Carbon Forecast: Thursday 18 June 2026

Queensland sits at the highest carbon intensity on the NEM right now at 0.67 tCO2/MWh with just 19.9% renewable penetration, driven by 4,433 MW of black coal and 968 MW of gas OCGT forming the bulk of its dispatch. NSW is next at 0.53 tCO2/MWh with renewables at 39.5% — wind is contributing 1,983 MW against a black coal base of 3,943 MW, with hydro and a small battery discharge rounding out the mix. Victoria sits at 0.51 tCO2/MWh with 57.5% renewable penetration; 3,885 MW of wind is running alongside 2,873 MW of brown coal, with gas OCGT providing minimal support. At the other end of the scale, South Australia is at 0.01 tCO2/MWh on 97.7% renewables — 1,726 MW of wind is doing virtually all the work, with a token 40 MW CCGT and negligible gas OCGT online. Tasmania holds at 0.00 tCO2/MWh with 100% renewable generation from 975 MW of hydro and 254 MW of wind.

The day's data shows a clear overnight trough in NSW and QLD intensity between roughly 01:00 and 03:30 AEST, when wind output was strongest relative to thermal dispatch. NSW touched 0.46 tCO2/MWh and QLD dipped to 0.54 tCO2/MWh during that window before morning demand ramp-up pulled thermal plant harder. QLD's intensity peaked at 0.72 tCO2/MWh around 10:00 AEST as coal and gas bore the full morning load. Both regions are now on a modest declining trajectory into the early evening as demand eases and wind holds up, though with solar off the board and no overnight solar recovery expected, intensity won't approach the pre-dawn lows again until wind conditions are confirmed.

For carbon-sensitive loads across the NEM tonight, the best scheduling windows are already open in SA and Tasmania — both are effectively at minimum attainable intensity and will remain so through the evening given strong wind across SA and sustained hydro in Tasmania. In NSW, the next low-intensity window is likely between 00:00 and 04:00 AEST Saturday as thermal cycling reduces overnight; expect intensity to edge back toward the 0.47–0.49 tCO2/MWh range seen in the early hours today if wind output is comparable. QLD offers no near-term green window without a significant shift in its generation mix — thermal plant dominates and solar won't contribute until after 06:00 AEST Saturday. Operators with flexibility to shift interruptible load or battery charging to SA or the overnight NSW window will find materially lower emissions exposure there.