Tasmania achieved 100% renewable generation during the evening of 28 June 2026, with hydroelectric output of approximately 2,936 MW and wind generation of 399 MW meeting regional demand entirely without fossil fuel generation. Regional Reference Prices (RRPs) remained stable at $70.20/MWh across the five-minute settlement periods from 20:10 to 20:30, slightly above the opening price of $68.80/MWh.
The binding constraint F_MAIN+RREG_0220 with marginal values ranging from $3.44 to $4.99/MWh indicates that a transmission or reserve requirement constraint was active during this period, preventing prices from falling despite the abundant renewable supply. The moderate constraint shadow prices suggest that whilst renewable generation was substantial, binding constraints limited market clearing and supported price levels consistent with the observed $70.20/MWh floor, rather than allowing prices to collapse to near-zero levels typical of unconstrained high-renewable periods.
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.