Please note:

The dates shown in this table are purely indicative, being based on peak demands calculated using operational metering data, and so the final triad dates may well be different from these dates.
When available, the final definitive triad dates ( as calculated in accordance with the Statement of Use of System Charging Methodology (chapter 4) at https://www.nationalgrid.com/uk/electricity/codes/connection-and-use-system-code?code-documents ) based on the latest available settlement metering data, are published on the National Grid website at https://www.nationalgrid.com/uk/electricity/charging-and-methodology/charging-policy-and-guidance normally at the end of March each year for the preceding Nov-Feb winter triad period.

The Peak Demand is used as a short hand way to describe the three settlement periods of highest transmission system demand (adjusted to exclude demand from Interconnectors) within a Financial Year. These represent the half hour settlement period of system peak demand and the two half hour settlement periods of next highest demand. These two periods of next highest demand must be separated from the system peak demand and from each other by at least 10 Clear Days, between November and February of the Financial Year inclusive. The Indicative Peak Demand Information on the BMRS does not constitute a forecast of when the Triads are expected to occur, but is a summary of publicly available demand data that may be of assistance in parties own triad forecasting activities.

Highest Demands so Far

Between November and February, this table shows the three settlement periods of highest demand (subject to the 10 Clear Day rule) in the triad period so far (i.e. since the start of November). Between March and October it shows the three settlement periods of highest demand in the previous triad period. In both cases the demand figures are based on operational metering, not settlement metering, and are therefore indicative only.

Highest Forecast Demands

Between November and February, this table shows the three highest demand peaks in the remainder of the triad period (i.e. up to the end of February), based on the 2-52 week ahead demand forecast. Between March and October it shows the three highest demand peaks for the next triad period, again based on the 2-52 week ahead demand forecast. Because the source data is at a weekly resolution rather than a daily resolution, the 10 Clear Day rule cannot be accurately applied. Instead, as an approximation to it, only demand peaks in non consecutive weeks are shown.

Indicative Peak Demand Information on the summary page is based on the TSD definition (see "Peak Demands" info tab).

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Please note:

The dates shown in this table are purely indicative, being based on peak demands calculated using operational metering data, and so the final triad dates may well be different from these dates.
When available, the final definitive triad dates ( as calculated in accordance with the Statement of Use of System Charging Methodolog... Show More