NEM Overview: Thursday 17 September 2026

NEM spot prices sit in a tight $88-114/MWh band across the mainland this morning, with WA1 the outlier at $132.18/MWh. NSW1 leads the eastern states at $113.94/MWh on demand of 8,213 MW, followed by SA1 at $99.74/MWh, QLD1 at $94.54/MWh, TAS1 at $92.04/MWh, and VIC1 the cheapest at $88.02/MWh. The NSW-VIC spread of roughly $26/MWh is unremarkable for this time of year, and no region is showing signs of scarcity pricing — this is a moderate, well-supplied morning across the grid.

Renewable penetration nationally sits at 47.8%, with wide regional variance. TAS1 is running on 100% renewables (1,067 MW hydro, 434 MW wind), and SA1 sits at 89.2% renewable with wind supplying 902 MW against just 42 MW gas OCGT and 83 MW gas CCGT — carbon intensity there is a low 0.0585 tCO2/MWh. VIC1 renewable share is 41.1% with wind contributing 2,377 MW alongside 3,734 MW brown coal. NSW1 and QLD1 are both tracking near 25-26% renewable, with black coal supplying 5,354 MW and 5,362 MW respectively, the two largest thermal blocks on the system. Cloud cover is heavy in VIC1 and TAS1 this morning (84% and 99%), capping solar output there, while SA1 and QLD1 are clear and cooler, supporting daytime solar ramp as the morning progresses.

The standout operational issue is SA1 voltage support. AEMO has flagged a foreseeable intervention from 2300 hrs tonight (18 September) due to voltage conditions, continuing a pattern of near-daily directions to AGL's Torrens Island B4 unit to remain synchronised over the past week. Traders should expect further directions today given this recurring signature. Separately, AEMO has flagged a Minimum System Load (MSL1) risk in SA1 for Monday 19 September between 1130-1430 hrs AEST, with minimum demand forecast at -178 MW at 1330 hrs — a reminder that strong rooftop solar and wind output continue to push SA1 toward negative operational demand around midday.

Interconnector flows are unremarkable and non-binding: NSW1 is exporting 1,082 MW to QLD1, VIC1 is exporting 248 MW to SA1, and Basslink is flowing 258 MW into VIC1. Grid stress score sits at 67.7, reflecting the ongoing SA1 voltage management rather than any mainland supply tightness. Expect prices to stay range-bound through the day, with SA1 the region to watch for further intervention notices this evening.