The regulator says its investigation found flaws in Engie’s operations, including insufficient resources to ensure its Dry Creek Power Station could respond quickly to dispatch instructions from Australian Energy Market Operator.

At the time, thousands of properties lost power when SA became disconnected from the national grid because of a transmission fault in Victoria.

“This was a very serious incident that required all market participants to act in accordance with their obligations,” AER chair Paula Conboy said in a statement today.

“The market needs to have confidence that generators will be there when called upon by AEMO.

“Failure to do so can compromise the reliability and security of the system.”

AER had issued three infringement notices to Synergen Power, part of the Engie group, over the December 2016 event which came less than three months after SA’s statewide blackout.

But the regulator said Engie had taken steps to avoid a possible reoccurrence including engaging an independent compliance expert to review and update its operating procedures.

It will also provide trading staff and plant operators with additional training.

At the time, then Energy Minister Tom Koutsantonis emphasised that the problems that caused the blackout were on the Victorian side of the border.

“South Australia’s grid operated effectively as an island and load began to be restored within half an hour,” he said.

While about 200,000 homes and businesses lost power for over an hour, BHP’s Olympic Dam operations in the north of the state were interrupted for about four hours, prompting a warning from the company that “Australia’s investability and jobs are placed in peril by the failure of policy to both reduce emissions and secure affordable, dispatchable and uninterrupted power”.

– with AAP