P350: Consultation on Methodology for Load Periods and Sample Settlement Periods 18 August 2021

This consultation details the proposed methodology for setting Load Periods and Sample Settlement Periods used in the derivation of Zonal Transmission Loss Factors (TLFs), as required by the Balancing and Settlement Code (BSC).


Who will this impact?

The consultation closed on 25 August 2021, and no responses disagreed with using the proposed methodology. The ISG were made aware of the outcome of the consultation, and approved the methodology and the actual Load Periods (LPs) and Sample Settlement Periods (SSPs) created.

How it impacts you

The newly created actual LPs and SSPs were published on the Elexon Portal on 31 August 2021, and will be used in the derivation of TLFs.

Summary of consultation

Views were sought from the Transmission Company and BSC Parties on continuing to use the same method as for previous years. The consultation period ended on Wednesday 25 August 2021 at 17:00. 

The methodology instructs Elexon to:

  • Divide the BSC Year into Electricity Forward Agreement (EFA) Days (23.00 – 23.00), and group the EFA Days
    within each week into blocks of consecutive Working and Non-Working Days. This divides the BSC Year into
    circa 104 blocks of consecutive EFA Days, with each week having a block with five Working Days and a block
    with two non-Working Days (except where there are Bank Holidays).
  • Split each of these blocks into six time bands, corresponding to the six four-hour blocks within the EFA Day.
    Each time band, within each block of days, is a LP, so there will be circa 624 LPs within the Reference Year.
  •  SSPs are then randomly selected from each LP, with one SP taken from EFA Block 1, one from EFA Block 2,
    but two SPs from each of the remaining four EFA Blocks. This means the total number of SSPs in the
    Reference Year will be circa 1040.
  • The sample (1,040 Settlement Periods from 17,520) will be large enough to be statistically representative, and increasing it further would require a change to the TLFA contract.

More details can be found in the consultation document on this page.

Further information

For questions, please contact the BSC Service Desk


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