VIC1 experienced brief negative pricing in two intervals on 1 June 2026 around 11:00–11:20 AEST, with the minimum price reaching −$0.05/MWh before deepening to −$2.99/MWh by 11:25. This minor negative pricing event occurred during a period of high renewable generation, particularly wind output exceeding 3,700 MW.
The negative pricing was driven by excess wind generation (approximately 7,415 MW combined) coinciding with high coal output (4,246 MW), creating an oversupply of inflexible generation that could not be rapidly curtailed to match lower demand during the late morning period. Network constraints, as indicated by binding constraint marginal values on the main and transfer branches, further constrained the ability to export surplus generation, forcing the market price negative to incentivise demand or reduce supply, with the severity deepening as the supply–demand imbalance worsened.
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.