Overnight trading was defined by a tale of two markets: soft to negative prices across the southern NEM driven by high wind generation, and persistently elevated prices in Queensland and Tasmania. SA1 opened the day at −$5/MWh at midnight before oscillating through multiple brief negative intervals, while VIC1 touched −$0.10/MWh across several off-peak periods. QLD1 averaged $59/MWh on the day — the highest NEM mainland figure — with a pronounced evening ramp pushing prices into the $130–$165/MWh range between 17:15 and 18:25 AEST. The VIC–NSW interconnector ran northbound at its export limit (856 MW), binding throughout much of the period and sustaining a ~$60/MWh price spread between the two regions. Watch for the winter morning demand ramp in VIC1 and QLD1 as the key price driver through today's early intervals.
TAS1 is the standout region today. At approximately 20:25 AEST on 3 June, Tasmania reached 100% renewable generation — hydro output totalling ~2,680 MW combined with ~260 MW of wind. Despite that milestone, the Regional Reference Price remained measured, ranging $80–$87/MWh, with a daily average of $80/MWh and a maximum of $104/MWh. The result reflects a well-managed supply-demand balance on the island grid. SA1 also recorded 95.9% renewable penetration during the early morning, driven by 1,731 MW of wind and ~425 MW of solar — a separate but equally notable data point for the day.
WA1 was far from quiet. The WEM recorded three discrete price spikes across the trading day: $263/MWh at the 04:00 interval (up 56% from the prior interval's $169/MWh), $361–$372/MWh for approximately 30 minutes around 10:25 AEST, and a further spike to $347/MWh in a single interval later in the day. The daily average of $142/MWh — the highest of any region tracked today — reflects these recurring bursts of tightness. The intraday baseline sat in the $127–$171/MWh range between spikes, suggesting underlying system conditions remained firm throughout.