NSW1 experienced sustained negative pricing at −$1.38/MWh and −$1.36/MWh across two intervals on 15 September 2026, following a sharp price decline from $65.51/MWh earlier in the evening. Prices transitioned through $0.00/MWh before turning negative, indicating a brief period of oversupply conditions.
The negative pricing was driven by high renewable generation (approximately 4,893 MW of solar and wind) combined with substantial black coal baseload output (4,420 MW), creating downward pressure on the marginal price during an evening period of lower demand. Multiple binding constraints with elevated marginal values—particularly T_BLINK_TV_NGZ at $8.35M and F_T+LREG_0050 at $18.64—constrained the system's ability to dispatch or ramp down inflexible generation, forcing marginal generators to offer negative prices to remain in the market and avoid forced withdrawal.
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.