Methodology

1. TCO Formula

Total cost of ownership over the chosen period (default 5 years) is:

TCO = Purchase cost
    + Energy cost (electricity or fuel over period)
    + Insurance (annual × period years)
    + Maintenance (annual × period years)
    + Loan interest (if applicable)
    - Residual value (at end of period)

All values in AUD. Energy cost uses annual km, efficiency (kWh/100km or L/100km), and regional energy prices.

2. Assumptions Explained

• Annual km — Distance driven per year. Used to compute energy cost.
• Electricity (c/kWh) — Price per kWh. Defaults by region (NSW, VIC, QLD).
• Fuel (c/L) — Petrol price per litre. Defaults by region.
• Insurance (annual) — Flat annual estimate. Defaults: EV ~$1,200, Petrol ~$1,000.
• Maintenance (annual) — Flat annual estimate. Defaults: EV ~$400, Petrol ~$800.
• Residual rate — Fraction of purchase price retained at end of period (e.g. 0.45 = 45%). Defaults: EV 45%, Petrol 50%.
• Period years — Comparison horizon (default 5 years).

3. OEM-First Vehicle Price Policy (Australia)

Vehicle MSRP and efficiency data follow a strict source hierarchy:

1. Official OEM Australia website pages (Build & Price / Model pages)
2. Australian government sources
3. Public datasets
4. Media references (fallback only)
5. Manual entries (temporary only, marked for review)

Approved OEM Australia sources:

• Tesla Australia
• BYD Australia
• Kia Australia
• Hyundai Australia
• MG Motor Australia
• Polestar Australia
• BMW Australia
• Mercedes-Benz Australia
• Volvo Cars Australia
• Nissan Australia

Government cross-check:

• Green Vehicle Guide

MSRP limitations: Prices exclude on-road costs (stamp duty, registration) unless noted. Regional dealer variations may apply.

Freshness: Records are marked needs_review when sourceCheckedAt exceeds 45 days (configurable via PRICE_STALE_DAYS). Verification SOP in docs/PRICE_PROVENANCE.md.

Regional prices — Electricity and fuel by state (NSW, VIC, QLD). Updated periodically.

4. Limitations & Disclaimer

• Estimates only. Actual costs vary with driving style, location, and market conditions.
• Insurance and maintenance use flat annual assumptions; real costs may differ.
• Residual values are estimates; resale markets fluctuate.
• Energy prices are regional averages; home solar, off-peak tariffs, or fuel discounts not modelled.
• Not financial or investment advice. Use for comparison only.