The last seven days of detected price spikes, negative pricing intervals, record renewables and binding grid constraints across the NEM and WEM. 25 May 2026 to 01 June 2026.
South Australia (SA1) experienced sustained negative pricing at $-1/MWh across two consecutive 5-minute intervals (04:05–04:10 on 1 June 2026), following a period of moderately low but positive pricing. This minor severity event occurred during early morning hours when solar generation was ramping up alongside substantial wind output.
South Australia (SA1) experienced exceptionally high renewable energy penetration of 95.5% during the early morning period of 1 June 2026, driven predominantly by wind generation (1,554.52 MW) and solar output (372.37 MW combined). Regional reference prices (RRP) declined steadily from $29.41/MWh to a floor of $18.65/MWh, reflecting the low marginal cost of renewable generation during this period.
Tasmania's electricity grid operated at 100% renewable penetration on 31 May 2026 between 20:05 and 20:30, with hydroelectric generation dominating supply at approximately 850–1,060 MW complemented by wind generation of 150–237 MW. Regional reference prices (RRP) remained relatively stable in the $80–87/MWh range throughout the period, with minor volatility suggesting a well-balanced market without significant supply-demand stress.
A major binding constraint event occurred in TAS1 on 31 May 2026, with the T_BLINK_TV_NGZ transmission constraint reaching an exceptionally high shadow price of $7.308 million, indicating severe transmission congestion. Regional electricity prices remained relatively stable in the $80–97/MWh range during the constraint activation period, suggesting the constraint was effectively limiting generation dispatch rather than driving spot price spikes.
A significant binding constraint (F_T+NIL_MG_R6) emerged in the NEM with an exceptionally high shadow price of $4,720/MWh, indicating severe transmission congestion or capacity limitations in the affected network region. This constraint was substantially more binding than concurrent constraints, with marginal values an order of magnitude higher than competing limitations.
QLD1 experienced sustained negative pricing during the early morning period of 31 May 2026, with minimum prices reaching -$1.18/MWh across 2 intervals. This minor event occurred during the 02:25–02:55 period, with prices fluctuating between $0 and -$1.50/MWh across seven consecutive settlement intervals.
NSW1 experienced brief negative pricing during the early morning of 31 May 2026, with spot prices reaching -$1.48/MWh in a single interval and sustaining around -$1.20/MWh. This minor event occurred across two intervals during an off-peak period characterised by high renewable generation (3,686 MW of wind and solar combined).
South Australia 1 (SA1) experienced a high renewable penetration event at 87.3% during the early morning period of 31 May 2026, with wind and solar generation collectively providing approximately 880 MW of the region's output. This high renewable penetration coincided with sustained negative spot prices ranging from -$1.88/MWh to -$0.10/MWh across five consecutive settlement intervals, indicating oversupply conditions.
South Australia (SA1) experienced brief negative pricing of approximately -$0.11/MWh across two consecutive intervals (00:15 and 00:20 on 31 May 2026), representing a minor pricing event. This followed a sharp price collapse from $1.10/MWh to negative territory, indicating a sudden surplus of renewable generation relative to demand.
Victoria (VIC1) experienced sustained negative pricing during two consecutive intervals on 31 May 2026 (00:10–00:15), with prices reaching −$0.10/MWh. This followed a period of near-zero pricing around midnight, reflecting oversupply conditions in the region during low-demand evening hours.
Tasmania achieved 100% renewable energy penetration on 30 May 2026 between 20:05 and 20:30, with hydroelectric and wind generation combining to meet all demand whilst gas-fired generation remained offline. Regional Reference Prices (RRPs) remained stable at approximately $80/MWh during this period, with a minor increase to $81.76/MWh in the final two intervals.
South Australia (SA1) experienced brief negative pricing with a minimum of -$0.11/MWh across two consecutive intervals (16:45 and 16:50 on 30 May 2026), representing a minor market event. Prices oscillated sharply between negative and positive territory during this period, with the negative pricing episodes separated by an interval of positive pricing at $8.51/MWh.
Victoria (VIC1) experienced minor sustained negative pricing over two intervals on 30 May 2026, with prices falling to approximately –$0.10/MWh around 17:00, following earlier positive pricing in the $5–$6/MWh range. The brief negative-pricing window reflects an oversupply condition in a tight dispatch window, before prices recovered to near zero.
The WEM experienced a major price spike in WA1 at 06:10 on 30 May 2026, with the RRP surging to $367.44/MWh—more than double the preceding interval price of $179.63/MWh. This spike occurred across a single trading interval during the early morning period, representing a sudden and significant market disruption.
South Australia (SA1) experienced brief negative pricing of -$0.09/MWh across two consecutive five-minute intervals (02:10–02:15 on 30 May 2026), representing a minor market event. The negative pricing occurred during the early morning period and was preceded by a sharp price spike to $9.10/MWh in the preceding interval, suggesting volatile supply-demand conditions.
Victoria (VIC1) experienced sustained negative pricing at -$0.10/MWh across two consecutive intervals (02:10–02:15) on 30 May 2026, with prices remaining near-zero in the following interval. This represents a minor but notable event driven by structural oversupply during an off-peak period with strong renewable generation.
South Australia (SA1) experienced extremely high renewable penetration of 97.6% on 30 May 2026 during the early morning period, driven by substantial wind generation of 1,714.54 MW and solar generation of 590.35 MW combined. This high renewable output resulted in volatile pricing, with the region reaching negative prices (down to -$0.09/MWh) at several settlement intervals between 02:10 and 02:30, indicating oversupply conditions.
QLD1 experienced sustained negative pricing of approximately $-2/MWh across two consecutive 5-minute intervals (00:15 and 00:20 on 30 May 2026), representing a minor market event during the overnight period. Prices subsequently recovered to $-1.35/MWh before returning to zero, indicating temporary oversupply conditions that were quickly resolved.
Tasmania (TAS1) achieved 100% renewable energy penetration during the evening of 29 May 2026, with hydroelectric generation totalling approximately 2,019 MW and wind generation around 519 MW, completely displacing fossil fuel generation. Spot prices remained relatively stable in the $87–$92/MWh range during this period, reflecting the low marginal cost of renewable generation.
A high-value binding constraint (F_T+NIL_MG_R6) emerged in the NEM with a shadow price of $4,419.79/MWh, indicating severe transmission congestion or network limitation in the Tasmanian interconnector or related regional constraint. This constraint dominated dispatch pricing, appearing multiple times across the binding constraint stack with the highest marginal value by a significant margin.
A major binding constraint on the Basslink interconnector (T_BLINK_TV_NGZ) manifested in Tasmania on 29 May 2026, generating an exceptionally high shadow price of $7.31 million, indicating severe congestion limiting power transfer between Tasmania and Victoria. Despite this substantial constraint value, regional reference prices remained modest at approximately $97/MWh, suggesting the constraint was effectively managing demand without triggering widespread price spikes.
The WEM experienced a significant price spike in WA1 at 04:55 on 29 May 2026, with the spot price reaching $310.03/MWh—a 42% increase from $218.76/MWh just five minutes earlier. This spike occurred as an isolated event within a single trading interval during the early morning period.
SA1 experienced high renewable penetration at 86.1% during the early morning trading period of 29 May 2026, with wind generation comprising the dominant source at 1,066.79 MW, supported by solar output of approximately 178 MW combined. Regional Reference Energy Prices (RRPs) remained relatively stable in the $68–$70 range across the five-minute settlement intervals, reflecting the abundant renewable supply.
Tasmania experienced a critical binding constraint event on the Blinking Billy to Tasmanian Valley transmission corridor (T_BLINK_TV_NGZ) with an exceptionally high shadow price of $7.31 million, indicating severe network congestion. Regional electricity prices ranged between $97–106/MWh during the event window (22:55–23:30 on 28 May 2026), reflecting the transmission limitation's impact on dispatch costs.
Tasmania achieved 100% renewable energy penetration during the evening of 28 May 2026, with hydroelectric generation supplying approximately 3,315 MW across the region whilst gas-fired generation remained offline. Prices remained relatively stable in the $87–$98/MWh range during this period, with the constraint F_T+NIL_MG_R6 binding with marginal values between $9–$21/MWh, indicating some transmission or network limitations.
A major binding constraint (T_BLINK_TV_NGZ) emerged in Tasmania on 28 May 2026 with an exceptionally high shadow price of $7.308 million, indicating severe transmission congestion on the Basslink interconnector between Tasmania and Victoria. Regional retail electricity prices remained relatively stable in the $97–102/MWh range during the constraint event, reflecting the constraint's localised impact on interconnector flow rather than wholesale price spiking.
The WEM experienced a moderate price spike in WA1 on 28 May 2026, with the spot price jumping from $178.50/MWh to $254.94/MWh over a five-minute window (10:35 to 10:50). The price escalation occurred across a single trading interval, representing a 43% increase from the preceding steady-state pricing.
QLD1 experienced sustained negative pricing during two intervals on 28 May 2026 at 04:25–04:30, with minimum prices reaching -$7.33/MWh, indicating oversupply conditions in the early morning period. The event was relatively minor and brief, occurring within a broader pattern of negative pricing between 04:25 and 04:50, with prices deteriorating further to -$25/MWh in subsequent intervals.
Tasmania's Blinking interconnector constraint (T_BLINK_TV_NGZ) became severely binding on 28 May 2026, generating an exceptional shadow price of $7.31 million per MWh—indicating critical transmission limitations preventing optimal power flows between Tasmania and Victoria. Regional prices spiked to $130.51/MWh by 03:00, with the constraint effectively restricting market competition and forcing higher-cost generation to clear the market during overnight periods.
Tasmania's electricity market reached 100% renewable generation on 27 May 2026, driven entirely by hydroelectric output (approximately 1,100–1,170 MW) with minor wind contributions. Prices remained elevated in the $87–$98/MWh range during the evening peak period, despite the high renewable penetration and zero gas generation.
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.