If you've been watching petrol prices bounce around in Perth lately, you're not alone. With unleaded regularly topping $2.20 a litre, plenty of people are starting to wonder: would an electric car actually be cheaper to run? The short answer is yes — and when you look at the cost per km for an EV vs petrol, the gap is bigger than most people expect.
How Much Does It Cost to Drive a Petrol Car Per Kilometre?
Let's start with what most of us are already paying for fuel. Unleaded petrol averages around $2.20 per litre in early 2026 (FuelWatch WA, 2026). If we think about a typical family car in Perth, it uses approximately 7-12 litres of fuel every 100km. Per kilometre, this is roughly costing you between 15c-26c, which can add up quickly. If we use 15,000km a year as a benchmark, fuel will cost you between $2,250 and $3,900. That's a lot, right?
What About an Electric Car?
This is where the Fuel vs EV comparison gets interesting. A normal EV charger will use between 15kWh-20kWh per 100km (AGL, 2026). On the standard Synergy residential tariff of about 32 cents per kilowatt-hour (Synergy, 2025), that comes to roughly 5 to 6 cents per kilometre. That's approximately 15c to 20c less than what you'd pay using petrol.
So, over the same 15,000km a year as a benchmark, you'll spend roughly between $750-$900 on electricity. This could potentially save you $1,350-$3,000 on fuel (CarsGuide, 2026).
What If You Charge Your EV With Solar Panels?
Here's where Perth drivers have a real advantage. Western Australia gets some of the best sunshine in the country, and if you've got rooftop solar panels you can charge your EV using the energy your home is generating. When charging from your own solar, the costs can drop to almost $0.
Even if you're not home during the day to plug in, pairing a home battery with your solar system means you can store that daytime energy and charge your car in the evening — still at a fraction of the cost of petrol.
So How Do They Compare Side by Side?
Here's a quick snapshot based on typical Perth driving of 15,000 km per year:
Cost per km — Petrol car: 15–26 cents; Electric car (grid): 5–6 cents
Cost per km (solar) — Petrol car: N/A; Electric car (solar): 1–3 cents
Annual fuel cost (15,000 km) — Petrol car: $2,250–$3,900; Electric car (grid): $750–$900
Annual fuel cost (solar) — Petrol car: N/A; Electric car (solar): $150–$450
Sources: FuelWatch WA (2026), Synergy (2025), CarsGuide (2026), Solar Choice (2026).
The difference is striking. Even charging entirely from the grid, an EV costs roughly a third of what a petrol car costs to run. Add rooftop solar into the mix and your driving costs can drop to almost nothing.
Frequently Asked Questions
Is it really cheaper to charge an EV than fill up with petrol?
Yes. On the standard Synergy tariff, driving an EV costs around 5 to 6 cents per kilometre. A petrol car typically costs three to four times that. If you charge with rooftop solar, the gap is even wider.
Do I need solar panels to make an EV worthwhile?
Not at all. Even without solar, an EV is significantly cheaper to run per kilometre than a petrol car. Solar simply makes a good deal even better — especially in Perth, where we get so much sunshine.
What about public charging — is that still cheaper than petrol?
Public fast chargers are more expensive than home charging, costing between 7-12c per kilometre. This depends on factors like system size and charging speed. Although public charging is still cheaper than petrol in most cases, 70%-85% of EV owners in Australia use home charging for ultimate cost-efficiency (EVenergi, 2023).
Curious about how solar and an EV charger could work together at your place? We're happy to have a chat — no obligation, no pressure. Give us a call on 9300 9324 or visit solaireconnect.com.au to learn more.
References
CarsGuide. (2026). Electric car cost per km: Do EVs actually save you money? https://www.carsguide.com.au/ev/advice/do-electric-cars-actually-save-you-money-83060
FuelWatch WA. (2026). Monthly average fuel prices. https://www.fuelwatch.wa.gov.au/retail/monthly
Gridly. (2026). EV charging costs Australia 2026. https://www.gridly.com.au/guides/ev-charging-costs
Solar Choice. (2026). EV charging costs explained: How much to charge your electric car? https://www.solarchoice.net.au/ev/charging/cost-to-charge-ev-in-australia/
Synergy. (2025). Standard electricity prices and charges – South West Interconnected System.
AGL. (2026, April 1). How much electricity does it take to fully charge an electric vehicle?
EVenergi. (2023, October). EV owner demographics and behaviours.