Interconnector Watch: Tuesday 21 July 2026

Three of six interconnectors are binding at 06:25 AEST, concentrating congestion on the Victoria-centred corridors while QNI and Directlink sit well within limits. VIC1-NSW1 is exporting 837 MW from Victoria into NSW, sitting right at its 837 MW export limit — fully utilised. Heywood (V-SA) is exporting 560 MW from Victoria into SA, also pinned at its 560 MW export limit, and Murraylink (V-S-MNSP1) is flowing 133 MW Victoria-to-SA, above its 88 MW import limit and constrained at its 132.65 MW export limit. Basslink (T-V-MNSP1) is running 384 MW Tasmania-to-Victoria, sitting exactly on its import limit but not flagged binding.

These flows are consistent with the current price stack: VIC1 is the cheapest region at $57.68/MWh, with TAS1 close behind at $57.09/MWh, while NSW1 ($80.10/MWh) and SA1 ($80.44/MWh) sit roughly $23/MWh higher. Victoria is exporting to both higher-priced neighbours simultaneously — into NSW via VIC1-NSW1 and into SA via both Heywood and Murraylink — and with all three export paths maxed out, Victoria's low-cost generation cannot fully arbitrage away the NSW and SA premiums today. QLD1 at $75.77/MWh sits between these bands, and QNI (NSW1-QLD1) is flowing 424 MW from QLD1 into NSW1 (negative convention), well inside its 1,201 MW import / 525 MW export limit, so no constraint is binding that corridor despite the $4.33/MWh NSW-QLD spread.

An active AEMO constraint set (CA_BRIS_59712B29, invoked 08:25 hrs 21 July, still in force) is managing NSW power system security and applies to both QNI and Directlink, though neither interconnector is currently binding under it. On the Heywood/Murraylink side, the Tailem Bend 275 kV capacitor bank outage (constraint set S-TBCP1, active since 18 July) continues to restrict V-SA transfer capability, consistent with Murraylink's binding import limit and Heywood sitting at its ceiling. Traders should expect the NSW and SA price premiums over VIC/TAS to pers