Interconnector Watch: Thursday 26 March 2026

VIC1-NSW1 (Heywood's northern cousin, the main Victorian export artery) is the standout story this interval, flowing 876.91 MW north into NSW1 and binding hard at its export limit. That constraint is directly reflected in the $41.44/MWh price spread between VIC1 ($33.33/MWh) and NSW1 ($74.77/MWh) — Victoria is exporting as much as the link physically allows but still cannot arbitrage the gap away. Heywood (V-SA) is simultaneously binding at its full 329.91 MW export limit westward into SA1, and Murraylink (V-S-MNSP1) is also binding at 184.22 MW into SA1. Together these two links are pumping maximum capacity into South Australia, yet SA1 prices are sitting at -$20/MWh — meaning renewable oversupply in SA1 is so severe that even fully saturated import capacity cannot clear it. Victoria, sandwiched between a binding export to NSW and binding exports to SA, is clearing at just $33.33/MWh, well below its neighbours on both sides.

Basslink (T-V-MNSP1) is carrying zero flow this interval, with an export limit of 125 MW available from Tasmania to Victoria but no energy moving. Tasmania is the highest-priced region on the NEM at $106.24/MWh, and the idle Basslink is a direct cause: with no southbound flow from Victoria and no northbound export occurring, Tasmania is effectively islanded from the cheaper mainland pool. The constraint history is relevant here — earlier today AEMO reclassified the Sheffield–George Town 220 kV double-circuit as a credible contingency due to lightning activity (notice 137368), which invoked constraint set T-GTSH_N-2 with Basslink on the left-hand side, restricting its capacity. That reclassification was subsequently cancelled (notice 137374) at 21:22 AEST, but Basslink remains at zero flow, suggesting other operational or economic factors are keeping it idle and leaving Tasmanian consumers exposed to the highest spot price in the NEM.

On the Queensland–NSW seam, QNI (NSW1-QLD1) is carrying a modest 29.94 MW northbound into QLD1 and is not binding, with 97.3 MW of export headroom remaining. The near-flat price spread — QLD1 at $77.53/MWh versus NSW1 at $74.77/MWh — is consistent with a lightly loaded link where marginal arbitrage is minimal. Directus (N-Q-MNSP1) is flowing 32.1 MW southbound into NSW1 and is essentially at its binding export limit of -32.1 MW. Earlier this morning, AEMO reclassified the Bannaby–Mt Piper 500 kV double-circuit as a credible contingency (notice 137288), placing both QNI and VIC1-NSW1 inside constraint set N-5A6+5A7_N-2; that reclassification was cleared at 17:59 AEST (notice 137369). The current binding state of VIC1-NSW1 is now driven by its own thermal limit rather than that network constraint, but traders should note the Yallourn–Rowville 220 kV lightning reclassification in VIC1 (notice 137376) remains technically