Carbon Forecast: Wednesday 20 May 2026

Tasmania is reading 0.00 tCO2/MWh at 100% renewable penetration — entirely hydro and wind — and is the lowest-intensity region on the NEM by a wide margin. South Australia sits at 0.4761 tCO2/MWh with 16.76% renewables, driven by gas OCGT (425 MW) and gas CCGT (404 MW) carrying the bulk of the 996 MW total, with wind contributing 109 MW and battery 58 MW. NSW is at 0.6511 tCO2/MWh with 25.96% renewables; black coal at 6,230 MW dominates, offset partially by hydro at 1,308 MW, wind at 490 MW, and battery at 360 MW. Queensland is near-identical at 0.6499 tCO2/MWh and 25.53% renewables, with black coal at 5,043 MW and wind at 946 MW the two largest contributors. Victoria is the highest-intensity region on the NEM at 1.0492 tCO2/MWh with only 9.3% renewables; brown coal at 4,408 MW is the dominant fuel, supplemented by gas OCGT at 549 MW, with wind contributing just 61 MW and solar at nil.

The day's trajectory is visible in the data. Each mainland region recorded its lowest carbon intensity in the overnight-to-early-morning window — NSW bottomed near 0.44 tCO2/MWh around 11:30–12:00 AEST when wind penetration pushed toward 50%, QLD dipped to 0.42 tCO2/MWh in the same period on similar wind output, and SA reached as low as 0.13 tCO2/MWh pre-dawn on strong wind. Victoria's overnight low was around 0.65 tCO2/MWh. From the morning peak demand period onward, all mainland regions climbed steadily, with VIC exceeding 1.10 tCO2/MWh through the afternoon and early evening as brown coal held its baseload position and wind generation collapsed to near zero. Intensity in all regions is now beginning to ease from the evening peak as demand softens.

For carbon-sensitive loads today, the overnight window from approximately 21:00 to 06:00 AEST represents the lowest-intensity opportunity across NSW, QLD, and SA, driven by wind output in the absence of solar. TAS is available as a low-intensity source at all hours. The post-peak easing now underway will continue through midnight, but NEM-wide intensity is unlikely to return to the day's lows until wind output recovers in the early hours of Friday morning. VIC remains the highest-intensity region throughout the day's dataset with no period below 0.65 tCO2/MWh, reflecting the structural weight of brown coal in that region's mix. Loads with flexibility to shift consumption to 23:00–05:00 AEST will capture the most favourable carbon conditions across the eastern states.