VIC1 experienced brief negative pricing at −$0.55/MWh across two intervals (23:45 on 3 September and 00:00–00:05 on 4 September 2026), interspersed with near-zero pricing. The region had very high renewable generation (2,383.53 MW wind and 1,077.11 MW solar) combined with 3,009.50 MW of brown coal generation, creating substantial oversupply conditions.
The negative pricing was driven by excess supply relative to demand during overnight low-demand periods when renewables remained elevated. The binding constraint F_TASCAP_RREG_0220 (with marginal values ranging from 4.66 to 6.99 $/MWh) restricted the system's ability to export or balance generation efficiently, forcing marginal generators into negative pricing territory to manage surplus output. The lack of dispatchable gas generation (0 MW OCGT and CCGT) and minimal battery output (4.99 MW) limited the system's flexibility to absorb the oversupply.
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.