VIC1 experienced sustained negative pricing at –$1.10/MWh across two intervals (19:40 and 19:55–20:00 on 21 July 2026), with prices recovering to near-zero or positive levels in surrounding intervals. The region was operating with high wind generation (approximately 3,500 MW) and brown coal (3,572 MW), with minimal gas and solar contribution.
The negative pricing episodes occurred when binding constraint F_T+RREG_0050 held marginal values of $3.63–$3.64/MWh, indicating an active regulation raise requirement constraint limiting the market's ability to absorb available supply. The combination of elevated wind and coal generation with constrained regulation capacity created a supply surplus relative to demand that could not be fully dispatched, forcing the market to pay generators to reduce output, thereby setting negative prices at the margin.
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.