There are plenty of valid reasons to prefer internal combustion engines—quick refueling, great infrastructure and maybe the sound of it. But environmental superiority isn't one of them.
There's a Swedish article that has been often quoted over the months regarding the environmental impact of EV batteries. Most people try to use Google Translate to translate it from Swedish into English and Google is not very good at it. Luckily, the Swedish are better in English than English speaking people are in Swedish as they do not even notice, that this article is based on a named report and a reference is given in the article. That original report is actually in English.
If you're predisposed to hate electric cars, then there's a wonderful story making the rounds that'll support your worldview. However, let's just look into some of the numbers stated in there and add some real world numbers into the mix.
Let's just assume both bodies of the electric car (EV) and the car with an internal combustion engine (ICEV) have the same weight and kindof the same material use.
Let's just assume a medium range car has 17 tCO2e emissions[1] for the manufacturing process for both EV and ICEV bodies. The difference is that the EV comes with the so highly criticised battery.
So let's use the numbers that the famous Swedish report[2] is based on and let's take the higher number to be more conservative: 200 kg CO2e per kWh or 0.2 tCO2e per kWh.
The Nissan Leaf (as a medium sized car) has battery with a capacity of 23.8 kWh, so according to the report the battery production would have cause a release of 23.8kWh*0.2tCO2e/kWh = 4.76 tCO2e.
Initial GHG emissions
So we have established that a Ford Mondeo created 17 tCO2e and the Nissan Leaf likely 17+4.76 = 21.76 tCO2e just to roll out of the factory.
Car batteries can reasonably expected to last 15 years. That assumption is based on own experience (both our Toyota Prius gen2 batteries were replaced after 14 years, they are warranted for 10 years and Tesla attributes their Model S battery a life of 8 years[3], the Nissan Leaf battery is warranted for 8 years[4].
Let's use the worst case scenario for the battery and have it replaced after 8 years.
And now we are getting into the question of what the car emission will be over just the life of its battery compared to the petrol car. Please note that I am going to choose a petrol car as I am comparing CO2e emissions, not CO2 emissions. A diesel car has better CO2 emissions, but worse CO2e emission compared to the petrol car.
CO2: Just plain Carbon-dioxide emissions
CO2e: Any Greenhouse Gas (GHG) that will affect climate change, adjusted for it's potential to do so (my lay words)
We now use the emission intensity published by MFE[5] and use 2.36 kgCO2e per litre for petrol (vs. 2.72kg CO2e for diesel) and 0.138kg CO2e for electricity purchased to charge my EV.
Now it comes down to my driving habits. My car is about 16 years old and drove 320,000km. So a pretty easy 20,000km/year.
Let's assume the Ford Mondeo uses 8.2 litres/100km as per Rightcar[6] and the Nissan Leaf would go 135 km on a battery charge. This is somewhat more complex as you never fully discharge the battery, so never fully use the 23.8kWh capacity. The US EPA found the numbers to be 0.212 kWh/km.
As a result the emissions per year for a 2015/2016 Ford Mondeo would be 20,000km * 8.2l/100km/l = 200*8.2l=1640l per year.
1640l*2.36kgCO2e/l = 3.87 tCO2e / year. For the expected 8 years that would be emissions of 3.87*8 = 30.96 tCO2e.
In comparison the Nissan Leaf would use 20,000km*0.212kWh/km*0.138kgCO2e/kWh = 0.585 tCO2e per year.
0.585tCO2e per year over the 8 years would be a total of 4.68 tCO2e.
Total GHG emissions over 8 years
Once we add the initial and the consumption numbers up, we arrive at.
Ford Mondeo:
17tCO2e + 30.96tCO2e = 47.96 tCO2e
Nissan Leaf:
21.76tCO2e + 4.68tCO2e = 26.44 tCO2e.
Now please let's keep in mind that I used the most conservative calculations and numbers in regards to the Leaf performance. It's based on the assumption that it runs straight off the NZ grid using standard power. It's also based on the assumption that the battery is made using a 50% renewable source energy, most countries other than the US have moved past that percentage. And the future will only bring betterment in those regards.
So even if your battery totally dies after 8 years which is unlikely based on past experience, then you are still only creating about half the emissions compared to a petrol car.
The above numbers also do not take into consideration that the EV uses significantly less oild than an ICEV with all its associated environmental issues and emitted CO2e.
On another note, after 8 years the Leaf battery is still there, ready to be recycled and otherwise used, the 13,120 l of petrol are gone forever.
Just for fun, let's assume the battery will last rather 14 years (based on my battery experience from a manufacture from 2001). I am too lazy to recalculate the battery GHG emissions based on the lower intensity numbers. 🙂
Extended battery life over 14 years
Ford Mondeo:
17tCO2e + (20,000km * 8.2l/100km/l * 2.36kgCO2e/l * 14 years / 1000kg) = 71.1856 tCO2e
Nissan Leaf:
21.76tCO2e + (20,000km*0.212kWh/km*0.138kgCO2e/kWh * 14 years / 1000kg) = 29.95168 tCO2e.
You see, the longer you go, the better it is. Of course. So do not buy a new car every few year, that's the real killer, remember, that's just 17 tCO2e min. just for a car.
Feel free to play with the numbers and maybe put a diesel car in as comparison.
[1] https://www.theguardian.com/environment/green-living-blog/2010/sep/23/carbon-footprint-new-car
[2] http://www.ivl.se/download/18.5922281715bdaebede9559/1496046218976/C243+The+life+cycle+energy+consumption+and+CO2+emissions+from+lithium+ion+batteries+.pdf
[3] https://www.tesla.com/support/vehicle-warranty
[4] https://www.nissanusa.com/electric-cars/leaf/charging-range/battery/
[5] https://www.mfe.govt.nz/sites/default/files/media/Climate%20Change/voluntary-ghg-reporting-summary-tables-emissions-factors-2015.pdf
[6] http://rightcar.govt.nz/vehicle-detail.html?q=g40221&bc=1|11||2|1487||&keywords=Ford%20MONDEO&Make=Ford&Model=MONDEO&selected=g40221
