Directions to NSW Generators – 28 October 2025 to 31 October 2025
During the period from 28 October 2025 to 31 October 2025, the Australian Energy Market Operator (AEMO) issued directions to New South Wales Market Participants to maintain the system within secure operating limits.
On 28 October 2025, the unplanned desynchronisation of Vales Point Unit 6 resulted in a system strength shortfall in New South Wales around 0100 hrs. To ensure the NSW System Strength requirement for secure operation was met, AEMO issued a direction to TUMUT3-1 to synchronise and operate in synchronous condenser mode for the provision of system strength at 0105 hrs 28 October 2025, which was cancelled at 0425 hrs on 28 October 2025. At 0816 hrs, Tumut 3 generating units came out of service, which would have resulted in a system strength shortfall in New South Wales. To resolve the security issue, AEMO issued a direction to TUMUT3-1 to synchronise and operate in synchronous condenser mode.
On 29 October 2025, AEMO identified a system strength shortfall in New South Wales from 0800 hrs due to insufficient synchronous units operating commercially. To resolve the security issue, AEMO issued a direction to TUMUT3-2 at 0825 hrs on 28 October 2025 to synchronise and operate in synchronous condenser mode for the provision of system strength, which was cancelled at 0950 hrs on the same day. At 1104 hrs, TUMUT3-2 was scheduled to come out of service, which would have reduced NSW system strength below the required level, requiring AEMO to issue a second direction to TUMUT3-2 to synchronise and operate in synchronous condenser mode from 1105 hrs until 1530 hrs on the same day.
On 30 October 2025, Snowy Hydro advised that TUMUT3-2 was planning to come out of service at 0700 hrs, which would have created a system strength shortfall in New South Wales. To resolve the security issue, AEMO issued a direction to TUMUT3-2 to remain synchronised in synchronous condenser mode for the provision of system strength at 0700 hrs which was cancelled at 0830 hrs on the same day. At 1446 hrs, Snowy Hydro advised that TUMUT3-5 was planning to come out of service, which would resulted in a system strength shortfall in New South Wales. To address the security issue, AEMO issued a direction to TUMUT3-2 to synchronise and operate in synchronous condenser mode for the provision of system strength from 1450 hrs which was cancelled at 1605 hrs on the same day.
On 31 October 2025, AEMO confirmed that six Murray units were expected to come out of service, which would have created a system strength shortfall in New South Wales. To resolve the security issue, AEMO issued a direction to TUMUT3-2 to synchronise and operate in synchronous condenser mode for the provision of system strength from 0715 hrs which was cancelled at 1415 hrs on the same day.
Where AEMO intervenes in the National Electricity Market (NEM) through the use of directions, AEMO must publish a report in accordance with National Electricity Rules (NER) clauses 4.8.9(f) and 3.13.6A.
The NEM Event report below satisfies those NER obligations and is based on information available to AEMO at the time of publication: