Carbon Forecast: Monday 18 May 2026

NEM carbon intensity at 06:30 AEST sits at opposite extremes across the five regions. Tasmania is at 0.00 tCO2/MWh with 100% renewable generation — hydro at 1,069 MW and wind at 105 MW accounting for all output. South Australia is next at 0.17 tCO2/MWh with 69.7% renewables, driven by 1,129 MW of wind against a gas mix of 198 MW OCGT and 294 MW CCGT. At the other end, Victoria sits at 0.93 tCO2/MWh with renewables at just 18.8% — 3,818 MW of brown coal dominates the mix, supplemented by 539 MW gas OCGT and 960 MW wind. NSW is at 0.71 tCO2/MWh (19.0% renewable), with 6,668 MW of black coal doing most of the work alongside 925 MW hydro and 482 MW wind. Queensland sits at 0.69 tCO2/MWh on 18.2% renewables, with 4,144 MW black coal and 934 MW gas OCGT the primary sources at this hour.

The day's trajectory is clearly visible in the data. SA has run an extended low-intensity window since approximately 14:30 AEST yesterday, when intensity fell below 0.21 tCO2/MWh on wind penetration climbing above 60%, and that window is still open now. The SA minimum of 0.16 tCO2/MWh was recorded around 20:00–19:30 AEST overnight. NSW and QLD both saw their cleanest periods in the overnight-to-early-morning band (roughly 02:30–09:00 AEST), with NSW intensity touching 0.60 tCO2/MWh and QLD around 0.44 tCO2/MWh during the pre-dawn wind period. Both regions have since deteriorated as morning demand ramps and solar has yet to contribute meaningfully at this hour. VIC experienced a sharp intensity spike from 12:00 AEST yesterday, jumping from 0.82 to above 1.03 tCO2/MWh and sustaining that level through the evening peak — it is now tracking down from that peak but remains elevated.

For carbon-sensitive loads, the current window is actionable in SA and TAS. SA has sustained sub-0.20 tCO2/MWh intensity for several hours and wind generation remains strong at 1,129 MW; barring a wind drop, this window is likely to persist through the morning. TAS is effectively zero-carbon for scheduling purposes at 0.00 tCO2/MWh. In NSW and QLD, the next lower-intensity window tied to solar generation will begin to develop from roughly 08:00–09:00 AEST as utility solar ramps, though winter irradiance limits the magnitude — expect modest intensity reductions of 0.05–0.10 tCO2/MWh rather than the deeper troughs seen in the warmer months. VIC offers no near-term low-intensity window; brown coal baseload is inflexible and wind at 960 MW is insufficient to shift the regional intensity materially until the mix changes structurally.