Credit: Bridie schmidt
Credit: Bridie schmidt

This is a question I get asked fairly often – to which I usually answer “How long is a piece of string?” as the combination of which EV you own, your annual driving distance, electricity tariff structure and your household electricity consumption together make the answer so variable that it is almost meaningless.

Nonetheless – I will now try to answer that very question!

Assumptions:

  • Annual average distance driven per light passenger vehicle in Australia1: 12,600 km
  • Average Australian household daily electrical energy use2: 19.2kWh
  • Average W/km for an EV3: 180Wh (or 0.18kW)
  • Average petrol consumption for light passenger vehicles in Australia4: 10.8L/100km
  • Average Australian ULP fuel cost5: $1.50/L

Calculations:

  • Average annual EV electrical use: 12600 x 0.18 = 2268kWh
  • Average household electrical use: 19.2 x 365 = 7008kWh
  • Fuel used for an ICE vehicle at 10.8L/100km and $1.50/L over the same distance: $2041.

Therefore an EV would add, on average, about 32% to the average usage component of a household electricity bill.

At a tariff of 30c/kWh, this equates to an additional $748 for the electricity. Putting these together: the EV saves just under $1300 just in vehicle fuel costs. (i.e. not including the reduced service and maintenance costs of an EV).

However – these ‘average’ figures are on their own quite meaningless. Electricity tariffs can vary from less than 10c/kWh overnight to well above 45c/kWh at peak times.

(It could even be ‘free’ if you have a big enough solar PV system to meet the charging needs of your EV). ICE vehicle fuel consumption can also vary widely on the choice of vehicle from under 5L/100km to over 20!

I’ll therefore leave it to you, the reader, to adjust these figures to meet your particular circumstances.

Based on the above figures – it is inarguable though that an EV is cheaper to run than an ICE vehicle, plus the EV has reduced servicing costs, reduced wear on the brakes, and no tailpipe emissions adding to local pollution problems.

And it has the capacity to continually reduce its energy CO2 emissions as the grid shifts from fossil fuelled to renewable sources: all unlike an ICE vehicle which is forever tied to running on carbon based fuels.

Notes:

  1. Australian Bureau of Statistics: Survey of Motor Vehicle Use, Australia, 12 months ended 30.6.18
  2. Australian Bureau of Statistics: 2012 Australian Household Energy Consumption Survey
  3. A rough (and probably excessive) figure that I chose to be half-way between the lowest and highest values for vehicle available on the Australian market (Source: Green vehicle guide, Renault Zoe at 133W/km and Jaguar I-Pace at 230kWh).
  4. Australian Bureau of Statistics: Survey of Motor Vehicle Use, Australia, 12 months ended 30.6.18
  5. Current average ULP per litre price as at 22nd April, 2019
Get up to 3 quotes from pre-vetted solar (and battery) installers.