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> “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 witho
by Tade0 3y ago
> “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.
- chasil 3y ago"Altiro gets around this problem by adding a little natural gas to ignite the iron powder when the boiler first starts up." You will also need a very specialized furnace, and supplies of CH4.
- Tade0 3y agoI 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.
- samus 3y agoThe 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.
- deleted 3y ago[deleted]
- SmooL 3y ago> 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.
- rootusrootus 3y ago> not good enough for grid-scale requirements 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.
- dgacmu 3y agoBatteries 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.
- xyzzyz 3y agoThere 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.
- gpm 3y agoFor anyone wondering List of pumped-storage hydroelectric power stations https://en.wikipedia.org/wiki/List_of_pumped-storage_hydroelectric_power_stations https://en.wikipedia.org/wiki/List_of_pumped-storage_hydroel... List of (non-hydro) energy storage power plants https://en.wikipedia.org/wiki/List_of_energy_storage_power_plants https://en.wikipedia.org/wiki/List_of_energy_storage_power_p... Largest battery plants in particular: https://en.wikipedia.org/wiki/Battery_storage_power_station#Largest_grid_batteries https://en.wikipedia.org/wiki/Battery_storage_power_station#... "Really small capacity" here apparently means "roughly 4 hours of discharging as fast as possible".
- fnordpiglet 3y agoIceland 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.
- caseyohara 3y agoIt'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.
- euroderf 3y agoI'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.
- Tagbert 3y agoAccording to: https://www.lehighcounty.org/Departments/Solid-waste-management/recycling-facts/Aluminum#:~:text=Aluminum%20Facts,%25%20post%2Dconsumer%20recycled%20aluminum https://www.lehighcounty.org/Departments/Solid-waste-managem.... "About 65 % of America's aluminum is currently recycled." That's pretty good. Much better than most materials.
- euroderf 3y agoA national can deposit mandate might help eh.
- elil17 3y agoTransmission 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.
- ben_w 3y agoYeah. Article says energy density of 11.3 kWh/litre. WolframAlpha says using that for all global electricity for a day is 33e9 kg iron: http://www.wolframalpha.com/input/?i=2%20TW%20%2A%201%20day%20%2F%2011.3%20kWh%2Flitre%20%2A%20density%20iron http://www.wolframalpha.com/input/?i=2%20TW%20%2A%201%20day%... Some estimates I did a while back and then wrote up nicely with ChatGPT said a global power grid would use about x100 that much iron: https://github.com/BenWheatley/Studies-of-AI/blob/main/Global%20power%20grid/raw-chatGPT-session.md https://github.com/BenWheatley/Studies-of-AI/blob/main/Globa... 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.
- _hypx 3y agoPipelines 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.
- lll-o-lll 3y agoHow 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.
- _hypx 3y agoBecause 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.
- lll-o-lll 3y agoWell, 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.
- bioemerl 3y agoWhat if the place with excess energy is America in the place was not enough is Europe?
- garyclarke27 3y agoAs you say weight is the issue. Iron is not a good solution for moving energy because it is so heavy. Aluminium would be a much better solution. See interesting chart of energy densities by weight and volume. https://en.wikipedia.org/wiki/Energy_density#/media/File:Energy_density.svg https://en.wikipedia.org/wiki/Energy_density#/media/File:Ene...