Interconnector Watch: Tuesday 23 June 2026

At 06:30 AEST, three of the NEM's six interconnectors are binding, and the resulting price spreads are stark. South Australia sits at $500.44/MWh — more than three times Victoria's $166.48/MWh — with both SA-facing interconnectors hard against their export limits. Heywood (V-SA) is flowing 244.41 MW into SA, pinned exactly at its 244.4 MW export limit, and Murraylink (V-S-MNSP1) is carrying 135.4 MW into SA, also at its 135.4 MW export cap. Together they are delivering around 380 MW into a region with only 1,672 MW of total demand, yet the constraints mean no additional Victorian supply can reach SA to narrow that $334/MWh spread. The Murraylink binding is compounded by two active network notices: a short-notice rating change on the Buronga B Bus 7118 220 kV isolator (constraint set N-BU_7118) invoked yesterday afternoon, and an earlier planned Murraylink outage notice (I-MURRAYLINK) that continues to affect both V-S-MNSP1 and VIC1-NSW1 transfer limits. The Roseworthy–Templers 132 kV line outage (constraint set S-TPRS) is also still active and is reducing SA import capability via both SA interconnectors.

QNI (NSW1-QLD1) is binding in the northward direction at its full -590 MW import limit, meaning Queensland is drawing 590 MW from NSW at the interconnector's maximum import capacity. With QLD at $134.04/MWh and NSW at $175/MWh, the $41/MWh differential reflects NSW as the higher-cost exporting region, and the binding constraint prevents further arbitrage flow from closing that gap. Directlink (N-Q-MNSP1) is flowing -91.05 MW (also NSW to QLD) against an import limit of -98.4 MW, placing it close to but not yet binding — a separate market notice remains active noting Directlink's output controls are unavailable until further notice (constraint set I-CTRL_ISSUE_TE), which limits AEMO's ability to vary its dispatch.

Basslink (T-V-MNSP1) is at zero flow, with Tasmania clearing at $79.23/MWh against Victoria's $166.48/MWh — a $87/MWh spread that would ordinarily incentivise northward export. The flat flow suggests either a scheduled outage window, a commercial or network restriction, or a dispatch outcome where the MNSP is not yet dispatched. The VIC-NSW interconnector (VIC1-NSW1) is carrying a modest 41.88 MW from Victoria to NSW against an export limit of 1,045.47 MW, placing it well below capacity and non-binding. Notably, AEMO invoked and then cancelled a negative settlement residue constraint (NRM_VIC1_NSW1) on this link during the 09:00–12:30 window yesterday, indicating earlier congestion in the VIC-to-NSW direction; traders should monitor whether residue accumulation resumes given the current flow level and pricing configuration.

The dominant market narrative this morning is SA's price isolation. With both Heywood and Murraylink binding at export limits and SA network constraints still active, there is no headroom for additional inter-regional supply to SA