There’s been some volatility recently across the NEM … particularly in South Australia but also across all regions:
1) on Monday evening 29th July 2024;
2) on Tuesday evening 30th July 2024;
3) And also this evening … Wednesday 31st July 2024.
Earlier today, Linton posted this ‘… initial pass over ENERGY bids during price volatility of 30th July 2024’ with a focus on South Australia … but we might find time to do something more broadly across the whole of the NEM (though perhaps not immediately).
Amongst the (many!) contributing factors NEM-wide will be the fact that both units at Callide C are now offline again.
(A) Callide C4 remains offline
As we have noted before, Callide C4 has been offline since 25th May 2021 and is expected to remain offline until 31st August 2024 … now exactly a month away.
(B) Callide C3 offline again
Readers will also recall that Callide C3 returned to service on 1st April 2024 after its own (not quite so) long outage, and has been operating since that time. Unfortunately we’ve seen that the unit came offline last Friday 26th July 2024 – as we see the snapshot from ez2view this afternoon at 15:25:
With respect to this unit, please note the following:
B1) Data gleaned from ez2view
This snapshot shows two widgets:
1) At the top is the ‘Generator Outages’ widget in ez2view, which shows expected return to service currently as Monday 26th August 2024.
2) At the bottom is the ‘Bids & Offers’ widget (filtered down to the CPP_3 unit and looking back 2 weeks), that shows the unit coming offline (ultimately with a trip) last Friday afternoon 26th July 2024.
B2) News Releases by CS Energy
For more context, worth referring to these two recent News Releases from CS Energy:
1) last Saturday 27th July 2024, the company wrote ‘Statement regarding injury at Callide Power Station’ … which includes the passage:
‘In a separate incident, CS Energy has brought Unit C3 safely offline to investigate a technical fault in one of its battery chargers.
At approximately 4pm yesterday, the Callide Operations team made the decision to safely bring Unit C3 offline. No one was injured.
CS Energy has begun an investigation into why this incident occurred and is assessing timeframes for any necessary repairs or replacement of equipment.
The affected equipment is within its warranty period, as it was commissioned in December 2023.
We have notified Workplace Health and Safety Queensland, and the scene is being preserved for the regulator. We have advised the Australian Energy Market Operator that Unit C3 is currently unavailable as part of our market disclosure requirements.’
2) then yesterday 30th July 2024, the company wrote ‘Update on Callide Unit C3 return to service’ … which reads:
‘The Callide C Power Station joint venture (JV) informed the market today of a revised return to service date for Unit C3 of 26 August 2024 (previously 3 August).
Unit C3 was safely brought offline last Friday after a technical fault occurred on one of its battery chargers. The Callide C JV provided an initial forecast of 3 August for the unit’s return to service until we could obtain a better understanding of timeframes for repairs and restoration of the charger.
The charger manufacturer has since inspected the charger at site and advised that it will undertake a rebuild and factory testing before returning it to Callide for installation and commissioning. This process is expected to take approximately four weeks.
Preliminary investigations by the battery charger manufacturer indicate that the fault was the result of a component failure within the charger and was an extremely rare event. The affected equipment is within its warranty period as it was commissioned in December 2023.
What occurred on Unit C3 last Friday was not the same type of incident as what happened with Unit C4 in 2021. CS Energy has additional redundancy built into its battery charger system because of the improvements we have made since the Unit C4 incident. These safeguards worked as designed last Friday and the team were able to safely shut down Unit C3 when the fault was detected.’
This new return to service expectation (26th August 2024) is as shown in the snapshot of the ‘Generator Outages’ widget in ez2view above.
CS Energy spent $38m of taxpayers’ money hiring lawyers over the past two years, including to fight the release of the landmark report into the company’s woes. The investigative report into the 2021 Callide C explosion compiled by forensic engineer Dr Sean Brady, cost taxpayers a further $10.4m.
Not sure if I’m missing something here but in the CS Energy response to Brady’s report it appeared that the key interlocks have now been removed to allow 2 batteries to be paralleled on the unit 4 dc switchboard. Given this was done quickly it presumably did not include upgrading/replacing the unit and station dc switchboards to allow double the fault current. Does this mean these dc systems are now in a much less safe state than their original design? It would seem to me that changing over from unit to station dc supplies with the unit online would never have been allowed for in the original design. This is unit protection after all. Just wait for the next outage. Did the dc electrical design documentation allow for dc switching with unit online? If not was a dc trip while replacing battery chargers with unit in service in 2021 an entirely foreseeable risk? And Brady states that the dc system relies on the charger, with the battery only providing a backup to the charger. I’m having trouble with this when dc oil pumps must always be available in an emergency. If a unit trip removes the ac then the dc oil pumps are the only thing preventing a catastrophe. It’s a long time since Callide C was designed, but maybe someone can reassure me that CS Energy’s “additional redundancy in the battery charger system since Unit C4” hasn’t exposed it’s people to far higher risk?
The state and federal governments have been forced to re-enter the business of electricity generation, storage and transmission and they are making a mess of it. Look what happened when CS Energy’s Callide C4 steam turbine was destroyed by ignorance (they turned off the critical 220vdc supply) and problems will continue until training,examination and advancement of critical personnel is controlled by a central authority. God help us if nuclear power stations are required.
Critical personnel at CS Energy lacked experience and knowledge of process safety.
Callide C4 management allowed unauthorised untrained maintenance staff to carry out the critical switching that destroyed the C4 turbine.
Their claim for an insurance payout is lost.
What is the total cost including lost income, damage, legal , enquiry and repairs?
The coverup continues, what is the history of the critical 220VDC batteries, what happened to the critical key interlocks that have been used for over 100 years to avoid what happened at Callide C4.
220V batteries should not be paralleled because of possible large fault currents, switching has be done offload, that is why key interlocks use to be used and only authorised trained operators should carry out these critical switching proceedures with the unit out of service.