Part 8 in Peter Aubourg’s Diary of an EV Driver

We’d only had our EV for a week or so when someone said to me that EVs are worse for the environment because of the embedded emissions of the battery. So, as an engineer, I was curious to find out the facts.

The easiest way to judge this is to look at all the emissions over the lifetime of the car, which is about 190,000km, the Australian Bureau of Statistics says. Let’s start with the embedded CO2 in the raw materials and manufacture of the car. An EV without the battery has slightly less than a petrol car, but then you add the battery and the EV has significantly more embedded emissions as it rolls out the showroom.

But as the petrol car starts up it is at a big disadvantage. Even modern petrol cars are incredibly inefficient, losing about 80% of their energy to heat. They just can not escape the basic physics of all heat engines. So to get the power they need, they have to burn the power for their waste heat and the power to make the car travel on the road, resulting in lots of “tailpipe emissions”.

The EV has more embedded emissions when new, but when driving, has less emissions, depending on where it sources its electricity. As the kilometres go by, there is a point where the petrol car overtakes the EV in terms of total emissions. If you are in Tassie, powering your EV on hydro power, that point is 23,000km and in WA where the electricity has the least renewables, the point is 38,000km. The eastern states are somewhere between these numbers. This assumes you are charging your EV from the grid. If you are charging it from excess solar from your roof, you could have your crossover point closer to the Tasmanian figure.

So, after this crossover point, the petrol car keeps producing its tailpipe emissions up to the end of its life, producing significantly more tonnes of CO2 than the EV. I’ve only had my EV for nine months, so it is going to take another year or so to reach the crossover point where it has produced less emissions than an equivalent petrol car with the same odometer reading. I will have to save any planet-saving self righteousness until then! However, I will still be enjoying the big fuel savings on the way.

The information for this article came from an excellent ABC article ‘Are electric cars better for the environment than fuel-powered cars?’ by Jo Lauder. Read it for more in-depth details.