Another example of (presumably VRE-induced) weakness in mainland frequency – Wednesday afternoon 10th December 2025

A quick article late on Wednesday afternoon 10th December 2025 with two charts from an extract of our higher-speed (i.e. at 0.1 second cadence) frequency readings from one of our devices in Brisbane:

2025-10-12-NEM-MainlandFrequency-4Hours

 

We can see that the frequency weakened late in the afternoon, falling down towards the Normal Operating Frequency Band.  So we zoom into the 1 hour timescale surrounding this to see more:

2025-10-12-NEM-MainlandFrequency-1Hour

As we can see in this zoomed-in view:

  • The weakness begins in the 16:50 dispatch interval (NEM time) and progresses from that point;
  • With the 17:00 dispatch interval particularly pronounced; and
  • The lowest point (down at 49.884Hz) at 17:00:04.5

 

Now this is important to note, because …


About the Author

Paul McArdle
Paul was one of the founders of Global-Roam in February 2000. He is currently the CEO of the company and the principal author of WattClarity. Writing for WattClarity has become a natural extension of his work in understanding the electricity market, enabling him to lead the team in developing better software for clients. Before co-founding the company, Paul worked as a Mechanical Engineer for the Queensland Electricity Commission in the early 1990s. He also gained international experience in Japan, the United States, Canada, the UK, and Argentina as part of his ES Cornwall Memorial Scholarship.

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