This has already been posted in a discussion on the EVIOM Facebook page but I thought it was a good point to make so here it is again:
When thinking about the CO2 emissions per mile of a fully electric vehicles versus a petrol or diesel equivalent you have to remember to account for the large amount of energy (electricity and fossil fuels) used to drill, refine and distribute the petrol/diesel.
The Leaf has a 24 kWh battery that takes it 100 miles. Let's say an equivalent petrol car uses 16 litres of fuel to cover the same distance. That's approximatky 72.6KWh of electricity to refine (ignoring extraction and distribution) the petrol to cover the same distance that the leaf covers on 24 kWh.
Consumption figures and CO2 emission are of course all estimations and as you've all seen they're are plenty of articles online with varying numbers arguing many different points.
In my opinion an EV is more efficient and wastes less energy than a petrol car and will get cleaner as long as renewable energy replaces more fossil fuel sources. In addition, and I can prove this with my finances, EVs are cheaper to run in terms of "fuel" and running costs. And the lack of exhaust emissions at street level makes it a much more pleasant option.