TAS1 experienced sustained negative pricing at $-15.01/MWh across five consecutive intervals (21:00–21:30 on 19 September 2026), following an initial negative price of $-8.74/MWh. The region's generation mix during this period was heavily weighted towards renewable sources, with hydro generation between 355–368 MW and wind generation between 353–385 MW, whilst gas OCGT remained offline.
The negative pricing reflects an oversupply of generation relative to regional demand, a condition typical when renewable output is high and flexible dispatchable capacity is unavailable or uneconomic to operate. The binding constraint F_T+LREG_0050 held a marginal value of $15.99–$40.99/MWh during the negative price intervals, indicating that a network or system constraint was active and pushing the region towards surplus conditions. With gas generation out of service and substantial hydro and wind output, the region lacked sufficient flexible downward adjustment mechanisms, forcing prices negative to incentivise demand response and reduce generation.
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.