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AEP’s Latest Flight Of Fancy–Cryogenic Air!

August 27, 2019

By Paul Homewood



AEP makes a fool of himself yet again, with a naive article about energy storage that would Jillian Ambrose might have written!

It is paywalled, so the DT won’t let me publish in full, but I have summarised the gist:



The curse of intermittency for wind and solar power may be conquered sooner than almost anybody thought possible.  A beautifully-simple technology from a British start-up has slashed costs to levels that drastically alter the calculus of long-term energy storage.

Highview Power is pioneering the use of "cryogenic" liquid air to store electricity for long enough periods to cover the lulls in renewable energy.

It appears close to doing so at levelized costs that will undercut competition from fossil fuel plants once scale is reached. Highview will almost certainly be the biggest company of its kind in the world by the early 2020s.

If it can deliver the full promise – big caveat – the cost break-through overcomes a key barrier for a future global economy driven primarily by zero-carbon energy. One oft-repeated argument against Britain’s North Sea wind expansion falls away. 


As was the case with Silly Jilly, AEP totally fails to comprehend just how much storage is needed to cover the intermittency of wind and solar power.

Battery and other forms of storage are fine for providing power for an hour or two, but the natural intermittency of wind power would require many days worth, if not more. As for solar, where you would need to store all of the summer output, when demand is low, to use in winter, storage is a non starter.

I have analysed wind output in January 2019, which was not an untypical winter month. During the month, wind output averaged 5468 MW, which was 15% of total generation, again not untypical.

There were, as you can see, very large variations within the month.




The longest consecutive period below the monthly average was from the 1st to the 7th of the month, a period of 133 hours.

The cumulative shortfall in output during this period, in relation to the monthly average, was 417813 MWh. This equates to 76 hours of wind generation at average output.

During this period, wind output averaged 2322 MW, or 42% of the average.

In other words, you would to store three days’ worth of wind power, just to cover January’s weather. There have been many occasions in the past when cold, anticyclonic weather has lasted for much longer than five days, and certainly been a lot more intense.

Realistically, you would need to plan for this sort of shortfall extending for a month at least.

To put these numbers into perspective, Tesla’s oft-quoted battery in S Australia is rated at 129 MWH. You would need 3240 of these to store 417813 MWh.

As for costs, the recently approved 50 MW / 32 MWh battery project at Whitelee wind farm is costing £20m. You would need 13056 of these to store 417813 MWh, giving a cost of £261 billion!


No matter how efficient Highview Power’s new system is, it is still going to run into the same problems of scale. Their pilot plant is only 15 MW.

As Jillian Ambrose before him, AEP totally confuses the role of small scale peakers, with which he compares this new system. Peakers, such as small gas and diesel engines, are not designed to cope with the intermittency of renewables, as he wrongly claims. They are there, as they always have been to manage spikes in demand.

During January 2019, OCGT for instance only averaged 5 MW, 0.01% of demand.

AEP claims cryogenic liquid air appears close to doing so at levelized costs that will undercut competition from fossil fuel plants once scale is reached.

This is a grossly misleading statement, as he is comparing with peakers, and not large scale CCGT plant, as he goes on to report:

Mr Cavada said the levelized costs for a one gigawatt (GW) plant comes in “way below” $100 per MWh. This is already cheaper than any other back-up option on the market, fossil or not. “In ten years from now, I can see that being $50.”

These are remarkable figures. Lazard estimates the levelized costs for gas peaker plants at $152-$206, new pumped-hydro at $152-$198, or a lithium-ion equivalent at $285-$581. Lithium batteries are superb for a few hours but the economics are not viable for utility power over long periods. 

Mr Cavada, Highview’s CEO, also notes that the process loses two fifths of the energy input:

Mr Cavada said the "round trip" efficiency of the Highview process so far is 60pc (ie two fifths is lost).

Does not sound very efficient to me! AEP’s logic is that there will be lots of “free” electricity available, which will help make the process viable:

The official Committee on Climate Change wants to go for broke with 75GW of offshore wind to meet the UK’s Net-zero 2050 target. Such scale means a wash of surplus power in the middle of the night or at times of low demand.

This implies "free" or ultra-cheap electricity for energy storage, since otherwise it would have to be curtailed by shutting down turbines – “off-peak waste electricity” in the trade jargon. The UK plans makes cryogenic liquid air almost unbeatable.

However, if wind farms have to give away half of their power free, that will simply double the cost of the rest. This makes a nonsense of regular claims about how cheap wind power now is .


The new cryogenic system may be cheaper than OCGT and batteries, but will do nothing to solve the problem of wind power intermittency.

  1. GeoffB permalink
    August 27, 2019 3:53 pm

    Beware of snake oil salesmen!!!

  2. August 27, 2019 4:13 pm

    The lack of knowledge of these people in the MSM is worrying. The only large scale storage is pumped, and Prof David MacKay looked into how much would be needed (in terms of TWh) to cover for wind lulls.

  3. Broadlands permalink
    August 27, 2019 4:18 pm

    Another “comedy hour”? Energy storage for a few days? The world is battling with Nature to geologically store CO2 permanently in massive amounts, leaving open all those other energy sources to do the job. This is crazy?

  4. August 27, 2019 4:21 pm

    Reblogged this on Climate-

  5. Chris Davie permalink
    August 27, 2019 4:32 pm

    The cryogenic side of the plant is the same as an oxygen plant – power requirement for air compression is huge. Could it be that this is the real revenue stream while receiving subsidies for the occasional release of compressed gas to generate power?

    • August 27, 2019 6:29 pm

      AEP called it arbitrage.

      What they plan to do is buy electricity when it is cheap, and sell at peak demand, when for short periods spot prices can be in the hundreds of pounds per MWh

      • Bloke down the pub permalink
        August 27, 2019 10:30 pm

        If the wind farms are being paid to turn off, rather than produce unwanted power, then wouldn’t this money be saved if electricity is bought when it is cheap?

    • August 28, 2019 12:41 am

      @Chris Davie.

      Let’s look at this from a Carnot Efficiency point of view. The Carnot efficiency is [ 1 – Tlow/Thot]. Air liquefaction happens at about -196 C or 77 Kelvin. Assume an ambient of 25 C or 298 K. The Carnot efficiency would be 1 – 77/298 = 0.74 or 74%. This assumes Zero entropy increase. In the real world, one is fortunate to achieve 50% of the Carnot efficiency. That leaves us with about 37% practical efficiency in liquefaction. Expansion is the same process, in the other direction. The overall efficiency is the product of the two or 0.37 x 0.37 = 13.7% cycle efficiency. Some 86% of the initial energy is lost. Seriously doubt the process could ever be more than 20% efficient at best. Any energy used to refrigerate stored cryogenics would lower the efficiency even further.

      Might be better off to use electrolysis to create hydrogen and then convert it to ammonia or methanol or as a feedstock for synthetic liquid hydrocarbons via Fischer-Tropsch process.

      Methinks the Liquid Air storage idea is not very practical. More Hype than useful.

  6. Nancy & John Hultquist permalink
    August 27, 2019 4:37 pm

    To be a replacement for existing technology (coal, gas, nuclear), solar and wind need to produce sufficient electricity to run a grid AND at the same time enough to maintain the grid when neither are producing. A full month’s worth might be enough, but I don’t know what the longest winter time need has been.

    Others have calculated the amounts of materials and land needed to (a) meet increasing demand, and (b) replace existing power providers. Matt Ridley, for one, has done this. Insofar as steel and concrete require coal to produce them, just getting enough wind turbines standing on the towers will require a major increase in mining, transport, and use of coal.

    Your compatriots – Jillian and Ambrose – need a lesson in scale “to comprehend just how much” is needed to get to their energy nirvana.
    Now folks are arguing for an all electric transport fleet, or
    for a total rebuild of things such that autos become a thing of the past.

  7. Athelstan. permalink
    August 27, 2019 5:12 pm

    As we wander in this Panglossian future invented by the hobgoblins of green, we drift onto the rocks of blackout reality, not fit for purpose aye you could say that although I might aver – the current horlicks of UK energy policy, even ‘not fit for purpose’ the phrase is made redundant, we’ve gone past redundant into the dreamscape only the insane can inhabit.

    Using sticking plaster bodging, as fictional solutions to reengineer a self inflicted dingbat energy policy all of their own fashioning! And again, the loons are purporting delusional concepts in order to repair a completely fubar energy policy which is predicated on a total fiction – AGW.

    How insane is it going to get, once more let it be said fixing a massive vacuum, in worse than useless contraptions and which are sinking the nation – what planet are they on?

    • August 27, 2019 5:49 pm

      Since we know that what the propagandists call “green” energy will lead to blackouts, I now call all this renewable energy “black(out)” energy.

      • Athelstan. permalink
        August 28, 2019 9:18 am

        yep, I’ll borrow that one Phil – please.

  8. It doesn't add up... permalink
    August 27, 2019 6:04 pm

    The Highview pilot plant is 5MW/15MWh. Just 3 hour duration. They plan for units of 50MW/500MWh, so 10 hour duration (but at least 16 hours 40 minutes to charge up)

    If the efficiency is just 60%, then the levellised cost has to include 5/3rds the cost of the power used to charge the system, plus the levellised cost of the plant. New wind will cost at least £65.09/MWh under CFDs, making the cost of power from this system more like £200/MWh in total assuming it is used to reduce wind curtailment. They seem to have decided on the optimum size, so to provide 1GW for 10 hours they would build 20 modules. It’s unclear where they see cost reductions coming from using a combination of mature technologies.

    It might be more interesting to see how the added gizmos designed to provide ancillary services performed.

  9. cajwbroomhill permalink
    August 27, 2019 6:07 pm

    Best, simplest, cheapest way to cut UK costs is to abandon decarbonisaltion completely.
    No drawbacks, other than to snakeoil merchants and embarrassed politicos.
    Our release of CO2 as a proportion of total world manmade output being 0.3 of 1%, even if the dodgy “science”about climate change causation by greenhouse gases were true, it is a negligible amount.
    No problem!.

    • dearieme permalink
      August 27, 2019 9:52 pm

      Yep. Stay the uproar by announcing a project to develop fission reactors based on Thorium to replace, eventually, …

      Do that under a more rational radiation safety regime than that based on the linear no-threshold model.

      • Steve permalink
        August 28, 2019 4:25 am

        Or we could do what the rest of the world does and build 34 conventional nukes on 7 years at half the cost of Mrs May’s European Pressurised Reactor.

      • Gerry, England permalink
        August 28, 2019 11:58 am

        Especially given the EDF design has yet to work in either Normandy or Finland and is way over budget at both sites. South Korea have a nice working design that we could use.

      • Roger B permalink
        August 28, 2019 2:29 pm

        The Chinese have two EDF EPR Reactors in service. Maybe their builds have not been continuously disrupted by the anti nuclear lobby.

  10. Brian permalink
    August 27, 2019 6:18 pm

    Jan 4, 2019 Why renewables can’t save the planet | Michael Shellenberger | TEDxDanubia

    Environmentalists have long promoted renewable energy sources like solar panels and wind farms to save the climate.

    • saparonia permalink
      August 27, 2019 7:58 pm

      1, Climate Change, previously called Global Warming is not a human issue. Our climate is declining as the Sun goes into Solar Minimum, even NOAA has published that we are facing a cold period as deep as the Dalton Minimum within the next decade due to the Sun. The “climate” is not getting warmer and we are not responsible for it’s changes.

      2, Nuclear power is being pushed onto us and we are told that the only alternatives is harming the climate. Nuclear makes a lot of money, it’s also deadly. Chernobyl and Fukushima are still Ongoing Disasters!! Our planet could end up as a Nuclear Wasteland. Nuclear might be a lot more cost effective in the short term but the cost of meltdown is Forever. We can recover from solar, wind, coal but never from nuclear accidents or sabotage.

      3. Why is no-one looking at how Tesla was producing clean free energy? He was silenced by General Electric because his electricity was Free.

      I’m sorry if this is naive but from the start they knew that they’d have quite a task getting the whole population to support nuclear power but this is all about Wealth, nothing else motivates our leaders.

      • It doesn't add up... permalink
        August 28, 2019 11:04 am

        3. Why is no-one looking at how Tesla was producing clean free energy?

        Tesla wasn’t producing free energy: it would have come at great cost that someone would have to pay. He was proposing that it should be distributed as electromagnetic radiation, a.k.a. radio energy. That does work (radio proves that), but it isn’t very efficient, and at high energies it may have other consequences. That’s why we use high voltage transmission lines instead. You can learn the underlying physics for free from a Nobel Laureate (highly recommended – I was introduced to this at age 14 by my teacher) here:

        Start with the chapter on Electricity in the Atmosphere for an entertaining read with no maths.

        Incidentally, if you live under a high voltage transmission line you could take some advantage of Tesla’s idea: there is sufficient radio energy from the line to power at least a torch bulb if you hook it up appropriately to a reception coil. However, power may be a bit sensitive to the precise location of your coil.

      • Roger B permalink
        August 29, 2019 10:27 am

        2, Nuclear power is being pushed onto us and we are told that the only alternatives is harming the climate. Nuclear makes a lot of money, it’s also deadly. Chernobyl and Fukushima are still Ongoing Disasters!! Our planet could end up as a Nuclear Wasteland. Nuclear might be a lot more cost effective in the short term but the cost of meltdown is Forever. We can recover from solar, wind, coal but never from nuclear accidents or sabotage.

        That’s a lot of alarmist statements.

        Chernobyl and Fukushima are both stable and in the clean up phase. The death toll, even using the anti’s figures, is far less than the deaths caused by coal mining and coal burning. The area around Chernobyl is portrayed as a nuclear wasteland, but people and animals continued to live there with little discernible problems and the other reactors in the Chernobyl complex continued producing electricity. The last one was shut down in 2000, 14 years after the accident.

        How could our planet become a Nuclear Wasteland? Pushing the all six Fukushima reactors into the Pacific ocean would increase the radioactivity in the sea by about 10%.

        A meltdown is certainly not for ever but the pollution caused by mining, especially for some of the materials required by wind and solar PV, is. The various toxic heavy metals do not have a half life, the radioactive materials produced by nuclear reactors either in normal production or in accidents do. The most active materials have the shortest half lives (basic physics) which is why it is a sensible practice to leave a reactor for 10s of years after decommissioning to reduce the radiation levels.

        Best regards


  11. Ivan permalink
    August 27, 2019 6:26 pm

    There are numerous technologies offering to store energy, and lots of people trying to develop them. If you look at the Energy Storage page on Wikipedia you will see a long list. Liquid air is well known. So far no sign of a method that can produce the massive reduction in costs needed to produce a business case for doing it on large scale.

    A classic case was Isentropic, the now bankrupt company. It achieved 72-80% efficiency, rather better than this case, with its demonstration facility, now taken over by Newcastle University for research purposes. This stores energy as a heat difference between two large buried gravel containers, with a pressurised argon atmosphere. It converts heat differences to energy and back using a reversible heat pump. It appeared promising as a more efficient/lower cost method than well-known methods like liquid air, etc.

    But it went bankrupt becase there is no business model for buik energy storage like this. I think people continue to offer them because they are hopeful of subsidy farming, and don’t seem to understand that no goverment subsidises them because it is so far from making sense.

    • dearieme permalink
      August 27, 2019 6:39 pm

      “don’t seem to understand that no government subsidises them because it is so far from making sense”: that’s not how government subsidies work.

      • Ivan permalink
        August 28, 2019 11:52 am

        Indeed subsidies can sometimes be available in cases where with careful analysis it makes little sense, if it pushes the right political buttons, eg the “rescue” of Rover Cars. Maybe that is what some people are hoping for. But so far, no government has seen any sense in subsidising this kind of thing, and it helps that the CCC says it is implausible. I think it helps that they see it as a rather technical issue and get technical advisors to point out the lack of sense in it.

  12. Vernon E permalink
    August 27, 2019 6:49 pm

    Paul: thank you for your analysis – I was almost persuaded by AEP’s article today.

  13. Gamecock permalink
    August 27, 2019 7:03 pm

    TL:DR – You also need substantial additional generation capacity to charge the storage system, whatever it is.

    ‘Battery and other forms of storage are fine for providing power for an hour or two, but the natural intermittency of wind power would require many days worth, if not more.”

    You right wingers cling to your belief that electricity should be available all the time. Change your belief, and weather dependent electricity will be fine.

    • dennisambler permalink
      August 27, 2019 11:23 pm

      Especially if you are in hospital having an operation for example.

      • Gamecock permalink
        August 28, 2019 5:12 pm

        That’s right. Why should your surgery be more important than your fine public servants looking concerned?

  14. It doesn't add up... permalink
    August 27, 2019 8:04 pm

    I did some slightly different sums to Paul’s, but using his January 2019 example month. I looked at total demand, as reflected in the sum of generation (which would therefore miss embedded demand and supply, but it will do for this purpose, including net supply from interconnectors (arguably we shout treat interconnector exports as additional demand). I then scaled up the wind production so as to provide for all the demand over the month, plus the energy that would be lost in round tripping through the storage at 60% efficiency.

    I found that

    – to meet demand, wind capacity would have to be scaled up by a factor of 8.
    – to balance supply and demand over the month would require over 3.9TWh of storage
    – the storage would have to start the month with 2.2TWh in stock to cover the deficit in generation in the early part of the month
    – the storage would have to be capable of absorbing up to 68GW
    – the storage would need to be capable of delivering 44.5GW (actual peak demand was 48.6GW)

    Looking at these figures in relation to Highview’s planned 50MW/500MWh standard units

    3.9TWh would require 7,800 units, while fortunately only 1360 are needed to cover the peak rate at which surplus wind must be stored, and just 890 to meet peak demand. So the real constraint is the TWh of storage needed. Of course, this is just one month, and we are assuming that it was possible to ensure we started (and ended) the month with 2.2.TWh in store. Other work I have done with 30 years of data suggests that to cover for seasonal variations and bad years, using wind and solar, we would need over 30TWh of storage at current levels of demand if we are not going to curtail.

    It’s generally far cheaper to overbuild capacity and curtail than to store, but you eventually reach absurdity whichever route you follow unless you allow for alternative backup from reliable generation.

    • It doesn't add up... permalink
      August 27, 2019 8:23 pm

      I should have added that the grid would have to deal with energy flows of up to 100GW to route surplus wind to storage units and supply demand – entailing another very substantial investment. It is presently designed with meeting demand of just over 50GW, so a doubling of investment might be called for.

  15. A C Osborn permalink
    August 27, 2019 8:25 pm

    There are some interesting comments, including in response to Paul’s.
    There are quite a few who are “believers” who will not be detracted by facts.

  16. CheshireRed permalink
    August 27, 2019 8:54 pm

    Yet again we’re trying to solve a problem that doesn’t exist with technology that isn’t as good as that which we already possess.

    When do we get to throw out the politico’s who enable this gibberish?

    • Gerry, England permalink
      August 28, 2019 12:04 pm

      Probably when we get the Harrogate Agenda adopted to introduce democracy to the UK. Instead of being cosy for 5 years having lied to the electors, every MP will be in fear of being ejected by their electorate for failing to perform. The HA also ends jobs for MPs so that Parliament holds the government to account as opposed to about half of the Tory MPs holding some sort of government post with extra cash on offer.

  17. Broadlands permalink
    August 27, 2019 9:12 pm

    The dilemma should be simple to see? Alternative energies do NOT lower CO2. They are supposed to provide the energy for those technologies that do…CCS and BECCS. The problem very quickly encountered is the fact that the amounts required to be geologically stored are too massive. Hundreds of billions of tons…and by 2050? Gibberish indeed.

  18. I_am_not_a_robot permalink
    August 27, 2019 9:47 pm

    This period in the history of the West will cause much wry amusement and head-shaking in centuries to come, how could any supposedly rational advanced civilisation squander so much of its wealth on intermittent energy sources without solving the long-term storage problem first:

  19. Graeme No.3 permalink
    August 27, 2019 10:25 pm

    Producing liquid air is a well developed technology and a modern plant produces around 3,000 tons per day. The global liquid nitrogen market size was estimated at 7.87 million tons in 2016 (or 10 million tons of liquid air), so it is a mature industry. The cost of liquid nitrogen seems to be between £180-240 per ton.
    Production requires lots of compression and COOLING. Liquid air will rapid expand once HEAT is supplied. A deal of engineering has gone into cost reduction and efficiency from the big producers.
    If the idea is to produce large scale storage between seasons, it follows that summer production would result in lots of surplus heat, and winter use in a lot of cooling (heat absorption). Not quite the desired effect on the Climate. Where, and how, do they propose storage of the heat?
    Question 1: how do they prevent fractionation (with liquid nitrogen ‘boiling’ first)?
    Question 2: If this idea has merit, why haven’t the big producers developed it further?
    I note that there seems to have been some academic interest in this idea in 2012, so assume that the idea is being recycled.

  20. Michael Adams permalink
    August 27, 2019 10:28 pm

    Why would wind farms give away their power for free when it is not needed by the Grid. They receive stinking amounts in the form of Constraint Payments to stop producing electricity when the Grid doesn’t need it. I understand that the price has been reduced but it used to be more per KW than when their were feeding it into the Grid.

    • Ivan permalink
      August 28, 2019 11:42 am

      In Germany, the market price of electricity occasionally goes negative, and more frequently can be very low. This is the wholesale price you pay, and you have to contribute to distribution costs also. The government pays the subsidy cost to the renewables provider and shares it across all customers. This doesn’t happen at the moment in Britain, we don’t have that much renewables yet. Our constrain-offs are mostly transmission constraints rather than demand constraints as happens in Germany from time to time. Germany has something approaching 40GW of solar, which overwhelms demand on a clear sunny day in the lighter months. But as renewables increase in Britain, and the transmission capacity is provided for it, we may get very low and even negative market prices from time to time as they do in Germany.

      But if I’ve spend a lot of money on an air liquifaction plant, am I only going to run it during those periods when the market price of electricity is very low? I think not. They aren’t that cheap. I think it is hard to say “I only want that liquid air produced when the energy is free, your other customers have to buy the more expensive stuff produced at other times”. So the idea that you can have very cheap liquid air, or hydrogen, etc, needs thinking through a bit more. It is only going to be reliably cheap if you have a way of making it that has such low capital costs you can afford only to run it when the electricity is cheap.

      It occurs to me that although there isn’t a business case for a bulk storage market, there is a niche market for peakers, and maybe this is what this can address. This is currently supplied by OCGTs – cheap reciprocating engines, the kind of thing hospitals etc have as back-up generators. It is typically very polluting of the air, and noisy too, and they are often located in urban areas. The air pollution aspect is now unacceptable. The question is what kind of an alternative very cheap generator can you build that runs cleanly, on some cheap-enough low carbon fuel, and ideally not too noisily, instead. It needs to be cheap enough that you will only run it for brief periods?

      The government/CCC is talking about hydrogen serving this purpose. So that the technology whose cost you have to beat to be an alternative. It is also helpful if the fuel (or “fuel” in the case of liquid air) is easily transportable and can be stored for weeks/months without high storage cost.

  21. August 27, 2019 10:54 pm

    According to Wikipedia, the total renewables in the US for 2018 was 17.64%. Yet the lunatics here in the UK were up to 51% before it came crashing down. This is a good (short) video –

    • dave permalink
      August 28, 2019 8:24 am

      The proposed facility will not store energy, it will store expensively manufactured cold. The turbines will only spin to the extent that ambient air can lose heat energy to the liquified gas. Of one thing you can be sure; electric generation will happen very slowly.

      I am reminded of the old saying, “Everybody has his own bright idea how to get rich in the stock market and retire. The ideas have one thing in common; they are all stupid as hell.”

  22. Roger B permalink
    August 29, 2019 10:03 am

    The business model for energy storage is difficult. In the past cheap nighttime electricity was stored to be released at the daytime peak. The surplus of Solar power in the middle of the day in summer has seriously damaged this model. This is a report from 2014 on the problems facing Swiss pumped storage systems:

    Best regards


  23. Colin Megson permalink
    August 29, 2019 12:40 pm

    July 2018 was THE month to pick on, Paul.

    A mere £472 billion of batteries would have dragged it up to the monthly average for the year.

    Mind you, for that we could also get 30 x 3200 MW Sizewell Cs to give us 757 TWh per year, of low-carbon, 24/7 electricity for 60 years. That’s all 340 TWh of electricity we currently use, plus taking care of the electricity needs of lots of EVs or heating:

    Search for: “july 2018 – told in 3 pictures”

  24. Steve permalink
    August 30, 2019 7:13 am

    This is rather late but I had time to look at the possibility of using this super efficient cryo system for plugging the gap when wind is zero for a week in 2050 when we are complying with the law and the CCC report.
    According to Fig 2.5 the total generation will be 645 TWh. Wind supplies 360 TWh. The capacity of the turbines is 75 GW giving 381 TWh at 58% efficiency. Assuming that gas with CCS, Beccs, nuclear and other firm keeps going, there will be a shortage of about 20,000,000 MWh for 7 days lull.
    But let’s be optimistic and say that 59% of the wind part of the cake goes missing and 14,868,000 MWh is needed.
    The scaled up cryos supply 50MW or 8,400 MWh over 7 days leading to the an order for 1770 cryos. Unfortunately, two thirds will be charging so triple that to 5,310. And of course that would have to be while the wind was blowing s few weeks before and with plenty of frozen air tanks around.
    I am not an engineer and mathematics with large numbers is not easy. Could someone check the figures please.

    • Steve permalink
      August 31, 2019 5:51 am

      Jus to add that the 8400 MWh cryos would be scaled up versions of the planned scaled up versions. If the type planned for 500 MWh were to be used, 89,208 may have to be ordered. And for a four week lull 356,832.

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