Looking more at (commissioning) operations at Waratah BESS through August 2025

Back on Friday 8th August 2025, we’d published an article ‘Recapping operations at Waratah BESS (including enablement for SIPS) … to August 2025’.

In the ~3 weeks since that time, we’d seen a fair bit of commissioning activity at the Waratah Battery (DUID = WTAHB1).

(A)  From Elsewhere

For understandable reasons, others like writing (and presumably the audience likes reading) about the progression of these big new fast assets – and I’d particularly noted two articles in quick succession on RenewEconomy:

1)  On Saturday 16th August 2025, Giles wrote about ‘Waratah, Australia’s most powerful battery, smashes output record again’.

2)  Then on Monday 25th August 2025 Giles had followed with ‘Super “shock absorber” battery smashes records again as it charges and discharges at unseen levels’.

… note that there were earlier articles, but I wanted to focus just on those in August, in the time period after my article on Friday 8th August.

(B)  What’s in the AEMO market data?

The above should be read in conjunction with a deeper dive into some of the AEMO market data … such as these two data points:

B1)  What can we see of WTAHB1 in Market Notices?

In the ‘Market Notices’ widget in ez2view, we can filter for specific keywords … in this particular case ‘WTAHB1’ … as a result of which we see quite a number of Non-Conformance Notices pertaining to this unit over the past year:

Worth readers understanding that this unit is still undergoing commissioning (and it is big, and fast) … but also worth highlighting MN128772 which was published at 12:05 on Friday 29th August 2025 as follows:

‘——————————————————————-
MARKET NOTICE
——————————————————————-

From :              AEMO
To   :              NEMITWEB1
Creation Date :     29/08/2025     12:05:20

——————————————————————-

Notice ID               :         128772
Notice Type ID          :         NON-CONFORMANCE
Notice Type Description :         Details of Non-conformance/Conformance
Issue Date              :         29/08/2025
External Reference      :         NON-CONFORMANCE Region NSW1 Friday, 29 August 2025

——————————————————————-

Reason :

AEMO ELECTRICITY MARKET NOTICE

NON-CONFORMANCE NSW1 Region Friday, 29 August 2025

AEMO has declared the following unit as non-conforming under clause 3.8.23 of the National Electricity Rules:

Unit:      WTAHB1
Duration:   29/08/2025 11:55 to 29/08/2025 12:05
Amount:     -638 MW
Constraint: NC-N_WTAHB1

Auto-generated on behalf of Manager NEM Real Time Operations

——————————————————————-
END OF REPORT
——————————————————————-’

B2)  What can we see of WTAHB1 in Dispatch Data?

Using the ‘Trends Engine’ within ez2view I’ve compiled this trend chart showing Availability, Output (both Target and FinalMW), and also Dispatch Error for WTAHB1 through August 2025:

Those with a licence to the software can open their own copy of this trend query here.

For this particular article:

1)  Note some quite large instances of Dispatch Error earlier in the month;

2)  But, focusing on Friday 29th August 2025, let’s flag the following large instances:

(a)  Dispatch Error of –638MW at 10:25 on Friday 29th August 2025;

(b)  Dispatch Error of +708MW at 10:45 on Friday 29th August 2025;

(c)  Dispatch Error of +638MW at 11:50 on Friday 29th August 2025;

(d)  Dispatch Error of –602MW at 12:00 on Friday 29th August 2025.

3)  And also to remember that (due to the direction of the Dispatch Error):

(a)  a positive number means under-performance, relative to Target.

(b)  a negative number means over-performance, relative to Target.

(C)  So what role did WTAHB1 play in two frequency incidents in August 2025?

Worth briefly flagging two different incidents…

C1)  The role of WTAHB1 in the Frequency Decay around midday on Friday 29th August 2025?

On Friday 29th August 2025 we noted a ‘Decay of mainland frequency at lunchtime on Friday 29th August 2025’ – and earlier today we followed up (in this Part 2 article) to identify that the frequency drop around midday:

1)  reached a floor where the lowest point was 49.847Hz (just outside NOFB) at 11:50:30.8 on Friday 29th August 2025

2)  which was outside of the NOFB (slightly)

Eagle eyes will note that this corresponds just slightly before the timing of the AEMO Market Notice for Non-Conformance at WTAHB1 – so I thought I would take a quick further (focused) look via the ‘Unit Dashboard’ widget in ez2view, ‘time travelled’ back to Friday at the 11:50 dispatch interval as follows:

As noted on the image, it seems quite likely that the sizeable under-performance at WTAHB1 (i.e. 638MW relative to Target at the 11:50 timestamp) would have contributed to* dragging the frequency below the lower bound of the Normal Operating Frequency Band.

* undoubtedly along with other factors …
(a)  such as the challenges of managing frequency with solar PV
(b)  along with possibly other factors as well.

So whilst we should celebrate the entry into the NEM of these large-size batteries, let’s remain cognisant that ‘bigger and faster’ is not necessarily always a good thing, in terms of keeping frequency stable.

PS1 … Hold Point 4 testing

One reader’s already pointed out that I could have noted (for everyone’s benefit) that the rebid reason shown in the  ‘Unit Dashboard’ widget snapshot above (i.e. ‘HP4’) speaks to Hold Point 4 testing.

(a)  That’s the reason for the Non-Conformance … so readers should not conclude from the incident (and the article was not intended to imply) that operational control was poor

(b)  The incident does provide another example to highlight why good control of injections into (and withdrawals from) the grid is important.

C2)  Helping or hindering, on Tuesday 19th August 2025?

On Tuesday 19th August 2025, we know that the mainland frequency spiked to 50.2Hz (outside of the NOFB) and remained that way for several dispatch intervals:

1)  there have been a number of articles written about this, and collated here.

2)  In the first article, Linton noted the time-range ‘between 11:45 and 12:20’.

3)  at this point, it appears that one of the main direct causes of this was one particular vendor of self-forecasts having some issues with their self-forecasts through this period

… as a result of which, a large (unexpected) amount of energy from dozens of Solar Farms was injected into the grid, driving frequency higher

Quickly zooming into the ‘Trends Engine’ chart (from ez2view shown above):

1)   I can see a Dispatch Error of +80MW at 12:05 on Tuesday 19th August 2025;

2)  Which would have assisted in trying to restrain the run of frequency through that period.

PS2 … PFR

In this case, it’s been pointed out that the Dispatch Error of +80MW was related to delivery of Primary Frequency Response.

PS3 … Hold Point, or PFR

I’ve not looked to check, but it’s quite likely that many (if not all?) of the earlier Market Notices about Non-Conformance at the unit (in the ez2view snapshot above) were also related to either:

(a)  Earlier hold point testing; or

(b)  Delivery of PFR.

Two examples to help highlight some complexities, not visible in entry-level data.