QLD1 experienced brief negative pricing on 29 July 2026 in the early morning period, with prices reaching −$1.49/MWh at 00:50 and −$1.31/MWh at 00:40, spanning two settlement intervals. The region maintained very low positive prices ($0.01–$0.13/MWh) across the wider period, indicating sustained over-supply conditions during low-demand overnight hours.
The negative pricing was driven by high solar generation (approximately 2,772 MW average across the two-interval window) combined with substantial black coal output (3,562 MW), creating structural excess supply during the overnight period when demand is minimal. Multiple binding constraints with positive marginal values—particularly F_T+LREG_0050 at $7.89/MWh—indicate that network or regulatory constraints on ramping or reserve provision were active, preventing efficient dispatch of the surplus generation and forcing prices negative to incentivise load response or generation withdrawal.
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.