Commodity Demand — SA1: Saturday 20 June 2026

South Australia's spot price sits at $90.58/MWh at 06:30 AEST with demand at 1,408 MW — a relatively modest load for a winter morning that nonetheless sits well above the overnight trough of 917 MW reached around 13:50 AEST. The price-demand relationship across today's data is instructive: as demand climbed from that overnight minimum through the morning peak, prices escalated sharply, reaching $259.93/MWh when demand hit 1,909 MW at 18:30 AEST and sustaining intervals above $200/MWh between roughly 18:05 and 19:10 AEST as demand held in the 1,850–1,965 MW band. The sensitivity is non-linear — demand above approximately 1,800 MW consistently produced prices above $120/MWh, while demand below 1,400 MW generally cleared in the $37–$77/MWh range. Wind output is currently 82.72 MW and solar is zero at this pre-dawn hour, with gas CCGT (504.64 MW) and gas OCGT (276.30 MW) carrying the bulk of scheduled generation. Carbon intensity sits at 0.492 tCO2/MWh with renewables at just 9.99% of the mix.

The demand trajectory today traces a classic winter Sunday profile: a slow morning build from the current 1,408 MW toward a forecast morning peak, with the forecast indicating prices rising to $93.75/MWh by 07:00 AEST and escalating sharply through the 17:00–19:30 AEST window. The most exposed period in the forecast is 18:30–19:30 AEST, where the model projects $168–$200/MWh, consistent with what was observed at equivalent demand levels earlier today. The morning ramp from 06:30 to 08:00 AEST is forecast to push prices from $94/MWh to $140/MWh, with the 08:30–10:00 AEST window the highest-priced block of the day at $150–$200/MWh. Wind potential for today is rated extremely low (avg 0.4), and with no solar contribution until mid-morning and minimal output given 17% average cloud cover, dispatchable gas plant is the marginal price-setter through virtually every interval.

One active market notice is directly relevant to SA's interconnector position: the Balranald–Buronga 220kV line constraint (CA_SYDS_594882A3) invoked on the V-SA and V-S-MNSP1 interconnectors remains in force following a short-notice rating change. This limits SA's ability to draw on Victorian capacity during tight periods, placing additional pressure on local gas plant at peak demand and contributing to the price premium SA carries relative to what interconnector flows might otherwise suppress. The Murraylink control issue flagged earlier has since been resolved (constraint set I-CTRL_ISSUE_ML revoked at 22:25), but the V-SA constraint from the Balranald line remains a live factor for today's morning and evening ramps.

For demand-side participants, the lowest-cost windows today sit in the 12:00–13:30 AEST (UTC 02:00–03:30) and 14:30–15:30 AEST (UTC 04:30–05:30) bands, where forecast prices average $68–$