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Things that aren’t true

It’s going to make a massive difference to the cost of energy for consumers, because, of course, our homegrown sovereign renewables are much, much cheaper than any other form of generation,” he says.

No, they’re not.

Highview Power, based in London, believes it has a solution: use cryogenic liquid air to store the electricity until it is needed.

The pioneering technology works by compressing air into a liquid and then cooling it to almost minus 200°C.

The liquid air is stored in an insulated tank at low pressure, which functions as the energy store. When power is needed, liquid air is drawn from the tank and pumped to high pressure.

Stored heat from the air liquefier is applied to the liquid air via heat exchangers and an intermediate heat transfer fluid. This produces a high pressure gas, which is then used to drive a turbine and generate electricity.

Chief executive Rupert Pearce says the loss of energy during the process is around 50pc, but much of the waste is through heat which can be recovered, taking its potential to about 70pc.

The thing we desire is power we can use – power when we want it. If renewables require all this sort of gubbins to achieve that then they’re not much, much, cheaper, are they?

The only important price is, after all, the price of the power we can use, when we want to use power.

24 thoughts on “Things that aren’t true”

  1. A heat engine with a thermal efficiency of 70%? Sounds unlikely..and where the hell is this waste heat going to be utilized? Unless the starving hordes are going to be camping next door to all those industrial compressors?

  2. The description does leave out the bit about also having big water tanks to act as the thermal store for the heat given off as the air is liquefied, but otherwise it is a fairly efficient process. As ever with any renewable energy storage you still have the problem of what to do if the wind doesn’t blow for a couple of weeks and you run out of stored energy. It also perpetuates the myth that the UK is a good location for renewable energy. It’s not.

  3. Since when was does a 30MW output count as ‘commercial scale’? I’d call that a pilot plant following their apparently successful proof of concept.

    And it stores enough to do that for ten hours. Better than current batteries but hardly enough to cover multi-day transfer. After which (not mentioned) you’re going to have to charge it up again. Which may or may not take a lot longer. In the meantime, you’ll spend a lot of time sitting on a full store waiting for the price go up or waiting for cheap supply to recharge.

    I’m a bit dubious that they’ll get paid for taking excess electricity too. Buy it when it’s cheaply available and sell it when the supply drops, sure.

    My suspicion is it won’t scale (like most of these technology demonstrators), and the business model won’t stack up. But hey, good luck to them, it looks interesting. Plus, if they’re running turbines, there are other possible revenue streams like frequency/voltage stabilization that wind/solar just can’t do and batteries can only do for a very short length of time, so maybe the bean counters have factored that in.

  4. If we need storage because unreliables cannot supply the grid when required, how is it imagined they can supply power to recharge batteries when required?

    It’s not joined up thinking. But then there is no joined up thinking when it comes to climate change, just madness.

  5. How does the cost and output compare to pumped storage – hypothetical question of course as we’d never be allowed to build a new reservoir in a National Park where all the decent height drops are and nobody lives.

  6. John B, good point that I didn’t make, but yes, recharging storage if it scales up to actual grid scale will become a major drain on the grid during the good times. At which point the cheap in/expensive out business model collapses again. The answer we’ll get of course will be we need more renewables to cover double the normal demand when the wind is blowing.

  7. I was a bit puzzled by the physics so perhaps someon can explain.

    If they going to store the iced air at low Kelvins, then don’t they need to keep it a high pressure, because otherwise it will expand too much ? What sort of volumes are they talking about.

    As for excess heat, they could build a swimming pool or more lucratively a gay megasauna next door.

  8. Like everything to do with the inevitable consequences of relying on renewables, it’s all

    ….. “I know an old lady who swallowed a fly…….”

  9. The article is rather badly written. I’m assuming that the last para quoted means they only lose 30% energy on the round trip. That’s pretty bad compared with batteries but if it were mega-cheap by comparison then that may be a secondary issue. I assume they could keep the liquefied air at atmospheric pressure as long as they kept it cool enough.

    Having said that, a 30MW prototype plant with 10 hour endurance is in no way a blueprint for the Gigawatts + days endurance required.

  10. Ottokring, I can maybe help a bit. The low temp thing is so that they *don’t* have to keep it at high pressure, the air will happily stay liquid at those temps at low pressure. That’s the key to the storage side, you only need insulation, and presumably you can do high volumes cheaply that way. Of course, that costs you energy on both ends, cooling down on the way in to get to the low pressure liquid state and both repressurising and reheating on the way out to get high pressure air to drive the turbines.

    I did like the bit in the article where it says that if it fails it just leaks air. Given the pressures and temps they’re probably operating at, if something breaks I don’t want to be anywhere near it 🙂

  11. Oh yes. Now I see.
    Thanks ltw.

    I tell you what confused me, this need to store Hydrogen at very high pressure for fuelling vehicles, but of course in that case it has to be available instantly as a gas and not be “thawed out” beforehand.

  12. There is competition for this idea that seems to be at a more advanced stage of engineering and commercial development, and does away with the cryogenics – the “CO2 battery”.

    As with Highview Power it only serves to make “renewables” slightly less unreliable.

  13. No worries Ottokring. Yeah, hydrogen is a very different beast in a lot of ways.

    Tractor Gent, at least they’ve got MW for power and MWh for energy right for a change. Earns a point from me.

  14. I reckon Ltw has it right that the storage doesn’t require pressure once cooled, it’s the cooling process that does. Also yes the thermodynamic efficiency of the generating part might be quite decent- _IF_ the Carnot limit is the relevant one- it’s around say (1-55/280) so ~80% efficient tops for that part of the overall system. If.
    I’d see H2O and CO2 icing as problems, but that’s what prototyping is for- they should have got those sorted by now.
    I think it’s a good sign that, at least in the article, they’re not pushing O2/N2 separation or trace gases like Argon as a byproduct revenue stream but are standing on the energy storage’s merits. Colocating this with intermittent thermal plant to help that with it’s cooling might eventually be a small technical win too.
    So yes if pumped storage isn’t feasible locally and if people must have excess wind generation so have electricity going begging, I see this as actually promising. !.

  15. I struggle to see where the energy is stored in a flask of liquid air.
    To create gas to drive a turbine, you will need to supply heat, to boil the gas and create a high-pressure flow to drive the turbine
    Or, you could use liquid water as the fluid, and the same source of heat. A steam engine, in other words. Or if the heat source is low-grade, a low boiling-point liquid in a closed cycle: ether, ammonia or freon perhaps.

    So is the liquid air just a gimmick? A funding con?

    I don’t dispute that it takes A LOT of energy to liquify a large tank of air, but what advantage is then gained?
    Cannot see it…

    NB re. the question above about hydrogen: liquid hydrogen is MUCH colder than liquid oxygen/nitrogen, and so far harder to store. Even in the best of tanks it’ll all boil off in a day.
    Also, you cannot liquify it directly by a compressor/expansion cycle, you have to get it cryogenic before you do that. Oh, and you need to shift it all to para-hydrogen (or is it shift to orth-, can never remember which). Liquid hydrogen is for the fairies. The Basil Brush of fuels.
    Boom boom.

  16. TtC, The liquid air isn’t the energy source, it’s a temporary store of working fluid. Heaps of energy in to cool it, little bit to store it. It then gets pressurized before it gets warmed (which supposedly is partly coming from heat scavenged from liquefaction previously), so a lot of the energy is coming from lots of air trying to get out of a small space. You’ve paid to compress it, you get some, but not all, of that back.

    The intermediate steps are why they’re looking at 50% electricity out vs in.

    I still don’t think it will stack up, but if they can raise the money it would be nice to find out.

    @NNNY Icing in this thing? Don’t even want to think about it. This is where scale up starts to bite you.

  17. The pressurised storage of liquid CO2 at ambient temps seems a lot less involved than unpressurised storage of liquid air at cryogenic temps. That you then have to pressurise the liquid air as well as heat it to get the work seems an added inefficiency.

    The CO2 battery outfit talks an efficiency of 75% and half the cost of Lithium Ion battery storage at current scaling.

  18. If one liquifies air, won’t all the gases involved form strata, because they liquify at different temperstures. NNNY mentions O2 and N2 separation, but won’t it happen anyway ?
    Does it matter ?

  19. Wasn’t there something recently about using silos filled with sand or something to store heat/energy? Seems like some sense is sinking in if they are getting around to trying to figure out an alternative to batteries as a storage medium for renewables. Of course what they won’t talk about is how this effectively makes renewables more expensive

  20. @ Tim the coder.

    The energy store is it “effectively” being highly compressed gas. The cryogenic cooling means that you can
    conveniently store it at atmospheric pressure in well insulated tanks. Vacuum insulation is the norm but with really big tanks other cheaper insulation like perlite is workable. You do need to put the heat back into it to get back to the high pressure gas needed to turn turbines. The easiest way to do this is with stored water warmed by the heat extracted from the air you liquefied though any source of low grade heat will work.

  21. Well, renewables have always been more expensive because of the need for backup. It’s just the boosters and all the other Net-Zero zealots refuse to talk about that. As for re-pressurising the air to drive a turbine efficiently, just add heat. The whole process relies on the heat of compression being stored for that purpose. You do need one of those thingies on steam locos to feed the liquid in against the pressure of the turbine gas flow though.

  22. Off the immediate topic but looking at the BOC online shop for liquid CO2 specs (50bar max filled pressure at 15C in cylinder, 180-200bar burst safety device fitted, which is less frightening than I remember), I see they are only taking CO2 orders from existing customers at existing levels, and applying surcharges. Bad time to open a keg pub.

    I would be a little worried that a fraction of the 50MWh in each of Energy Dome’s pressure vessels when full could be released rapidly, and also that a cold therefore ground-hugging cloud of the rest of the CO2 could do a mini Lake Nyos. 50MWh is around 4 Grand Slams worth so potentially oops. But they will have thought of that and found safe fixes, eg BOC’s manifolded pallet of cylinders.

  23. As others have stated, this is clearly some sort of pilot scheme which doubtless will be able to attract some grift money – sorry, high tech investment.

    Does any sort of demonstrator hardware exist or is the funding to try and build one?

    Just more “green” bollocks. I like to think there is some sort of competition between these grifters to see who can get actual money for the most mapcap scheme. The bar is pretty high though. this one is particularly interesting. Again, total bollocks and about as likely to appear in the real world as the contents of cunter biden’s laptop, but it will sound very convincing to technological illiterates who “want to believe” (ticks an awful lot of their “want to believe” buttons so respect to these particular grifters).

    Returning to the actual issue though, liquid air is a damned sight safer than hydrogen though. Used to use liquid nitrogen quite a lot in my early work days. Well remember filling peoples lunchboxes (not that lunchbox, perverts) with it. And you could happily pour it over your open palm (as long as your fingers were splayed and your palm flat so it would just boil and roll off, like water on a hotplate). There was always somebody when invited to try who would cup their hand and let it gather.

    These days something like that would doubtless be racist, colonialist, patriarchal, sexist………….homo/trans/………..phobic……….brexiteer, gammon, immperialist………

    Please, build ALL these things and let them fail, spectacularly and predictably. The bitch fight among the various fanatics would be a joy to behold.

    Just hope they don’t build the liquid air store next to the liquid hydrogen one.

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