Interconnector Watch — Saturday 9 May 2026

At 06:35 AEST, two interconnectors are binding and driving the most significant price spreads on the NEM. Heywood (V-SA) is at its export limit of 515.77 MW into South Australia, fully binding, and Murraylink (V-S-MNSP1) is similarly pinned at its 81 MW export ceiling into SA. Together these two links are pushing a combined 596.77 MW from Victoria into South Australia, yet SA still sits at $138.00/MWh — a $29.01/MWh premium over Victoria's $108.99/MWh. The binding status on both SA interconnectors signals that additional Victorian supply cannot reach SA at this moment; the price spread is a direct consequence of that transfer ceiling. Heywood's utilisation is at 100% of its current export limit, and the constraint set notices for the Armidale transformer outage and Directlink leg failure, while nominally affecting northern links, underscore that network contingencies across the NEM are currently squeezing transfer margins system-wide.

On the QNI corridor, NSW1-QLD1 is flowing 714.85 MW southbound from Queensland into NSW — 66% of its 1,074 MW import limit — and is not currently binding. That flow is consistent with Queensland's $105.04/MWh price sitting below NSW's $118.53/MWh, with the spread of $13.49/MWh incentivising northward arbitrage that is, in this interval, running in reverse: Queensland generation is being exported south. The N-Q-MNSP1 (Directlink) is flowing 41 MW southbound into NSW at roughly 34% of its 121.9 MW import capacity and is non-binding, though it carries an active inter-regional transfer notice due to the unplanned outage of Directlink's No. 3 leg, which has invoked constraint set N-MBTE_1 and reduced the link's effective transfer capability. The separately active N-AR_TX constraint, stemming from the Armidale No. 3 330/132 kV transformer outage on 8 May, continues to limit N-Q-MNSP1 on its left-hand side, so the apparent headroom on QNI should be interpreted cautiously — the active constraints are suppressing the effective export limit rather than the modelled thermal rating.

Basslink (T-V-MNSP1) is exporting 7.69 MW from Tasmania into Victoria, well within its ±125 MW symmetric rating and comfortably non-binding. Tasmania at $88.20/MWh is the lowest-priced region on the NEM, and the modest northward flow reflects a price incentive to send Tasmanian power into Victoria ($108.99/MWh), though the 7.69 MW magnitude suggests either hydro scheduling constraints or available capacity is being held back. The VIC1-NSW1 interconnector (VIC-NSW) is carrying 251.24 MW northbound from Victoria into NSW, utilising roughly 23% of its 1,108.52 MW export limit — well clear of its ceiling and non-binding. The $9.54/MWh NSW-VIC spread is narrow enough that this flow is modest relative to the link's capacity. No active constraint notices are applying directly to VIC-NSW or Basslink at this interval.

The dominant market dynamic this morning is the price isolation of South Australia. Both links into SA are fully constrained at their export limits