We were very disappointed to see customers without power. We aim to have all our generation online on the highest demand days and on Friday we could not achieve that.
We had two units offline at the Yallourn power station in Victoria. Unit 3 was withdrawn from service around midnight Thursday with a boiler tube leak. This leak occurred Wednesday night but we were able to keep the unit online throughout Thursday, despite significant deterioration.
Keeping this unit online helped make sure no homes were without power on Thursday. Unfortunately, we could not keep the unit on for Friday.
Unit 4 has been offline for regular maintenance. Regular maintenance on Yallourn’s generation units is essential; there are four units, and they’re normally serviced every 3,500 hours of generation, or four to five months.
Unit 4 was originally scheduled for early January to prepare it for an uninterrupted run over summer. The work was postponed twice, including once at short notice to provide capacity during heatwaves in Victoria and New South Wales earlier in the month. By the time the unit came offline it had been operating well beyond the normal length of service.
A contributing factor to the timing of Unit 4 was the outage on Unit 3 which ran into January. We strive to keep at least three Yallourn units online at any time because the weather is unpredictable.
Once the heat in mid-January had passed, we took Unit 4 offline for maintenance with the three other Yallourn units in service. At that time the extreme heat that eventuated on Thursday and Friday was not in the forecast. Had the extreme weather been apparent, we would have considered delaying the outage again.
Even if we had kept unit 4 online, the potential of a forced outage remained. After almost five months online, this unit needed maintenance.
There are still a few hot months ahead and we are doing all we can to have our plant online to supply power to our customers.