Resolves YES if the Western Australia South West Interconnected System (SWIS) Wholesale Electricity Market (WEM) time-weighted annual average wholesale price for calendar year 2028 exceeds A$150/MWh, as reported by AEMO on its WEM data dashboard and Quarterly Energy Dynamics WA section.
Resolution evaluated once on the settlement date against the published figure.
Settlement: 31 May 2029 — about five months after year-end, allowing AEMO time to publish confirmed calendar-year averages.
Created: 2026-05-04
The forward drivers, project schedules, and strike calibration below reflect public information available on the creation date. Coal-plant retirement dates, transmission and storage commissioning, gas-supply contracts, capacity auctions, and policy interventions in electricity markets have moved repeatedly in both directions over the past several years and are likely to continue moving. The notes below are a starting point, not a forecast — they may be materially out of date within months. Cross-check current operator schedules, ISP/ESOO updates, and exchange forward-curve prices before forming a view.
Recent history — WA SWIS annual average (A$/MWh, calendar year)
2020: ~A$30
2023: ~A$90 (price-tripling story per Australia Institute, Dec 2024)
2025: Q3 A$101.76 (+27% YoY), AEMO QED Q3 2025
SWIS pricing tracks domestic gas tightly — about one-third of WA electricity is gas-fired, and exposure to LNG-export-linked gas pricing has grown since the 2020 onshore gas export approvals.
What could push 2028 higher
Capacity shortfall. AEMO's 2025 WEM ESOO forecasts a 425 MW capacity shortfall for 2027–28 (assuming all probable projects), 932 MW without. Reserve Capacity Price for 2028–29 is set at A$491,700/MW (ERA, 2025).
Coal retirements. Collie Power Station (~340 MW) closes late 2027. Muja D follows in late 2029.
Bluewaters supply uncertainty. Bluewaters (~440 MW) coal supply: Griffin Coal mining State Agreement expires mid-2026; without replacement, capacity loss extends well beyond Collie.
Domestic gas pricing linked to LNG-export parity continues to rise; WA gas-fired marginal pricing accordingly.
What could push 2028 lower
Investment pipeline. ~1,600 MW committed and probable generation + storage (728 MW battery storage) potentially online by 2027–28.
Federal Capacity Investment Scheme co-investment in WA targeting additional ~1 GW renewables and storage through 2027.
Rooftop solar penetration continues, suppressing daytime prices and deepening the duck-curve trough.
Battery commissioning at scale (Synergy Kwinana, Collie) shifts cheap midday solar into evening peak.
How the A$150/MWh strike was calibrated (as of creation date)
Anchor: 2025 trailing A$100+ (Q3 actual A$101.76).
Net of factors: Capacity shortfall + Collie closure + gas-price linkage all push directionally up; renewable / battery buildout offsets but unlikely to fully absorb coal loss immediately. A$150/MWh sits above the current trailing average but consistent with capacity-shortfall pricing observed historically in tight reserve-margin years.
The strike itself does not move; the underlying capacity balance and gas trajectory certainly will.
Alcoa relevance
Alcoa's Western Australian alumina refineries (Wagerup, Pinjarra, Kwinana) are among the largest electricity consumers in WA; combined load exceeds 600 MW, predominantly gas-fired CHP plus grid draw. Sustained SWIS > A$120/MWh raises gas-cost passthrough and erodes refinery cash margin — particularly significant for Kwinana, which was placed in care-and-maintenance in 2024.
Forward-curve reference
No deep public forward curve for SWIS; consult AEMO 5MS data dashboard and ERA published energy-offer-price ceilings.
Resolution sources (priority order)
AEMO WEM Quarterly Energy Dynamics — WA section (2028 reports)
ERA WEM market summary
Open Electricity SWIS view for cross-check
Related markets across the cluster (calendar year 2028)
Upstream supply:
Producers (CY2028):
Electricity hubs (CY2028):
Same market, other calendar year:
1,000