Western Australia Electricity Cost Calculator
Enter your usage details below. Defaults are based on Western Australia's 2025-26 representative rates for the South West Interconnected Network (SWIS). WA operates its own grid separate from the eastern states. Perth has excellent solar conditions, comparable to Queensland.
How the calculations work
Daily cost
Each appliance's daily cost is calculated as:
cost = (watts ÷ 1,000) × usage (kWh/day) × rate ($/kWh) × days + supply charge × days
For example, a 2000W appliance running 3h/day at 30¢/kWh:
(2000 ÷ 1,000) × 3 kWh × 0.30 × 30 days = $5.40
Where the supply charge is a fixed daily cost added regardless of usage.
Solar estimate
Annual solar production splits into two parts — what you use at home and what you export to the grid:
annual production (kWh) = system size (kW) × output (kWh/kW/year) self-consumed (70%) = annual production × 0.70 exported (30%) = annual production × 0.30 self-consumption savings = self-consumed kWh × electricity rate export earnings = exported kWh × feed-in tariff rate
The 70/30 split is a representative assumption — actual self-consumption rates vary from 20% to 50% depending on household occupancy patterns and usage timing.
Frequently Asked Questions
How is Western Australia's electricity different from the eastern states?
Western Australia's main grid, the South West Interconnected Network (SWIS), covers Perth and surrounding areas and is separate from the National Electricity Market (NEM) that covers the eastern states. This means WA electricity prices, networks, and regulations are managed independently. Regional WA (outside the SWIS) is served by Horizon Power at typically higher costs. WA's isolation means it has its own energy market dynamics, with significant wind and solar penetration.
What does electricity cost in Perth?
Perth residential electricity costs around 30 cents per kWh with a daily supply charge of approximately 92 cents/day as of 2025-26. These are roughly in line with the national average, though somewhat lower than NSW and SA. The state-owned retailer Synergy offers residential plans, and there is an active retail market with several private retailers competing.
Is solar worth it in Western Australia?
Yes — WA has excellent solar conditions, with Perth receiving around 4,600 kWh per kW of installed solar per year, comparable to Queensland. Solar uptake in Perth is among the highest in Australia. Feed-in tariffs in WA are reasonable, and with daytime electricity usage common due to the lifestyle, self-consumption rates are high, making solar economically attractive. A 6.6kW system in Perth typically saves $900-$1,300 per year at current retail rates.
What is the feed-in tariff in WA?
Western Australia's feed-in tariff rates vary by retailer. Synergy, the state-owned retailer, offers a feed-in tariff around 7-8 cents per kWh for excess solar exported to the grid. Private retailers may offer different rates. As with all states, maximising self-consumption is more valuable than relying on export earnings, because each kWh self-consumed saves the full retail rate of approximately 30 cents rather than earning around 7 cents from export.