Living on an island … in Broken Hill

Certainly not forgotten (amongst the articles about the weather related transmission issues in South Australia beginning Thursday 17th October 2024) was the transmission tower event about 24 hours earlier (late on Wednesday 16th October 2024) on the ‘X2’ line between Buronga and Broken Hill in western NSW.

On Thursday morning 17th October, Dan Lee posted about ‘Seven transmission towers collapse near Broken Hill overnight’.  In this article we’ll explore a bit more…

Grabbing page 5 from the 2024 TAPR from TransGrid, we can identify where this X2 line is located:

My understanding is that this stretch is ~250km in length, so even surveying the damage might not have yet been fully possible given the remoteness and inclement weather.

Utilising the ‘Trends Engine’ within ez2view I’ve charted a trend of output from various generators located in Broken Hill as follows:

Coloured by fuel types, we can clearly see the change in generation mix …

1)  Before the break – utilising a combination of supply from Silverton Wind Farm (by Tilt Renewables), Broken Hill Solar Farm (by Tilt Renewables), Broken Hill BESS (by AGL Energy), and imports/exports from eastern NSW

2)  After the break – supply from the GB01 unit in the Broken Hill GT (noting that GB02 seems to have been deregistered at some point … no time to check, at this point).  Likely that there are other smaller embedded diesel generators

A few points to note and/or questions to explore:

1)  Worth noting that the Broken Hill community would be operating as its own ‘frequency island’ at this point, disconnected from everyone else.

… so Dan could add one other one to his list of transmission tower failures and frequency islands in this article from 16th December 2022.

2)  Given the frequency island, the diesel gensets (and whatever other embedded generators are running) would be providing the ‘Keeping the Lights on Services’ for the local community – with the VRE unable to run.

3)  At some point (i.e. if time permits) we might investigate the nature of the constraints or instructions in place to keep Silverton WF and Broken Hill SF offline during this period.

4)  It jumped out at me that both Silverton Wind Farm and the Broken Hill BESS came offline in the exact same dispatch interval when the towers came down:

(a)  The 23:30 dispatch interval (NEM time) on Wednesday 16th October 2024

(b)  And that the BESS has not started discharging again since that time (empty, or for some other reason?)

5)  Spare a thought for the lost revenue at Tilt Renewables in recent days:

(a)  With both Silverton Wind Farm and Broken Hill Solar Farm their assets

(b)  Along with a ~13 hour loss of production from Snowtown 1 Wind Farm in South Australia.

6)  Finally, comparing the size of the outputs above (i.e. before, and after) and noting the much larger size of units in the ‘before’ case, it might help readers understand why the MLFs in the area have dropped through the floor, as Dan Lee illustrated/animated in this article back in 2022.

That’s all for now…