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Breakdowns force National Grid to issue power supply crunch alert

May 11, 2016

By Paul Homewood  




From yesterday’s Telegraph:

A series of power plant breakdowns and the partial failure of a key electricity import cable forced National Grid to issue an urgent call for more power to keep the lights on on Monday night.

One power plant was paid more than 30 times the usual price of power after the Grid issued the "Notification of Inadequate System Margin" (Nism) requesting more electricity be generated.

A Nism alert has not been issued in summer months since 2008 as the warm weather means power demand is normally lower.

But the combination of a large number of power plants being shut down for maintenance, the series of unplanned shutdowns and wind power being lower than expected together forced Grid to take the unusual step.

Experts said the multiple breakdowns – believed to be primarily old coal and gas plants – showed the urgent need for more investment in reliable new power plants.

National Grid said about  1,700 megawatts of capacity was unexpectedly taken off the system yesterday.

In addition, a problem forced the part closure of a National Grid-owned interconnector cable importing power from France, with the loss of another 500 megawatts.

At the same time, Britain’s wind farms generated about 500 megawatts less power than expected.

National Grid issued an alert at 7pm calling for 1,500 megawatts of power plant capacity to start generating between 7pm and 9.30pm.

National Grid said the highest price it paid to a plant to help it through the crunch was £1,250 per megawatt-hour of power. It is understood this was to E.On’s  Connah’s Quay power plant.

Nism alerts used to be relatively common but had barely been used in the last few years due to a healthy surplus of power plants on the electricity grid. However, that surplus is being eroded as old coal plants are mothballed and shut.

In November, National Grid issued its first Nism since February 2012 and was forced to use "last resort" measures to keep the lights on by paying businesses to use less power.

Dr Jonathan Marshall, energy analyst at the Energy and Climate Intelligence Unit said that Monday’s Nism alert showed "once again that the UK power system badly needs new investment".

"Seven sources of electricity failing simultaneously just shouldn’t happen, and the presumption must be that the age of these plants increased the chances of failure."

A spokesman for  National Grid said: "The notice that was issued is part of our standard toolkit for balancing supply and demand and when issued is not an indication there is an immediate risk of disruption to supply or blackouts; it is an indication that we would like our power held in reserve to be higher."

A spokesman for the Department of Energy and Climate Change said: "By issuing a NISM, National Grid is doing its job to make sure there is enough electricity to power our homes and businesses.

"It is simply a tool National Grid uses to ask power stations to respond and generate more electricity for a short period of time.

"We are clear that delivering energy security for our families and businesses is non-negotiable and this is just part of making sure they have secure and affordable energy supplies they can rely on."

A spokesman for E.On’s power plant division Uniper declined to confirm the price it was paid.



Demand was running at around 33GW on Monday evening at 8.00pm.




While there was never any prospect of power cuts, this episode shows how near to the bone power capacity is.


The Committee on Climate Change’s 5th Carbon Budget suggests that the UK will need about 25GW of new dispatchable capacity by 2025, to replace old plant bring shut.

  1. AndyG55 permalink
    May 11, 2016 11:38 am

    “about 1,700 megawatts of capacity was unexpectedly taken off the system ”

    unexpectedly.. all at once.

    Maybe the coal-fired electricity owners have decided its time to send a message 😉

    About bl***y time !!!

    • May 13, 2016 5:38 pm

      Sounds like the infrastructure needs new investment. Guessing the plans went offline because they’re getting old.

      Build some new plants and that won’t be a problem. The Greens wont like it.

  2. AndyG55 permalink
    May 11, 2016 11:44 am

    What should happen now is that the fossil fuel power stations should say..

    we will guarantee to supply 24/7,

    if you will guarantee to buy 24/7

    This is something un-reliables could NEVER say.

  3. saveenergy permalink
    May 11, 2016 12:09 pm

    Maybe ALL power suppliers should be forced to guarantee to supply an agreed amount of energy ± 5% at an agreed price & if they cant produce it themselves – then they have to buy from someone who can (whatever the price).

    How they generate & how much is (within the law) up to them & over supply is their problem not someone else’s.

  4. AlecM permalink
    May 11, 2016 1:12 pm

    Keep on squeezing those CCC balls, central power generators, until their eyes pop and these retards agree to relinquish their control of this Utility.

  5. May 11, 2016 3:45 pm

    “the real question for this typical Elon Musk construct is not whether the company is the next SunEdison, but whether Tesla will be the next SolarCity.”

    SolarCity Corp (SCTY): The Beginning Of The End?

  6. It doesn't add up... permalink
    May 11, 2016 5:30 pm

    I don’t think this is the whole story. I looked at the performance of wind forecasts against actual generation previously – and these showed a strong tendency to underperform when the forecast was above about 5.75GW:

    This in fact strongly suggests that wind output is being curtailed at this level, perhaps because of grid constraints (Scotland can only export 3.5GW to England, as shown here: ). There is also the question of the impact of high levels of wind generation on grid stability, especially at lower levels of demand, when grid inertia may prove inadequate. Here’s the comparison between forecast and actual on the day, together with the day ahead half hourly settlement prices:

    But wait – there’s more. The pattern of interconnector flows is rather strange:

    Overnight the BritNed line had been supplying a slightly reduced 800MW of coal based power into a low priced market. It stopped completely for the rest of the day – suggesting that there was additional demand in ?Belgium to be met. The later drop in French flow may be part of the same syndrome. Also notable is that the Irish were importing during the day, although wind was clearly operating at reasonable levels – did they too have an outage?

    Putting it all together gives the following apparently unremarkable UK picture (apart from the price spike):

    The price spike does seem to correlate with sundown – was the ramp rate required to replace solar across the continent partly responsible for the general supply tightness?

  7. It doesn't add up... permalink
    May 11, 2016 5:32 pm

    Ugh! lost a long post with much careful research and links – just disappeared when submitted.

    • May 11, 2016 6:27 pm

      It was in moderation! Just fished it out

      • It doesn't add up... permalink
        May 11, 2016 6:39 pm

        Thanks – there are now two versions! Some added info below

  8. It doesn't add up... permalink
    May 11, 2016 6:04 pm

    In bits:

    I don’t think we have the whole story.

    I previously posted this analysis

    which shows that actual wind production never seems to reach higher forecast levels above about 5750MW, strongly suggesting it is curtailed. Further evidence for curtailment comes from the apparent limit of 3.5GW on Scottish power exports to England

    and there may also be considerations about limitations to grid stability.

  9. It doesn't add up... permalink
    May 11, 2016 6:13 pm

    Wind production on the day against day ahead forecast looked like this:

    Forecast levels certainly extend into the zone where curtailment apparently occurs, but without information on actual curtailment it is hard to be sure.

  10. It doesn't add up... permalink
    May 11, 2016 6:22 pm

    There’s more: the role of interconnectors seems very odd:

    The BritNed line was feeding about 800MW of coal based power into a low priced market overnight, but then stopped altogether for the rest of the day. Indeed, it has remained at zero flow since. There was a small partial compensating boost from the French up to full capacity before they dropped almost 1 GW as the sun went down – was this to help with the ramp rate required by the loss of solar on the Continent or some other outage?

    It’s also notable that the Irish were importing power during the day, despite reasonable wind levels, as if they are short of dispatchable power too.

    (Charts show the 48 half hourly settlement periods during the day)

  11. It doesn't add up... permalink
    May 11, 2016 6:35 pm

    The price spike shown is in the settlements the previous day for day ahead power, so clearly the problem was actually anticipated by the market, and was not the consequence of some unexpected wind shortfall. Indeed, the assembled picture for UK supply looks otherwise unremarkable:

    Except perhaps for the low levels of conventional Hydro, which were doubtless constrained by the Scottish interconnection limit. This does at least explain the BritNed outage:

    Planned maintenance.

  12. 3x2 permalink
    May 12, 2016 6:36 pm

    Lunatics and Asylum are both parts of a phrase that comes to mind.

  13. It doesn't add up... permalink
    May 12, 2016 9:54 pm

    I should have thought this through properly. If they’re hoping to supply 380TWh/year, we’ll probably need more dispatchable capacity than today to meet peak demand – that probably means over 40GW of CCGT to add to the 13GW in the rest of their plan, even though its average utilisation will be under 35%. Of course, it would be far better to dispense with the renewables and boost the utilisation on the CCGT.

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