[HN Gopher] Energy Dome's approach to long-duration energy storage
___________________________________________________________________
Energy Dome's approach to long-duration energy storage
Author : colincooke
Score : 39 points
Date : 2022-06-28 19:22 UTC (3 hours ago)
(HTM) web link (www.canarymedia.com)
(TXT) w3m dump (www.canarymedia.com)
| henearkr wrote:
| That 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 wrote:
| Capturing co2 from air is a waste of energy as long as there
| are chimneys discharging the stuff by the ton.
| henearkr wrote:
| I 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
| for all emitters, it 's just that I think that a partial PSCC
| is a bad path)_
| driest wrote:
| sorry 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-batte...
|
| citing from this: "In Energy Dome's system, carbon dioxide is
| compressed at a pressure of 60 bar which heats the gas to 300degC
| 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 290-300degC causing the stored heat."
| SkyPuncher wrote:
| The trade-off here is these seem to be substantially simpler
| and cheaper than batteries. No fancy metals, no wear cycles, no
| risk of spontaneous fire. In fact, the up-front environment
| impacts seem significantly less than that of battery storage.
| These are still a good solution when the power supply you're
| using is in excess - as is common with most natural sources
| (solar, wind, hydro, etc).
|
| Lastly, it's worth remembering that not everything is competing
| against an "optimal" solution. This may be a _very_ viable
| system for infrastructure that simply sheds excess energy.
| Shedding of excess energy results in 0% efficiency gains.
| Additionally, this type of storage potentially offsets the need
| to run a secondary system for peak/off-cycle loads. That in
| itself can be a massive energy savings.
|
| -----
|
| Finally, it seems that power plants are actually terribly
| inefficient at converting an energy source to electric. Coal -
| 33%, gas - 42%, and combined cycle - 60%.
|
| http://needtoknow.nas.edu/energy/energy-sources/fossil-
| fuels....
| Animats wrote:
| _storing the thermal energy from the compression process._
|
| They're not storing heat. They're dumping the heat, and store
| liquid CO2 near ambient air temperature. Here's some analysis
| of CO2 liquefaction cost, from an unrelated project.[1] You can
| have multiple stages of compression, with heat exchangers
| between them to get the temperature down. How to set this up is
| a good homework problem in thermodynamics.
|
| It's not clear if this is profitable, but it's a lot better
| than some of the other ideas. Ones such as the crane and
| concrete block thing, or the electric trains full of rocks on a
| hill thing, or the giant rock cylinder with water underneath
| thing.
|
| [1]
| https://www.researchgate.net/publication/293044124_Simulatio...
| googlryas wrote:
| But heat loss improves as the product is scaled up(heat loss is
| function of surface area, whereas total heat is a function of
| volume, which grows quicker than surface area), so at a certain
| point you could make this big enough to let you store energy
| efficiently on a seasonal basis?
|
| Also the same reason elephants can't have metabolisms as fast
| as mice, or else they would spontaneously combust.
| [deleted]
| jackmott42 wrote:
| Do 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?
| sschueller wrote:
| Is this any more effective than just pumping water into a higher
| reservior? It seems like a lot of stuff can fail here.
| rr888 wrote:
| Anyone 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.
| chomp wrote:
| > 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
|
| 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.
| cwp wrote:
| > 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]
| jefurii wrote:
| "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."
| elric wrote:
| What 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.
| nrdgrrrl wrote:
| tatersolid wrote:
| Isn'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...
| Invictus0 wrote:
| Summary:
|
| > 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 wrote:
| Huh. I wonder if that CO2 gets released.
| henearkr wrote:
| It 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 wrote:
| > 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.
| henearkr wrote:
| My solution (to use exclusively DAC for the CO2 supply)
| looks like _that_ difficult to you? I really think it is
| the best way to go.
|
| It is different, in my opinion, to emit CO2 to create
| material goods that will last, and to create CO2 _for
| itself_ that maybe will be vented for maintenance and
| will need to be refilled.
| phire wrote:
| No, they need to keep the CO2 gas pure, so they can
| pressurize it again.
|
| That's what the dome is for, storing the uncompressed gas.
| Presumably there is a much smaller metal pressure vessel for
| storing the liquid CO2.
| ok_dad wrote:
| 10 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.
| SideburnsOfDoom wrote:
| As 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?
| aidenn0 wrote:
| The 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 wrote:
| They are turning c02 from a gas into liquid form. So I assume
| they can store it indefinitely.
| laurencerowe wrote:
| I 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.
| dataangel wrote:
| there'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
| sacred_numbers wrote:
| I 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.
| karmajunkie wrote:
| I 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.
| sydthrowaway wrote:
| It will be us Europeans that save us all, rather than the
| Americans stumbling overthemselves chasing clicks.
| dang wrote:
| We've banned this account for repeatedly posting unsubstantive
| and flamebait comments. Please don't create accounts to do that
| on HN.
|
| If you don't want to be banned, you're welcome to email
| hn@ycombinator.com and give us reason to believe that you'll
| follow the rules in the future. They're here:
| https://news.ycombinator.com/newsguidelines.html.
| binbag wrote:
| 75% is an awfully round number for efficiency!
| _ph_ wrote:
| Its worse than batteries, but basically on top of everything
| else. Pumped storage is about the same, hydrogen, power2gas,
| all worse.
| nostromo wrote:
| I 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%.
| leecarraher wrote:
| I 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.
| api wrote:
| The 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.
| tomohawk wrote:
| Neat. 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.
___________________________________________________________________
(page generated 2022-06-28 23:00 UTC)