System frequency at 11 am in 2026

Here we present system frequency measured by Global-Roam’s high-speed logger in Brisbane.

We’ve filtered the data to between 10:48 and 11:30 each day, for all days between 1 March and 23 June, 2026. Each day’s frequency series is a grey line. The red line is the mean, by time of day.

A tendency towards low frequency at 11 am

We are detecting a tendency towards under-frequency conditions just after 11am. The tendency emerges in April and gets stronger in May and June. By June the dip in frequency just after 11 am is clear.

The dip extends outside the PFR deadband (+/- 0.015 Hz). Cheap power tariffs leading to a sudden (and emerging as material) increase in electric load are suspected to be the key driver of the dip.

By 11:05 a new dispatch run sets new supply targets to correct the imbalance. So, by 11:06, we observe frequency recovering to its typical ranges and patterns in the leadup to the end of that dispatch interval (11:10).

Other aspects of note include:

• The predisposition of the Hz values to be around 50.02 and 49.98. It swings between these points and spends little time between.
• The frequency excursion of 10 April was just prior to the time range we study here, at 10:30, so not shown.