Tasmania's electricity market experienced 100% renewable generation on 1 July 2026 between 20:05 and 20:30 UTC, with hydro and wind providing the entire supply mix whilst gas-fired generation remained offline. Regional reference prices rose modestly from $50.12/MWh to $53.12/MWh over the 25-minute period, despite the absence of thermal generation.
The price increase occurred despite high renewable penetration, indicating that constraint binding—rather than fuel-source competition—drove the marginal cost signal. Multiple binding constraint instances with positive marginal values ($3.43–$6.80/MWh) indicate that network or ancillary service limits were restricting the dispatch of available renewable capacity, forcing additional generation to be priced above its operating cost. The rising price trajectory alongside steady hydro and wind output supports a constraint-driven mechanism rather than a generation-cost driver.
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.