Busting electric car myths: just how green is an EV?

MYTH: the grid burns fuel so EVs aren't low carbon

I thought even electric-car doubters had finally grasped that this is a myth, but I saw it crop up again the other day, so we need to lay it to rest. "Electric cars don't reduce CO2 because grid electricity is generated with fossil fuels." Some of it is, but nevertheless they do.

In 2021 UK electricity took 214g/kWh on average to generate and send through the grid. That includes, for the gas component, the drilling and distribution of the gas. On windy, sunny days, CO2 was less because of all the wind and solar; with no wind and darkness the fossil content rises. So charge your car on a windy night.

Now, 1kWh will get a normal EV about 5km. That's real-world driving, and accounting for onboard charger losses when you plug it in. So 214g/kWh divided by 5km/kWh equals 43g/km CO2. As more renewables are installed in coming years, the embedded CO2 in electricity will fall and your EV will get greener.

No combustion car can get close. (Don't count PHEVs because they only beat the EV target if they use some electricity as well as the fuel, so they're effectively being EVs for that portion.) A Toyota Yaris hybrid might crack 70mpg, which is 92g/km.  Most of us get an actual, not WLTP, petrol consumption of 40mpg, meaning 160g/km. And that's just tank-to wheel. Luckily petrol now has a biofuel component which somewhat offsets the well-to-tank oil portion.

So, round figures, an average EV is responsible for about a quarter of the CO2 in driving than an average petrol car.