Cross posted from Clive Best. Clive is a physicist of some distinction and a climate and energy blogger with coding skills that go beyond the norm. In this post he explains the portion of UK wind power generation that is metered by BM reports and that portion that is not. This is vital to the understanding of load factors, economics and the efficiency of UK wind power.
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)|
|Greater Gabbard Offshore||501|
|Griffin Wind Farm||204|
|Gwynt y Mor offsgore||592|
|Sherringham Shoal Offshore||315|
|West of Duddon Sands||382|
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|
|Braes of Doune||74|
|Berry Burn Wind Farm||66.7|
|Beinn An Tuirc 2||43.7|
|Burbo Offshore Wind||90|
|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|
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.