Carbon Forecast: Monday 25 May 2026

NEM-wide carbon intensity sits at markedly different levels across regions at 06:30 AEST. Tasmania is at 0.00 tCO2/MWh with 100% renewable penetration, driven entirely by hydro (1,040 MW) and wind (214 MW). South Australia is next at 0.43 tCO2/MWh with 26% renewables, though that mix is currently gas-heavy — OCGT at 457 MW and CCGT at 395 MW dominate, with wind contributing only 128 MW and solar yet to materialise. NSW sits at 0.71 tCO2/MWh (19% renewables), with black coal at 6,223 MW accounting for the bulk of output. Queensland is at 0.72 tCO2/MWh on 16% renewables, with black coal at 4,740 MW and OCGT at 648 MW. Victoria carries the highest intensity on the mainland at 0.95 tCO2/MWh on 22% renewables, with brown coal at 4,566 MW and wind at 1,093 MW the two dominant sources.

The data pattern across the past 24 hours reveals a clear structural feature: each region records its lowest intensity in the overnight-to-early-morning window (roughly 09:30–14:30 AEST the previous cycle), when coal scheduling stays relatively flat but wind output is sustained and — in the pre-dawn period — NEM-wide demand is at its softest. SA reached as low as 0.09 tCO2/MWh overnight when wind was supplying over 84% of local demand. NSW troughed near 0.53 tCO2/MWh and QLD near 0.57 tCO2/MWh in the same window. The morning demand ramp from around 05:30–08:00 AEST consistently pushes intensity up across all mainland regions as gas peakers and additional coal capacity are dispatched.

For today's outlook, the most favourable low-intensity windows for carbon-sensitive loads are concentrated in two periods. First, right now through approximately 09:00 AEST — wind is still running, solar hasn't ramped, and demand hasn't peaked. SA in particular can offer sub-0.25 tCO2/MWh windows if wind output recovers toward overnight levels; currently it is suppressed at 128 MW, which explains why SA intensity is elevated relative to its overnight performance. Second, a midday solar window is expected from roughly 10:00–14:00 AEST in NSW, VIC, and QLD, which historically shaves 0.05–0.10 tCO2/MWh off intensity in those regions on autumn days with reasonable irradiance. Tasmania remains at or near zero intensity throughout the day regardless of the time window.

Carbon-sensitive scheduling should prioritise Tasmania for any interconnect-accessible loads, note that SA's current gas-dominant mix makes it less attractive than its overnight profile suggests, and treat the 18:00–21:00 AEST evening peak as the highest-intensity period across all mainland regions — QLD reached 0.81 tCO2/MWh at 05:25 AEST (19:25 UTC) in the last cycle, the highest recorded reading in the dataset.