South Australia (SA1) experienced exceptionally high renewable energy penetration of 95.5% during the early morning period of 1 June 2026, driven predominantly by wind generation (1,554.52 MW) and solar output (372.37 MW combined). Regional reference prices (RRP) declined steadily from $29.41/MWh to a floor of $18.65/MWh, reflecting the low marginal cost of renewable generation during this period.
The high renewable penetration was driven by strong wind conditions combined with dawn solar generation, whilst demand remained relatively low during the 01:35–02:10 overnight window. Binding transmission constraints, particularly F_T+NIL_MG_R6 (marginal value $17.87/MWh), prevented further price compression and indicate that network limitations rather than generation costs were constraining dispatch, forcing some lower-marginal-cost wind generation to be curtailed and supporting a floor price around $18–20/MWh.
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.