NSW1 experienced sustained negative pricing at approximately −$10/MWh across three consecutive 5-minute intervals (02:15–02:25 on 13 September 2026), with prices remaining negative through 02:45. The event occurred during a period of high solar generation (2085 MW) combined with significant wind output (366 MW) and baseload coal generation (2090 MW), creating a supply-demand imbalance.
The negative pricing reflects oversupply conditions typical of high renewable generation periods, where solar and wind output exceed immediate demand requirements. The binding constraint with the largest marginal value (F_T+LREG_0050 at $74.99/MWh) indicates a physical network limitation was active during the event; however, the large gap between this constraint's shadow price and the negative market price suggests the constraint was not the primary driver of negative pricing. Instead, the negative prices appear to be driven by the fundamental supply–demand mismatch created by the combination of high renewable generation and low underlying demand at the 02:15–02:45 trading window, requiring market participants to accept negative prices to manage excess generation.
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.