NSW1 experienced sustained negative pricing at $-7/MWh across two intervals (03:35 and 03:55–04:05 AEST) on 29 August 2026, with prices oscillating between negative and positive values within a 35-minute window. The negative pricing occurred during pre-dawn hours when solar generation remained substantial at 3,112 MW alongside coal baseload of 3,113 MW, creating oversupply conditions.
The binding constraint F_T+LREG_0050 carried significant marginal values ranging from 35.59 to 46.58 across the affected intervals, indicating a tight constraint limiting the region's ability to export excess generation. Combined with high instantaneous solar output during shoulder hours and inflexible coal generation, the region faced downward pressure on pricing; negative prices emerged when the marginal constraint became the primary price setter, forcing generators to accept negative returns rather than curtail output.
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.