QLD1 experienced sustained negative pricing across two consecutive intervals (00:30 and 00:35 on 12 September 2026), with prices reaching a minimum of –$1.40/MWh. The region had strong solar generation (approximately 5,170 MW combined) alongside substantial coal output (2,920 MW), resulting in excess supply conditions during the early morning period.
The negative pricing reflects a supply surplus in QLD1 during low-demand early morning hours when solar generation remained elevated. Multiple binding constraints with marginal values between $3.44–$4.99/MWh indicate that network limitations on contingency protection and regulation services constrained the ability to relieve supply pressure through interconnector flows or load adjustment, forcing the market to price below zero to incentivise reduced generation and demand response.
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.