Three out of four units at the huge Yallourn brown coal generator were shut down on Friday afternoon and early Saturday morning due to flooding at the mine site caused by the downpours that hit the region late last week.
The 1480MW brown coal generator operated on a single unit for around 72 hours to conserve coal stockpiles. One unit returned to service early on Tuesday but it is not clear when the remaining units will be brought back into service.
“At EnergyAustralia, safety is our highest priority. As a precaution, on Friday afternoon all people were asked to leave the mine and equipment was removed, which allowed us to closely assess the situation,” the company’s head of energy Liz Westcott said in a statement on Monday.
“Yallourn’s generation output is being maintained at an appropriate level to help conserve coal while also ensuring that demand for energy continues to be met.” She said there had been no injuries.
Westcott said some limited mining activities had been permitted, but independent geotechnical experts and its onsite team continuing to monitor the mine, including the Morwell River Diversion, for any further signs of ground movement following the recent storms.
EnergyAustralia said it was confident there would be no supply shortfall. Demand is usually low in winter, and it has its gas plants at Newport and Jeeralong operating when needed, although likely at a significantly higher price point.
“We continue to update the Australian Energy Market Operator (AEMO),” Westcott said. “Separately, they have confirmed that power supply is sufficient to meet demand in all National Electricity Network regions, including Victoria.
“While there is enough generation in the system, storms and flooding have damaged powerlines across the region and this is why some customers have been left without power.”
According to The Age newspaper, about 25,000 customers in the region remain without power five days after the storms damaged power lines and other equipment.
Yallourn was due to close in 2032, but brought the closure date forward to 2028 under a deal with the Victoria government.
For a deeper dive into the impacts of the Yallourn outages, you can read this and other articles over at Watt Clarity.
The outage at Yallourn follows an explosion at the Callide coal generator in Queensland late last month that took all four units offline. Two units will return in the next week, and another early July. It is expected to take at least a year to replace the damaged unit. Some experts have suggested a big battery would be a better investment.
Update: In a later statement, EnergyAustralia said further instability and “visible cracks” had been revealed in its coal mining area, and as a result the mine had been evacuated and a planned resumption of coal mining cancelled.
It said options being studied include temporary measures to seal visible cracks and “pursue all options to divert the river water and reduce risks.”
It added: “We had planned to continue coal mining today; however, we have suspended access to impacted areas until further geotechnical assessments have been completed and risk assessments revised to address the changes observed.”