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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.
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 accura…
"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.”"
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.
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…
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.
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 accura…
The article says this. It wraps up with: "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 transmis…
Why not just skip the middleman? Use renewables?
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 accura…
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?
> 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…