South Australia (SA1) experienced sustained negative pricing at -$1/MWh across two intervals on 1 June 2026 during the morning period, with prices recovering to around $8.50/MWh immediately following. The region's generation mix was dominated by wind output (2,055.51 MW) with minimal solar contribution and moderate gas generation, creating an oversupply condition.
The negative pricing was driven by excess renewable generation, particularly high wind output (2,055 MW) coinciding with zero solar generation and low demand during the early morning period, forcing generators to accept negative prices rather than curtail output. Network constraints, evidenced by binding transmission constraint F_T+NIL_MG_RECL_R6 with a marginal value of $42.03/MWh, restricted the ability to export excess SA generation to adjacent regions, exacerbating local oversupply and compelling price-taker renewables to operate at negative rates to remain online.
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.