VIC1 experienced sustained negative pricing over an 8-interval period from 19:35 to 20:10 on 12 September 2026, with prices ranging from -$5/MWh to -$8.01/MWh. The region was supplied predominantly by wind generation (approximately 2,958 MW combined) and brown coal (2,249 MW), with minimal contributions from other sources.
The negative pricing resulted from a significant oversupply of generation relative to demand, with wind resources dominating the generation mix during a period of lower consumption. The binding constraint F_T+LREG_0050 carried substantial marginal values ranging from $14.29/MWh to $18.28/MWh, indicating a constraint was actively restricting dispatch; this constraint limited the ability to export excess generation or reduce wind output, forcing down-regulation and pushing prices into negative territory as generators faced financial incentives to reduce output rather than operate at loss.
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.