TAS1 experienced sustained negative pricing across two consecutive intervals (23:50 and 23:55 on 10 September 2026), with the minimum price reaching −$4.67/MWh. The negative pricing occurred during a period of high renewable generation, particularly hydroelectric output exceeding 800 MW in the final interval.
The negative pricing was driven by binding constraints with significant marginal values (up to $4.99/MWh), indicating physical limitations in accommodating the available generation. High hydro and wind generation during this period created downward pressure on prices, and when combined with the operational constraints reflected in the binding dispatch equations, generators were required to bid negative to maintain dispatch, resulting in the observed negative regional reference prices.
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.