10 ms·
Energy Dome’s approach to long-duration energy storage
- ok_dad 4y ago10 hours of discharge time (20 MW power peak with 200MWh energy storage) is good, but not "long term" to me. It is barely sufficient for storing solar/wind overnight. "Long term energy storage" to me is several days or more at peak power. I'm excited for all these different methods, though, because unlocking energy storage is key to reducing carbon emissions, since most of the base load is from carbon emitting power sources. Edit: I clarified that I meant the amount of energy stored not how long the gasses themselves can be stored. "Long term energy storage", to me, should be defined as being able to discharge at max power for like a day or more, and this tech is more "medium term" storage, again in my opinion.
- karmajunkie 4y agoI guess depending on the storage mechanism, the length of stored time isn't really an area of concern. I routinely store full propane tanks for months, for example. Its a significantly smaller molecule but I would think similar timescales could be achieved with CO2.
- aidenn0 4y agoThe plant they are building can store 10 hours worth of electricity at maximum delivery power (200MWh @ 20MW). TFA does not say how long they can store the electricity for.
- Flozzin 4y agoThey are turning c02 from a gas into liquid form. So I assume they can store it indefinitely.
- laurencerowe 4y agoI expect it becomes financially unviable if they end up storing it for long. Daily charge/discharge allows them to amortize their annual cost of capital across 365 cycles. Weekly or seasonal storage is going to be much less cost effective.
- aidenn0 4y agoCalm, cloudy days do happen, so we either need seasonal storage, or need to be okay with much less electricity on such days.
- SideburnsOfDoom 4y agoAs per the headline, it's "long-duration storage" meaning that you can potentially wait a while (days, weeks) before that discharge of stored energy. From the article: "many hours up to many days" > "Long term energy storage", to me, should be defined as being able to discharge at max power for like a day or more, "Long term money storage" should be defined as storing more than $10 000 - yes, no, or irrelevant?
- ok_dad 4y ago> “Long term money storage" should be defined as storing more than $10 000 - yes, no, or irrelevant? Your example should be more like “a long term emergency savings is 6 months of your budget” vs. “a short term emergency savings is 2 months of your budget”
- dataangel 4y agothere's a guy on Twitter that runs sims of Australia's power usage that claims 5 hours of storage is enough for year round use of renewables so 10 hours could be a big deal
- ok_dad 4y agoLink? Overnight you would need “length of night time” as the minimum capacity for a grid to support zero carbon base generation, assuming all renewables, so he must be using a value with carbon base generation support, I’m assuming we need even more storage when we eliminate carbon base generation.
- imtringued 4y agoI don't know what you mean by carbon base generation. You need to compensate for shortfalls in renewable production.
- sacred_numbers 4y agoI have never understood that sentiment. If you define long term energy storage as being able to discharge at max power for a day or a week you are penalizing superior storage technologies for no reason. Let's say that you have two technologies that have the same cost per KWh, the same round-trip efficiencies, etc. Now let's assume one of them has a maximum discharge rate of C/100 so that at maximum power it lasts for 100 hours. Let's assume the other technology has a maximum discharge rate of 1C, so at maximum power it lasts for 1 hour. For the same price, you could have either a system that only works for long term storage or a system that would be considered "short term" storage even though it has the same capacity and the same price as the long term option. There may be some exceptions, but generally whenever you have short term storage you automatically have the option of long term storage as well by just discharging at a lower rate.
- ok_dad 4y agoSure, but I’m in the industry and it’s standard to talk about hours of storage based on the power max and energy capacity.
- Invictus0 4y agoSummary: > Energy Dome’s novel approach to long-duration energy storage dispenses with batteries altogether. Instead, the company erects enclosures that resemble tennis bubbles and fills them with carbon dioxide gas. Excess electricity can be used to pressurize the gas into liquid form, storing energy; turning the liquid back into a gas releases that energy, turning a turbine and regenerating electricity. > As detailed in Canary Media’s previous reporting, this approach has a few advantages relative to other long-duration storage attempts: > It uses off-the-shelf equipment from mature industrial supply chains. That means Energy Dome doesn’t need to build its own factory, a capital-intensive step that other long-duration startups needed to do. It also means Energy Dome doesn’t need to spend years on laboratory science — it just needs to prove that the equipment all works together the way it’s supposed to. > The dome is supposed to deliver round-trip efficiency of 75 percent, meaning 75 percent of the energy that goes into the process comes back out at the end. That’s less than typical battery efficiency but a lot better than many long-duration storage contenders. > Carbon dioxide is easier to compress and store at ambient temperature and atmospheric pressure compared to other gaseous storage vehicles, like hydrogen or air.
- foobarian 4y agoHuh. I wonder if that CO2 gets released.
- henearkr 4y agoIt looks like it's captive in the big bubble even in decompressed form, however I think it is always a bad idea to create more CO2 on purpose (it can be released by accident or for maintenance), which is why I really hope this startup can work hand-in-hand with direct-air-capture facilities.
- nomel 4y ago> however I think it is always a bad idea to create more CO2 on purpose If the net CO2 generated is reduced significantly, then it's a net good thing. CO2 is a byproduct of all sorts of industrial processes that we depend on, so I don't think they'll have a problem finding a supply.
- sydthrowaway 4y ago
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- binbag 4y ago75% is an awfully round number for efficiency!
- _ph_ 4y agoIts worse than batteries, but basically on top of everything else. Pumped storage is about the same, hydrogen, power2gas, all worse.
- nostromo 4y agoI tend to trust round numbers more than other numbers for this very reason... When people make up stats, they use numbers like 63% or 87%, not 75%.
- kumarvvr 4y agoYeah, but this can scale up.
- leecarraher 4y agoI wish they had data on the estimated cost to build and operate. Best i can guess is that $11M might get them 200Megawatt/hours -> $0.055 per watt hour which would be cheaper than any chemical battery based energy storage, albeit at the cost of reduced efficiency (75% vs 95% for lithium-ion). This is similar to pump storage, but less geographically dependent.
- ncmncm 4y agoCost is central to viability. Cheapest storage wins. But there are a lot of different costs: capex and opex cost per kWh to store energy, capex and opex cost per kW to bank energy, capex and opex cost per kW to extract energy, cost for conversion losses, cost for banked energy losses, plus extra specific costs and sometimes specific benefits. Some of those costs will change radically with time as circumstances change; cost for conversion losses of all methods will fall as top line generation gets cheaper. This is why synthetic fuels will be so important, despite low efficiency and high capital cost: the "specific benefits" exceed those. Operating this thing via captured CO2, and feeding hydrocarbon synthesis and carbon sequestration, might improve its viability.
- henearkr 4y agoThat makes me chuckle that they use CO2. It would look like a good idea only if they somehow compel their customers to buy only CO2 coming from a direct-air-capture facility. Or even better, if they attach a small direct-air-capture device to their "bubble". (it would not need to be extremely efficient, as I understand that the CO2 is then captive of the storage [I'd add... in a normal operation mode... because we never know what can happen with incidents and that's why I push for DAC before it's too late and it's already everywhere])
- lolc 4y agoCapturing co2 from air is a waste of energy as long as there are chimneys discharging the stuff by the ton.
- henearkr 4y agoI agree, but wouldn't a partial PSCC (point source carbon capture) also legitimize the polluting industries? (I'm assuming here that not all of their emitted CO2 is long-term stored, otherwise of course that also solves another problem) Can we both fight for the disappearance of the chimneys, and depend on them? At the very least, we need to be ready for the absence of these chimneys as if it could happen overnight, for the simple reason that we really need for it to happen overnight (it won't, but that's bad, and we need to keep thinking it's bad). (I precise: I would be completely in favor of a total PSCC, it's just that I think that a partial PSCC for any chimney is a bad path)
- euroderf 4y agoTry looking at it this way: One CO2 capture is operational at scale, the price of its capture becomes a known quantity, and this can be used as a price point for determining a general carbon tax.
- lolc 4y agoThe original comment suggested to use CO2 captured from air for the storage facilities. Yet takes more energy to remove CO2 from the atmosphere than to remove it from exhaust. We'd be burning coal to extract CO2 from the air!
- api 4y agoThe nice thing about this is that it requires nothing even as exotic as batteries. It seems like you can build it out of off the shelf stuff.
- ncmncm 4y agoBatteries are always the most expensive storage. You use those where round-trip efficiency matters more than cost.
- rr888 4y agoAnyone know of a reason why they dont use air? or even Nitrogen. EDIT I guess compressing to liquid, CO2 can be stable at <31 deg C at 5ATMs which is what they use. Liquid Nitrogen has to be kept very cold, even under pressure.
- cwp 4y ago> Carbon dioxide is easier to compress and store at ambient temperature and atmospheric pressure compared to other gaseous storage vehicles, like hydrogen or air.
- deleted 4y ago[deleted]
- chomp 4y ago> Carbon dioxide is easier to compress and store at ambient temperature and atmospheric pressure compared to other gaseous storage vehicles, like hydrogen or air. CO2 phase diagram: https://www.wolframalpha.com/input?i=co2+phase+diagram https://www.wolframalpha.com/input?i=co2+phase+diagram Nitrogen phase diagram: https://www.wolframalpha.com/input/?i=nitrogen+phase+diagram https://www.wolframalpha.com/input/?i=nitrogen+phase+diagram You can see that CO2 is way more reasonable to store liquid at ambient temps.
- ncmncm 4y agoA utility-scale project under construction in Chile banks liquid nitrogen and heat. Insulated low-pressure tankage is cheap. It will be interesting which will turn out more practical.
- elric 4y agoWhat happens if the dome ruptures and suddenly releases all its CO2 into the surrounding air? Will it hang around long enough to be dangerous for people (or other living things which like to breathe). Given that they're cycling between gaseous and liquid states, there's presumably quite a bit of CO2 involved.
- tatersolid 4y agoIsn’t this setup a giant BLEVE-bomb? Where will these be built? Shouldn’t they be buried rather than surface domes? https://en.wikipedia.org/wiki/Boiling_liquid_expanding_vapor_explosion https://en.wikipedia.org/wiki/Boiling_liquid_expanding_vapor...
- mikewarot 4y agoBLEVE explosions are caused by a positive feedback loop between escaping vapor combusting and then feeding more heat back into a container, causing a further rise in temperature. CO2 isn't combustible, and if it were to vent, it would lower the temperature, not raise it.
- tatersolid 4y ago200MWh is equivalent to about 860kg of TNT. That’s a pretty big boom if your pressure vessel fails catastrophically, even without any combustion.
- bouvin 4y agoAccording to other posters, liquid CO₂ can be stored at 5 atm pressure which is trivial from an engineering POW.
- driest 4y agosorry to disappoint, but this article glosses over a pretty significant constraint that prevents this from being long-term storage at all: storing the thermal energy from the compression process. storing thermal energy over long periods of time is a pretty lossy process, and that 75% efficiency number will be out the window if one tried to use this system for seasonal storage. this system fills the same space as battery storage, which it is also marketed for (over night storage for solar power). here is a more detailed post on the matter: https://www.rechargenews.com/energy-transition/new-co2-battery-will-make-wind-and-solar-dispatchable-at-an-unprecedented-low-price/2-1-1044755 https://www.rechargenews.com/energy-transition/new-co2-batte... citing from this: "In Energy Dome’s system, carbon dioxide is compressed at a pressure of 60 bar which heats the gas to 300°C liquid. The heat is then extracted and stored in “bricks” made of steel shot and quartzite for later use, cooling down the CO2 to an ambient temperature. The gas is then condensed into liquid form and stored in carbon-steel tanks. ‘Our lithium-ion battery will have double the energy density of standard Li-ion for same price’ When electricity is required, the liquid CO2 is run through an evaporator to turn it back to a pressurised gas, which is then warmed up back to 290-300°C causing the stored heat."
- deleted 4y ago[deleted]
- jackmott42 4y agoDo we need to store energy seasonally to make big strides in increasing the share of solar and wind on the grid? Or only daily/weekly?
- driest 4y agois that relevant? the premise of the article was "long term storage", and my comment aimed at putting that into perspective.
- ncmncm 4y agoA week or two is the longest almost anybody should need to bank energy. Mostly you just need a few hours of high-efficiency storage to maintain local resiliency. Beyond, say, the 4 hours' worth cycled every night, round trip efficiency matters little. Beyond a week, burning liquified ammonia imported from tropical solar farms wins. Probably you keep a week's worth of that on hand to burn while you wait. There is no need for storage (beyond use for load-leveling and peak shaving) until after renewable generating capacity is overbuilt enough to charge it from. (The alternative would be to recharge storage by burning NG: You would better burn that NG and deliver the power to users instead of drawing down and then recharging storage from it.) Until then, capital is better spent building more renewable generating capacity itself, displacing more coal, than on storage. But building the factories that will build the storage that will someday be needed should happen now, because we will need a lot, and making automated factories takes a long time. And that is happening. Some of those may end up idle as cheaper methods replace theirs, but for at least a few decades, demand will be insatiable.
- sschueller 4y agoIs this any more effective than just pumping water into a higher reservior? It seems like a lot of stuff can fail here.
- danans 4y ago> Is this any more effective than just pumping water into a higher reservior? Many places don't have a lower and higher reservior needed for pumped hydro. This can be sited almost anywhere.
- ncmncm 4y agoPumped hydro mostly just needs a hill. But building the dikes might cost more than building liquid CO2 tankage, for a given storage capacity. It will all come down to what is cheapest, overall. That will take time to learn. If opex is cheap, a more expensive will remain equally useful as a method that turns out, eventually, to be cheaper to build.
- tomohawk 4y agoNeat. It's like a hydraulic hybrid for the grid. Hydraulic hybrid vehicles recapture 75% to 80% of braking energy for reuse, which compares very favorably to electric batteries. Something like this paired with intermittent sources like solar and wind could make them viable.
- ncmncm 4y agoThey are already viable. This thing will displace NG turbine back-up. Or, in volume, whatever turns out cheapest will. Zero opex will beat mined and transported NG pretty quickly once enough renewables + storage is built out.
- tomohawk 4y agoThey are only viable when paired with other systems to make up for the times when the sun is not shining or the wind is not blowing within spec. A system like this makes a nice pairing, but then you need double the capacity of intermittent since when it is working it needs to not only feed the load, it also needs to feed the storage. It's not long term storage, though, like diesel, gas, coal. Those can sit around for a really long time. EDIT Actually, since the system is 75% efficient, you will need more than double the intermittents.
- ncmncm 4y agoNo, they are viable right now: they are deployed right now, and are in use right now. During times that they do not produce, other methods will continue to be used. NG will be decreasingly viable as it becomes unable to compete with local storage, transmission lines, and finally imported synthetics. Nukes will be wholly unable to compete. They will all be mothballed, even the new ones, anywhere that government has not mandated that they be kept operating, and coerced funding for that from a captive market or taxes (as now). Such coercion will become increasingly unpopular. It is not clear whether geothermal will be able to compete. If so, and if with new technology it becomes practical in more areas, it will be in the mix with everything else. Geothermal is very unlikely ever to become as cheap as solar, but might not be displaced by imported synthetic ammonia. There will of course be plenty of overbuild, in places. But with the transportability of synthetic fuel and grid power, that need not be anywhere close to what you would need for a wholly independent site. Long-distance transmission lines will favor overbuild where capacity factors are higher, but falling cost will favor local overbuild. Anhydrous ammonia stored at a few atmospheres keeps indefinitely. Hydrogen stored underground keeps indefinitely.
- jefurii 4y ago"It was designed according to ancient ziggurat mound proportions used in votive worship. Like the mounds it collects energy and recirculates it. In this case the Dome collects the Orgone energy that escapes from the crown of the human head and pushes it back into the Medulla Oblongata for increased mental energy. It's very important that you use the foam insert...or better yet, get a plastic hardhat liner, adjust it to your head size and affix it with duct tape or Super Glue to the inside of the Dome. This allows the Dome to "float" just above the cranium and thus do its job. Unfortunately, sans foam insert or hardhat liner, the recirculation of energy WILL NOT occur."
- kevin_b_er 4y agoThis is an odd quote, so I had to look it up. This quote appears to be related to this piece of headwear: https://weburbanist.com/2013/06/30/ziggurat-hat-deconstructing-the-devo-energy-dome/ https://weburbanist.com/2013/06/30/ziggurat-hat-deconstructi... The headwear and the energy storage company appear completely unrelated aside from the name chosen.
- jefurii 4y agoYep, it's a quote describing the Energy Dome hat worn by members of the visionary/weird music group Devo. It's not completely unrelated -- they do have the same name.
- mikewarot 4y agoIt's not perfect, it it's not a scam, and has a reasonable round-trip efficiency at scale big enough to be useful. This will be helpful in our transition away from liquid fossil fuels.
- credit_guy 4y agoNo such type of idea will ever work. Because by definition, any long term storage solution will be able to sell energy and make a profit only a few number of times, and won't be able to recoup its CAPEX expenditure. Let's say that by long term you mean 6 months (the typical period envisioned, i.e. you charge during the Summer months, and sell during the Winter months). Then you'll be able to sell energy once a year. If your system has a lifetime of 20 years, then you need the CAPEX to be only 20 times higher than the annual profit. Let's further say you charge during Summer at zero cost, and sell during Winter at 40 cents/kWh (this is about 3 times the average cost of electricity in the US for 2021). Then the cost of this system should not be more than $8/kWh. For comparison the cost of a Tesla Powerpack is about $700 /kWh [1]. So for any system to have any hope to be "long term storage solution" it needs to be 100 times cheaper than the Tesla Powerpack. In reality it needs to be about 1000 times cheaper, due to numerous other factors: less than 100% round-trip efficiency, the high cost of financing (driven by the significant risk of the project, which is driven by the huge uncertainty regarding future potential competing technologies, such as Hydrogen), operating and insurance costs, etc. There is a way to solve the long term storage system. You need to solve the apparent paradox that if your system is designed to be long term, then you can't buy and sell very frequently. Here's how you solve it: you buy and sell in different markets. You buy (solar) electricity in Morocco pretty much all year long, convert it to Hydrogen, or some other form of chemical storage (ammonia, hydrogen peroxide, methanol, synfuel), and ship that to Germany, where it is converted to electricity, again all year long. This way, you buy every single day and sell every single day. You are able to recoup your CAPEX costs, and make a handsome profit. There are no other ways to solve the long term storage problem. The EU knows that, and this is why it is betting so heavily on Hydrogen. [1] https://electrek.co/2020/03/31/tesla-powerpack-price-commercial-solar/ https://electrek.co/2020/03/31/tesla-powerpack-price-commerc...
- ncmncm 4y agoStorage beyond a week or two will not be needed, most places. But storage for between four hours' peak usage and there needs to be cheaper than batteries. That is where schemes like this will compete. A pure storage play using does not need to be viable. Utilities will integrate generating capacity and storage to deliver on service level agreements. But synthetic hydrogen and ammonia shipped around will be a huge market, not least because they are massively useful for other than for banking energy.
- kumarvvr 4y agoJust curious. How much liquid CO2 will be required for storing the energy mentioned in the article?