The second transformer at Waratah BESS is operational (for testing)

Yesterday afternoon we’d written ‘What’s up with Waratah BESS? Is the second transformer back early?’ following a glimpse at some earlier-than-expected changes to the MT PASA DUID Availability data set for the Waratah BESS unit.

On Saturday morning 11th April 2026 (with the advantage of ‘next day public’ data) we can use the ‘Bids & Offers’ widget in ez2view (snapped at 09:45 NEM time) to take a look at bids for the unit – 7 days backwards and 7 days forward (in PD-ST PASA data):

This confirms that:

1)  in a rebid received at 17:53 NEM time  on Friday 10th April 2026 the second transformer was placed back in service

… the rebid reason was ‘HVT2 Return to service – SL’

2)  with the capacity lifted in PASA Availability to 700MW (discharge and charge)

… which implies the 3rd transformer (i.e. the one that was damaged to the point of needing replacement) is still to come back into service.

3)  The earlier (plant-related rebids ) point to a short period of testing earlier that day.

(a)  note that in the ‘Notifications’ widget within ez2view, I’d had an alert set up to let me know when there was a large change in FinalMW within a single 5-minute period

(b)  that alert had not triggered yesterday with the oscillations in output

(c)  which makes me wonder* whether a somewhat less aggressive ramping was used yesterday used than was the case last year?

 * I have not specifically looked in detail to compare ramping with the ramping used in October 2025 that triggered the failure, so it’s more a hunch at this point.

PS on Monday 13th April 2026

Information provided by Akaysha Energy on Monday 13th April 2026 gives a fuller picture (any mistakes in the following still mine!):

1)  Remediation work to ensure all three transformers are operational at the Waratah Super Battery by the end of 2026 is progressing as planned.

2)  As part of this work, with respect to the second high-voltage transformer (HVT2):

(a)  remembering that this was previously taken offline as a precautionary measure,

(b)  it’s has now been re-energised … which is what we saw on Friday and over the weekend.

(c)  HVT2 will now undergo a program of testing over the coming weeks to confirm performance and reliability before returning to operational service.

(d)  During this testing phase, there may be periods where HVT2’s capacity is visible in the National Energy Market.  This reflects testing activity and does not mean that the Waratah Super Battery has increased its operational capacity.

(e)  But important to note that HVT2 has not yet been returned to fully commercial operational service.

3)  The third high-voltage transformer (HVT3) is still offline and being repaired … no new news on this one.

4)  Until that time, the Waratah Super Battery continues to operate safely and is currently delivering 350MW under its System Integrity Protection Scheme (SIPS) arrangements. The remaining capacity is scheduled to come online by the end of 2026.