A major binding constraint (T_BLINK_TV_NGZ) on the Basslink interconnector between Tasmania and Victoria activated with an extremely high shadow price of $7.308 million, indicating severe transmission congestion limiting power flow. Regional reference prices spiked to $190.21/MWh during the constraint period before declining sharply to $87.20/MWh once the constraint was relieved, reflecting the artificial scarcity premium imposed by the interconnector limitation.
The constraint was triggered by Tasmania's strong hydro generation (~2,995 MW combined across multiple units) during a period when interconnector capacity to Victoria was insufficient to accommodate the available supply, likely due to pre-existing network limitations or outages on the Basslink cable. The extraordinarily high shadow price ($7.308M) relative to normal constraint values indicates the interconnector was tightly binding with significant economic dispatch disruption, forcing Tasmania to either curtail its low-cost hydro output or accept the substantial constraint rent allocation rather than export excess generation southward.
Causal analysis generated by gridIQ's synthesis model from live AEMO market data: dispatch prices, generation mix, interconnector flows and market notices in the interval surrounding the event.