More about that decay of mainland frequency at lunchtime on Friday 29th August 2025 (i.e. Part 2)
Taking a second look at the midday decay of mainland frequency on Friday 29th August 2025.
Market Operations
Mainland frequency drop with Loy Yang A1 trip on Saturday evening 30th August 2025
On Saturday evening 30th August 2025 there was a trip (and then subsequent recovery) of the Loy Yang A1 unit - we take a look at frequency change.
Queensland’s minimum ‘Market Demand’ point drops lower still, on Sunday 31st August 2025
Worth a quick note with a NEMwatch snapshot at 10:35 (NEM time) on Sunday 31st August 2025 to mark the ‘lowest ever*’ point for ‘Market Demand’ nudging lower still in the Queensland region.
Unplanned outage on Yallourn Unit 2 extended another ~month (with new RTS expectation 22nd October 2025)
As a further update on outage expectation for the damaged YWPS2 (which tripped with 'LP turbine issue' on Tue 26th August) the latest return to service expectation is now not until 22nd October 2025.
Decay of mainland frequency at lunchtime on Friday 29th August 2025
As another case of frequency disruption on the mainland grid, we spotted this trend occurring just before midday on Friday 29th August 2025.
Unplanned outage on Yallourn Unit 2 pushed out ~2 weeks (with new RTS Thursday 25th September 2025)
An updated look (as at 14:10 on Thu 28th Aug 2025) of expected return to service for YWPS2
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.
Frequency change with Yallourn unit 2 trip
We assess whether the trip at Yallourn 2 on 26 August 2025 was large enough to drive a frequency disturbance.
Peeling the onion a little more – Solar Farm performance on Tuesday 19th August 2025, with the frequency spike to 50.2Hz
As the 5th article in an evolving series that progressively explores the (apparent self-forecasting glitch and) frequency spike on Tuesday 19th August 2025, we take an early look at Solar Farm performance.
Prices spiking again in South Australia (for Lower 1 second FCAS) on Wednesday 27th August 2025
A very short article with a snapshot from ez2view at the 11:15 dispatch interval – highlighting that Lower 1-second FCAS prices in the South Australian region are spiking (yet again!).
Notable forced outage at Yallourn Unit 2 … due to ‘LP turbine issue’
A first article about an unplanned (and potentially significant) outage at Yallourn unit 2 that began on Tuesday 26th August 2025 due to 'LP turbine issues'.
Several coal units offline (on Wednesday 27th August 2025) with unplanned outages
A short note with a snapshot of the ‘Generator Outages’ widget in ez2view (at 08:30 on Wed 27th Aug 2025) to highlight some coal units offline.
Following the 2025 ESOO, MT PASA shows forecast Low Reserve Conditions in the South Australian region (Dec 2026 to March 2027)
Following from the release of the 2025 ESOO last Thursday, the subsequent weekly MT PASA run warns of *forecast* LRC (and unserved energy) in South Australia.
The current burst of production at Tamar Valley CCGT coming to an end, on Thu 28th August 2025?
An article in the Australian by Colin Packham prompts a look in AEMO data about expectations for when Tamar Valley CCGT might be switched off.
Administered Pricing for FCAS services in South Australia ended on Sunday 24th August 2025 … so what’s next?
On Sunday 24th August 2025, Administered Pricing for FCAS in South Australia ended ... when will the ‘S-TBTU’ constraint set re-emerge?
Three broader questions (re)triggered by the Frequency Spike on Tuesday 19th August 2025
The (concerning) frequency spike across the NEM in the middle of the day (Tuesday 19th August 2025) has triggered many proximate questions - understandable - but also has raised these 3 Broader Questions.
Unit deviations from target on Tuesday 19th August 2025
It appears it was unit availability used to set the target for dispatch that went awry, rather than unit output.
A ~50-day view of rising spurts of volatility in the LOWER1SEC FCAS market in South Australia
With Administered Pricing in South Australia ongoing today, we take a longer-term look (across the past ~50 days) in the escalating pressure on Cumulative Price for LOWER1SEC FCAS in South Australia.
Network outage on Tailem Bend – Tungkillo 275kV line ended Tue 19th Aug, but Administered Pricing Continues into Wed 20th Aug (part 3)
Part 3 in an evolving series of articles about a series of the network outage(s) on the Tailem Bend - Tungkillo 275kV line that's driven LOWER1SEC prices through the roof and triggered Administered Pricing...
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.