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Capacity Market–CCGT & Storage

December 9, 2016

By Paul Homewood




A few more thoughts about the Capacity Market Auction for 2020/21.




Lack of new build CCGT

As I mentioned earlier, there only appears to be about 600MW of new CCGT, and half of this is expanding an existing site.

It has been argued that the government should not worry about which particular technologies win out. We should instead let the market decide which is cheapest.

And to the extent that the objective is to provide standby capacity during peak periods, this may be OK.

This argument however ignores a much wider concern, and that is that we will continue to need a lot of gas capacity for baseload, even well into the 2030s. (Assuming coal is phased out, and new nuclear is limited).


DECC’s Energy and Emissions Projections, for instance, still assume gas to be generating nearly 100 TWh in 2030. This is as much as was produced last year.




Because some older plant will be shut down, DECC say that an extra 15GW of gas capacity will be needed by the mid 2020s.


While small scale peakers, such as diesel generators, battery storage, OCGT and demand side response may be able to cope for short periods, but can they really provide 100 TWh a year, week in week out?


As the BEIS analysis of levelised costs pointed out, CCGT is much more capital intensive, in terms of capacity. That is why new CCGT projects are finding it so hard to compete at the Capacity Auction.




But because CCGT is so much more efficient, its cost per MWh are also much less:





Put simply, alternatives to CCGT could neither produce at the outputs demanded, nor do it commercially viably.







Various storage projects have won 3.2GW of contracts. Centrica, for instance, boast that their 49MW battery storage facility at Roosecote, which will be one of the world’s largest of its kind, will be capable of holding enough power to meet the needs of around 50,000 homes, responding to fluctuations in demand in under a second.



Roosecote Storage diagram 


But the real question is just how long this power can be supplied for.

Centrica will earn over a million pounds a year in capacity payments for Roosecote, but would it have been worth building otherwise?

  1. Joe Public permalink
    December 9, 2016 6:20 pm

    From Centrica’s diagram:

    “Air conditioning units. Industrial sized units help to keep the building cool”

    Translation: “Industrial sized heat pumps move heat from inside to outside building, and so contribute to global warming”

  2. spetzer86 permalink
    December 9, 2016 7:56 pm

    Wonder if there’s also a liquid cooling system for the batteries? That’d be more efficient than air conditioning. How much power does the facility use just keeping itself functional?

  3. December 9, 2016 8:10 pm

    I believe that some existing CCGTs are mothballed, and were waiting for this auction to un-mothball, so the score may not be as bad as it looks, but there is an ongoing war between the “Transition Industry” and Proper Power Stations, only a sensible govt can save the latter from defeat.

    The 3.2GW of storage probably includes the existing pumped storage.

  4. Curious George permalink
    December 9, 2016 9:45 pm

    Politicians measure energy storage in Gigawatts. They measure distances in miles per hour.

  5. Dave Ward permalink
    December 9, 2016 10:24 pm

    Unless Centrica have developed AC batteries that’s a p**s poor diagram! Where are the Chargers / Inverters needed to convert AC to DC and vice-versa? Even if they are using bi-directional units they still aren’t shown…

  6. Svend Ferdinandsen permalink
    December 9, 2016 11:22 pm

    Just look at this place a couple of times a day.
    And then say with a straight face that wind and solar can supply what is needed, it’s just a case of taxation and incentives to achieve the paradise of the fossil free future with allways good weather..

  7. December 10, 2016 9:45 am

    How can you plot short-term storage capacity like Hydro and Batteries, that might only run for a few hours or minutes, on the same chart as generators like coal and gas that can run 24/7/365 ? And also, do the intermittent ‘green’ backup technologies like Hydro and Batts get priority access over more reliable gas and diesel backup? If so will we see the same pattern of investment as primary power supply – where generators that actually work become uninvestable because of the way the government have rigged the market in favour of expensive green generators that only work intermittently.

  8. catweazle666 permalink
    December 10, 2016 5:18 pm

    will be capable of holding enough power to meet the needs of around 50,000 homes

    How many aluminium smelters is that equivalent to?

    • December 15, 2016 8:15 pm

      The idea is houses use 1KWh on average, of course some hours it’s practically zero, but on a winters evening tea time each house will use a lot more, so the battery migjt be keeping 50,000 houses going for a lot less than 1 hour.

  9. December 15, 2016 8:11 pm

    Here in Brigg There will be 3 PS next door to each other: the original Centrica (which was previously mothballed, now will act as embedded grid generator),
    – the newish small straw 80MW PS,
    – and Centrica are building a new 50MW gas due to them signing a 15 yr Rapid Response contrast. The deal also includes a similar plant in Peterborough, a 49MW battery complex in Cumbria, 370MW Kings Lynn CHP

  10. Earth Monitor Russ permalink
    December 29, 2016 11:01 am

    You can’t store electrical energy in batteries. Batteries produce electrical energy. You don’t fill them with electricity when you “charge” them, you simply recondition the battery so it can reach its full potential again. While those electrons are spoiling the metals in the battery and making electrical energy available to use, the battery is slowly losing its ability to produce energy in the circuit its attached to, hence the voltage drops and the current weakens as the internal impedance rises.
    Let me reiterate. You cannot store electricity. If you tried to store electrons, they would naturally repel each other which would be impossible to overcome. But considering the electrons only make electrical energy available in a circuit and are NOT the electricity, then the whole concept of storage becomes meaningless. Even a capacitor (a real theory proposal for storage), only pushes electrons across a barrier to create a potential. You don’t add electrons to a capacitor, so capacitor storage is another fraud.

  11. Jack Broughton permalink
    December 29, 2016 1:25 pm

    Flexible generation is more efficient than storage (loss of 40% power avoided). However, an insidious part of the greenies plot is to scrap the coal fired power stations as soon as possible to prevent them being used once the truth is accepted that carbon dioxide is not dangerous. Ferrybridge demolition contracts have been awarded and they will soon remove that as a potential real generator.

    The existing coal fired power stations could have life extensions as a low cost and guarantee low real-cost power: the lunatics have almost won the war (sadly for the UK).

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