The week of 3–10 May 2026 opened with a tale of two markets: deep negative and near-zero pricing across Victoria and South Australia on Sunday the 3rd, before conditions tightened sharply from Monday evening onward as cooler autumn temperatures began to bite across the southern states. The NEM's transitional autumn demand profile was on full display — overnight troughs pulling prices into negative territory in renewable-heavy regions, while morning and evening peaks delivered sharp upward spikes, particularly in SA1, NSW1, and VIC1 from Tuesday through Friday. By mid-week, the market had clearly shifted gears, with daily averages climbing across most regions and intraday spreads widening considerably.
Tasmania's week was operationally notable, with the persistent binding of network constraint T_BLINK_TV_NGZ attracting shadow prices of $7,308,000/MWh on multiple occasions across the period — one of the more striking constraint signals seen in the region in recent memory. Despite the extreme shadow price, TAS1 spot prices remained contained, largely in the $88–$106/MWh range, indicating the constraint was limiting network flows rather than driving the regional reference price. Tasmania also achieved 100% renewable penetration on multiple evenings throughout the week, a routine operational outcome for the predominantly hydro-based region.
In Western Australia, the Wholesale Electricity Market (WEM) delivered a broadly stable but elevated week relative to NEM averages. WA1 daily averages held in the $82–$116/MWh band across the period, with Tuesday the 5th recording the week's WEM peak average of $116/MWh and an intraday high of $260/MWh — coinciding with the same mid-week demand tightening that pressured eastern markets. Overall, this was an active week with clear autumn demand signals across both markets.
Sunday 3 May was the week's softest session, with SA1 averaging -$1/MWh (touching -$35/MWh intraday) and VIC1 averaging $0/MWh (minimum -$4/MWh). QLD1 and NSW1 also recorded negative minimums on the same day. These negative pricing events reflect strong midday renewable output against subdued Sunday demand — a pattern that has become a regular autumn feature in the southern and south-eastern regions.
The market tone changed materially from Monday 4 May. By Tuesday 5 May, SA1 surged to a daily average of $109/MWh with an intraday peak of $290/MWh, while VIC1 averaged $78/MWh and reached $190/MWh. NSW1 and QLD1 both averaged in the mid-$80s with intraday highs above $150/MWh. The Thursday 9 May session was the week's final strong day, with SA1 averaging $97/MWh (max $145/MWh) and VIC1 $81/MWh (max $126/MWh), driven by the morning winter demand ramp visible in the daily narratives — NSW1 demand recorded at 7,896 MW by 06:35 AEST.
The WEM traded in an elevated but orderly range across the week. Daily averages moved between $82/MWh (8 May) and $116/MWh (5 May), with intraday highs reaching $260/MWh on 5 May and $161/MWh on 6 May. The WEM's relative premium to NEM averages (particularly against VIC1 and SA1 on weaker NEM days) remained evident. Price minimums stayed firmly positive throughout the week — a contrast to the negative pricing seen in several NEM regions — with the weekly floor sitting at $42/MWh on 9 May.
Tasmania was the headline renewable story of the week, achieving 100% renewable penetration on at least six separate evenings between 4 and 10 May. Generation was dominated by hydro, ranging from approximately 215 MW to over 850 MW depending on the session, supplemented by wind contributions of up to 176 MW. Gas OCGT units remained offline across all of these periods, confirming no thermal backup was required. While
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