A collation of articles pertaining to Tuesday 19th August 2025. On this day …
1) We saw a continuation of Administered Pricing for all 10 x FCAS products in the South Australian region:
(a) following the initial triggering of AP on Saturday 17th August 2025.
(b) which flowed from an outage on one Tailem Bend – Tungkillo 275kV line (represented in the ‘S-TBTU’ constraint set)
2) We also saw a large frequency spike across the NEM lasting ~30 minutes and outside of the Normal Operating Frequency Band in the middle of the day.
In this article we take a look at operations of Waratah BESS through August 2025 - including some large Dispatch Errors on several days: (a) including Fri 29th Aug 2025, and how WTAH1 apparently...
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.
On Sunday 24th August 2025, Administered Pricing for FCAS in South Australia ended ... when will the ‘S-TBTU’ constraint set re-emerge?
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.
It appears it was unit availability used to set the target for dispatch that went awry, rather than unit output.
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.
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...
Among other aspects, a large dip in solar UIGF aligns with the frequency deviation observed on 19th August 2025.
On Tuesday the 19th of August between 11:45 and 12:20 there was a significant frequency deviation on the mainland.
With Administered Pricing of all 10 x FCAS products in South Australia continuing into Monday 18th August 2025 (no surprise there), we take a second look.