South Australia (SA1) experienced sustained negative pricing across three consecutive intervals on 11 June 2026, with prices ranging from −$0.08 to −$0.09/MWh. The region was characterised by high wind generation (1712.79 MW) and minimal dispatchable load, creating structural oversupply during the evening shoulder period.
Negative pricing resulted from binding constraints with significant marginal values, particularly constraint F_T+RREG_0050 (marginal values 5.35, 5.35, 5.34, and 3.35 $/MWh), which restricted the ability to export excess generation or manage supply-demand balance. The combination of high wind output, low solar contribution (0 MW), minimal gas-fired generation (40.11 MW combined), and limited battery discharge (16.67 MW) left the market unable to shed surplus renewable generation, forcing negative pricing to reduce marginal consumption and clear the 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.