It was a week of two very different markets. The first half (5–7 July) saw firm but unremarkable pricing across the eastern states, with WA1 running persistently hot at averages of $138–157/MWh. Then 8 July delivered the standout event of the week: a severe volatility episode that sent Victorian, South Australian and Tasmanian prices into extraordinary territory, with VIC1 touching a maximum of $19,070/MWh and averaging $359/MWh for the day, alongside TAS1 ($323/MWh average, $17,050 max) and SA1 ($336/MWh average, $16,971 max).
By contrast, the back half of the week swung hard the other way. From 11 to 12 July, sustained wind generation across Victoria, South Australia and Tasmania pushed prices to near-zero or negative for extended stretches — VIC1 and SA1 both averaged just $7/MWh on 11 July, with TAS1 at $12/MWh. Queensland and New South Wales tracked a more conventional path through the week, with NSW1 averaging between $69–116/MWh and QLD1 between $50–88/MWh.
WEM's WA1 region was the most consistent story of the week — persistently elevated pricing well above eastern-state averages, punctuated by repeated moderate spikes into the $250–260/MWh range.
The 8 July event dominates this week's price data. SA1 spiked to $875/MWh across two intervals around 09:15–09:20, following a run-up from $493.89/MWh, while TAS1 hit $382/MWh and VIC1 $366/MWh in the same morning window — all preceding the extreme intraday blowouts that pushed daily averages into the hundreds of dollars. NSW1 also firmed to a $235 maximum that day.
At the other extreme, 11–12 July saw sustained negative pricing across VIC1, SA1 and TAS1, with troughs of −$64/MWh in VIC1, −$7/MWh in SA1 and TAS1, and NSW1 and QLD1 both dipping briefly negative (−$2 and −$1 respectively) in the early hours of 12 July as solar and wind output outpaced overnight demand.
WEM note: WA1 remained the most consistently elevated region in the NEM/WEM comparison all week, averaging between $138–157/MWh with moderate price spikes recurring almost daily — $260.44/MWh (8 July), $252.41/MWh (9 July), $250.03/MWh (10 July), $252.46/MWh (11 July) and $252.46/MWh again on 12 July, alongside a sharper $813 maximum recorded on 7 July. These spikes were generally brief, single-interval events tied to rapid demand ramps rather than sustained shortages.
Tasmania recorded 100% renewable penetration on three separate occasions this week (10, 11 and 12 July), with combined wind and hydro output reaching approximately 1,600 MW and driving regional prices into negative territory each time. South Australia posted several very high renewable readings too — 93.5% on 10 July, 97.7% on 11 July and 97.6% on 12 July — all wind-led, with output ranging from roughly 1,100 MW to 1,800 MW.
Victoria's wind fleet also had a strong week, with output peaking near 7,500 MW on the evening of 11 July alongside around 3,266 MW of brown coal generation — illustrating how large wind contributions and inflexible baseload can combine to create oversupply conditions and negative pricing even with substantial thermal generation still online.
Tasmania's T_BLINK_TV_NGZ constraint bound repeatedly through the week — on 9, 10 and 12 July — each time registering an exceptionally high shadow price of $8.352 million, coinciding with periods of strong hydro output and volatile regional pricing. This recurring constraint is worth watching for anyone with Tasmanian exposure, given its persistence across multiple sessions.
Elsewhere, a major NEM-wide constraint (F_S+TBTU_R1) reached a shadow price of $208,800/MWh around the 8 July volatility event, roughly 2,000 times the value of secondary binding constraints at the time — consistent with the severe price spikes recorded that day. Two further F_T+RREG_0050 constraints registered shadow prices of $368 and $216 during the week.
FCAS pricing was subdued overall. RAISEREG averaged $6.34/MWh for the week — the highest of the eight FCAS services — while all other raise and lower services averaged well under $1/MWh. No material FCAS price spikes were recorded this week.
Gas hub prices eased modestly through the week. Brisbane STTM slipped from $12.27/GJ on 7 July to $11.25/GJ by 12 July, Sydney STTM moved between $11.04 and $11.66/GJ, and Adelaide STTM ranged from $10.51 to $11.51/GJ. Victoria's DWGM tracked in a similar $10.28–$10.66/GJ band across the days reported.
LGC prices continued their recent pullback, closing the week ending 10 July at $5.25 — down from $7.00 the prior week and well below the $8.50 peak recorded for the week ending 26 June. This follows a strong run-up from $2.20 in late May, and the latest reading suggests some moderation after that rally.
With winter demand patterns still driving strong swings between high-wind, negative-price windows and tighter evening peaks, expect continued volatility across Victoria, South Australia and Tasmania. The recurring Tasmanian transmission constraint bears watching, as does WA1's pattern of near-daily moderate price spikes. On the commodity side, keep an eye on whether LGC prices stabilise after recent volatility, and monitor gas hub prices for any tightening as southern winter demand persists.
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