Carbon Forecast: Sunday 31 May 2026

NEM-wide carbon intensity sits at sharply divergent levels across regions at 06:30 AEST. Tasmania is at 0.00 tCO2/MWh with 100% renewable generation — hydro at 1,059 MW and wind at 153 MW accounting for all output. South Australia is at 0.021 tCO2/MWh with renewables at 95.7%, driven by 1,771 MW of wind with only 81 MW of gas CCGT and 49 MW of battery discharge making up the remainder. At the other end of the range, Victoria is the highest-intensity region on the NEM at 0.937 tCO2/MWh with renewable penetration at just 23.2% — 4,369 MW of brown coal dominates the mix, with 1,306 MW of wind the only material renewable contributor and hydro at a negligible 16 MW. NSW sits at 0.634 tCO2/MWh (28% renewables), with 6,264 MW of black coal providing the bulk of generation against 1,080 MW of wind, 797 MW of hydro, and 453 MW of battery discharge. Queensland is comparable at 0.621 tCO2/MWh (29% renewables), with 4,307 MW of black coal, 945 MW of battery, 720 MW of wind, 147 MW of gas OCGT, and 142 MW of hydro.

The intraday trajectory through today is well established by the overnight data. In NSW and QLD, intensity troughed in the 01:00–05:30 AEST window — NSW reached as low as 0.382 tCO2/MWh (57% renewables) and QLD dipped to 0.399 tCO2/MWh (54%) — before morning demand ramp lifted coal dispatch and pushed intensity back above 0.60 tCO2/MWh by 07:00. VIC followed the same pattern, troughing around 0.572 tCO2/MWh in the 03:00–04:30 window before brown coal output lifted intensity through the morning to a peak above 1.03 tCO2/MWh in the 16:30–18:00 AEST range. SA's wind-driven mix has remained consistently low across the entire 24-hour period, ranging only between 0.021 and 0.089 tCO2/MWh, with no material deterioration even through morning peak demand.

For carbon-sensitive scheduling today, the optimal windows have already passed for NSW, QLD, and VIC — those regions are now in their higher-intensity daytime operating band. SA and TAS are effectively open all day for low-carbon load dispatch, with SA intensity expected to remain at or below 0.09 tCO2/MWh provided wind output holds at current levels. The next favourable window in NSW and QLD will open from approximately 23:00–01:00 AEST tonight as overnight demand eases and coal dispatch pulls back relative to wind, likely returning NSW below 0.45 tCO2/MWh and QLD below 0.42 tCO2/MWh based on the pattern observed across the prior overnight period. VIC's next trough will follow the same timing, though even at its overnight low it does not approach SA or TAS intensity levels given the brown coal base