Power generator Engie has paid $60,000 in penalties after the Australian Energy Regulator found it failed to respond promptly to calls for more power from an Adelaide power station during a blackout in 2016.
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 the 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 on Thursday.
"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.