NSW households faced the threat of rolling blackouts on Saturday evening after devastating bushfires forced the disconnection of the state’s electricity link with Victoria.
The Australian Energy Market Operator urgently called on emergency reserves in a bid to keep the lights on, while NSW energy minister Matt Kean, who had on Friday warned of a risk to the power link from the Snowy Mountains, urged the public to cut their power consumption.
Wholesale electricity prices rocketed to their maximum $14,700 a megawatt-hour, while Victorian prices plunged to negative $213.70/MWh.
“Have just lost transmission lines in snowy region. Expected tight supply situation around 6pm,” Mr Kean tweeted.
“Asking everyone to reduce unnecessary electricity usage. Please turn off pool pumps, lights in unoccupied rooms and avoid using washing machines and dishwashers.”
Paul Italiano, chief executive of NSW transmission grid owner TransGrid, said the company had been forced to take the Upper and Lower Tumut substations offline due to fires, effectively cutting off NSW from Victoria. That has isolated NSW and Queensland from the rest of the National Electricity Market.
The closure of the two key substations in the Snowy Mountains region resulted in the loss of 900 megawatts of power from Victoria that would have flowed into NSW, he said. That, combined with extremely high temperatures, higher than had been forecast, put NSW supplies under pressure despite what had appeared ample generation supplies on Friday.
“We haven’t lost power,” Mr Italiano told The Australian Financial Review. “[But] we are chewing up the reserves that we had.”
Mr Italiano said that while AEMO had called on emergency back-up reserves, it was still uncertain whether the system would be able to cope with the higher than expected demand and the line outage without forced blackouts later on Saturday.
AEMO said there was “currently no immediate impact on consumers in either state” from the disconnection of NSW from Victoria. It said it had activated emergency supply contracts to help compensate for the loss of the Victorian link and also called on consumers to temporarily cut back their energy use but lowering air conditioning and avoiding running multiple appliances at once.
But it warned blackouts were a distinct risk.
“Should the situation worsen further and AEMO loses all reserves available and energy unavailability continues to risk impacting the security of the National Electricity Market, as a last resort, AEMO may be forced to instructed controlled load shedding in NSW,” it said.
In full recognition of a tight electricity market throughout the summer, AEMO said in early December it had organised up to 1600MW of back-up supplies that it could call on in an emergency, involving “demand response” as well as extra generators.
NSW had been expected to have ample generation on Saturday, but record temperatures in some areas, including 48.9 degrees in Penrith, meant demand was higher than anticipated, Mr Italiano said.
Almost 33,000 customers were in any case without power in the Bateman’s Bay and Moruya region on Saturday evening as bushfires hit poles and wires, NSW rural power distributor Essential Energy said.
Customers will not regain their power connection until at least Sunday “as safe access is not available to the damaged area,” Essential said, adding it would only be able to advise of a time when power might be restored when it could assess the situation.
Paul McArdle, an electricity market watcher at Global-ROAM, said it was “no surprise” to see NSW’s wholesale power price spike to the market cap of $14,700/MWh after the loss of the connection with Victoria.
Mr Italiano said TransGrid said that while backburning had helped protect the Upper Tumut substation from fire risk, damage to some mechanical equipment at the site meant the company could no longer operate it remotely so it had to be powered down.
Meanwhile the Lower Tumut substation was completely surrounded by fire, meaning it had also to be taken offline.
The two substations form the point where the NSW and Victorian power grids connect.