Interconnector Watch: Monday 25 May 2026

Heywood (V-SA) is the standout constraint this interval, flowing 460.1 MW from Victoria into South Australia at its binding export limit of 460.1 MW. That hard cap is directly reflected in SA's price premium: SA1 sits at $257.83/MWh against VIC1's $125.27/MWh, a spread of $132.56/MWh that Heywood cannot arbitrage away. Two active market notices compound this — the Tailem Bend 275 kV East Bus outage (constraint set S-TB275_E_BUS) has been curtailing V-SA capacity since 24 May, and the Koorangie–Wemen 220 kV line outage (V-KOWE, invoked 25 May) is also placing equations on Heywood's LHS, further tightening the SA export corridor. Murraylink (V-S-MNSP1) is carrying just 30.1 MW VIC-to-SA, well below its 30.07 MW export limit — effectively also at its binding export ceiling — though it contributes little relief given the scale of SA's demand at 1,458 MW.

VIC-NSW (VIC1-NSW1) is flowing 399.7 MW northward from Victoria into New South Wales, against an export limit of 954.8 MW, leaving meaningful headroom at roughly 42% utilisation. The $13.42/MWh price gap between NSW1 ($138.69/MWh) and VIC1 ($125.27/MWh) is consistent with this flow direction but the spread is modest enough that the interconnector is operating comfortably within limits. QNI (NSW1-QLD1) shows a southward flow of 75.8 MW into NSW, at its binding export limit of -50.12 MW — noting the export limit is set at -50.12 MW while actual flow is -75.77 MW, which warrants close attention as the flow appears to be pressing against or through the constrained export ceiling. QLD1 and NSW1 prices are closely aligned at $139.95/MWh and $138.69/MWh respectively, confirming limited arbitrage opportunity across QNI at present.

Basslink (T-V-MNSP1) is carrying zero flow in either direction this interval, with Tasmania priced at $106.12/MWh — the lowest in the NEM. The import and export limits of ±125 MW are both intact and the interconnector is not binding, but the price differential between TAS1 and VIC1 ($19.15/MWh) would ordinarily support a northward flow; the flat position may reflect scheduling, hydro dispatch decisions, or transient dispatch dynamics. N-Q-MNSP1 (Directlink) is carrying 26.7 MW southward from Queensland into NSW at its binding export limit of -26.73 MW, though at that scale the market impact is minor. Looking ahead, AEMO will activate Murraylink dynamic rating forecasts (VSML_RAT_LIM_DYN and SVML_RAT_LIM_DYN) in pre-dispatch and PASA from 1000 hrs Wednesday 27 May, which will alter how Murraylink's rating is modelled in forward schedules — traders with SA or VIC exposure should review pre-dispatch outputs from that point.