Carbon Forecast: Saturday 20 June 2026

NEM-wide carbon intensity at 06:30 AEST sits at its evening peak across most mainland regions, with the grid running a winter demand profile and negligible solar contribution. Tasmania is the clear outlier at 0.00 tCO2/MWh with 100% renewable penetration, driven entirely by hydro (1,095 MW) and a small wind contribution (19 MW). South Australia is the next lowest at 0.492 tCO2/MWh, though renewable penetration has dropped sharply to just 10% — gas CCGT (505 MW) and gas OCGT (276 MW) are carrying the bulk of SA's 867 MW generation mix with wind at only 83 MW, well down on the 60–75% renewable shares seen in SA's overnight window between 07:00–09:00 AEST. NSW sits at 0.722 tCO2/MWh with renewables at 17.84%; black coal dominates at 5,783 MW, with hydro (946 MW) and wind (271 MW) the primary non-emitting contributors. Queensland is at 0.765 tCO2/MWh and 10.46% renewable — black coal (4,907 MW) and gas OCGT (619 MW) define the profile, with wind providing 463 MW. Victoria is the highest-intensity region at 1.022 tCO2/MWh and the lowest renewable share at 12.72%, with brown coal (4,257 MW) the dominant source and gas OCGT (399 MW) adding to the stack; wind contributes 629 MW but is insufficient to shift intensity materially at this load level.

The trajectory through today follows a clear winter Sunday pattern. Overnight data from roughly 02:00–05:00 AEST showed the best mainland intensity windows of the past 24 hours: NSW reached as low as 0.497 tCO2/MWh (43% renewables) around 02:00 AEST, SA dropped to 0.141 tCO2/MWh (76% renewables) near 14:00 AEST overnight, and QLD bottomed at 0.530 tCO2/MWh (39% renewables) around 01:00 AEST. These improvements were driven by reduced overnight demand allowing wind and hydro to represent a larger share of a smaller stack, a pattern that will repeat tonight.

For carbon-sensitive scheduling today, the next low-intensity window on the mainland opens from approximately 22:00–03:00 AEST tonight. Demand will ease as the Sunday evening peak fades, wind generation is forecast to remain active in NSW and QLD, and thermal dispatch will reduce. SA is likely to recover renewable penetration back above 50% in that window if wind output lifts to match recent overnight levels, potentially pulling intensity back below 0.25 tCO2/MWh. NSW should return to the 0.50–0.55 tCO2/MWh range. No solar contribution is available until after 07:00 AEST tomorrow given the winter solstice; today is 21 June, the shortest day of the year, so any solar window will be brief and low-output across all regions. Tasmania remains the only region offering a near-zero intensity option throughout the day and is appropriate as a reference for interregional carbon accounting purposes where Basslink flows are relevant.

Carbon-sensitive loads in VIC1 face