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.
Three subsidiaries of AGL Energy have been fined $3.5 million for failing to obtain 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, according to federal court justice Anthony Besanko.
He found that the company didn't inform the Australian Energy Market Operator AEMO about a protective setting within their wind farms that caused turbines to power down moments before the blackout.
He said that AEMO's ability to determine the secure operating limits of the power system, and to ensure its resilience during abnormal conditions, was compromised because of this conduct.
This resulted in a risk that AEMO would not be able to maintain the power system in a secure operating state. The Australian Energy Regulator AER originally claimed that the failure was a factor in the blackout, but withdrew the allegation during the proceedings.
Three other South Australian wind farms, including Snowtown, Hornsdale and Clements Gap, have been fined more than $2.5 million for similar breaches.
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 it had been contracted to provide.
An unexpected outage at the Kogan Creek coal plant in Queensland in 2019 caused grid disturbances.
The battery had been paid to be on stand-by to quickly produce power to help restabilise the grid in the event of such outages.
In October 2019, there was an unplanned outage at the Kogan Creek Power Station in Queensland, Justice Besanko said.
He said that the battery did not power up when needed.
After the event, the battery's owner agreed to repay more than $3.3 million for providing contingency services that it had not delivered over a four-month period.
AER Chair Clare Savage said the fine would send an important message to the whole market at a time when many new operators are connecting to the grid.
It is important that generators do what they say they can do if we want to keep the lights on through our market's transition to more variable renewable generation, she said.
AEMO relies on accurate information and compliance with offers and dispatch instructions to ensure that it can effectively stabilise frequency deviations.