The week of 17–24 May 2026 delivered a tale of two halves across the National Electricity Market. The opening days — Sunday and Monday — saw elevated wholesale prices across the NEM, with NSW averaging $131/MWh and $181/MWh respectively, and Queensland posting $103/MWh and $176/MWh. Winter demand profiles were firmly asserting themselves, with textbook morning peaks pushing prices well above $200/MWh in multiple regions on 18 May. From Tuesday onwards, however, conditions softened markedly. A combination of strong wind generation, mild overnight demand, and persistent overnight oversupply drove average prices back to mid-double-digit territory across most mainland regions, with Victoria and SA averaging as low as $49–$62/MWh across Wednesday and Thursday.
Tasmania was the standout story of the week, achieving 100% renewable generation on multiple consecutive evenings — 18 through 24 May — driven by hydro and wind. Despite this remarkable run, Tasmanian prices remained relatively firm, averaging $96–$119/MWh across the week, reflecting the persistent activation of the T_BLINK_TV_NGZ transmission constraint. This binding corridor, between Blinking Point and Tasmanian Valley, carried a shadow price of $7.308 million on at least five separate occasions — a recurring signal that internal network congestion, rather than fuel scarcity, was the primary pricing driver in the island state.
In the WEM, Western Australia tracked its own rhythm. WA1 opened the week at an average of $138/MWh on 17 May before easing through the mid-week lull to $99/MWh on 22 May, then rebounding modestly to $117/MWh by 23 May. Two moderate price spikes — $263/MWh on 18 May and $251/MWh on 20 May — punctuated an otherwise orderly market. Overall, the week reinforced winter's grip on demand patterns while simultaneously demonstrating how abundant renewable supply can suppress prices during off-peak windows even as cold-weather loads build through morning and evening peaks.
Price volatility was concentrated in the early part of the week, with 18 May the most elevated day across the NEM. NSW hit a daily average of $181/MWh with an intraday high of $341/MWh; Queensland reached $176/MWh average with a $338/MWh peak; and Victoria averaged $170/MWh with a $300/MWh intraday ceiling. South Australia's 18 May average of $155/MWh reflected similar morning-peak pressure, though wind generation provided a meaningful offset during daylight hours.
The contrast by week's end was sharp. By 23 May, SA averaged just $50/MWh, Victoria $49/MWh, and both QLD and NSW settled around $58/MWh. Negative pricing events were a recurring feature of the quieter overnight and early-morning windows:
Tasmania was the notable exception, with its daily minimum never dipping below $63/MWh across the week — a consequence of constrained export capacity limiting the relief valve that interconnector flows typically provide.
The WEM experienced a moderately active week. WA1 averaged between $99/MWh and $146/MWh across the seven trading days, with the highest average on 18 May at $146/MWh. Two moderate price spikes are worth noting: a single-interval spike to $263/MWh on 18 May at 10:10 AWST, and a spike to $251/MWh on 20 May at 04:35 UTC. Both were isolated to single trading intervals and resolved quickly, suggesting temporary supply-demand imbalances rather than sustained constraint conditions. By 22–23 May, WA1 had settled into a calmer $99–$117/MWh range, broadly consistent with seasonal mid-May norms.
Tasmania's renewable run was the headline of the week. The region achieved 100% renewable penetration on six separate occasions across 18–24 May, with hydro carrying the bulk of the load — often at 2,900–3,600+ MW combined across multiple units — supplemented by wind contributions of 59–272 MW. Notably, gas peaking plant remained offline during several of these periods. Despite the clean generation stack, Ta
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