SA had two warnings that reliance on wind power meant statewide blackout was likely

TWO reports from the nation’s electricity market operator warned that South Australia’s high reliance on wind energy made a statewide blackout more likely if connections to Victoria failed.

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TWO reports from the nation’s electricity market operator warned that South Australia’s high reliance on wind energy made a statewide blackout more likely if connections to Victoria failed.

The Australian Energy Market Operator is reviewing the events of last week and says while a vicious storm that ripped through the state’s north was the “root cause” of supply interruptions, it remains unclear why a “cascading failure” of the rest of the network occurred.

SA suffered an unprecedented statewide blackout which has created huge costs for major employers like Arrium and Nyrstar and forced hospitals to run on backup generators.

In a 2014 report, AEMO identified challenges in using wind power while maintaining stability in a network which had largely been built to accommodate supply from traditional generators.

To prevent a tripping of the system, the electricity network must be maintained at 50 Hertz. Traditional fossil fuel generation is referred to as a “synchronous” supply because it naturally runs at this level. Wind is often not, and must be balanced out as it feeds into the broader network.

Hydro power used heavily in Tasmania does supply synchronous renewable energy, as can other potential electricity sources like baseload solar thermal power being considered for Port Augusta.

In the 2014 report, AEMO stated SA was at risk of a “collapse of the power system” if the Victorian interconnector went down while wind supplied most of the state’s local generation.

“If a non-credible separation event occurs concurrently with low or no synchronous generation in SA, a lack of power system inertia will cause a fast rate of change of frequency, potentially triggering protection systems that will disconnect SA generation,” it stated.

“Sudden loss of the Heywood Interconnector from a previously normal system condition is historically very rare. In a scenario where Northern Power Station, Pelican Point Power Station, and Torrens Island Power Station are offline prior to separation, AEMO would have no way of regulating frequency in SA following separation from the NEM at Heywood. Widespread load shedding and tripping of generation in SA by protection schemes would occur.”

The toppled electricity towers north of Melrose, which came down in high winds. Picture: Dylan Coker

Figures provided to The Advertiser by AEMO show that 70 per cent of the power being generated within SA at the time of the blackout was coming from wind sources, and the remainder from Torrens Island Power Station and Ladbroke Grove gas generator. Before the failure of the interconnector, SA had been drawing about a third of its total power from Victoria.

In another report released in August, AEMO again warned that existing emergency frequency control schemes were “increasingly unlikely to prevent a black system across SA”.

Grattan Institute energy program director Tony Wood said understanding why SA had a complete blackout was “the most important question”, rather than the political fight over renewables.

“I don’t think we’ll know the full story for a while, because it will come down to analysing almost millisecond by millisecond what actually happened in that critical half an hour,” he said.

“The best information I have is that the spread wasn’t made any worse by the wind power, but I wouldn’t make that comment categorically until we have the reports from technical people.”

Premier Jay Weatherill has also rejected suggestions wind power was in any way to blame, saying the blackout would have occurred under any energy mix.

“This is a weather event, not a renewable energy event,” he said last week.

Pictures: SA superstorm and its chaotic aftermath

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