NSW1 experienced sustained negative pricing over three intervals on 16 September 2026 around 03:00–03:15 AEST, with the minimum price reaching −$4.31/MWh. The event occurred during a period of high solar generation (3,263 MW) and strong wind output (373 MW) relative to coal-fired baseload (2,635 MW), typical of low-demand overnight conditions with excess renewable supply.
The negative prices were driven by a binding constraint (F_T+RREG_0050) with a marginal value of $4.79/MWh during the most severe price interval, indicating that the constraint limited the ability to export or balance excess generation. The combination of high solar and wind output exceeding local demand, coupled with the active binding constraint, forced generators to pay for dispatch—a mechanism that typically emerges when renewable generation cannot be economically shed and interconnector or network limits prevent effective flow redistribution.
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.