QLD1 experienced sustained negative pricing of approximately –$1.73/MWh across two consecutive intervals (23:25–23:30 on 12 June 2026), representing a minor but notable event. The region was operating with high solar and wind generation (approximately 6,198 MW combined) alongside substantial black coal output (3,380 MW), creating a supply-demand imbalance during late evening demand trough.
The negative pricing reflects excess generation in QLD1 that could not be economically withdrawn or exported, forcing generators to pay for dispatch. Multiple binding constraints with elevated marginal values (ranging from 3.59 to 6.8 $/MWh) indicate transmission or operating limit constraints were restricting the region's ability to balance supply, preventing generators from reducing output or exporting surplus energy. The persistence of minimum-load coal generation combined with high variable renewable output during low-demand periods created structural oversupply that dispatch pricing mechanisms could not clear.
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.