QLD1 experienced sustained negative pricing during two intervals on 26 August 2026 at 04:40 and 04:45, reaching a minimum of −$3.51/MWh. This occurred during the early morning period when solar generation was ramping up to approximately 2,850 MW, coinciding with high black coal output of around 3,600 MW.
The negative pricing reflects excess supply relative to demand during the shoulder solar generation period, exacerbated by the inflexibility of base-load black coal generation which remained at high output levels. Multiple binding constraints with marginal values between $3.50–$4.99/MWh indicate that network or system service limitations were constraining the market solution, preventing more efficient dispatch of flexible generation and forcing downward price pressure to clear the surplus 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.