrote:
| If you're pulling carbon from the atmosphere, the process
| would theoretically be carbon neutral. I think this is one of
| the goals for SpaceX's Starship vehicle.
|
| In practice, I'd have reservations about widespread
| manufacture of methane. Existing methane infrastructure is
| often leaky and methane itself is a far more powerful
| greenhouse gas than carbon dioxide. That isn't to say that
| manufacturing methane shouldn't be considered, but it's
| extremely shortsighted to say that methane manufacture is the
| _only_ storage technology that should be considered.
| ncmncm wrote:
| You would like for carbon pulled from the atmosphere to be
| incorporated into something that would not immediately dump
| it back into the atmosphere again, such as carbon nanotubes
| to put in cement to strengthen concrete.
| jjoonathan wrote:
| How much does it cost to create methane at 60% efficiency? Have
| we fundamentally advanced beyond the Sabatier process?
| ncmncm wrote:
| Cost, meaning what does the equipment cost to buy and
| operate?
|
| The cost of equipment will be coming down fast.
|
| It needs, anyway, a supply of hydrogen and carbon. As
| hydrogen gets more valuable for other processes, its price
| might even go up. Extracting carbon from the atmosphere costs
| a few hundred dollars a ton; that cost might go down. The
| oxygen has to be stripped off, which costs energy you will
| hope to get back.
| tinybrotosaurus wrote:
| There is only a small number of good mechanisms (such as the
| one you pointed out) in the world. In today's world this is a
| problem. People and groups of people need to bring something
| different to the "table" in order to get or stay relevant. In
| essence, every now and then people have the worst of incentives
| to pump and hype some exotic technology in order to secure that
| good old government money.
| pfdietz wrote:
| Where do you get the carbon to make the methane?
| credit_guy wrote:
| > we can create methane at about 60% efficiency now
|
| Do you have a source for that? Also, where does the carbon for
| the methane come from? With iron/rust there is no carbon in the
| cycle.
| ncmncm wrote:
| Methane synthesis needs a source of carbon.
|
| Generally, anhydrous ammonia is a more practical medium where
| pure hydrogen won't do. It just needs hydrogen and air as
| input.
| baybal2 wrote:
| tapland wrote:
| A lot of single use hand warmers use iron powder. The ones with a
| small satchel inside an air tight plastic package that start
| reacting as soon as the package is opened.
| originalvichy wrote:
| I didn't pick this up from their landing page. How circular is
| this? Meaning how much iron are they losing during the capture
| phase? The language makes it seem like a closed loop but I assume
| there's still some loss?
| jacquesm wrote:
| .1% per cycle afaict.
| matthewfcarlson wrote:
| Obvious marketing aside, I just love the idea of a grungy
| steampunk esk traveling to the stars story. But all powered by
| rust.
| photochemsyn wrote:
| Looks pretty interesting. Note this is a coupling technology,
| i.e. the power input is at the reduction stage when iron oxide is
| reduced back to metallic iron via the use of hydrogen (generating
| water). To make it a non-fossil process, you have to scale up
| hydrogen-from-water using wind/solar:
|
| > "The resulting iron oxide is a solid material, so it can be
| captured after the combustion process. It is then reused by
| regenerating it with green hydrogen into flammable iron fuel. In
| this way, iron fuel offers a revolutionary method to store energy
| in a circular and carbon-free fashion."
|
| It has some real advantages over shipping hydrogen, as hydrogen
| is tricky to work with, relative to methane. There is an
| alternative process, developing direct-air-capture of atmospheric
| CO2 and using the hydrogen to reduce the CO2 to CH4, which has
| the advantage of being able to use existing natural gas pipelines
| for transport and distribution. In contrast this iron process has
| some long-term storage advantages; it could serve as a way to
| store excess wind/solar power over longer periods i.e. months.
| The notion it could be used to fuel long-distance shipping is
| also intriguing: ships could use hydrogen to regenerate their
| iron fuel at the end of each voyage.
|
| However this all depends on massive scale-up of hydrogen-from-
| water. That hydrogen can be used in many industrial processes,
| including also fossil-fuel-free steel production. Without that,
| this iron process can't be run at any scale.
| galangalalgol wrote:
| Is there a way to make an iron oxygen battery, maybe a thermal
| single use one? Direct to electricity is so much more efficient
| than combustion. I don't want to trade oil wars for lithium
| wars, iron wars seem less likely, so that is a plus.
| dragontamer wrote:
| Of course. Iron has an anode voltage of 0.2V though. A far-
| cry from Li-ion's more useful 3.7V.
|
| EDIT: My search-engine abilities apparently failed me. I'm
| seeing 0.44V as the voltage... well... whatever Iron's
| voltage is... it is pretty small. That's my point.
|
| There's a reason we didn't make Iron batteries. Iron
| definitely stores electrons, but the voltage dropoff leaves a
| lot to be desired...
| mountainboy wrote:
| NI-FE (nickel-iron) are pretty good batteries that
| basically never die. terribly expensive though, and
| comparatively low power density.
| jacquesm wrote:
| The voltage isn't really relevant.
| dragontamer wrote:
| Voltage * Electrons == energy.
|
| Iron stores 2 electrons at very low voltage. That
| fundamentally limits its energy density.
|
| Li-ion stores ... some number... of electrons at 3.7V.
| Looking at the periodic table, I think 1 electron? In any
| case, the big 3.7V drop really changes its energy / power
| characteristics.
|
| You'll need additional cells to increase either voltage
| or current (doesn't matter which: electric-engineers can
| convert either voltage or current into power). But
| without fundamentally good voltage or current (ie: stored
| electron) stats, you're just not going to have much
| energy storage.
|
| And if each of those cells are heavier because you're
| using say... a heavier element (ex: Iron) instead of
| lighter elements (ex: Hydrogen or Li-ion), then its that
| much worse.
| jacquesm wrote:
| They're not aiming to use this for a mobile application.
| dragontamer wrote:
| I'm sure they aren't.
|
| But the status-quo for chemical energy storage (that is
| burned / re-released) is maybe Hydrogen?
|
| If you don't care about weight / density issues, then a
| giant steel-tank containing many/many tons of Hydrogen
| Syn-gas might be a better storage option than iron?
|
| Hard to say really. I'm willing to see people experiment
| with the technology. Iron is one of the most abundant
| elements after-all, so any use of Iron will almost
| certainly have raw cost-benefits.
|
| But will it be cheaper to use the iron as energy storage?
| Or is it cheaper to turn the iron into steel, and then
| pump Hydrogen into the Steel like a balloon and
| pressurize-store Hydrogen at 10,000PSI or whatever?
| jacquesm wrote:
| It's like all engineering problems a matter of trade-
| offs. Hydrogen has very high energy per unit mass but
| very low volumetric energy density. In other words: if
| storage space is plentiful it may be a good solution. But
| hydrogen installations have all kinds of other
| constraints acting on it that may make hydrogen less good
| for a particular application. The typical way to convert
| hydrogen to electricity is either through fuel cells or
| by burning it to drive a turbine. You then need to take
| into account the conversion losses for both the splitting
| and the whole recombination cycle all the way to
| electrons again (end-to-end efficiency) to end up around
| from anywhere between 20 and 50 % or thereabouts.
|
| That's usable but not great and the installations tend to
| be costly and somewhat fragile due to all kinds of
| attributes that hydrogen atoms have which they impart on
| the materials that that installation is made out of. For
| instance, hydrogen tends to make metals brittle so
| regular ductwork isn't going to work. Hydrogen
| installations also have the bad habit of going 'foom' due
| to the extremely low activation energy.
|
| So there is some pressure to try to find a storage system
| that is both cheap, doesn't use exotic materials, is
| chemically stable and reasonably energy dense and has a
| round-trip efficiency as high as can be achieved.
|
| This is a complex problem to put it mildly and there is a
| whole raft of technologies that are being examined all of
| which have different trade offs making them more or less
| applicable to certain applications.
|
| The 'Iron cycle' is one of those, it isn't a winner on
| all or even a majority of dimensions but it has some
| interesting properties, notably: the cycle is uses only
| commonly available materials, it doesn't require long
| term storage of the hydrogen (which can be produced and
| used in the same cycle step), the materials involved are
| stable in both forms (pure iron vs iron oxyde), it is
| _reasonably_ (not super) energy efficient and it has an
| energy density which for stationary applications is not
| problematic.
|
| The biggest questions at this point in time are: does it
| scale and does it do so cost effectively. If the answer
| to both of those are 'yes', which this experiment in
| scaling up the cycle to 5MW should answer then it will at
| least be a viable contender, much more so than many other
| schemes that I've seen come by in the last couple of
| years.
| ncmncm wrote:
| Hydrogen embrittlement is a problem only when you are
| trying to keep the hydrogen at high pressure. But there
| is no need for that, in most cases.
|
| Most of the bulk hydrogen storage plans involve
| underground storage at a pressure that would not cause
| trouble. Where more density is needed, e.g. aircraft
| fuel, liquid form is favored, again at low pressure.
| jacquesm wrote:
| I think it is more accurate to say that there is a
| relationship between hydrogen embrittlement, pressure,
| material structure, hydrogen purity, duration of exposure
| and that depending on all of these it can be a smaller or
| larger problem but it never is 'no problem', you need to
| design around it somehow or it will get you.
|
| And for liquid storage you have to count on some H2
| boiling off and for underground storage you will need to
| be _extremely_ careful about possible ignition sources.
| mrfusion wrote:
| You could wire them up in serial to increase the voltage.
| jfengel wrote:
| Can you really add nineteen .2V sources together to get
| one 3.8V source? I know that the basic high-school
| version of E&M says that serial voltages add, but does
| that work in real life? Or is that the frictionless-
| massless-pulley of electricity?
| photochemsyn wrote:
| Battery technology development is a huge field with a long
| record of failed promises (often related to issues like
| lifetime, flammability, manufacturing cost, etc.).
|
| One interesting recent development is the replacement of the
| cobalt needed in lithium batteries with iron. Cobalt wars in
| Africa's Congo are a current issue:
|
| https://nextmoneyng.com/2021/12/22/the-cobalt-war-the-
| sino-a...
|
| Now it seems that cobalt can be replaced with iron with no
| efficieny/storage capacity losses:
|
| https://crm.org/articles/a-clean-industry-revolution-the-
| lit...
|
| Lithium itself doesn't really seem replaceable for where it's
| used, in applications that demand relatively high energy
| density and voltage.
| otherotherchris wrote:
| The world has a nearly infinite supply of lithium.
|
| Evaporating naturally occurring brine in poverty stricken
| shitholes is just a lazier way of extracting the tiny
| amount that we've used historically rather than capital
| intensive extraction from spodumene, clay, and geothermal
| or desalination wastewater.
| bdamm wrote:
| Conveniently, lithium is also abundant and can be mined
| from many different sources, including the ocean. So wars
| over lithium seem unlikely, and lithium shortages also seem
| unlikely since the main constraint is over scaling up
| efficient mining.
| imtringued wrote:
| I hope that lithium recycling is going to be more cost
| effective than extracting new lithium. In theory it
| should be a very straightforward process compared to
| mining.
| dragontamer wrote:
| 1. Iron is heavy -- This means it costs more to transport iron
| fuel, compared to lighter fuels like methane, propane, or butane
| (aka: gasoline).
|
| 2. Iron is dense -- ?? Not discussed in the webpage. But
| something like Hydrogen (despite being very light) takes up a lot
| of space. Hydrogen is so light that its volume becomes a problem.
| Iron does seem to solve that issue at least.
|
| 3. Iron is renewable -- Iron turns into Rust, and the rust can
| turn back into Iron easily. This makes Iron more comparable to
| Redox-flow batteries or Hydrogen.
|
| ----------
|
| Funny thing is: I was just discussing with someone else in my
| social circles about how Iron/Rust is exactly the same process as
| battery-chemistries. Just... worse. Iron-electricity has less
| voltage than Li-ion or Zinc, or other elements.
|
| But the Iron -> Rust -> Iron process is a well known process for
| "storing energy". We just usually don't care about the energy
| storage part, and more about the physical properties of Iron, and
| preventing it from turning into Rust (which is weaker, redder,
| more stains, etc. etc.).
|
| Experimenting with Iron-based energy storage seems like it'd be
| destined for failure? Its one of the oldest elements and the
| chemical process has been known for a while. However, the only
| way to be sure that its a bad idea is to try it. So we should
| experiment with it, at least a little bit, to really make sure
| that we didn't miss anything here. Iron is a hugely abundant
| element after all... if at all else, it can be used as a "cheap"
| energy storage mechanism as opposed to a "quality" energy storage
| mechanism.
|
| After all, a lot of our energy is just wasted (ex: Solar Panels
| during the peak days just turn off). Instead of turning off solar
| panels when the grid is overloaded, maybe store the excess
| electricity in cheap iron? 40% round-trip efficiency is still
| better than 0%.
| [deleted]
| jacquesm wrote:
| They way I understand it this is used as a cycle so it won't be
| transported other than during the initial construction of the
| plant.
|
| There are some properties here that are interesting (see other
| comment in this thread) and that may make this into a viable
| technology for specific applications.
| tzs wrote:
| They are aiming at heavy industry use where weight should't be
| a problem. From the site:
|
| > A detrimental side of iron fuel that it has a relatively low
| specific energy density. Therefore, it cannot be used in
| applications in which weight is of importance such as cars,
| trucks and planes. Also, it can only be transported in an
| economic manner by ship or train. However, most of the heavy
| industries are located on railways or waterways. Therefore,
| iron fuel is applicable to those industries.
| [deleted]
| dv_dt wrote:
| Re: the heavy, For vehicle applications where power/weight is
| more important, iron based processes are maybe not as viable,
| but I would think the Iron is mostly being considered for grid
| or industrial storage.
| nmasse-itix wrote:
| Is the 40% an estimation from your side ? I could not find the
| efficiency numbers on the official webpage...
| dragontamer wrote:
| No, its not an estimation at all.
|
| I'm just grabbing a random number. Basically, it doesn't
| matter how well it performs because the current "solution" is
| just wasting energy at peak periods on the grid right now.
| deltaonefour wrote:
| The overall solution to our energy problems is not singular.
| From what I'm seeing no single technology can replace our
| current energy infrastructure. It must be a multi-pronged
| approach with different technologies supporting each other.
|
| I envision iron to be one component of a complicated green
| energy future if such a future even possible as many sources
| day it's too late.
| ncmncm wrote:
| We will end up with a few best-favored systems, after a wide
| variety are tried.
|
| Odds-on favorites include hydrogen synthesis, ammonia
| synthesis, pumped hydro (up hills and up out of underground
| cavities), liquified air, and various battery technologies.
| But there will without doubt be some surprise break-outs, and
| maybe surprise duds.
| aqme28 wrote:
| Pretty neat idea! My first concern is that iron is pretty heavy
| for a fuel. It looks like you get about 4.8kJ/g from burning
| iron, and somewhere around 10x that for most hydrocarbons.
|
| In other words, I wonder if iron is so heavy that you pretty much
| have to do this burn/reduce cycle in close proximity of
| eachother. Useful for a battery maybe but not as much for a
| transportable fuel, except maybe for boats and trains
| intrasight wrote:
| I thought the same after reading on that web page about
| transport. Iron is like 20 times heavier than LNG. Plus is
| doesn't "flow" like a liquid. I doubt that iron will play a
| role in energy transportation.
| LordHeini wrote:
| How does a process work that makes Iron from Rust using only
| electricity?
|
| Conventional blast furnaces use a reducing gas or coal for the
| reduction.
|
| The website has no link to anything concrete here (but mentions
| conventional furnaces).
|
| And also, how on earth do you make iron dust from the iron after
| reducing it back from its rust state?
| jacquesm wrote:
| it doesn't 'only' use electricity, it uses hydrogen for the
| reduction process, and the hydrogen can be made using
| electricity.
|
| As for the second: you don't recast it as pig iron, you keep it
| in its fragment state.
| LordHeini wrote:
| Using hydrogen would make no sense whatsoever since hydrogen
| could be stored anyway.
|
| "fragment state" is something that does not exists.
|
| You got a large vessel of molten iron, you pour that into a
| form, take the slack off and that is it.
|
| Maybe one could use a fall tower to make small iron pellets
| like the ones used for making lead shot.
|
| That would need to be done in an oxygen free environment
| using some inert gas.
|
| The whole process seems quite impractical.
|
| And something else: Pure Iron rusts quite easily so how do
| you store it? You can not store a large bucket full of iron
| pellets for your oven in a cellar.
|
| So storage would need an enclosed container.
|
| The whole idea is just weird.
| jacquesm wrote:
| > Using hydrogen would make no sense whatsoever since
| hydrogen could be stored anyway.
|
| Storing and using hydrogen to turn it back to electricity
| at scale is not a simple problem (see my other comment in
| this thread).
|
| > "fragment state" is something that does not exists.
|
| In the article they are pretty clear about using very small
| particulate, both for the 'pure' state as well as for the
| 'burned' state.
|
| > You got a large vessel of molten iron, you pour that into
| a form, take the slack off and that is it.
|
| This has absolutely nothing to do with the process as
| described in the article, you are discussing the casting of
| pig iron, here we are talking about an oxidization and a
| reduction process based on powder sized grains of iron.
|
| > Maybe one could use a fall tower to make small iron
| pellets like the ones used for making lead shot. > That
| would need to be done in an oxygen free environment using
| some inert gas.
|
| This also has absolutely nothing to do with the process as
| described in the article.
|
| > The whole process seems quite impractical.
|
| That's the problem with strawmen.
|
| > And something else: Pure Iron rusts quite easily so how
| do you store it? You can not store a large bucket full of
| iron pellets for your oven in a cellar. > So storage would
| need an enclosed container.
|
| Yes, like the storage for any other kind of fuel.
|
| > The whole idea is just weird.
|
| It's weird because you don't appear to understand the first
| principles of the process described in the article, which
| is already operating at a smaller scale and which they will
| now scale up to 5 MW to gather more data about costs and
| scaling efficiency.
|
| >
| RandomLensman wrote:
| Why not use silicon? SiO2 is plenty where there is sunshine:
| create silicon power, ship, burn, dispose of sand... Definitely
| more energy per kg and probably also per volume
| jacquesm wrote:
| Because it isn't a closed cycle, so you need a continuous
| stream of bulk materials in and out.
| rocqua wrote:
| As per [this random image google spat
| out](https://www.researchgate.net/figure/Energy-storage-
| capacity-...) this is about 50% efficient. Which I think is the
| same round-trip efficiency for hydrogen. With higher efficiencies
| if not the full capacity is used.
|
| Might be a nice alternative for storage of energy surpluses,
| because storage is dense in terms of volume, and storage is not
| complicated by storage tanks and massive pressures.
| leoedin wrote:
| Combustion based energy generation is a pretty well understood
| process at this point - so we have very good numbers for
| efficiency. The absolute best efficiency we can get out of
| hydrocarbons - using combined cycle gas turbines - is about
| 60%. Given that iron would probably have to be combusted
| externally (similar to coal) you'd expect similar thermodynamic
| efficiencies - the best coal plants are about 42% efficient.
|
| So I'd expect the closed cycle efficiency of this to be at best
| 42% - assuming a 100% efficient regeneration phase (highly
| unlikely). It's probably more like 20% or less.
|
| Poor efficiency for energy storage isn't necessarily a
| dealbreaker - if the capital cost per kWh stored is low then it
| may still have a place in the mix - but it's unlikely to be a
| silver bullet.
| jl6 wrote:
| Personally I think it's a great idea to have lots of energy
| storage options each with slightly different tradeoffs for
| use in slightly different niches.
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