Queensland region (QLD1) experienced sustained negative pricing across three settlement intervals on 19 September 2026 at 02:20–02:30 AEST, with prices reaching −$8.50/MWh. The negative pricing persisted through the 02:20–02:55 period, indicating excess generation relative to regional demand during off-peak hours.
High solar and wind generation (approximately 3,500 MW combined) coinciding with low overnight demand created structural oversupply in QLD1. A binding constraint (F_T+LREG_0050) with a marginal value of $103.84 actively limited dispatch flexibility, preventing generators from reducing output or ramping down further, forcing the market price negative as the only mechanism to clear excess 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.