NSW1 experienced sustained negative pricing at -$7/MWh and -$3.42/MWh across two intervals during the early morning period of 4 September 2026. The region's generation mix was dominated by solar (3,507.51 MW) and coal (2,405.53 MW), with significant wind contribution (716.9 MW), creating an oversupply condition typical of low-demand periods.
The negative prices were driven by a binding constraint (F_T+RREG_0050) with marginal values ranging from $3.42 to $4.42/MWh, which limited the ability to export or curtail excess supply and forced generators to accept negative pricing to remain dispatched. The high renewable output (solar and wind totalling 4,224.4 MW) combined with continued coal generation during a low-demand overnight period created structural oversupply that could not be efficiently managed within the active constraint, resulting in the requirement for negative pricing to incentivise demand response and balance the system.
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.