TAS1 experienced sustained negative pricing at approximately -$1.16/MWh across 7 consecutive 5-minute intervals during the evening of 28 July 2026. The region maintained moderate hydroelectric generation (497–506 MW) alongside wind and gas capacity, resulting in a local energy surplus situation.
The negative pricing was driven by binding constraints with material marginal values, primarily the F_TASCAP_RREG_0220 constraint which held marginal values ranging from $3.43 to $5.50 across the affected intervals. These elevated constraint marginal values indicate that physical transmission or operational limits were forcing the market to accept negative prices to manage excess local supply and maintain system security, as reducing generator output became economically preferable to violating the binding constraint.
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.