National Grid Electricity System Operator has confirmed this winter’s periods of peak demand, known as Triads.
Transmission charges for large businesses are based on these periods, the three half hours of highest demand that are at least 10 days apart, between November and February.
But the cunning trick is that National Grid only reveals them retrospectively – and failing to hit a Triad can be very expensive.
As a result, many firms curb consumption or switch to onsite generation over winter evenings to try and reduce their bills.
Fear of missing a Triad results in an estimated 2GW of demand reduction when a peak period is deemed likely.
That reduction is encouraged by an army of consultants, who send Triad warnings to their clients, aiming for the coveted prize of guessing the three peaks in the lowest number of calls.
Winter 2018/19 Triads were:
- Thursday 22-Nov-18 from 17:00-17:30 with peak demand at 45.3MW
- Monday 10-Dec-18 from 17:00-17:30 with peak demand at 45MW
- Wednesday 23-Jan-19 from 17:30-18:00 with peak demand at 46.9MW
The three peaks continue a downward trend – the lowest for around quarter of a century.
The Triad mechanism looks set to be scrapped as part of Ofgem’s charging review, but will likely remain in place for a few years yet.