TAS1 experienced sustained negative pricing over a 3-interval window during the early morning period of 1 September 2026, with the minimum price reaching −$20.99/MWh. The region's generation mix was dominated by wind (320–431 MW) and hydro (334–353 MW) with no gas-fired generation active, creating an oversupply condition.
The negative pricing was driven by the combination of high renewable generation (750+ MW total wind and hydro) during a low-demand overnight period with no flexible gas generation available to reduce output. Binding constraints with marginal values of $61.04 and $22.46 (F_T+LREG_0050) and additional constraints at $12.20, $10.67, and $7.46 (F_TASCAP_RREG_0220) indicate that physical or regulatory limits on generation withdrawal or interconnector flows prevented adequate export or load absorption, forcing the market price negative to manage the surplus.
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.