South Australia (SA1) experienced sustained negative pricing across two settlement intervals on 2 June 2026 around midday, with prices reaching approximately −$0.10/MWh. The negative pricing occurred intermittently across a seven-interval window, indicating brief periods of energy surplus rather than sustained oversupply.
The negative pricing was primarily driven by high wind generation (1,967 MW) coinciding with low demand during midday hours, creating a supply surplus that forced marginal generators to pay for dispatch. Tasmananian transmission constraints (F_TASCAP_RREG_0220 and F_T+RREG_0050) binding with significant marginal values indicate that inter-regional network limitations prevented efficient energy export from SA1, trapping renewable generation and forcing the market price negative to manage the constraint violation.
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.