QLD1 experienced sustained negative pricing at approximately -$2.50/MWh across five consecutive intervals during early morning peak solar generation on 22 May 2026, with prices remaining negative for approximately 15 minutes. The event was classified as minor severity, with minimum pricing reaching -$2.16/MWh across the two-interval window specified.
The negative pricing was driven by a significant solar generation surplus (approximately 4,805 MW combined solar output) coinciding with low demand during the 04:35–05:15 pre-dawn shoulder period, creating an oversupply situation that required generators to pay to dispatch. Binding network constraints, particularly the Tasmanian RoCoF regulation constraint (F_TASCAP_RREG_0220) with marginal values of $7.79–$9.99/MWh, likely restricted the efficient export of excess generation to adjacent regions, trapping dispatchable coal and gas generation in QLD1 and forcing price suppression through negative pricing to balance supply and demand.
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.