QLD1 experienced sustained negative pricing for two consecutive intervals (01:15–01:20 on 4 June 2026), with prices falling to −$2.50/MWh. The region was operating with high solar generation (approximately 2,341 MW average) combined with substantial coal baseload and wind output, creating excess supply conditions during a low-demand period.
The negative pricing reflects classic oversupply: high renewable generation (solar and wind totalling ~3,244 MW) combined with inflexible coal generation (~3,079 MW) during overnight hours when demand was minimal. Multiple binding constraints with non-trivial marginal values (F_S++HYSE_R60 at $25/MWh and F_S++TBTU constraints at $19–20/MWh) indicate network congestion was limiting export capacity and forcing the region to absorb excess local generation, necessitating negative dispatch prices to incentivise load or discourage further generation.
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.