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UK wind farms could face weekend ‘switch-off’

May 23, 2020

By Paul Homewood



h/t Philip Bratby


As expected, a wind weekend is coinciding with low demand over Bank Holiday weekend, leading to potentially more wind power than the grid can cope with:


Expected low electricity demand in the UK over the upcoming Bank Holiday weekend because of Covid-19 could see several distributed-connected wind farm operators paid to cut output in order to manage the grid.

National Grid ESO said that small-scale renewable generators with over 2.4GW of capacity – including 1.5GW of wind power – have so far joined a new scheme called the Optional Downward Flexibility Management (ODFM) service.

ODFM is an opt-in service for small-scale renewable generators to receive payments from National Grid ESO if the network operator asks them to turn down or turn off their electricity generation.

National Grid ESO structuring and optimisation manager Amy Weltevreden said: “This capacity through the ODFM service is giving us additional options to manage the transmission network by reducing the amount of electricity supplied at the local network level to ensure there’s not too much power on the grid.”

Weltevreden said that although there are a lot of big wind farms connected to the network, much of the renewable electricity generated comes from these smaller units or what is called distributed or embedded generation.

She said: “Because they’re not connected directly to our transmission system, in the past we haven’t had as much ability to control the power they’re producing to balance the grid.

“If the wind is blowing and the sun is shining, that power they’re generating is being fed into the grid and having an effect on supply and demand.

“For example, in the middle of the day, when sunshine is strongest and solar generation peaks, we will see national demand being suppressed.

“While we don’t see the effects of this generation in real-time in the same way that we can with a big transmission-connected generator, we can forecast with a good degree of accuracy the power they’ll be producing given the likely weather conditions.

“And this is how we’re able to extract the most value from the ODFM service.

“If we’re anticipating the wind blowing at a given time when we’re also expecting low demand, we’re now able to instruct these smaller scale distributed generators to reduce output to help balance the system.

“As with any actions we take to balance the electricity system, they’re carried out in economic order, with cheaper actions taken first, to ensure we operate the system as efficiently as possible for consumers.”

Weltevreden said that on previous recent holiday weekends – Easter and VE Day – demand had been down by as much as 20% on last year in the UK.

National Grid ESO estimates that measures to balance the system this summer as a result of the Covid-19 impact on demand will cost about £500m more than the same period last year.

So-called Balancing Services Use of System charges were £333.2m (€372m) from May to August 2019, with the forecast for this year at £826.3m.

However, if National Grid ESO had not developed new approaches to combat Covid-19 impacts the cost would be higher at about £1.04bn, it said.


So far over the last 24 hours, wind power has averaged about 9GW, and peaked at 11GW. This suggests wind power is running at around two thirds of capacity. (These figures relate to metered output, and excludes embedded output, which as the article notes appears as reduction in demand):



But what is particularly striking is that dispatchable sources, mainly CCGT, nuclear and biomass, have been steadily supplying about half of the demand.

Even on a windy day of low demand, it seems that unreliable wind and solar power are unable to cope on their own.


And because of this unreliability, the National Grid is forking out £500m of our money to balance the grid in constraint payments and the like.




The National Grid have helpfully laid out their costings for us:



They blame this increase in cost on COVID-19, which has resulted in reduced demand. But what they omit to tell us is that, as wind and solar capacity continue to be ramped up, these grid balancing problems will become a permanent feature.

Indeed, with plans to double wind capacity by 2030, along with increased solar power, their problems will become more daunting and costly to solve.

  1. May 23, 2020 7:39 pm

    This is the latest from National Grid ESO (22nd May):

    “It may seem strange that having less electricity on the system causes problems.

    The problems arise due to some of the technical properties of a grid such as:


    These properties are never stable and require constant management. We use the generators connected to the network to manage these properties by varying their output up or down depending on what is required.

    With demand at unprecedented lows, fewer generators are needed to meet national electricity requirements than ever before.

    However, having fewer generators connected means we have access to fewer generators to provide stabilising services.

    Therefore, our approach is to ensure that those generators capable of providing the most stabilising services are connected.

    To achieve this, we have a range of tools available to us. In the last couple of weeks, we have also developed some new approaches to managing system stability.

    These new approaches are essential to ensure we continue the safe and reliable supply of electricity.

    Both the existing and new tools cost money and using them more frequently drives up the overall costs.”

    No it doesn’t seem strange at all to me (it may seem strange to National Grid ESO). We have been saying this for several years now.

    If they want the most stabilising services connected, why have they shut down half of Sizewell B? Sizewell B can operate in Automatic Frequency Response Operation to provide both inertia and stability.

    You cannot trust what National Grid ESO say.

    • Curious George permalink
      May 23, 2020 9:15 pm

      Phil, you are too technical, and not progressive. This shows that nobody really needs nuclear. Ratepayers are better off paying through their noses.

  2. Ian Magness permalink
    May 23, 2020 7:47 pm

    Sorry to be thick here but whilst I understand the concept that you are putting across – ie the extraordinary extra costs of having unreliables in the system. What my brain cell is missing here however, is NG’s self-congratulatory statements about “well, if we hadn’t done this (“development of new services”) it would have cost you over £1bn, so aren’t we clever”. What are they referring to? Surely, the £800m+ shouldn’t be necessary in the first place (if we’d stuck with nuclear, coal, gas etc) so why are they praising themselves?

    • May 23, 2020 8:02 pm

      You are correct. In the good old days of the CEGB (before renewables), the modern, most efficient and cheapest to run power stations would provide baseload with flexible power stations ramping their power up and down to follow demand (load follow). The older, less efficient and more expensive to operate power stations (marginal) would be the last to run up as demand rose and the first to deload as demand fell. There were no extra costs associated with balancing the system. So NG are congratulating themselves for costing consumers only £826m in balancing services instead of £1,039m, whereas they should be telling us that they are costing us an additional £826m to cope with the problems brought about by useless, intermittent and expensive wind and solar power.

      • Graeme No.3 permalink
        May 24, 2020 11:23 am

        Phillip Bratby:
        The TV news today in South Australia is that the Grid Controller is installing the first 2 Frequency Condensers. These will absorb (some of the surplus wind generation) and release it when the output from wind (or solar) drops substantially. This will provide enough time for the backup diesel generators to start up (actually some are required by regulation to be running all the time). Much as coal fired stations (now demolished) supplied free of charge.
        The second set will be installed later this year. All up the cost is only $A160 million or about $20 per head. This is merely the first step in providing stability to the S.A. grid**. Following that we can expect (government? subsidised) batteries and ludicrous pumped storage hydro***.

        **Given than the local Minister for electricity wants to move rapibly to 78% renewables, and the backup (including the big battery) could supply 3-5 minutes only, I expect this to increase,
        *** The ‘new’ State Government is subsidising solar+batteries to cover(?) the drop off in ‘renewables generation’ as the period of peak demand arrives as the wind drops and the sun sinks in the west. This has avoided attention by local politicians.

  3. May 23, 2020 7:56 pm

    Obscene is the only word for it

  4. MrGrimNasty permalink
    May 23, 2020 7:57 pm

    Dear Emily’s twitter account is a jaw-dropping insight into how she and other people that comment have lost the plot. It’s the fault of nuclear for not being flexible!

    “What are all these costly measures? First up there’s this £50 million+ contract for EDF to halve the power output from Sizewell nuclear plant, freeing up space on the system for more flexible plants that National Grid needs to have running.”

    • May 23, 2020 8:11 pm

      Yes, she is incapable of understanding that it is not a good idea to stop Sizewell generating at ~£25/MWh and providing grid stability so that we can pay offshore wind to generate at >£150/MWh whilst destabilising the grid. But then she does not know what she is writing about as she has a degree in history and politics.

      • Chaswarnertoo permalink
        May 24, 2020 10:45 am

        Dunning Kruger in action. A typical Karen.

    • Gerry, England permalink
      May 24, 2020 10:37 am

      I don’t think Emily has gained any knowledge since her Twitter picture was taken!

  5. Geoff B permalink
    May 23, 2020 8:27 pm

    This mess is going to get worse, no more wind and solar should be installed, we have to build more gas. How did the National Grid embrace intermittent generation, they have been negligent in not recognising the problems in advance.

    • May 23, 2020 8:48 pm

      National Grid has no say in what is connected to its grid or the distribution networks. It does not like to upset the government by stating what problems the government’s insane renewable energy policies will cause. It is only interested in profit, which it makes from building all the infrastructure needed to connect wind farms etc to the grid. It gets fined by Ofgem when things go wrong, but the CEO and directors get well-rewarded and will have moved on when the fan really gets hit. If the complete system was still operated and designed by the CEGB, with engineers involved in all decisions, I doubt we would have got into this mess. As it is, decisions are made by politicians and. like most big companies, National Grid is run by financial people.

      • Chilli permalink
        May 23, 2020 9:23 pm

        I agree with your points Philip but if the CEGB did still exist it would be just as infested with eco-loons and climate alarmists as DECC / BEIS given that policy would be dictated by the same idiotic virtue-signalling politicians.

      • Stuart Brown permalink
        May 23, 2020 9:29 pm

        Phillip, your response to Mr GN above nailed what I have been spluttering too much to put into words. But the CEGB weren’t perfect. Engineers (like me), given a free rein, are perfectionists and sometimes put that above reasonable cost. I think the CEGB did – they were a nationalised industry after all.

        The best engineers are also very clever (most probably less like me) and able to turn a crock of cr@p into something that actually works – nothing inspires like a challenge!

        Somewhere in the middle is best, perhaps. How that can be achieved is another question.

  6. michael saxton permalink
    May 23, 2020 9:08 pm

    The ‘unseen’ costs of renewables!

    Sent from my iPhone


  7. Gamecock permalink
    May 24, 2020 12:40 am

    ‘the National Grid is forking out £500m of our money to balance the grid in constraint payments and the like’

    Who are the geniuses who set this up?

  8. May 24, 2020 7:28 am

    The Telegraph reveals record constraint payments of £9.3m to wind farms on Friday.

    “Dr John Constable, director of Renewable Energy Foundation, a UK charity that monitors energy use, said: “Overdeployment of renewables in the UK, particularly uncontrollable wind and solar, has resulted in a very fragile electricity system, which is inflexible and unable to deal with accidents and unexpected circumstances at a reasonable cost to consumers. Grid balancing expenditure so far this year is already horrific and by the end of the summer it will be terrifying. This is a national embarrassment, and a disgrace to the management of the electricity sector who have complacently allowed this crisis to develop over the last decade.””


    • Mad Mike permalink
      May 24, 2020 10:39 am

      Yes, but the reply was

      “RenewableUK’s director of strategic communications, Luke Clark, said: “Wind is one of the UK’s biggest power sources, generating 30% of our electricity in the first quarter of this year.

      “Investing in new grid infrastructure is vital so that renewable generators can continue to provide consumers with the massive quantities of cheap electricity we need to achieve net zero emissions.

      “Constraint payments are the cheapest way for National Grid to run the electricity network within its current limits.

      “All types of generation, including fossil fuels, receive them, but unlike older technologies, wind farms can turn off or on within a matter of seconds, and so wind is often called on by National Grid to vary its output. So it’s actually the best way to keep bills as low as possible.”

      As far as i know fossil fuel energy producers don’t get constraint payments. I cannot find any reference to fossil fuel generators receiving any constraint payment whatsoever.

      If all these renewables are so cheap “so that renewable generators can continue to provide consumers with the massive quantities of cheap electricity” why is my electricity bill continuing to rise?

      Pity this article was not open to comment in the DT

      “Scottish onshore wind farms are far and away the largest beneficiaries of constraint payments, receiving 94% of the total in 2019, and approximately the same proportion averaged over the last ten years (see Figure 2). Scottish onshore wind received nearly £130 million in 2019, and more than £607 million over the decade. The remaining 6% of payments has largely gone to English offshore wind farms, with smaller fractions for Welsh onshore and Scottish and Welsh offshore wind farms”

  9. Andrew permalink
    May 24, 2020 8:18 am

    Perhaps we could appeal to the nation’s patriotism and get everybody to turn on all of their electrical appliances at suitable times. People could turn their ovens and kettles etc on and off as they hear the wind vary in strength and spot clouds approaching the sun.. It might turn out cheaper.

  10. May 24, 2020 8:57 am

    More than half of the Name Plate value the UK electricity generation fleet now consists of Weather Dependent Renewables, Wind (Onshore and Offshore) and Solar.

    But the Productivity that those Weather Dependent Renewables achieved on 2019 was:
    Onshore Wind ~22.9%
    Offshore Wind ~31.7%
    Solar ~10.5%.
    Overall, UK Weather Dependent Renewables gave a combined productivity about 20.9% in 2019.

    It is hardly surprising that on occasions Weather Dependent Renewables produce unwanted power because they cannot be controlled to match demand. Nonetheless, on average to achieve 1 unit of power output one has to install about 5 units of Weather Dependent Renewables.

    Using generation cost data from US Energy Information Administration, when one combines the capital cost / Gigawatt installed with their true productivity factors the costs / Gigawatt installed becomes:
    Onshore Wind ~£4,800 million / Gigawatt
    Offshore Wind ~£11,500 million / Gigawatt
    Solar ~£10,500 million / Gigawatt

    These effective capital costs have to be compared with Conventional generation technologies:
    Nuclear ~£5,600 million / Gigawatt
    Gas-firing ~900£million / Gigawatt

    Conventional generation technologies produce at ~90% productivity and can generally be controlled to match demand.

    Especially with Weather Dependent Renewables being paid a high price for their production and also being paid not to produce their excess power whenever overproduction occurs, how can this possibly be considered to be good business?

  11. Mack permalink
    May 24, 2020 9:58 am

    Well put Phillip and, in the parallel universe in which the NG lives, they call this ‘operating the system as efficiently as possible for consumers!’ Pure comedy gold.

    • Gerry, England permalink
      May 24, 2020 10:48 am

      In defence of National Grid, that statement is true given that the morons in government make the laws under which National Grid and the generating companies must operate. It is no surprise that NG see no benefit in pointing out that the laws made by a succession of governments have made this expenditure necessary given that they have to work with the government. OFGEM used to be the independent voice of the consumer until Milliband turned it into another government agency thus taking away their ability to point out all this waste of money.

      • Mack permalink
        May 24, 2020 10:39 pm

        Alas, Gerry, the statement is only true if loaded with false caveats. Where ‘falsity’ lives ‘lies breed’. It’s a nonsense, as any true qualified engineer would notice.

        The fact that they ‘have to get along’ with the government in order to do their jobs is but an excuse for their complete failure to do their jobs properly for the ‘public good’ and confront government where necessary. The complete surrender of their professional expertise in response to the prevailing ‘winds’ of puffery and make believe science will, when this whole sad history is recorded in years to come, reveal them to be the weakest, shallowest and most pathetic members of a, once, great band of individuals who brought the industrial revolution to the world.

  12. May 24, 2020 10:27 am

    Tell the wind energy suppliers they have to buy batteries with the constraint payments.

    • Graeme No.3 permalink
      May 24, 2020 11:25 am

      old brew:
      Demand that their output can only be plus or minus 10% and you will find a lot of windfarms being sold very cheaply.

  13. James A permalink
    May 24, 2020 2:56 pm

    Interestingly, my electricity went off last night for a few hours. I can’t find information online to explain why.

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