The last seven days of detected price spikes, negative pricing intervals, record renewables and binding grid constraints across the NEM and WEM. 13 May 2026 to 20 May 2026.
NSW1 experienced sustained negative pricing of approximately $-9/MWh for two consecutive intervals (03:10–03:15) on 20 May 2026. This minor severity event occurred during a period of very low electricity demand in the early morning, with prices dropping sharply from positive levels before recovering.
A severe binding constraint on the Quorn to Playford network path (C_N_QUORNP_009_L_H) in the NEM resulted in an exceptionally high shadow price of $7.308 million, indicating extreme scarcity of transmission capacity on this critical link. This constraint binding far exceeded typical network limitations, suggesting a significant supply-demand imbalance or generation configuration that created bottleneck conditions on South Australia's interconnecting infrastructure.
QLD1 experienced minor negative pricing with a minimum price of -$1.5/MWh across two settlement intervals on the evening of 19 May 2026. The negative pricing was brief and sporadic, with prices returning to zero or near-zero levels in adjacent intervals, indicating a temporary supply-demand imbalance rather than sustained constraint.
Tasmania (TAS1) reached 100% renewable energy penetration on 19 May 2026, with hydro and wind generation totalling approximately 3,444 MW whilst all gas-fired generation remained offline. Regional reference prices remained stable at $96.18/MWh across the nine consecutive settlement intervals, indicating a well-balanced supply-demand situation despite the high renewable share.
South Australia (SA1) experienced high renewable penetration of 85.5% on 19 May 2026 during the early morning period, driven predominantly by strong wind generation of 873 MW combined with solar output of approximately 408 MW. The high renewable influx resulted in a downward pressure on spot prices, which fell from 65–66 $/MWh to approximately 34 $/MWh over the 35-minute period.
Tasmania (TAS1) achieved 100% renewable energy penetration on 18 May 2026 during the evening peak period, with Regional Reference Prices (RRP) remaining stable around $96.22/MWh. The renewable generation was predominantly supplied by hydroelectric output (approximately 2,952 MW combined across multiple generators) supplemented by wind generation (approximately 272 MW), with minimal thermal generation required.
The WEM experienced a moderate price spike in WA1 on 18 May 2026, with the RRP rising sharply to $263.34/MWh during the 10:10 trading interval, representing a 104% increase from the previous interval's $129.05/MWh. This spike was isolated to a single trading interval before prices stabilised, suggesting a temporary supply-demand imbalance or constraint breach.
Tasmania's electricity market experienced a major binding constraint event on the Tasmanian-Blinkwater-Tuggerah 330kV interconnector (T_BLINK_TV_NGZ), with an exceptionally high shadow price of $7.31 million per MWh, indicating severe transmission congestion limiting power flow. Regional electricity prices fluctuated between $96.14–$110.20/MWh during the 05:25–06:00 settlement period, reflecting the constraint's impact on dispatch and pricing.
A high-value binding constraint (F_T+NIL_MG_R6) emerged in the NEM with an exceptionally elevated shadow price of $4,293/MWh, indicating severe congestion or transmission limitations in the Nil Magnet region 6 corridor. This constraint was significantly more binding than concurrent constraints, with shadow prices an order of magnitude higher than competing binding limitations such as Tasmanian capability constraints.
Tasmania (TAS1) experienced very high renewable penetration at 95.2% on 17 May 2026 during the evening period, driven primarily by substantial hydroelectric generation totalling approximately 3,158 MW across multiple units. Regional electricity prices remained relatively stable in the $96–$110/MWh range during this period, with minor volatility likely reflecting the transition from daylight hours when rooftop solar generation ceases.
A major binding constraint (T_BLINK_TV_NGZ) in Tasmania emerged on 17 May 2026 at approximately 16:35–17:00 with an extremely high shadow price of $7.308 million, indicating severe transmission congestion on the Basslink interconnector between Tasmania and Victoria. Whilst region reference prices remained relatively modest at approximately $96–$101/MWh, the constraint's marginal value suggests critical limitations in power transfer capacity during this period.
A severe binding constraint event occurred on the Basslink interconnector (T_BLINK_TV_NGZ) in Tasmania on 17 May 2026 at approximately 11:05 UTC, with an exceptionally high shadow price of $7.308 million indicating acute transmission congestion. Regional reference prices spiked sharply from ~$96/MWh to $110.08/MWh during the constraint binding, reflecting the tight supply-demand balance and limited interconnector capacity.
A critical binding constraint (T_BLINK_TV_NGZ) on the Basslink interconnector between Tasmania and Victoria activated in TAS1 on 17 May 2026, generating an exceptionally high shadow price of $7.31 million, indicating severe transmission congestion. Regional electricity prices spiked modestly to $114.13/MWh during the constraint event, reflecting the transmission limitation's impact on market dispatch. The constraint remained binding across multiple settlement periods during the early morning trading session.
The WEM experienced a moderate price spike in WA1 on 16 May 2026 at 20:10, with the RRP jumping to $263.34/MWh—a 65% increase from the previous interval's $174.40/MWh. The spike was isolated to a single five-minute trading interval within an otherwise stable evening pricing period.
Tasmania achieved 100% renewable electricity generation on 16 May 2026 between 17:35 and 18:00, with hydro and wind sources combining to meet all demand. Regional reference prices (RRP) remained moderate at approximately $88–$97/MWh during this period, reflecting the abundant renewable supply.
A major binding constraint (T_BLINK_TV_NGZ) emerged in Tasmania on 16 May 2026 at approximately 17:35–18:00, with an exceptionally high shadow price of $7.308 million indicating severe transmission congestion on the Blinking Billy to Table Valley circuit in the non-governed zone. Regional electricity prices remained moderate at $88–97/MWh despite the constraint, suggesting the binding limit was reached before wholesale prices fully reflected scarcity conditions.
A major binding constraint on the Blink-Tarraleah to Northgate 220 kV transmission line (T_BLINK_TV_NGZ) in Tasmania resulted in an exceptionally high shadow price of $7.308 million, indicating severe transmission congestion. The constraint significantly impacted dispatch economics, with spot prices rising sharply to $115.16/MWh in the 10:50 settlement interval, up from the ~$96/MWh baseline observed in preceding periods.
The WEM experienced a moderate price spike in WA1, with the RRP reaching $255.20/MWh during the 20:40 interval on 15 May 2026, representing a $23.16/MWh increase from the preceding interval. The spike was isolated to a single trading interval, with prices moderating slightly to $252.87/MWh in the following period, suggesting transient supply-demand tension rather than sustained market stress.
Tasmania achieved 100% renewable energy penetration on 15 May 2026 during the evening peak period, with hydroelectric generation (approximately 1,512 MW combined) and wind generation (approximately 708 MW combined) meeting all electricity demand. Regional reference prices remained stable around $95–96/MWh for most of the period, before rising sharply to $105.92/MWh in the final 5-minute settlement interval.
The WEM experienced a moderate price spike in WA1 on 15 May 2026, with the regional reference price (RRP) reaching $253.86/MWh during the 10:15 trading interval, representing a sharp 41% increase from the preceding five-minute period. This spike was isolated to a single trading interval, with prices subsequently stabilising in the $180–$210 range before the event.
The Western Australian Wholesale Electricity Market (WEM) recorded a moderate price spike of $261.04/MWh at midnight on 15 May 2026, occurring across a single trading interval. This followed a sustained period of elevated prices in the preceding half-hour, with prices climbing from $163.65/MWh to a peak before easing slightly and then surging to the interval high. The spike, while notable, remains well below the WEM market price cap, indicating a moderate tightening of supply conditions rather than a full emergency dispatch scenario.
South Australia recorded near-total renewable penetration of 97.8% during the late evening period of 14 May 2026, driven overwhelmingly by wind generation of approximately 1,737 MW alongside modest solar contributions. Spot prices were highly volatile across the observed settlement intervals, swinging from near-zero and slightly negative values (0 $/MWh and -$0.04/MWh) to spikes above $100/MWh, reflecting the inherent instability of a grid operating with minimal dispatchable thermal backing. Overall, the event was classified as minor, with gas plant (CCGT and OCGT) providing a small but critical system security role.
Tasmania's grid achieved 100% renewable penetration during the 17:40–18:00 AEST window on 14 May 2026, powered entirely by a combination of hydro (approximately 757–778 MW) and wind generation (approximately 170–181 MW), with no gas-fired generation dispatched. Spot prices remained relatively stable and modest, ranging between $88.16 and $88.79/MWh, indicating a well-supplied market with no significant price stress despite the high renewable share.
The Western Australian Wholesale Electricity Market (WEM) recorded a moderate price spike of $251.27/MWh at 17:50 AWST on 14 May 2026, occurring across a single trading interval. This spike was the culmination of a sustained price escalation over the preceding 25 minutes, with prices rising from approximately $176/MWh at 17:25 through to the peak, representing a roughly 43% increase over that period. The event is classified as moderate in severity and was short-lived, confined to one interval at the peak price.
The Western Australian Wholesale Electricity Market (WEM) recorded a moderate price spike reaching $260.53/MWh at 08:30 AWST on 14 May 2026, sustained across a single trading interval. Prices had been escalating progressively over the preceding 25 minutes, rising from approximately $215/MWh to the peak, suggesting a sustained tightening of supply conditions rather than an instantaneous shock. The spike remained well below the WEM market price cap, classifying it as a moderate event.
A major binding network constraint, T_BLINK_TV_NGZ, was active in Tasmania (TAS1) on 14 May 2026 during the 06:40–07:05 AEST window, recording an exceptionally high shadow price of $7,308,000. Despite this constraint, spot prices in TAS1 remained relatively modest and stable, ranging between approximately $106 and $107/MWh, suggesting the constraint did not directly trigger a price spike in the region. The Tasmanian generation mix at the time was dominated by hydro output of roughly 1,040–1,160 MW alongside 119–142 MW of wind generation.
The Western Australian Wholesale Electricity Market (WEM) experienced a moderate price spike of $263.34/MWh at 00:25 AWST on 14 May 2026, occurring across a single five-minute trading interval. This represents a sharp escalation from the preceding intervals, where prices had been trending in the $135–$173/MWh range before surging nearly 90% above the immediately prior interval. The spike was brief and isolated, with no sustained elevated pricing observed across the sampled period.
South Australia recorded a very high renewable penetration of 96.05% during the late evening period on 13 May 2026, driven predominantly by wind generation (781.71 MW) supplemented by solar (386.98 MW combined) and small battery contributions. Spot prices remained relatively modest, ranging between approximately $23.57 and $35.72/MWh across the observed dispatch intervals, indicating the grid was managing the high renewable share without significant stress. A minimal gas presence (primarily OCGT at 143.96 MW and CCGT at 43 MW) provided stabilising capacity.
Tasmania's grid achieved 100% renewable penetration during the early evening of 13 May 2026, driven entirely by hydro and wind generation with no gas-fired output recorded. Generation was approximately 1,050–1,065 MW in aggregate across the interval, with hydro contributing the majority (~850–870 MW) and wind providing the remainder (~175–200 MW). Wholesale prices remained stable and unremarkable at $96.24/MWh throughout the observed period.
Events are detected automatically by gridIQ from AEMO dispatch and constraint data, then enriched with AI-generated causal analysis. For the full searchable archive, see the event history. For deeper context on price spikes and negative pricing, read the negative-price explainer or browse live electricity prices by region.