Interconnector Watch: Monday 18 May 2026

The dominant flow on the NEM right now is VIC→NSW via the VIC-NSW interconnector (QNI's Victorian counterpart), carrying 778 MW northbound against an export limit of 1,360 MW — utilisation sits at roughly 57%, leaving headroom but already the largest single cross-regional transfer on the network. That flow is consistent with Victoria pricing $14.70/MWh below NSW ($83.44 vs $98.14/MWh), with surplus Victorian generation arbitraging into the higher-priced northern market. QNI (NSW1-QLD1) is the standout binding constraint this interval: flow sits at -34 MW southbound and is pinned exactly at its import limit of -34.41 MW, confirming the constraint is active and limiting the volume of Queensland energy that can move into NSW. Despite QLD pricing at $100.07/MWh against NSW's $98.14/MWh, the binding QNI constraint prevents meaningful southbound arbitrage from closing that $1.93/MWh spread — the price differential is effectively floored by the transmission limit rather than generation cost convergence.

Heywood (V-SA) is carrying 326 MW westbound from Victoria into South Australia against an import limit of -386 MW, placing it at 85% of its constrained capacity — the tightest utilisation of any unbound interconnector on the network right now. That flow supports SA's $73.96/MWh price sitting $9.48/MWh below Victoria; were Heywood unconstrained and flows to increase, the SA-VIC spread would compress further, but the current margin to the limit still gives AEMO some room. Murraylink (V-S-MNSP1) is carrying only -27 MW into SA and remains subject to two active AEMO market notices from 16–17 May following an unplanned outage of the Redcliffs converter station, with constraint set I-ML_ZERO still invoked. At a nominal -27 MW against an import limit of -107 MW, Murraylink is operating well below its pre-outage capability; traders should treat its SA export capacity as effectively curtailed until AEMO confirms restoration.

Basslink (T-V-MNSP1) is at zero flow this interval, sitting mid-range within its ±125 MW limits and not binding. Tasmania prices at $96.22/MWh are $12.78/MWh above Victoria, which would ordinarily incentivise southbound export from Victoria into Tasmania, but zero flow suggests either a scheduled outage window, commercial scheduling, or the Murraylink-related constraint set (I-MURRAYLINK referenced VIC1-NSW1 and V-S-MNSP1 on its LHS) is indirectly influencing dispatch. Traders should note the Armidale No.3 330/132 kV transformer outage constraint (N-AR_TX, active since 8 May) continues to affect N-Q-MNSP1 limits; Directlink is currently flowing a modest 9 MW northbound into Queensland, well within its 22.72 MW export limit and not binding. The combined picture is one of Victoria acting as the NEM's central dispatch node today — exporting heavily north, west, and with capacity available south — while QNI's binding southbound constraint and Murraylink's curtailed capacity are the two live transmission restrictions shaping regional price separation.