SA1 experienced sustained negative pricing at approximately −$8/MWh across three consecutive intervals during the early morning period of 9 September 2026. The region's generation mix was dominated by wind (1259 MW) and solar (113 MW combined), with minimal dispatchable generation, creating structural oversupply.
The negative prices reflect surplus renewable generation that could not be economically curtailed or exported, forcing generators to pay for dispatch. Binding constraints with marginal values of $5.40–$5.47/MWh indicate transmission or reserve regulation limits preventing efficient redistribution of excess supply, trapping generation within SA1 and forcing the marginal generator into negative pricing territory to clear the local market.
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.