NSW1 experienced sustained negative pricing across three intervals on 15 September 2026, with the lowest price reaching −$8.10/MWh. The event occurred during early morning hours (04:15–04:50) when solar generation (2,612 MW) and wind generation (1,582 MW) together supplied approximately 56% of the region's total output, whilst demand was low.
Negative pricing in NSW1 reflects a supply surplus driven by high renewable generation coinciding with low overnight demand, requiring dispatchable generators to operate below marginal cost or exit the market. The binding constraint F_T+LREG_0050 held consistently with marginal values ranging from $18.13 to $104.03/MWh, indicating that a transmission or network limitation was actively constraining the market solution and preventing efficient price resolution across the region during this period.
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.