South Australia (SA1) experienced a period of very high renewable penetration at 93.9% during late evening hours on 23 September 2026, with wind and solar generation totalling over 768 MW. Regional reference prices (RRP) fell to near-zero levels ($0.01/MWh) across three consecutive intervals before spiking to $24.42/MWh in one interval, indicating rapid demand-supply dynamics.
The extremely low prices during the high renewable periods reflect the oversupply of zero-marginal-cost wind and solar generation relative to local demand at that time of day. The price spike at 23:25 and subsequent volatility suggest a binding constraint with a marginal value of $4.57–$4.97/MWh became active, likely limiting the ability to export excess renewable generation or balance supply, which forced the market to discover price through scarcity or constraint-induced adjustments rather than continued low pricing.
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.