Interconnector Watch

NEM-wide interconnector flows at 06:30 AEST this Monday morning show two binding links driving material price divergence across the system. VIC-NSW (VIC1-NSW1) is exporting 1,081.52 MW northward from Victoria into New South Wales and is binding at its export limit — every available MW of transfer capacity to NSW is in use. Simultaneously, Heywood (V-SA) is exporting 36.05 MW from Victoria into South Australia and is also binding at its export limit of 36.05 MW. These two binding constraints directly explain the price ladder: Victoria clears at $46.80/MWh, the cheapest mainland region, while NSW sits at $65.01/MWh and SA at $49.04/MWh — the constrained links prevent Victorian generation from fully arbitraging those spreads away. The $18.21/MWh NSW-VIC spread and the $2.24/MWh SA-VIC spread are floor-to-ceiling outcomes of binding export capacity, not marginal supply differences alone.

Queensland is importing 551.47 MW from NSW via QNI (NSW1-QLD1), with the link running well within its limits (import limit -1,164 MW, export limit 880.27 MW) and not binding. QLD clears at $59.14/MWh against NSW's $65.01/MWh — a $5.87/MWh spread that reflects the cost of the southward haul plus Queensland's own marginal generation. QNI's headroom means this spread could compress further if NSW prices spike, but no binding constraint is capping that adjustment right now. Notably, the Larcom Creek–Calliope River 275 kV line outage (constraint set Q-LCCP_8859, active since 02:40 AEST 5 April) is imposing transfer limit variations on both QNI and N-Q-MNSP1 (Terranora); traders should monitor whether that network constraint tightens QNI's effective export ceiling during higher-demand periods today.

Basslink (T-V-MNSP1) and Murraylink (V-S-MNSP1) are both at zero flow, with Basslink carrying a 125 MW export capability unused and Murraylink set at zero on both limits. Tasmania at $90.16/MWh is the highest-priced NEM region and would ordinarily incentivise southward exports via Basslink, but zero scheduled flow indicates either a scheduling or operational constraint preventing dispatch — traders should verify Basslink availability status. Terranora (N-Q-MNSP1) is carrying a modest 33 MW southward (Queensland to NSW direction), well within its ±121 MW/38.8 MW envelope and not binding.

The residue notice history on VIC1-NSW1 is relevant context: AEMO invoked then cancelled a negative settlement residue constraint (NRM_NSW1_VIC1) on 4 April, indicating that the high northward flows through VIC-NSW have recently produced settlement residues that breached the allowable threshold. With the link now binding at full export capacity again this morning, residue accumulation risk on that directional interconnector remains live for settlements purposes — hedging positions that assume NSW-VIC convergence should account for this.