QLD1 experienced sustained negative pricing during the 21:35–21:40 settlement intervals on 2 September 2026, with the minimum price reaching −$3.73/MWh. The event occurred during high solar generation (approximately 2,548 MW combined) and moderate thermal output, with prices collapsing sharply from $20.46/MWh to negative territory within two intervals.
The negative pricing was driven by excess generation relative to demand, with high solar output coinciding with inflexible baseload coal generation (4,360 MW). Multiple binding constraints with positive marginal values—particularly F_TASCAP_RREG_0220 at $7.34/MWh and F_T+RREG_0050 at $4.45/MWh—indicate network or regulatory constraints limited the region's ability to export or balance excess supply, forcing prices negative to incentivise demand response and curtailment. The rapid price deterioration suggests demand-side flexibility and storage were insufficient to absorb the generation surplus during this evening demand period.
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.