South Australia (SA1) experienced very high renewable penetration of 96.55% during the evening of 20 September 2026, with wind generation dominating at 847.37 MW and solar contributing 265.62 MW across two time periods. Real-time prices declined sharply from 23.3 $/MWh to a low of 10.55 $/MWh before recovering slightly, reflecting the abundance of low-marginal-cost renewable supply.
The high renewable penetration and low prices were driven by substantial wind generation output coinciding with evening solar output in South Australia. Multiple binding constraints with relatively modest marginal values (ranging from 2.99 to 4.97 $/MWh) indicate that network or system limitations were active, but the constraint-related price support was minimal, allowing the low-cost renewable dispatch to set prices close to zero across much of the period.
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.