VIC1 experienced sustained negative pricing at −$2.86/MWh for two consecutive intervals (23:50–23:55 on 9 September 2026), representing a minor severity event. Prices recovered sharply to positive levels in the preceding and subsequent intervals, with the negative spike occurring during high renewable generation (solar 1511 MW, wind 1105 MW combined) and significant brown coal output (3717 MW).
The negative pricing occurred with binding constraints F_TASCAP_RREG_0220 and F_T+RREG_0050 active, with marginal values of 4.67–4.99 and 4.2 respectively, indicating constraint-driven suppression of VIC1 generation bids. High instantaneous renewable output combined with inflexible brown coal generation likely created excess supply that required downward pressure on prices to clear the market under the active transmission or regulation constraints.
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.