[HN Gopher] Highview Developing 50MW/500MWh Liquid Air Energy St...
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       Highview Developing 50MW/500MWh Liquid Air Energy Storage Facility
       in Chile
        
       Author : kieranmaine
       Score  : 80 points
       Date   : 2021-07-05 11:20 UTC (11 hours ago)
        
 (HTM) web link (highviewpower.com)
 (TXT) w3m dump (highviewpower.com)
        
       | BurningFrog wrote:
       | Couldn't find anything describing any details of the actual
       | technology, even in the FAQ (https://highviewpower.com/faq/).
       | 
       | Mostly wondering where and how they store the liquid air. Metal
       | tanks? Underground caverns?
        
         | ncmncm wrote:
         | Metal tanks. Liquified air is pretty compact. Probably, as the
         | tech matures they will move to burying them, and the heat
         | reservoirs too. For a pilot plant, keeping everything exposed
         | and maintainable is important.
         | 
         | As they get bigger, storing the heat removed in molten salt
         | might prove useful.
         | 
         | The tradeoff of excellent underground insulation vs.
         | accessibility for maintenance is tricky. For the case of molten
         | salt, expectation of corrosion complicates it further.
         | 
         | With any luck, plummeting aerogel insulation cost will make the
         | question moot.
        
       | driverdan wrote:
       | This press release doesn't say anything about system efficiency.
       | If it was high they'd be promoting that fact. Since it involves
       | refrigeration it's probably quite low. That makes me wonder why
       | they went with this system.
        
         | rsynnott wrote:
         | They claim 70%:
         | https://en.wikipedia.org/wiki/Cryogenic_energy_storage#Effic...
         | 
         | > That makes me wonder why they went with this system.
         | 
         | Cost, presumably. The stated figures would give $300/kWh, which
         | seems to be about where the all-in cost for lithium ion
         | facilities lands, but this would likely have a longer lifespan.
        
           | Gibbon1 wrote:
           | Offhand impression. With thermal storage systems. Round trip
           | efficiency numbers range from really bad at 50%. To really
           | good at 80%. Batteries are probably 80-90 percent efficient.
           | 
           | Notably to me is that cost per mega watt hour varies a lot
           | more than two to one. Which says to me energy storage is
           | economically feasible using a number of different
           | technlogies.
        
       | andy_ppp wrote:
       | Yes, I've wondered what the issue is with doing things like this,
       | I mean surely there's a way to do this with molten salt blocks
       | too. What is the efficiency on this and how easy is it to
       | maintain!?
        
         | Olreich wrote:
         | People are working on molten salt batteries:
         | https://ambri.com/technology/ is the only commercial one I know
         | of though.
        
         | aaron695 wrote:
         | Liquid air energy storage systems: A review (August 2021)
         | https://www.sciencedirect.com/science/article/pii/S136403212...
         | 
         | "Liquid Air Energy Storage systems have the potential to be a
         | competitive local and grid scale energy storage technology.
         | They also have the potential to facilitate the penetration of
         | renewable energy technologies. However, there is a clear
         | disconnect between what has been proven in literature, and what
         | has been demonstrated in practice."
        
           | mattashii wrote:
           | > August 2021
           | 
           | I'm very concerned with the credibility of that source based
           | on this alone. Unpublished and/or future-dated articles are
           | to be taken with a pile of salt.
        
             | asah wrote:
             | molten salt? ;-)
        
             | patall wrote:
             | What you are seeing is the online preview, August 2021 is
             | when it appears in print.
             | 
             | This kind of publishing is becoming more and more common,
             | most likely to boost the journals impact factor (average
             | number of citation within 2 years of publication). It's
             | sketchy but doesn't say much about the article, only the
             | journal.
        
               | epistasis wrote:
               | Nothing sketchy about the journal either. The next issue
               | may come out in August due to the publication schedule
               | and article queue. But there's no reason to delay
               | availability of the article after it's addressed all the
               | reviewer and editorial concerns.
        
         | bob1029 wrote:
         | Molten salt is going to be way more efficient on a round-trip
         | basis. According to wikipedia, its something like 70% for
         | molten salt, and 25% for cryogenic.
         | 
         | There are likely other engineering factors involved, but those
         | efficiency figures are pretty damning on the surface.
        
           | ajnin wrote:
           | > 25% for cryogenic
           | 
           | Also from Wikipedia, the efficiency if 25% if you let the
           | heat of liquefaction and the "cold" of vaporization go to
           | waste, but it can be improved to 70% if you store that heat
           | and re-inject it in the cycle.
        
         | Cthulhu_ wrote:
         | I'd think one major issue at this scale would be heat generated
         | when pressurizing, and heat lost (= freezing) when
         | depressurizing, the latter which could cause weakness and
         | damage in any materials affected. But, I'm not a scientist or
         | anything, take this armchair take with a grain of salt -
         | there's other places where they do a lot with
         | compression/decompression at scale, e.g. natural gas storage
         | and transport.
        
       | whoknowswhat11 wrote:
       | I've pumped scuba tanks and other light pressure stuff - in those
       | applications a fair bit of energy is lost to waste heat. Curious
       | how this is handled in terms of efficiency
        
         | twobitshifter wrote:
         | Heat is the output of the depressurization process so I would
         | think that would not be a problem.
        
         | mschuster91 wrote:
         | The article is a bit light on details, but I'd guess that both
         | heat and cold generation (due to compression and decompression
         | of the air) could be used for a district cooling system.
        
         | fghorow wrote:
         | The company's "technology description" video makes clear that
         | storage of both "waste" heat and cool is an explicit part of
         | their system.
        
       | tgtweak wrote:
       | Interesting concept. At $150,000,000 for 500MwH = $300/KwH of
       | energy storage. Tesla's Megapack solution is $300/KwH also,
       | giving this a good running chance if they can get costs down with
       | scale.
       | 
       | I like that it can potentially run for decades without chemical
       | degradation, and that it is environmentally friendly since most
       | of the parts (compressors, dryers, generators, tanks) can be
       | recycled down the line with minimal environmental impact.
       | 
       | Things that seem concerning at first glance:
       | 
       | * Maintaining sub -196'C requires a lot of complex refrigeration,
       | monitoring and pressurization equipment, which can be prone to
       | failure (see Hampson-Linde cycle). The expansion factor of liquid
       | air to air is roughly 800x.
       | 
       | * Round-trip energy efficiency: I can't see a system taking
       | electrical input to produce liquid air on the way in and
       | similarly to run a turbine generator on the other end without
       | having substantial losses both ways... I believe Tesla is around
       | 88% on their system.
       | 
       | * Gasses used in refrigeration continue to be an environmental
       | and health concern even with modern compounds.
       | 
       | Hopefully with some cost scaling or proof of longevity it can be
       | a valid solution.
       | 
       | 1. https://en.wikipedia.org/wiki/Hampson%E2%80%93Linde_cycle
        
         | asdfadsfgfdda wrote:
         | The linde cycle is not used industrially, they are using a
         | reverse brayton cycle. This cycle use air as the refrigerant,
         | and is probably the most widely distributed industrial cycle in
         | the world (because liquified gases do not transport easily).
        
         | [deleted]
        
         | boringg wrote:
         | What do they use for the refrigerant? Refrigerant leaks have
         | some of the highest green house gas potentials of all
         | compounds. Depending on the product > 2000 times global warming
         | potential of CO2.
        
           | tjoff wrote:
           | _> Depending on the product  > 2000 times global warming
           | potential of CO2._
           | 
           | Doesn't say much without any volumes attached to it.
        
             | boringg wrote:
             | Thats per unit volume. So as an example 1 tonne of HFC-23 =
             | 12400 tonne of CO2e (Carbon Dioxide Equivalence) in terms
             | of global warming potential.
        
               | tjoff wrote:
               | And what if you have 1 tonne of HFC-23 vs. 300000 tonne
               | of CO2e ?
        
           | asdfasgasdgasdg wrote:
           | I would imagine a facility like this would have much better
           | monitoring for refrigerant pressure drops than a typical
           | consumer-grade system, plus a staff onsite that would be able
           | to close valves and rapidly find and repair leaks.
        
             | IgorPartola wrote:
             | Not to be too glib, but that's what we imagined about
             | Chernobyl as well.
        
               | tw04 wrote:
               | And we were right. Chernobyl was the result of repeated
               | bad actions that people knew were bad actions at the
               | time.
               | 
               | Furthermore Chile has a democratic government, not a
               | communist dictatorship, so it's extremely unlikely for
               | something like that to occur there.
        
               | soperj wrote:
               | I don't agree with the poster, but Fukushima? 3-Mile
               | island? I don't think the democracy has anything to do
               | with it.
        
               | andromeduck wrote:
               | Fukushima and three mile island killed a combined total
               | of one person vs a hundred in the rushed, botched and
               | completely unnecessary evacuation.
               | 
               | Oil & Gas kill far more people every hour of every day.
               | 
               | If we followed your logic trains and cars and airplanes
               | would have never taken off.
        
               | pornel wrote:
               | The fact that you can name _all_ the major incidents is a
               | testament of the safety of the technology (it really is
               | -- see deaths per TWh of various technologies).
               | 
               | Fukushima was hit by an earthquake and tsunami. Most
               | deaths attributed to the Fukushima disaster were people
               | who froze to death because they couldn't afford heating
               | after electricity price hike caused by Fukushima's
               | shutdown.
               | 
               | Keep in mind that nuclear plants have been operating
               | since these incidents all over the world, without further
               | problems. There are over 440 reactors are running right
               | now. Even _the_ Chernobyl power plant kept operating the
               | remaining three reactors until the year 2000.
        
               | arcticbull wrote:
               | And even they they only, to my knowledge, shut down the
               | remaining three reactors in exchange for funding from the
               | international community for the New Safe Containment
               | sarcophagus. Nine other similar RBMK reactors have
               | continued to operate (albeit with some safety retrofits)
               | since then without incident.
        
               | IgorPartola wrote:
               | Not having a totalitarian government is a necessary but
               | not a sufficient condition to prevent covering up of
               | accidents.
        
               | arcticbull wrote:
               | Singapore is basically a totalitarian state and I'd trust
               | them with a nuclear reactor. Depends on the situation I
               | suppose.
        
               | pornel wrote:
               | This is like using Hindenburg as a caution against party
               | balloons.
        
               | staunch wrote:
               | The Hindenburg disaster should definitely serve as a
               | caution against using _hydrogen_ party balloons.
               | 
               | https://www.youtube.com/watch?v=FH5JwHeKnZo
               | 
               | https://www.youtube.com/watch?v=6DUIcCq0Hes
        
               | asdfasgasdgasdg wrote:
               | Despite your disclaimer, I do feel this is too glib. What
               | is the takeaway? Yes, a bad thing happened one time at
               | that facility (and others, at other times). That doesn't
               | have much bearing on what I said. It is still reasonable
               | to suspect that refrigerant leaks will not be a major
               | problem at this facility.
        
               | IgorPartola wrote:
               | I am saying that in general I would prefer a system
               | that's safe by design, not by the fact that there are
               | going to be people there who can make very human mistakes
               | and create a problem. It is all relative: is it safer to
               | run a facility like this or to transport a tanker-full of
               | crude oil across waterways? But just saying that well
               | there will be people there to open a valve when bad
               | things happen is naive.
        
               | asdfasgasdgasdg wrote:
               | When comparing the risk of refrigerant leaks in cooling
               | systems in general vs heat exchange systems at a highly
               | technical and actively monitored facility, it is relevant
               | that the facility is actively monitored and probably has
               | much better controls than typical refrigerant-using
               | installations. It's not naive to observe that most
               | refrigerant leaks are likely from systems that are not
               | monitored (i.e. almost all residential systems and
               | probably most commercial ones).
        
             | Freestyler_3 wrote:
             | No matter how fast they notice it, a leak will have a huge
             | impact even if just for a second. Bigger system means
             | bigger pipes or faster transport, either will result in
             | more loss than what a whole consumer grade system can
             | possibly contain. But like someone said, they most likely
             | wont be using any consumer grade gasses. Big systems use
             | gas that is more dangerous for humans nearby, but has no
             | impact on the ozon.
        
           | asdfadsfgfdda wrote:
           | They likely use air as the refrigerant, like most air
           | liquefaction plants.
        
             | boringg wrote:
             | Fair enough - I am unfamiliar with refrigeration at scale.
             | As long as none of the HFC, PFCs, HFE, CFC etc compounds
             | are used seems like a low risk.
        
             | ncmncm wrote:
             | THIS. Nobody uses freon for industrial-scale refrigerant.
             | 
             | Even at intermediate scale, ammonia is preferred.
        
         | contravariant wrote:
         | * Round-trip energy efficiency: I can't see a system taking
         | electrical input to produce liquid air on the way in and
         | similarly to run a turbine generator on the other end without
         | having substantial losses both ways... I believe Tesla is
         | around 88% on their system.
         | 
         | Well you can just power an engine on the temperature gradient.
         | That's going to incur some losses though. This seems to be the
         | downside of storing energy cooling stuff, you have to fight the
         | second law of thermodynamics both ways.
        
           | ncmncm wrote:
           | You get to run _both_ a heat engine, on the temperature
           | difference, _and_ a turbine, on the resulting boiled-off gas.
           | So, you get benefit of thermodynamics both ways. Furthermore,
           | the heat engine uses heat pumped out and saved from
           | liquifying the gases.
           | 
           | It is typically a mistake to assume people behind an
           | innovative development, that they are spending $150M on, are
           | idiots.
        
         | kolinko wrote:
         | As for the price per kWh, I guess this system scales
         | sublinearly (as opposed to more or less linearly with LiIon).
         | They can probably increase the number of tanks storing oxygen
         | in the future for way less than $300kWh (assuming they keep the
         | same system wattage).
        
           | mcot2 wrote:
           | Batteries should see drastic declines as well. $300 is
           | already considered a steep price even though it is the all-in
           | price. We are talking about $50 at the cell level for LFP
           | chemistry soon.
        
           | CydeWeys wrote:
           | I came to precisely the opposite conclusion. Batteries keep
           | getting cheaper every year, while air pressurization
           | technology does not (that is a very mature technology). So if
           | this air pressurization is only the equal of batteries in
           | year one, then it's already lost.
        
             | hokkos wrote:
             | The point is not about future price evolution, but the
             | marginal price of storing 1h more, if you just need another
             | tank it will be cheaper than having the same energy in a
             | battery, with the same system to store and destore the
             | liquid air. Li-ion is not a good fit for long term storage.
        
               | CydeWeys wrote:
               | This system is already 500 MWh (that's huge). How much
               | better scaling do you think it's going to get beyond
               | that?
        
               | ncmncm wrote:
               | The expensive part is the 50MW bits. They can build out
               | storage capacity cheaply, because it is just tankage.
        
         | Robotbeat wrote:
         | I mean... you can recycle batteries, too. And the environmental
         | "issue" with batteries is largely a red herring (steel mining
         | and even recycling would look bad if you had a campaign of
         | misinformation against it like batteries do, cherry-picking
         | dramatic industrial-scale images without comparison with what
         | it is replacing). $300/kWh isn't anything to really write home
         | about.
         | 
         | Not opposed to it, though. While I don't think it's a slam-dunk
         | win against batteries by any stretch, it's good enough not to
         | be a waste of money if someone builds one (which is probably
         | true for that cement-block gravity energy storage thing).
        
           | usrusr wrote:
           | "you can recycle batteries"
           | 
           | It has been done, in a laboratory. Scrap steel is routinely
           | sold at market rate.
        
       | markvdb wrote:
       | Low-tech magazine has run a few quite interesting articles about
       | storing energy in compressed air. [0]
       | 
       | [0] https://www.lowtechmagazine.com/compressed-air/
        
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