Posted by Linton CorbetTuesday 25^th August 2026  5:07 PM   Topic: 2026-08-25
On Tuesday 25 August SA Power Networks had planned to conduct its annual test of its ability to temporarily curtail rooftop solar generation.
A high-level overview of the what, why and how of the test is described the SA Power Networks announcement. It explains that the capability to temporarily curtail rooftop PV is needed to manage electricity grid stability when rooftop solar exports are very high and electricity demand is very low, to avoid an unstable electricity grid.
A high-level overview of the what, why and how of the test is described in the announcement. We note:
The test will check:
In the leadup to the test, at 10:00 (NEM time) AEMO’s small scale rooftop PV forecast was indicating there would be 1179 MW exporting in SA at peak.

A south to southwesterly airstream was driving thicker morning cloud away from Adelaide. This is seen in teh Bureau of Meteorology SatView image below. Patchy cloud cover and temperatures in the low teens followed.

It is likely too early to say how much of an impact the test had on demand or other electricity data inidcators. More data, or more analysis, or both is likely needed to assess the test.
In the Trends chart below we observe an increase in SA demand between 15:00 and 15:30 aligning with a decline in rooftop PV. A return to possibly normal demand levels appears by 16:00 and this aligns with a weakening of the rooftop PV decline.
We know there was cloud cover that would create output variability. Further, demand levels appear to have been well below the forecast 1179 MW peak, reaching 879 MW at 14:30. These aspects indicate that fluctuations in the data might be attributable to many things.

WattClarity compiled a list of three different causes/drivers of distributed PV curtailment. In that article, we say “distributed” to encompass small scale rooftop systems and larger commercial systems found distributed throughout the network.  Summarising, for ease of access:
This ability to curtail rooftop PV export levels is sometimes referred to as an emergency backstop mechanism. In SA, the Smarter Homes regulations set out requirements that support  ability to achieve this.
AEMO’s Learnings from industry implementation of emergency backstop mechanisms for distributed resources offers insights into how these mechanisms have been implemented and used (as of 2025).  This report includes learnings from SAPN’s experiences.
Paul McArdle Tue 25^th February 2025 
A question from a client led me to take a (very quick) look at curtailment over the recent weekend (Saturday 22nd and Sunday 23rd February 2025) at New England Solar Farm 2 … with this article a prompt for something deeper that will follow later (time permitting).
Paul McArdle Mon 4^th October 2021 
Looks like AEMO will be announcing a new ‘lowest point’ for Operational Demand in NSW later, given what has happened on Monday 4th October 2021 (Labour Day holiday).
Paul McArdle Mon 29^th September 2025 
On LinkedIn someone wrote about the QLD price dropping to the Market Price Floor for the 10:05 and 10:10 dispatch interval today (Mon 29th Sept 2025). So I had a quick look
Paul McArdle Sat 17^th April 2021 
Looking back at Tuesday 13th April 2021 – a day in which the ex-tropical cyclone Seroja in Western Australia caused some wobbles in rooftop solar PV output in South Australia.
Your email address will not be published.
Comment

Name *

Email *

Website



Δ

© 2026 | WattClarity by Global-Roam Pty. Ltd.

source