Tasmania (TAS1) experienced high renewable penetration of 90.4% during the evening period of 18 July 2026, with hydroelectric generation dominating the mix at approximately 1,063 MW average and wind contributing around 99 MW. Regional reference prices remained relatively stable in the AUD $48–55/MWh range across the seven five-minute intervals, with a minor spike to $54.58/MWh at 20:15 UTC.
The sustained high renewable penetration was driven by strong hydroelectric output from Tasmania's hydro fleet, which consistently supplied over 1,000 MW throughout the period. Multiple binding constraint identifiers (F_TASCAP_RREG_0220 and F_T+RREG_0050) with marginal values ranging from 3.69 to 7.46 $/MWh indicate that network or operational constraints were actively limiting dispatch; these constraints added modest upward pressure to the marginal cost of supply but were insufficient to materially elevate prices given the abundant renewable generation available.
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.