NSW1 experienced sustained negative pricing at approximately -$8 to -$9/MWh across eight consecutive 5-minute intervals during the early morning period of 19 September 2026. The pricing event occurred during a period of high renewable generation, with solar and wind together contributing over 4,200 MW to the NEM generation mix.
The negative pricing reflects oversupply conditions in NSW1 during an off-peak period when demand is minimal. A binding constraint (F_T+LREG_0050) with a persistent marginal value of $103.84 appears to have restricted the ability to export excess generation, effectively trapping surplus renewable output within the region and forcing prices negative to clear the market.
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.