Interconnector Watch: Sunday 17 May 2026

The single binding constraint this morning is on QNI (NSW1-QLD1), where flow sits at -189.08 MW — essentially at its import limit of -189.07 MW — meaning Queensland is importing from NSW at the maximum rate the constraint allows in this direction. That binding condition is directly reflected in the price spread: NSW1 prices at $216.85/MWh against QLD1's $214.07/MWh, a $2.78/MWh differential that is narrow but directionally consistent with the constrained northward transfer. With QLD demand running at 6,574 MW and the interconnector unable to pull additional supply from NSW, QLD is relying on local generation to cover the balance. The Armidale No.3 330/132 kV transformer outage (invoked 8 May, constraint set N-AR_TX still active) continues to limit N-Q-MNSP1 (Directlink) capacity; that interconnector is currently carrying zero flow.

Murraylink (V-S-MNSP1) is completely out of service following an unplanned outage at the Redcliffs converter station, with constraint set I-ML_ZERO invoked since 0145 AEST on 17 May. Both active market notices confirm the outage remains unresolved. Murraylink's rated capacity sits around 220 MW in either direction, so its absence removes a meaningful arbitrage path between VIC and SA. Despite this, Heywood (V-SA) is carrying 161.05 MW from VIC into SA, running at roughly 27% of its 586 MW export limit — well clear of binding. The VIC1-SA1 price spread is $4.05/MWh ($204.94 vs $200.89), modest given Murraylink is offline, suggesting Heywood is providing sufficient transfer to prevent meaningful price divergence between the two regions for now.

Basslink (T-V-MNSP1) is exporting 250 MW from Tasmania into Victoria, above its stated import limit of 170.99 MW — worth noting that the import/export limit convention here reflects the TAS-to-VIC direction being the export direction, and the flow is within the 357.5 MW export limit at 70% utilisation. This flow is commercially rational: TAS1 prices at $110.22/MWh are roughly $90/MWh below VIC1's $200.89/MWh, providing a strong arbitrage incentive. VIC-NSW (VIC1-NSW1) is transferring 232.13 MW northward from Victoria into NSW, at 17% of its 1,344 MW export limit — not constrained, with the $15.96/MWh NSW-VIC spread providing the pull. Directlink (N-Q-MNSP1) carries zero flow, consistent with its reduced capability under the Armidale transformer constraint. Traders should monitor Murraylink restoration timing closely; its return to service will reintroduce a competing VIC-SA transfer path and could compress the Heywood flow and narrow SA spreads further.