One image to summarise the sequence of events in the Frequency Spikes of Fri 10th and Sat 11th April 2026

It’s Sunday 26th April 2026, which means that:

• It’s 16 days since the frequency spike (at 10:30) on Friday 10th April 2026; and
• It’s 15 days since the almost identical frequency spike (at 14:20) on Saturday 11th April 2026.

These events are still of keen interest to us, for several reasons – but we’ve been otherwise focused on current, new and prospective clients these since then, so have not been able to add much to the collations of articles

We’ll have to wait a number more days before we can re-commence the analysis – but we wanted to present this single image which summarises the sequence of events (for a number of Semi-Scheduled units) over three dispatch intervals across the pair of frequency spikes.

This should frame the analysis and results that will follow…

Useful pre-reading here to provide context to the above are:

• With respect to the structure of dispatch intervals:
  • This ‘… first step into the complexities of) the Dispatch Interval in the Real World’; and also
  • and also AEMO’s own ‘NEM Dispatch Timing Fact Sheet’
• And, with respect to specifics of Semi-Scheduled units (which are the focus here, and were the main cause of these particular frequency spikes), Linton’s article ‘What inputs and processes determine a semi-scheduled unit’s availability’

Finally it’s worth remembering that there were 201 x Semi-Scheduled units registered at the times of these two spikes … so (as alluded to in this ‘… big clue to one causal factor in both frequency spikes’) there are really 201 different stories:

… albeit a number of those stories have clear similarities summarised in the above.