Victoria experienced sustained negative pricing in VIC1 on 19 September 2026, with prices declining from -$8.42/MWh to a minimum of -$50.11/MWh across three intervals between 21:20 and 21:30. The region had high renewable generation (5,470 MW of wind and 361.5 MW of solar) combined with substantial brown coal output (1,726 MW) and battery discharge (78.91 MW), creating an oversupply condition.
The negative pricing was driven by excess supply generation relative to regional demand, with the generation mix showing high instantaneous renewable output that could not be readily curtailed. A binding constraint with marginal values ranging from $15.99 to $40.99 was active during the event, indicating that physical system limitations constrained the market's ability to balance supply and demand, forcing the market to clear at negative prices to incentivise demand response or generation reduction.
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.