VIC1 experienced two brief periods of negative pricing at -$0.1/MWh on 17 August 2026, occurring in the final settlement interval and again two intervals later, before prices recovered to normal positive levels. The negative pricing was isolated and minor in severity, with only two intervals affected across the observed period.
The negative pricing episodes coincided with very high wind generation (approximately 2,800–2,900 MW) combined with significant brown coal output (3,686 MW), creating an oversupply situation during low-demand evening periods. Multiple binding constraints with substantial marginal values (ranging from $4.95 to $12.72/MWh) indicate the market was operationally constrained, suggesting that dispatch inflexibility and network limitations prevented efficient equilibration of supply and demand, forcing prices into negative territory as a relief valve for excess 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.