A high-severity binding constraint (T_BLINK_TV_NGZ) in TAS1 reached an extreme shadow price of $8.352 million, coinciding with a sharp spot price increase from $30.18/MWh to $90.42/MWh in the 00:05 settlement period on 21 August 2026. Tasmania's generation mix remained dominated by hydro (955–1226 MW) and wind (369–430 MW) throughout the event window.
The extraordinary marginal value of the T_BLINK_TV_NGZ binding constraint—vastly exceeding all other active constraints—indicates acute transmission or operational congestion that directly drove the price spike. The constraint's dominance over secondary binding constraints (F_T+RREG_0050 at $7.18, F_MAIN+RREG_0220 at $4.68, and others) suggests the primary limitation was this single network element rather than a shortfall in generation capacity, as hydro and wind supply remained substantial throughout the period.
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.