The owners of four wind farms in South Australia and the state's big Tesla battery have been fined more than $4 million over two separate breaches identified during major grid disturbances.
Federal Court Justice Anthony Besanko fined three subsidiaries of AGL Energy a total of $3.5 million for failing to seek approval for critical systems settings on their Hallett 1, 2, 4 and 5 wind farms in the state's Mid-North for more than three years, including on the day of the 2016 statewide blackout.
He found the company failed to inform the Australian Energy Market Operator (AEMO) about a protective setting within their wind farms, which caused turbines to power down moments before the blackout.
"The resulting harm of this conduct was that AEMO's ability to determine the secure operating limits of the power system, and ensure its resilience during abnormal conditions, was compromised," he said in his judgement.
"This, in turn, created a risk of impairing AEMO's ability to maintain the power system in a secure operating state."
The Australian Energy Regulator (AER) originally alleged the failure was a "contributing cause" of the blackout, but withdrew the allegation during proceedings.
Three other South Australian wind farms, including those at Snowtown, Hornsdale and Clements Gap, have been previously fined a total of more than $2.5 million for similar breaches.
Tesla battery fails in Queensland outage
In a separate judgement, Justice Besanko fined Hornsdale Power Reserve --- which owns the 150-megawatt Tesla battery at Jamestown -- $900,000 for failing to provide grid stabilisation services that it had been contracted to provide.
The failure was identified when an unexpected outage at the Kogan Creek coal plant in Queensland in 2019 caused grid disturbances.
At the time, the battery had been paid to be on stand-by to rapidly produce power to help restabilise the grid in the event of such outages.
"In October 2019, there was an unplanned outage at Kogan Creek Power Station in Queensland," Justice Besanko said.
But he said the battery did not power up when needed.
The court heard that investigations after the Kogan Creek incident had revealed the battery had been unwittingly been under-delivering on promised stability services since Tesla had performed a firmware update in July 2019.
After the event, the battery's owner agreed to repay more than $3.3 million it had received for providing contingency services that it had not, in fact delivered, over a four-month period.
A warning to energy operators
AER chair Clare Savage said the fine would send an important message to the whole market at a time when many new operators were connecting to the grid.
"It is vital that generators do what they say they can do if we're going to keep the lights on through our market's rapid transition to more variable renewable generation," she said.
"AEMO relies on accurate information and compliance with offers and dispatch instructions to ensure it can effectively stabilise frequency deviations."
