Interconnector Watch: Tuesday 1 September 2026

Heywood (V-SA) is the standout this morning, running at 545 MW from Victoria into South Australia and binding against its export limit of 545.46 MW — effectively maxed out. This aligns with a live AEMO constraint set (CA_SYDS_59A889E5, invoked 0955 hrs and still active) managing power system security in VIC, which is capping V-SA and its companion link, Murraylink. Despite Heywood's full export, SA1 still holds the highest regional price at $88.06/MWh, above VIC1's $75.87/MWh — a $12.19/MWh spread that would normally attract more interconnector support, but the security constraint is limiting further transfer capability into SA.

Murraylink (V-S-MNSP1) is sitting at zero flow with both import and export limits set to zero — fully constrained off under the same VIC security event. With Heywood saturated and Murraylink unavailable, SA1 is currently isolated from additional Victorian supply beyond what Heywood already delivers, leaving its price elevated relative to the mainland.

On the eastern side, VIC1-NSW1 is flowing solidly at 567 MW from Victoria to NSW, well within its 603.46 MW export limit (around 94% utilised) and not binding. This flow is consistent with NSW1's higher price ($84.79/MWh) drawing on cheaper Victorian generation ($75.87/MWh). Further north, NSW1-QLD1 (QNI) is flowing 527 MW from QLD into NSW, a modest 48% of its 1083.52 MW import limit, with QLD1 priced at $78.55/MWh — cheaper than NSW1, supporting the northward pull. Directlink (N-Q-MNSP1) is a minor counter-flow of 17 MW from QLD to NSW, well inside its limits and not binding. Basslink (T-V-MNSP1) is exporting 298 MW from TAS1 to VIC1, at 82% of its 363.7 MW export limit, consistent with TAS1 holding the lowest price in the NEM at $70.08/MWh and continuing to support Victorian demand without approaching a binding constraint.

Overall, the only binding constraint in the NEM right now is Heywood, and it's a direct consequence of the active VIC security constraint set rather than pure economic congestion. This is keeping SA1 prices elevated relative to VIC1 despite Heywood running at full tilt, while the NSW-VIC and QNI corridors continue to reflect normal economic flow patterns from lower- to higher-priced regions without capacity restriction. WA1, outside the NEM, is trading separately at $124.56/MWh with no interconnector linkage to these dynamics.