NSW1 experienced sustained negative pricing, reaching a minimum of −$3.49/MWh over 2 intervals during the evening of 4 September 2026. Prices declined sharply from $57.39/MWh around 20:35 to negative territory by 21:00, reflecting a rapid shift in market conditions over approximately 25 minutes.
The negative pricing was driven by an excess of low-marginal-cost generation, particularly 1,726 MW of wind and 453 MW of solar output coinciding with elevated black coal generation (3,352 MW), which together produced supply that exceeded demand. Multiple binding constraints with marginal values between $3.48–$4.44/MWh constrained the ability to export or dispatch this generation efficiently, forcing the marginal unit into negative pricing territory to balance supply and demand.
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.