Interconnector Watch

Three of the NEM's six monitored interconnectors are binding at the 06:30 AEST interval, and the flow pattern is one of Victoria supplying both its neighbours to the east and west simultaneously. VIC1-NSW1 (Vic–NSW) is exporting 550.61 MW to NSW at its export limit of 550.61 MW — fully bound northward. Heywood (V-SA) is simultaneously exporting 658.09 MW into SA, also pinned at its export limit. Murraylink (V-S-MNSP1) adds a further 109.62 MW westward into SA, likewise binding at both its import and export limits. Together, Victoria is pushing roughly 1,318 MW across its borders in this interval while pricing at $55.56/MWh — the lowest in the NEM — consistent with local supply comfortably covering regional demand of 5,137 MW with surplus available for export.

The binding flows into SA and NSW directly explain the price premiums in those regions relative to Victoria. SA sits at $69.93/MWh, a $14.37/MWh spread above VIC1, reflecting that even with Heywood and Murraylink both at capacity, SA demand of 1,359 MW is being met at a marginal cost above what VIC1 generators are clearing. NSW clears at $64.89/MWh, a $9.33/MWh spread over Victoria, with QNI (NSW1-QLD1) carrying a modest 69.09 MW northward into Queensland at 11.8% of its 583.31 MW export limit — well short of binding. The Northern Interconnector (N-Q-MNSP1) flows a negligible 9 MW northward, also unconstrained. Neither QNI nor N-Q-MNSP1 is materially influencing prices at this interval.

Tasmania is the price outlier at $85.92/MWh on demand of 1,016 MW. Basslink (T-V-MNSP1) is recording zero flow in this interval against an export limit of 125 MW, meaning Tasmania is neither importing from nor exporting to Victoria right now. The constraint notice history is relevant context: the Gordon–Chapel St 220 kV lines in TAS1 were subject to repeated lightning-driven reclassifications as credible contingency events across 11–12 April, with the most recent cancellation issued at 09:19 AEST on 12 April. While the F-T-CSGO constraint set affecting Basslink's left-hand side has now been revoked, the current zero-flow position on Basslink warrants monitoring — Tasmania's $30/MWh premium over Victoria is consistent with the island operating in an effectively islanded posture this interval, with no arbitrage relief coming via Basslink.

The settlements residue notice on VIC1-NSW1 from 10 April — where the NRM_NSW1_VIC1 constraint operated between 19:00 and 19:45 AEST to limit northward flow — has been cancelled and is not affecting today's dispatch. With VIC1-NSW1 already binding at its export limit, traders should note that any further increase in Victorian surplus or reduction in NSW local supply will not translate into additional northward flow without a corresponding limit increase; the spread is being set by the binding constraint, not by marginal cost convergence.