AEMO publishes report: ‘Frequency Monitoring–2025 Q3’
On or before 13th November 2025, the AEMO published its ‘Frequency Monitoring – Quarter 3 2025’ report:
frequency control
A quick look at some of the market dynamics around the NEM during this afternoon’s frequency episode
This afternoon we saw mainland frequency briefly step above its normal operating band for approximately 20 minutes — potentially the result of a data glitch. In this quick piece, we unpack some market dynamics...
Belatedly highlighting the AEMO’s ‘Technical Review of the NEM Frequency Control Landscape’ from July 2025
Back in July 2025 we saw the AEMO had released this ‘Technical Review of the NEM Frequency Control Landscape’ … but are only noting this here now.
Tasmanian demand drop on 16 August 2025 – part 2
We follow on from A 292MW drop in "Market Demand" in Tasmania, on Saturday 16th August 2025 enlisting this "Part 2" to understand the sequence of events using 4-second data.
High level view of some contributing factors to 19 August frequency spike
Among other aspects, a large dip in solar UIGF aligns with the frequency deviation observed on 19th August 2025.
Mainland Frequency Spikes to 50.2 on Tue 19th August 2025
On Tuesday the 19th of August between 11:45 and 12:20 there was a significant frequency deviation on the mainland.
Three headline observations, about the use of proxies for System Frequency in Frequency Control mechanisms
Various authors have shared articles about frequency, frequency control and Regulation FCAS in recent times (including 6 from Linton). Here's three things that jumped out to me in these pieces of analysis.
Incentivising primary frequency response
The implementation of the Primary frequency response incentive arrangements rule is driving change in how system frequency is controlled and paid-for. The changes stem from how the NEM will incentivise primary frequency response. 6...
About System Frequency
The NEM operates at a frequency of 50 hertz (Hz) which means the alternating current should cycle 50 times a second between positive and negative voltage.
Last Friday’s large and (mysterious) apparent drop in NSW ‘Market Demand’ (part 3) … what helped restrain frequency?
Friday 31st January 2025 (appeared to) experienced a very large drop in demand in NSW in a single dispatch interval - but we're now suspecting some form of data/operational glitch. However we wonder, if...
Mainland grid frequency: cat ears and golf
It was captured by a keen eyed reader, that the distribution of mainland grid frequency in recent times now exhibits cat ears.
Fast frequency recovery, on Wednesday 3rd April 2024
Fourth article on Wed 3rd April 2024, pertaining to the earlier coincident trip of ER01 and ER02 units at Eraring Power Station.
Missing megawatts and phantom generation
Seven days ago, AEMO notified the market of a Scheduling Error from 24th Jan 2024 to 7th March 2024. A client asked us what it meant - so guest author Allan O'Neil has helped...
The NEMs frequency behaviour – how is it going?
Following recent online discussions, Bruce Miller has produced this in-depth analysis of frequency behavior in th NEM.
Investigating last Friday’s frequent frequency swings
Allan O'Neil provides an explainer about how small deviations in supply and demand are managed in the NEM, in order to help us understand the apparent swings in frequency that we noted in QLD...
Twelve hours of Mainland NEM System Frequency on Friday 3rd February 2023
Another article today presenting 12 hours of history of System Frequency (to ~14:00 on Friday 3rd February 2023) with a few questions added. Comments welcome!
AEMO release preliminary report into the trip of the South East – Tailem Bend 275 kV on 12 November 2022
Last week the AEMO released a preliminary report into the trip of the South East – Tailem Bend 275 kV line that caused SA to be islanded from the rest of the NEM for...
A messy separation: a look at the frequency swings in SA during Saturday afternoon’s islanding event
Dan Lee takes a quick look at 5-second frequency data to show SA's separation from the rest of the NEM and the ensuing frequency swings on late Saturday afternoon.
AEMC published Final Rule on Fast Frequency Response (FFR)
A quick note following AEMC publication of final determination on Fast Frequency Response (FFR).
There were 3 events on Tue 25th May – and it seems likely that QNI separated briefly in Event 2
A deeper look at the frequency data (our own, and also from some others) reveals a number of other interesting things about what happened on Tuesday 25th May 2021 in Queensland.