We can see that the frequency weakened late in the afternoon (Wednesday 10th December 2025), falling down towards the Normal Operating Frequency Band.
We’ve already posted about how ‘Mainland Frequency dragged downwards around sunset, on Sunday 30th November 2025’. Here, we see how underperformance across Large Solar Farms was a major cause.
This late afternoon weakness in system frequency (on Sunday 30th November 2025) seems noteworthy.
An update of earlier article (from 8th Sept 2025) comparing Frequency Excursions with instances of large AggROT across Semi-Scheduled units - for 2025 Q3 and 2025 Q4 (ytd).
I’m not sure if related to the severe weather warnings for both QLD and NSW today, but here’s a quick record of some afternoon weakness in frequency control on Saturday 15th November 2025.
With respect to the ~17:00 period on Thursday 30th October 2025 (and the frequency drop, possibly outside the NOFB), we take a look at the Dispatch Error of individual Semi-Scheduled units to find patterns.
We’ve just noted the frequency drop on Friday afternoon 31st October 2025, and so take a look at 'Aggregate Dispatch Error’, to see if it's likely we are correct in our hypothesis - that...