Re-Issuing of Period Profile Class Coefficients impacting Settlement from January to September 2023

Between 27 January 2023 and 24 September 2023, the Supplier Volume Allocation Agent (SVAA) issued incorrect Daily Profile Coefficients (DPCs) to Non Half Hourly Data Collectors (NHHDCs) on 85 Settlement Days.

Estimates of Annual Consumption (EAC) and Annualised Advances (AAs) calculated by NHHDCs using these inaccurate Coefficients were incorrectly apportioning the volume to each Settlement Period.

Following re-publication of the profile data, there are expected mismatches between the profile data used by the NHHDCs and the SVAA for the same periods, resulting in an over/under calculation of Settlement volumes for affected Suppliers. 

Elexon first became aware of an issue on 18 September 2023 when a BSC Party notified one of Elexon’s Operational Support Managers of unusual patterns in its Profiled NHH consumption for Settlement Dates in September 2023.

Profiling issues identified

Elexon is aware that 85 Settlement Dates in 2023 had incorrectly calculated profiling data. This breaks down to the following Settlement Dates: 

  1. 27 January 2023 to 25 March 2023 
  2. 31 July 2023,  30 August 2023 and 4 September 2023
  3. 5 September 2023 (the Autumn/Winter Start Date) to 24 September 2023

Elexon’s investigation

Elexon teams investigated between 20 and 22 September 2023 and confirmed that the queries raised by Parties were the result of incorrect Daily Profile Coefficients, and that the set of Settlement Dates impacted are those outlined above.  

Our investigation also confirmed:

  • An issue with the Sunset Time that has impacted all the Settlement Dates above. 
  • An issue with the Autumn/Winter 2023/24 Regression Coefficients that has impacted Settlement Dates (listed as point 3) above. 

Circulars issued

To alert the industry to the problem, we issued the following circulars

  • EL03993: Update: Correction of profile data impacting Settlement – 27 February 2024
  • EL03979: Correction of Period Profile Class Coefficients impacting Settlement – 9 February 2024
  • EL03914: Re-Issuing of Daily Profile Data Reports (D0018s) – 26 September 2023
  • EL03912: Re-Issuing of Daily Profile Data Reports (D0018s)-  25 September 2023


Elexon has raised and validated a Trading Dispute (DA1395), with the Trading Disputes Committee (TDC) at its March 2024 meeting. See the full detail in this paper.

Likewise, we presented a paper on the issue at the April 2024 BSC Panel meeting. (See paper 349-09 in the downloaded Zip folder). 

We have also formed an Expert Issue Group, consisting of consisting representation from industry of all impacted parties. This includes:

  • Non Half-Hourly (NHH) Suppliers
  • NHH Data Collectors (NHHDCs)
  • NHH Data Aggregators (NHHDAs).

The role of the Expert Issue Group

The role of this Expert Issue Group will be to: 

  • Assist with the assessment and impact of the issues caused, ensuring it is reflective and accurate from an impacted party perspective. 
  • Collaborate on solutions for correction and/or support in the determination of past impact, versus risk to future settlement operations 
  • Offer advice and feasibility of any (and all) proposed solutions, from a Party and industry perspective.

A Full Terms of Reference for the group is in this document

Next steps for the Expert Issue Group

Through this Expert Issue Group, Elexon will agree solutions with members and take these back to the TDC for formalisation, including industry updates, and if applicable, instruction(s) for correction. 

In order to keep all interested parties up to date on the content of the Expert Issue Group workshops, a summary of discussion points including thinking and actions will be published below: 

Expert Issue Group 1 (8 May 2024)


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