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.


There are no major highlights.

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.


The majority of GGCFs have been within the expected range. The expected range is +/- 10% from the mean since autumn 2020. Some volatility from April onwards (particularly around the days when lockdown restrictions were lifted in phases e.g. May 17th and June 21st) is mainly due to the change in Profiling Coefficients, which now include lockdown data. Elexon will investigate any outliers.  


Zero GCF value in the GSP Group _B on 8 October 2020 is due to an issue with a subset of the NHHDA/HHDA data submissions. It is expected to be resolved in the next SVAA Settlement Run (RF) due on 25 November 2021. Please refer to the Circular EL03321 for more details.


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