NEM Overview: Tuesday 18 August 2026

Spot prices are showing a wide interregional spread this morning, with WA1 the standout at $133.34/MWh while SA1 sits in negative territory at -$4.26/MWh. NSW1 ($64.05/MWh) and QLD1 ($61.01/MWh) trade in the $60s, while VIC1 ($10.65/MWh) and TAS1 ($13.05/MWh) are near the bottom of the range. The VIC1-NSW1 interconnector is exporting 803.6 MW north and is currently binding, helping explain the discount in VIC1 relative to NSW1, while Basslink (T-V-MNSP1, -400.5 MW) and V-SA (250 MW) are also binding, both operating at their limits.

Renewable penetration across the NEM sits at 50.5% on gridIQ's composite score, but the regional split is stark. SA1 is running at 93.56% renewable with wind contributing 1200 MW against total demand of just 1403 MW, and carbon intensity there is very low at 0.032 tCO2/MWh. TAS1 follows at 84.4% renewable (hydro 316.8 MW, wind 358.2 MW), and VIC1 sits at 55.2% with wind output of 3558.5 MW well above brown coal's 2898.2 MW. NSW1 (23.97% renewable) and QLD1 (21.27% renewable) remain more reliant on black coal, with NSW1 black coal generation at 5335 MW and QLD1 at 5118.6 MW; carbon intensity in both regions sits above 0.66 tCO2/MWh.

SA1 is under active AEMO intervention for voltage control, with a direction issued to AGL's Torrens Island B2 unit to synchronise and follow dispatch targets from 0000 hrs today, expected to run until 1500 hrs. This follows a foreseeable intervention notice flagging insufficient synchronous generation to maintain voltage control in the region — worth watching given SA1's high wind share and low synchronous generation base. Grid stress reads 57.6 on today's composite score, and price stability is soft at 47.5, consistent with the wide regional price spread and ongoing interconnector constraints on Basslink and V-SA.

Today's weather outlook supports continued strong wind output in SA1 (8.5% average wind potential) and VIC1, with cooler conditions across the southern states (NSW1 minimum 8.8°C, TAS1 6.2°C) keeping heating demand elevated but cooling demand at zero NEM-wide. Solar potential is modest across the board given cloud cover, with QLD1 the best-placed region for solar today at 26.6% average potential. Traders should watch SA1 pricing closely given the active intervention event and the region's exposure to wind variability against a thin synchronous generation base.