Tasmania experienced sustained negative pricing over three intervals on 31 August 2026, with prices declining to -$6.31/MWh at 22:15. The event occurred during a period of elevated renewable generation (hydro and wind combining to provide approximately 900 MW) with no gas generation online.
The negative pricing reflects an oversupply condition in TAS1 during this period, driven by substantial hydro and wind output that exceeded local demand. Multiple binding constraints with varying marginal values indicate transmission or network constraints were active during the price depression, with one constraint showing particularly elevated marginal values (up to $232,000) early in the event, suggesting export limitations or interconnector constraints restricted the region's ability to clear excess generation into adjoining markets.
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.