VIC1 experienced sustained negative pricing with the minimum spot price reaching −$4.40/MWh over a 2-interval period on 15 September 2026 at 23:50. High renewable generation (wind at 1,596 MW and solar at 1,126 MW) combined with significant brown coal output (2,955 MW) created an oversupply of energy in the region during off-peak evening hours.
The negative pricing reflects a supply surplus relative to demand, typical of high renewable penetration during low-demand periods. Multiple binding constraints with positive marginal values (ranging from $3.79 to $4.99/MWh) indicate that network limitations constrained dispatch flexibility, preventing adequate export of excess generation and forcing the marginal generator to accept negative prices to maintain dispatch balance.
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.