South Australia (SA1) experienced sustained negative pricing at −$1/MWh across three consecutive intervals late on 16 June 2026, with prices falling to −$2/MWh at the trough. The region's generation mix was heavily dominated by wind (1,707.68 MW) and solar (57.87 MW combined), with modest gas-fired generation (210.96 MW combined), creating excess supply conditions.
The negative pricing reflects classic oversupply conditions driven by high renewable generation relative to demand during late evening hours. Multiple binding constraints with significant marginal values indicate network transmission limitations were active during this period, with constraint F_S++SETB_L60 showing the highest marginal value at $20/MWh, suggesting that export capacity out of SA1 was constrained and prevented the region from dispatching excess wind generation, forcing prices negative to encourage demand response or 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.