NSW1 experienced sustained negative pricing, reaching -$4.26/MWh in the 22:55 interval on 14 September 2026, with prices declining sharply from near-zero levels over a 15-minute window. The event occurred during a period of high solar generation (2404 MW) and moderate wind generation (487 MW) combined with substantial coal capacity (3111 MW) online.
The negative pricing reflects an oversupply condition where high renewable generation combined with inflexible baseload coal output exceeded regional demand and export capacity. A binding constraint with marginal values ranging from $4.97 to $6.80/MWh was active during this period, indicating that transmission or reserve capability limitations prevented the region from freely exporting excess generation, forcing prices downward to incentivise load absorption and generation 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.