Tasmania operated at 100% renewable generation between 07:05 and 07:30 on 18 September 2026, with hydro and wind supplying approximately 1,079–1,363 MW. Despite high renewable penetration, regional prices escalated sharply from $13.06/MWh to $76.87/MWh over 15 minutes, then moderated slightly, suggesting supply or network constraints tightened considerably during this period.
The rapid price rise despite abundant renewable output indicates binding constraints rather than fuel scarcity drove marginal costs upward. Multiple binding constraints—including F_TASCAP_RREG_0220 with marginal values up to $7.79/MWh and F_T+RREG_0050 with consistent $4.73/MWh contributions—collectively added approximately $12–18/MWh to the marginal price, accounting for a substantial portion of the observed price trajectory. The binding constraint structure suggests network or regional ramp rate limitations constrained the dispatch of renewable energy, forcing the market to recognise these network limitations through higher dispatch costs despite surplus generation availability.
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.