A textbook overnight-to-morning pattern played out across the NEM: negative pricing hit five of six mainland/island regions between 21:00 and 07:00 as wind, solar and inflexible coal baseload combined to oversupply the grid, before a sharp evening-to-morning ramp reversed the picture entirely. NSW1 led the turnaround, spiking to $293.79/MWh by 06:30 AEST on demand of 7,673 MW, with VIC1 ($252.65/MWh), TAS1 ($233.80/MWh) and QLD1 ($246.61/MWh) all riding the same peak-demand wave. A binding constraint (F_T+RREG_0050) touched a $1,002/MWh shadow price at points overnight, underlining tight regulation conditions during the transition. Watch the evening peak again today for a repeat of this negative-to-triple-digit swing.
South Australia was the standout: 95–100% renewable penetration in the early hours (636 MW wind, 439 MW solar) drove prices as low as -$20/MWh, while carbon intensity fell to 0.137 tCO2/MWh — the lowest on the mainland. Heywood interconnector sat pinned at its -304.78 MW import limit exporting VIC1-to-SA1 power, and SA1 later swung to a $198/MWh daily peak as the evening ramp took hold, a 24-hour range of well over 200 MWh/MWh in either direction.
WA1 traded in a comparatively tight band, averaging $104/MWh over the past 24 hours with a $137/MWh peak — no extreme events reported. Compared with the volatility on the east coast, WA's day was orderly, though the average sits above most NEM regions' 24-hour averages.
No LOR conditions are forecast across the NEM in the next 48 hours. East-coast gas hub prices firmed slightly day-on-day, with STTM Brisbane at $10.91/GJ and STTM Adelaide at $10.60/GJ (both up from $10.82/GJ and $10.20/GJ respectively). LGCs continued to soften, closing the week ending 28 August at $7.25, down from $8.50 a fortnight earlier.