NSW1 experienced sustained negative pricing on 13 July 2026, with the RRP falling to −$5.58/MWh during the 05:20 interval. This occurred during early morning periods when solar generation (2,138.87 MW) and wind generation (1,448.97 MW) combined with battery discharge (500.7 MW) created significant excess supply, while black coal generation (3,458.24 MW) remained inflexible.
The negative pricing was driven by the NEM's requirement to clear surplus renewable and battery generation during low-demand morning conditions. Binding constraint F_TASCAP_RREG_0220 remained active across all intervals with marginal values ranging from $4.97 to $7.79/MWh, indicating that constraint-induced dispatch requirements forced additional generation onto the market despite low demand, pushing prices below zero. The combination of high renewable penetration, insufficient demand-side flexibility, and the constraint's persistent binding situation created conditions where generators were forced to accept negative returns to remain dispatched.
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.