Efficiency is quite low: 40%-60%. I would say it's only worth it if the marginal cost of producing the hydrogen is close to 0.
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Iron as an inexpensive storage medium for hydrogen
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Re: Iron as an inexpensive storage medium for hydrogen
#32Efficiency is quite low: 40%-60%. I would say it's only worth it if the marginal cost of producing the hydrogen is close to 0.
This not a problem at all when using PV. Plus, the generated heat can be used.
Re: Iron as an inexpensive storage medium for hydrogen
#33Efficiency is quite low: 40%-60%. I would say it's only worth it if the marginal cost of producing the hydrogen is close to 0.
Cut down for another 60%-80% efficiency for producing the hydrogen.
https://www.sciencedirect.com/science/article/pii/S136403212...
Unless you also have a nuclear reactor to perform the high-temperature electrolysis process. https://en.wikipedia.org/wiki/High-temperature_electrolysis
Which only Japan seems to be working on building at the moment. https://www.hydrogeninsight.com/production/japan-plans-hydro...
It's cool tech, and I like that it's researched. But I think it's not a breakthrough that could realistically help the grid at the moment.
Re: Iron as an inexpensive storage medium for hydrogen
#34At scale, what I don’t get is this requires a lot of energy to kickstart the reaction (heating the iron ore to 400 degrees). Where is that energy coming from when energy production is constrained in winter. Or would the plan be to slowly heat over fall?
The right question is what the efficiency of this process is. End to end, not just the charging/discharging. Both charging and discharging seems to require a lot of heat. Waste heat is essentially lost energy that is released in the form of heat. I assume the discharge reaction is exothermic. That would be the energy stored in the summer months. Heating up a lot of tons of iron during charging is also not going to be…
would you mind explicitly listing the 4 conversions?
I see:
1) generation 2) storage efficiency (energy while storing divided by energy upon release)
what are the other 2 you had in mind?
Re: Iron as an inexpensive storage medium for hydrogen
#35[deleted]
Re: Iron as an inexpensive storage medium for hydrogen
#36production and conversion are inefficient compared to other sources of energy, as up to 60 percent of its energy is lost in the process.
Lost, as in turned into heat? Is it possible to capture that heat during production and conversion, and use it to run a turbine?
In winter I think the plan is to use the heat for district heating.
(which is also kinda interesting since in parts of Switzerland district heating through waste management facilities starts to be a problem due to a reduction of the amount of waste available)
Re: Iron as an inexpensive storage medium for hydrogen
#37Re: Iron as an inexpensive storage medium for hydrogen
#38Efficiency is quite low: 40%-60%. I would say it's only worth it if the marginal cost of producing the hydrogen is close to 0.
This not a problem at all when using PV. Plus, the generated heat can be used.
The issue is that it's a self-defeating mechanism. PV doesn't produce zero energy during wintertime, they just produce less. You're going to be building additional PV to charge the Season Battery, but those additional panels will also be providing power during the winter.
If your battery's efficiency gets bad enough the added winter power from those extra panels is going to be enough to cover the winter shortage - so you don't even need the battery at all. You'd essentially just be turning a huge amount of power into heat for nothing.
Re: Iron as an inexpensive storage medium for hydrogen
#39Earlier quoted context omitted.
My immediate thought is, why not store it as peroxide? It takes more energy to make too, but at least it's liquid rocket fuel instead of gaseous rocket fuel.
I hear peroxide conversion efficiency can be as low as 30%, and concentrated peroxide is quite dangerous.
> Efficiency Admittedly, the current, non-optimized, technical trial-level efficiency of the here-built system was very low, with an overall storage efficiency of 11.4%,
So far their is even lower, though they claim a theoretical max of 79%. Storing large amounts of energy that's ready to be used is rarely not dangerous in any case. Except maybe potential energy of a tank of water on a mountain.
Re: Iron as an inexpensive storage medium for hydrogen
#40This seems to be the most important problem to be solved for a green, future grid. So I’m happy there’s a new solution shown every other month. It’s annoying that they always seem to contain some hand-wavy efficiency calculations. I think this one didn’t even consider the losses from hydrogen production? Is there a benchmark out there, of these long-term electricity storage solutions? Like: you get 1 MWh at 25 deg C,…
The focus on efficiency can be short sighted though. The whole point of storage is that the energy you sell is more expensive than the energy you buy. If the profit margin is high enough then you can afford to waste energy through inefficiency. And grids with lots of renewables will naturally have times where energy is cheap and times when it is expensive. Also, I doubt this will exist in isolation. It will probably…
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