NEM Overview: Wednesday 20 May 2026

Spot prices are sitting in a tight $102–$140/MWh band across the NEM at 06:25 AEST, with NSW1 the highest at $140.41/MWh on demand of 8,231 MW, followed by SA1 at $138.00/MWh and QLD1 at $131.67/MWh. VIC1 prints $128.72/MWh against 5,774 MW of demand, while TAS1 is the clear outlier at $102.20/MWh — a $38/MWh discount to NSW1 that reflects Tasmania's near-full hydro dispatch (1,218 MW hydro, 60 MW wind, 100% renewable penetration). The NSW1–QLD1 spread is worth watching: the NSW1–QLD1 interconnector is binding at its import limit of –440 MW, meaning Queensland is pushing power south at the interconnector ceiling and constraining further flow. That binding condition is likely contributing upward pressure on NSW1 prices relative to QLD1's $131.67/MWh.

NEM-wide renewable penetration sits at 39.9% per the current grid score. The bulk of that comes from NSW1 (hydro 1,166 MW, wind 549 MW, battery 251 MW discharging) and QLD1 (wind 854 MW, battery 503 MW discharging, hydro 97 MW). SA1's renewables are modest this interval — wind at 150 MW and near-zero solar given the overnight hour — with gas OCGT (364 MW) and CCGT (395 MW) carrying the load against 1,394 MW of regional demand; carbon intensity there is 0.47 tCO2/MWh. VIC1 is running predominantly on brown coal (4,385 MW) with minimal wind (63 MW) and hydro (46 MW), giving it the highest carbon intensity on the NEM at 1.11 tCO2/MWh. Grid stress is elevated at 75/100, consistent with the binding NSW1–QLD1 interconnector and the South Morang F2 500/330 kV transformer outage in VIC1, which remains active until 17:00 today and is constraining inter-regional transfer limits across T-V-MNSP1, V-SA, VIC1-NSW1, and V-S-MNSP1 (constraint set V-SMTX_F_R invoked).

Two active market notices warrant attention. The South Morang F2 transformer outage (scheduled off until 17:00 AEST today) is the most operationally significant — it continues to bind transfer equations across multiple interconnectors and traders should monitor for constraint relaxation near the 17:00 return. Separately, a QLD1 non-conformance was declared against SWANBBF1 at 21:25–21:30 last night (–117 MW deviation), and while that event has cleared, it signals unit behaviour worth tracking in Queensland's balance today. The Mudgeeraba–Terranora lightning reclassification in QLD1 has been cancelled and reverted to non-credible; no constraint sets remain invoked. The most recent MT PASA (19 May) identifies no low reserve conditions across the forward outlook.

For today's trading, the morning demand ramp will be the key test. NSW1 temperatures are forecast to reach