A short (and slightly belated) note to record that the outage on one Tailem Bend – Tungkillo 275kV line outage ended yesterday (Tuesday 19th August 2025) morning.
Remember that:
1) This outage was reflected in the ‘S-TBTU’ constraint set;
2) Which had been a root cause driving the Lower 1 Second (i.e. FFR) FCAS price in South Australia sky high for a sustained period;
3) Which had driven the Cumulative Price to the Cumulative Price Threshold triggering Administered Pricing across all 10 x FCAS commodities in South Australia
4) As discussed earlier in part 1 and part 2.
The end of the Outage…
Some of this is illustrated in this mashup of two separate constraint equation related widgets in ez2view, both focused on the same outage:
We see:
1) At the top is the ‘Constraint Sets’ widget, which has the Gantt-style representation filtered down to those constraint sets pertaining to ‘Tailem Bend’ or ‘Tungkillo’
2) At the bottom is the specific ‘Constraint Set’ details widget focused specifically on the ‘S-TBTU’ constraint set;
Note that, whilst the constraint set has now become un-invoked, it’s set for round 2 next week (Tuesday 26th, Wednesday 27th, Thursday 28th and Friday 29th August 2025) … so watch this space!
… but Administered Pricing continues (for now)
Worth highlighting, however, that (even though the outage ended yesterday morning) AEMO has continued with Administered Pricing for another day – as noted in MN128611 as follows:
‘——————————————————————-
MARKET NOTICE
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From : AEMO
To : NEMITWEB1
Creation Date : 20/08/2025 03:55:12
——————————————————————-
Notice ID : 128611
Notice Type ID : ADMINISTERED PRICE CAP
Notice Type Description : Administered price periods declared.
Issue Date : 20/08/2025
External Reference : [EventId:207] AP STARTED for market ancillary services in SA1 at 20 August 2025 0355
——————————————————————-
Reason :
AEMO ELECTRICITY MARKET NOTICE
Issued by Australian Energy Market Operator Ltd at 0355 hrs on 20 August 2025
ADMINISTERED PRICE PERIOD DECLARED in SA1 region.
AEMO has determined that the rolling sum of the uncapped market ancillary Lower 1 Sec services prices for the SA1 region over the previous 2016 trading intervals has exceeded the cumulative price threshold (CPT) of $1,823,600.00.
In accordance with Clause 3.14.2(b) of the National Electricity Rules, AEMO has determined that an administered price period will commence at the trading interval starting 0405 on 20 August 2025 and will continue through to the end of that trading day.
An administered price cap (APC) of 600 $/MWh will apply to all trading intervals during this administered price period. This APC will apply to all market ancillary service prices in the SA1 region.
AEMO will continue to monitor the rolling sum of the uncapped market ancillary service prices and issue further Market Notices as required.
This is an AEMO autogenerated Market Notice.
——————————————————————-
END OF REPORT
——————————————————————-‘
We need to take a few days before the effect of the volatility last Friday washes through the rolling sum.
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