No backup: Yallourn emergency sparks wider power warning

Flooding at the Yallourn coal power station southeast of Melbourne has put a spotlight on the lack of backup in the power system.

The collapse of the Morwell River banks (L), has let water flood in the Yallourn power station mine site in Victoria.

EnergyAustralia has raised concerns over the lack of back-up power in the electricity system, saying reliability will face new threats as incidents including its own Yallourn coal plant emergency and Queensland’s Callide explosion cut baseload supplies in the grid.

Thousands of Victorians will ­endure freezing winter conditions for weeks without electricity in the wake of devastating storms with flooding forcing EnergyAustralia to cut nearly 90 per cent of power capacity at Yallourn, which supplies one-fifth of the state’s electricity needs.

Flooding at the Yallourn power station – about 145km southeast of Melbourne – caused cracks in the banks of the Morwell River Diversion and the wall of a mine, running the risk of flooding to the mine and an extended shutdown for the coal plant. The Victorian government warned on Thursday that flooding of the mine could see Yallourn stop operating for months.

Yallourn is producing at just 12 per cent of its capacity with three of its four units down and along with the Callide explosion had shown vulnerabilities in the system, EnergyAustralia chairman Graham Bradley said.

“As we get fewer and fewer critical baseload coal power stations in the system as they progressively close, each one of those events will have a much bigger impact on the overall reliability of the east coast electricity network than would have been the case 10 years ago or even today by definition,” Mr Bradley said. “You need more than adequate backup capability to firm renewables but also step in for them if they‘re not available.”

“These two incidents – Yallourn and Callide – are a little bit of a warning about the importance of a co-ordinated policy across state and federal governments to ensure all that back up is well and truly in place before we see further closures.”

EnergyAustralia will close Victoria’s Yallourn coal power plant four years early in 2028 while AGL Energy’s Liddell coal plant will exit in the 2022-23 summer, sparking a demand for generators to build new supply to avoid a spike in power prices.

Origin Energy’s 2880 megawatt Eraring plant, which supplies 20 per cent of NSW’s daily power needs, will switch off the first of its four units in 2030. A second will exit a year later leaving Australia’s largest coal-fired power station running at only half capacity until the final two generators close on its scheduled retirement date of 2032.

EnergyAustralia chairman Graham Bradley. Picture: Nikki Short

The EnergyAustralia chairman said it was too early to make a call on the length of disruption to Yallourn.

“I wasn’t trying to suggest Yallourn was going to take weeks or months to fix. I’m getting daily updates. But it is way too early and I’m not on the spot. My comment was that more generally you can get a major one off event like a Callide failure on a major piece of equipment that can often take a long time to correct,” Mr Bradley said.

EnergyAustralia will now present a plan on Friday to safeguard Yallourn after an “energy emergency” was declared by the Victorian government with several options being investigated.

“They put in an emergency declaration and the next stage is we say this is what we think you should direct to happen to relieve any risks. The main risk is that the floods down there may be threatening the stability of the Morwell River diversion which is the big channel that's put in place to take the river’s coal to be mined on either side of it,” Mr Bradley said. “It’s not used to having that much water or rain and there are a number of engineering solutions being explored and water diversion possibilities too.”

The Australian Energy Market Operator, which runs the electricity grid, said it is working with energy generators and enough power is available in Victoria to meet demand with no supply issues currently forecast.

“However, we’re continuing to monitor the current risk due to flooding in the Latrobe Valley,” AEMO noted.

EnergyAustralia has been running its 510MW Newport gas plant on the west bank of the Yarra River near maximum capacity in the last week, data shows.