TAS1 experienced negative pricing at −$0.59/MWh and −$0.53/MWh across two consecutive intervals on 18 August 2026, following a sharp price collapse from $0.55/MWh. The region had substantial wind and hydro generation (approximately 700–1050 MW combined) with lower demand conditions during the afternoon period.
The negative pricing was driven by excess renewable generation relative to regional demand, requiring downward price pressure to clear the market. Binding constraints—particularly F_T+LREG_0050 with a marginal value of $26.06 and the F_TASCAP_RREG_0220 constraint family with marginal values of $3.44–$4.99—indicate that network and system security limits were active in setting dispatch outcomes, preventing lower-cost or zero-cost generation from being curtailed and forcing prices negative to manage surplus supply.
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.