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Iron fuel shows its mettle

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Re: Iron fuel shows its mettle

#71

Post by SmooL »

Tade0 wrote: post #50

> “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 prop…

> 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.

Re: Iron fuel shows its mettle

#72

Post by rsaesha »

jerf wrote: post #61
obblekk wrote: post #14

> 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…

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 p…

>Earth is a big ball of iron.

No it's not.

Inside the crust both Si and Al are more common.

There is plenty of Fe, which is all in oxide form. Mining and processing required.

Re: Iron fuel shows its mettle

#73

Post by marcosdumay »

jerf wrote: post #61
obblekk wrote: post #14

> 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…

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 p…

> 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.

Re: Iron fuel shows its mettle

#74

Post by fnordpiglet »

Tade0 wrote: post #50

> “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 prop…

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.

Re: Iron fuel shows its mettle

#75

Post by red-iron-pine »

kinnth wrote: post #23
intothemild wrote: post #16

Earlier quoted context omitted.

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. Why not just skip the middleman? Use renewables?

Renewables are exceedingly bad at storing energy for times when sun or wind isn't blowing so you always need a mix.

That's not a wind or sun problem, that's a battery and transmission problem.

Re: Iron fuel shows its mettle

#77

Post by kaliszad »

PaulHoule wrote: post #52
juujian wrote: post #25

Earlier quoted context omitted.

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…

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: https://en.wikipedia.org/wiki/Spin_isomers_of_hydrogen freshly liquefied hydrogen contains a lot of stored energy in that form which will…

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.

Re: Iron fuel shows its mettle

#78

Post by mirekrusin »

obblekk wrote: post #14

> 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…

Can't you just make pulsating/spinning magnet to capture it?

Re: Iron fuel shows its mettle

#79

Post by rsaesha »

hn_throwaway_99 wrote: post #62
balaga01 wrote: post #29

Earlier quoted context omitted.

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…

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.
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