Interconnector Watch: Wednesday 20 May 2026

QNI is the standout story this interval, binding hard at –544 MW on its import limit as power flows from NSW into Queensland. With NSW priced at $150.71/MWh against Queensland's $138.88/MWh — a $11.83/MWh spread — the constraint is actively preventing the price gap from closing. QNI's export limit sits at –64.94 MW, meaning the binding import limit is the operative ceiling on northward flow, and there is no headroom left on this interconnector. Every other interconnector is unbound this interval.

Basslink (T-V-MNSP1) carries 211.58 MW from Tasmania into Victoria, sitting comfortably within its 350 MW export limit but notably above its 172.07 MW import limit — that asymmetry reflects the active South Morang F2 transformer outage (constraint set V-SMTX\_F\_R, in place until 1700 AEST 22 May), which is curtailing transfer capability on T-V-MNSP1, V-SA, VIC1-NSW1 and V-S-MNSP1 simultaneously. Tasmania's $112.21/MWh price, well below Victoria's $140.08/MWh, confirms Basslink is transporting into the higher-priced region and arbitraging as much of that $27.87/MWh differential as the constrained limit allows.

Heywood (V-SA) is exporting 344.28 MW from Victoria into South Australia against an export limit of 548.94 MW, leaving reasonable headroom. The SA–VIC spread of $8.74/MWh ($148.82 vs $140.08) is modest and consistent with unconstrained flow in this direction. VIC-NSW carries 190.31 MW northward from Victoria into NSW with ample export capacity (1,441.34 MW limit), though it is worth noting the South Morang outage is also constraining this corridor and may tighten limits as the day progresses. Murraylink (V-S-MNSP1) is the most notable infrastructure caveat: a series of AEMO market notices since 16 May confirm an unplanned outage of the Redcliffs converter station, with constraint set I-ML\_ZERO invoked. Despite this, the data shows 27 MW flowing VIC-to-SA on Murraylink this interval — traders should treat this figure with caution given the active outage notices and verify current AEMO NOS status before relying on it.

The net picture across the NEM at 06:30 AEST is one binding constraint (QNI, NSW import direction) shaping the largest regional price spread, a South Morang-induced reduction in Victorian corridor headroom across four interconnectors that runs until tomorrow afternoon, and Murraylink's operational status remaining unclear. NSW at $150.71/MWh is the price-setter among the eastern states, with Tasmania isolated at $112.21/MWh by the combination of Basslink's reduced import limit and its own lower-demand profile.