On Tue, 21 Jan 2020 23:21:24 +0000 (GMT), "Dave Liquorice"
wrote:

On Tue, 21 Jan 2020 19:32:22 +0000, Andy Burns wrote:

gonna be tight this evening...

Looks like the evening peak started mid-morning instead ...

Yes, yesterday and today have had fairly flat and high day time
demand profiles. Unlike the working days last week (or even the
weekend) with lower demand morning/afternoon and defined early
evening peak.

Why?

Quite possibly Triad avoidance

The three peak half hour demands over the period November to February, separated
by 10 days determine how the Transmission Use of System charges are apportioned
to commercial and industrial consumers.

The Grid Operator regularly publishes the predicted Triad demands and weeks in
which they might occur but the possible Triads (as in day and half hour period)
are published the day after the event with the actual Triads formally declared
after the end of the Triad period.

A common industry practice by utilities is prediction of the actual Triads as
avoidance of demand in a Triad equates to lower bills for the rest of the year.

Triads should normally but not always occur at around 1600-1900 hours, but they
will always be on weekdays, so it makes sense to push your own peak usage to
outside that period which also avoids a clash with the domestic peak at
1800-1900. So the usual outcome is a much flatter demand curve.

So in a production environment running with the possibility of a flexible and
variable downtime, a shift changeover between say 4pm and 8pm with maintenance
performed in those periods can pay huge benefits. You just run production
longer, faster and harder away from the triad periods such as overnight or
indeed most of the day away from the peak demand times.

But it's all temperature, wind chill and light level dependent.

Take yesterday as an example, the forecast demand peak was 46480MW at 17:30, the
actual was 45318MW at 19:00

The three previous highest demands that met the Triad criteria were 44292MW at
17:00 on the 18th November, 44102MW at 17:00 on 2nd December and 43487MW at
16:30 on 17th December.

So pending any futures peaks until the end of February, yesterday, 21st January,
was almost certainly a Triad day, having both higher demand than all three
previous Triad peaks and meeting the criteria of being separated by 10 days from
all of them.

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