Explainer: Emissions from electric vehicles are lower than petrol cars in Australia

Sadly, it seems that various members of our current national government still rubbish electric vehicles (EVs), claiming that their greenhouse emissions are greater than from ICE (Internal Combustion Engine) vehicles.

With the release of the 2020 National Greenhouse Accounts Factors comes the time for me to update my article on the carbon footprint of EVs in Australia … and yet again point out they should be checking their own department’s data before making such misleading statements!

A kinder interpretation of their confusion may be that new vehicle windscreen stickers for petrol and diesel vehicle emissions fail to reflect their full ‘well-to-wheel’ greenhouse gas emissions, but the data for electricity does, so a quick comparison of CO₂ numbers seems bad for EVs.

It is possible to make a full ‘apples to apples’ comparison of ICE vs EV. In fact, the data and methodology on how to calculate it is published by the Federal Government Department of Industry, Science, Energy and Resources. (The document can be found here.)

Note: This is now the third time I have done this exercise, beginning with the 2012 data, then 2017, then now. With the release of the 2020 NGA Factors the comparisons over the eight years make for interesting reading – as you will soon see.

For the purposes of this exercise, I have chosen to compare the closest EV available here to a Toyota Corolla – in this case a Kona electric seemed a good comparison as it is capable of replacing a Corolla for all usage. (That is – a medium sized EV hatch with a good range, capable of carrying 5 passengers and a bit of luggage).

I have also chosen to compare them over 10,000km per year, as this makes it a simple exercise to extrapolate the data for your own situation. (For example, if you do 20,000km a year – double the numbers. For 5000km, halve it).

Using the 2020 National Greenhouse Accounts (NGA) Factors data, and applying the calculation methods as described there, I present the results graphically below. Feel free to send them to your local member.

Graph 1: Full CO₂-e* comparison: current Kona electric vs current and 2012 Toyota Corolla

*See note 3 below, or the NGA Factors document, for a fuller explanation of what CO₂-e is.

Conclusions:

If you buy an EV over an ICE vehicle for city travel and run it exclusively from the grid, the answer is an emphatic “Yes, you will significantly reduce your CO₂-e emissions compared to an equivalent ICE vehicle for all Australian power grids.”

(See graph 1 above).

The answer is slightly more nuanced if you choose a new ICE Corolla over a new Kona electric for all travel (i.e. meet the criteria for the combined vehicle test cycle). In this scenario, the answer changes for one state. That state is Victoria, where the Kona electric CO₂-e emissions are 2.3% greater than a Corolla on the combined cycle. (1.50t for the Corolla vs 1.54t for the Kona).

This gap, by the way, has narrowed significantly since 2017, when it was 5.3%. As Graph 2 shows, the grid is ‘greening’ year on year and it should not be long until even EVs travelling out of Melbourne into the Victorian countryside are more ‘green’ that an ICE vehicle.

Graph 2: full kg CO₂-e per kWh for each state grid 2012 to 2017

However, all this applies when comparing the choice of a new EV over a new ICE vehicle. A look at Graph 3 shows that Corolla fuel consumption figures have significantly reduced over the previous decade, meaning that replacing an older ICE vehicle with a new EV improves this equation very much in favour of the EV.

Graph 3: Full CO₂-e comparison: current model versus 2012 Toyota Corolla

And finally: if you add a tailored combination of grid connect solar PV, green power and/or a battery back-up system, personal greenhouse emissions for EV use can be reduced even further – meaning EVs are always the best choice.