Interconnector Watch: Wednesday 19 August 2026

Interconnector flows across the NEM are moderate this morning, with no hard binding constraints on the major links despite an active local network limitation in NSW. QNI (NSW1-QLD1) is carrying 660 MW from QLD into NSW, using roughly 53% of its 1243.5 MW import limit — comfortably inside capacity despite the Sydney West-Vineyard 330kV line outage that's had constraint set N-SWVY_29 invoked since yesterday afternoon, capping transfer capability across N-Q-MNSP1, NSW1-QLD1 and VIC1-NSW1. Directlink (N-Q-MNSP1) is flowing a modest 25 MW NSW-to-QLD, well short of its 114 MW import limit, though it remains constrained separately by the ongoing control-system unavailability (I-CTRL_ISSUE_TE) flagged since 14 August.

Basslink (T-V-MNSP1) is the tightest link in the system, exporting 214 MW from TAS into VIC against an import limit of 186 MW — this sits above the nominal limit shown, reflecting the technical limitation constraint (I-VT_000) invoked Monday that's been managing flows out of Tasmania since. This flow direction is consistent with TAS1 holding the lowest price in the NEM at $75.73/MWh, pushing supply north into VIC1 ($80.78/MWh). VIC1-NSW1 is exporting 130 MW from VIC into NSW, around 25% of its 514 MW export limit, tracking the $3-4/MWh price gap between the two regions.

Into SA, both interconnectors are running light: Heywood (V-SA) at 39 MW and Murraylink (V-S-MNSP1) at 18 MW, both VIC-to-SA, using only a fraction of available headroom. The NRM_VIC1_SA1 negative residue constraint that applied through yesterday evening has now been cancelled as of 18:00 AEST, removing that residue-management overlay on these flows — SA1 pricing at $80/MWh sits close to VIC1, consistent with light net transfer. Murraylink also remains under its own control-system constraint (I-CTRL_ISSUE_ML) since 14 August, limiting dispatch flexibility on that link independent of price signals. Overall, regional price spreads today are narrow (QLD1 $76.41 to NSW1 $84.19, excluding WA1's isolated $128.46/MWh), reflecting these sub-capacity interconnector flows rather than any transfer constraint binding at the margin.