GSP Group Correction Factors data from the Trading Operations Report


The page below details highlighted GSP Group Correction Factors (GGCFs) data from the previous month. This data is acquired from BSC Agents and inputted to the Trading Operation Monitoring Analysis System (TOMAS) database.

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Distribution of Half-Hour GGCFs across all GSP Groups

The chart bellow shows the distribution of GGCFs, as per the latest Settlement Run data, for each Settlement Period in the last complete season and the latest three complete years. Again it shows the effectiveness of profiling, with the ideal being a narrow distribution centered on 1.


The distribution of HH GSP GCFs, across all GSP Groups, for March 2022 continues to be further left than for the same month in previous years. This is likely to be caused by the unexpected GCFs seen over the past few months which continue to be investigated (see “Daily Average GSP Group Correction Factor by GSP Group” graph commentary for further details). 

Half-Hour Correction factors by Settlement Period volume 

The following is based on Initial Settlement (SF) Run for the latest month and is weighted across all GSP Groups.

The chart below shows, for each of the day types used in profiling, a volume weighted average, such as adjusted to reflect the relative sizes of each GSP Group (in terms of total daily energy consumption), of the GGCFs across all GSP Groups by Settlement Period.

The source data are GGCFs from the Initial Settlement (SF) Run taken over the latest month for which SF data is available. The average is taken, for each Settlement Period, over the one month interval to create plots of volume-weighted GGCFs for the periods from Monday to Friday, for Saturdays and for Sundays included in the data set. It allows comparison of profiling for different day types and shows intra-day profiling effects.

Anything between 0.9 and 1.1 is considered reasonable. Values outside this range may indicate issues with load profiling or metering data.


The weighted GGCFs breakdown by day type is between 0.9 and 1.1, indicating no issues with load profiling nor metering data.

Daily Average GSP Group Correction Factor by GSP Group

The chart below is based on the latest Settlement Run for the last two years.

This chart shows the daily average GGCF using the latest Settlement Run data for each GSP Group for the last two years. It shows both profiling and metering effects, as per the earlier explanation on the effects of profiling and metered volumes.


For the first six months of 2021, the majority of GGCFs have been within the expected range (+/- 10% from the mean). Volatility seen in GCFs in April and May 2021, especially around the easing of lockdown restrictions, is mainly due to Profiling Coefficients now include lockdown data.  

 More recently, GCFs have become more volatile. Corrections to a wind farm in North Scotland, along with a number of small sites, have started to impact on the TLFs for the regions as new data enters settlement. Elexon continue to work with distribution companies, NG ESO and other industry parties to identify potential causes. Any findings will be shared with relevant stakeholders in due course. 


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