Untangling UK Wind power production

There are currently 6044 operational wind turbines in the UK with a total capacity of 12.133 GW. Do we know how much electrical power they generate? The answer is not simple. These 6044 turbines are installed in over 700 sites, some of which are very large while others are only a single turbine.  There are 3 ways to connect them to the Grid.

1. Direct transmission line to the Grid. This is suitable only for large wind farms especially off-shore. The output of such wind farms is metered through the ‘balancing mechanism’, from which Gridwatch and this site get their live updates. A full list of these directly connected wind farms are given below.

Wind Farm Capacity (MW)
Arecleogh 120
Clyde 462
Carraig Gheal 46
Crystal Rig 138
Greater Gabbard Offshore 501
Griffin Wind Farm 204
Gwynt y Mor offsgore 592
Hadyard Hill 130
Humber Offshore 220
Harestanes 126
London Array 720
Lincs Offshore 540
Ormonde 160
Sherringham Shoal Offshore 315
Thanet Offshore 300
West of Duddon Sands 382
Whitelee 511
Walney Offshore 369
Westermost Rough 205

Total Capacity = 7.1 GW

I had thought that these were all the ‘metered’ wind farms included in the Balancing Mechanism BM reports. However I later discovered that those in category 2 are also metered because they receive constraint payments.

2. Secondly there are wind farms that are registered  with the Balancing Mechanism, but are ‘BM embeded’ in the local distribution network. These large to medium wind farms are still visible to the Balancing Mechanism and their output is metered. We know this as they receive constraint paayments to disconnect when there is too much wind. This is the list of such wind farms

Baillie Wind Farm 52.5
BETHW-1 29.75
Braes of Doune 74
Berry Burn Wind Farm 66.7
Beinn An Tuirc 2 43.7
Burbo Offshore Wind 90
CLDRW-1 37
Clachan Flats 15
Dalswinton Windfarm 30
Gordonstown 13
Goole Fields Wind Farm 34.476
Glens of Foudland 26.7
Gunfleet Sands Demo 11.7
Great Yarmouth Power Limited 405
Hill of Towie 48
Minsca Wind Farm 36.8
E_RHEI-1 52
Tullo Extension 25

Total capacity = 1.1GW

Therefore the total metered capacity of wind farms within the BM system is simply the sum of category 1 and category 2.

Total Metered Capacity = 8.2 GW

The real-time output from category 1 and 2  wind farms is shown below:

3. Now there are about 600 smaller wind farms ranging from 1 up to to 40 turbines that have a connection to the regional Distribution Network Operator (DNO) and are paid ‘Feed-In Tariffs’ (FITS). These smaller wind farms are not part of the balancing mechanism and are therefore not metered centrally. Their net effect on the National Grid is to reduce demand slightly via the local distribution network. They must have an on-site transformer to convert generated DC to 3-phase AC and connect to the local DNO. They may also use generated energy locally and then get paid a discount because it is ‘green’. The exported electricity  is metered locally and receives the FIT as shown below.


The estimated total FIT capacity of these 600 farms =  3.8 GW (the difference of 12GW and the metered total).

Unfortunately the output from wind farms in category 3 is never made public. It is impossible to know the real-time power from these wind farms. What I originally set out to discover was  what percentage of  total wind power is measured by the Balancing Mechanism. It has been a headache to get all this information together, but I think we can now estimate the total output from all UK wind farms. To do this we can simply assume that the load capacity for the  feed-in wind farms is the same as that for the metered farms, (which may be optimisitic as the largest farms are off-shore). Under this assumption  the correction factor to be applied to the BM reports values is 12/8.2 = 1.46.  So the actual wind power  from all UK wind farms to electricity generation in the UK right now is:

Therefore I will in future increase the BM reports values for wind power output by this factor to better reflect the actual situation.


  1. UK Wind Energy Database (UKWED)
  2. Elexon
  3. Variable Pitch
  4. Renewable Energy Foundation

About Clive Best

PhD High Energy Physics Worked at CERN, Rutherford Lab, JET, JRC, OSVision
This entry was posted in Energy, renewables, Science, wind farms and tagged . Bookmark the permalink.

22 Responses to Untangling UK Wind power production

  1. Euan Mearns says:

    Clive, VERY useful analysis.

    • Clive Best says:

      Thanks Euan. Can you imagine how difficult it would be to untangle solar? Transparency should be a point of principal for all interests receiving public subsidies.

      • Joe Public says:

        The £amount of subsidies paid to individual wind & solar farms should be published by NG; and, aggregate proportions should be shown on every electricity bill.

  2. Pier says:

    dear clive one question: you write a book with Madrigali?
    see this site http://www.meteoclima.net

  3. A C Osborn says:

    Clive, so according to Gridwatch, during the last 30 days Wind has actually hit pretty close to 100% output a couple of times?
    Around the end of March and the 11th of April.

    • Clive Best says:

      No – the metered wind output NEVER exceeds about 6.3GW. 100% would be 8.2GW. The reason is simply that the national Grid cannot handle more than 6.3 GW of wind power. This is what the constraint payments are all about. We all pay via the National Grid wind farms to disconnect from the Grid when the wind blows too strongly. Some days we pay a few wind farms a several million quid for a few hours disconnect!

      The main bottle neck is the transmission lines from Scotland to England. Scotland has some of the biggest wind farms with the strongest winds but can’t use the power locally. National Grid have plans to increase capacity which we will pay for through our bills. The wind farms get off ‘scot free’ and can’t lose. whatever happens.

      There is no point in building any new large off-shore wind farms until the grid gets updated. This is the hidden cost of wind – several billion quid in power lines all over our countryside.

  4. Ron Graf says:

    Clive, I especially like the meters. Did you create the graphics? It’s very effective marketing if the power companies did not think of it themselves. I pay eight cents per KHW in eastern USA. What is the average in the UK?

    • clivebest says:

      The meters are based on a free HTML5 package – Rgraph. It uses Javascript/Ajax to update the values live from the Grid everytime you load the page.

      Electricity prices in Europe are very interesting. They seem to be proportional to how much subsidies are paid to renewables. These are the prices in Euro-cents per kWh


      Denmark and Germany has the most expensive electricity in Europe and the largest wind farm fleets. French electricity is 80% nuclear. Poland and Hungary are mostly based on coal. Government policy determines electricity prices it would seem.

      • Joe Public says:

        Electricity prices also fluctuate Time-of-Day.

        For (UK) domestic users, there are usually day- and night-rates. Something of the order of: Day 17.510 p/kWh, Night 5.950 p/kWh

        For large Industrial / Commercial users, they are ½-hourly metered, whereby their peak ½-hour demand affects their ‘unit’ price. For the entire month.

    • Ron Graf says:

      Correction: 7 cents USD is what I pay for the power but I also pay 5 cents for transmission to my utility which is the part I can’t shop for. Here is the US electricty rates for Jan 2015 broken by USA states and sectors. The average in USD cents is:

      2014 10.13
      2015 10.19

  5. PhilH says:

    Doesn’t this article confuse the UK with GB? The National Grid and its Balancing Mechanism serves just GB – NI’s grid was separate, and is now (increasingly?) integrated with that of the RoI.

    According to the UK Wind Energy Database, GB currently has 5651 operational turbines, with a capacity of 11,528 MW. (NI having the difference from the article’s figures: 393 turbines of 606 MW capacity.)

    How does this alter the conclusions of this article?

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  9. dear Clive, have some truth / reality:

    They are a ”climate from changing Stoppers” by building those stupid wind turbines for electricity…?! Let me tell you about reality: -”before Nikola Tesla invented hi voltage electricity – Edison had to produce electricity on the spot, where is used; because 240 volts has very high resistance in the cable – in 2-3km cable most electricity is lost by resistance, cable overheats. So: Tesla invented hi voltage in the power stations AND the transformer, to reduce it back to 240 volts in the town / suburbs, to be used. Well; those wind turbines produce ”low voltage” electricity – only when the wind is from appropriate direction – on the top of the hill. From the top of the hill, to the city main greed, if is 10-15-30km, almost all electricity is LOST BY THAT ”RESISTANCE” in the cable, but you as user are paying more than double price; FOR SOMETHING THAT YOU DON’T GET at all!!!

  10. Grant says:

    A small update observation.

    The bmreports web site started indicating a total of metered wind capacity as 8972 MW a few weeks ago. So presumably and addition 700 MW or so suddenly came on line?

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