SA1 experienced sustained negative pricing at −$1/MWh across two consecutive intervals (17:15 and 17:20 on 15 September 2026), marking a minor but noteworthy market event. Prices had been declining from $57.72/MWh earlier in the trading period before dropping into negative territory, then recovered to $58.03/MWh in the following interval.
The negative pricing was driven by high wind generation (1,528.79 MW) coinciding with constrained export capacity from the region, as evidenced by binding constraints F_S++SETB_L6 and F_S++SETB_L60 with marginal values around $4.89–$4.90/MWh. With minimal controllable generation available (only 82.13 MW of gas-fired capacity online and negligible solar and battery output), the region lacked sufficient flexible load or storage to absorb the excess wind supply, forcing prices negative to incentivise demand response or constraint relaxation.
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.