Interconnector Watch: Saturday 12 September 2026

Three of the NEM's six interconnectors are binding at 20:30 AEST, and the flow pattern reflects a Victoria awash with low-cost generation pushing energy in both directions to its neighbours.

VIC-NSW (VIC1-NSW1) is exporting 794 MW from Victoria into NSW and is bound at its export limit of 794 MW — fully utilised. This flow is consistent with the price spread: VIC sits at -$5/MWh against NSW's $42.45/MWh, so Victorian surplus generation is flowing north to help meet NSW demand (6,548 MW) at the maximum allowable transfer. Heywood (V-SA) is also binding, importing 676 MW into SA at its import limit, again Victoria supplying a lower-priced neighbour — SA sits at -$4.53/MWh, close to VIC's -$5/MWh, so the spread here is minimal and Heywood is more about capacity utilisation than price arbitrage. Murraylink (V-S-MNSP1) is running well below its limits at just 27 MW into SA, non-binding, doing little heavy lifting alongside Heywood.

Basslink (T-V-MNSP1) is bound at its import limit, drawing 417 MW from Tasmania into Victoria. This is a constrained outcome rather than a pure economic one: an active market notice (constraint set I-CTRL_ISSUE_BL, in force since 07:35 AEST on 11 September) flags a Basslink control system fault preventing it from following dispatch targets, capping the interconnector at reduced transfer capability. TAS at -$4.62/MWh and VIC at -$5/MWh are near parity, so the bind reflects the control constraint rather than price-driven congestion.

On the northern boundary, QNI (NSW1-QLD1) is flowing 627 MW from QLD into NSW, well inside its 1,134 MW import limit — not binding — consistent with the modest $4.41/MWh spread between QLD ($38.04/MWh) and NSW ($42.45/MWh). Directlink (N-Q-MNSP1) is barely used at 25 MW, non-binding. Settlement residue notices show NRM_VIC1_SA1 and NRM_NSW1_VIC1 negative residue constraints have been triggering and clearing repeatedly since 10 September, reflecting the sustained low/negative VIC pricing driving residue accumulation on VIC-SA and NSW-VIC flows — the VIC1-SA1 constraint most recently ceased at 16:00 AEST on 12 September. Overall, Victoria's negative pricing is the dominant driver today, exporting to both NSW and SA at full capacity while Basslink's fault artificially caps Tasmanian import flow.