Are electric cars really good for the environment?

I’ve long wondered whether electric cars are more fuel efficient than petrol cars. Below is my analysis.

The G-Wiz is probably the best-known of our all-electric vehicles. Its maximum range is 48 miles, requiring 9.66kWh of electricity, or 4.96 miles per kWh. This, I’m guessing, is in its most fuel efficient mode.

Coal-based energy production emits 950g of CO2 per kWh. So at maximum efficiency, a G-Wiz powered by coal-produced electricity emits 191g of CO2 for each mile driven.

Now take my Mazda 3, offering roughly 39 miles per gallon of petrol. Under the ‘perfect’ fuel/air mixture, petrol burning produces 2.36kg of CO2 per litre, or 10.73kg per gallon. This equates to 275g of CO2 for each mile driven, 44% less carbon efficient than a coal-sourced electric car.

A petrol car that can achieve 56mpg will have the same carbon production as a G-Wiz, assuming the G-Wiz’s energy is sourced from coal.

Electric cars are not in themselves environmentally friendly. But they give us options for fuel production that petrol cars don’t afford us. Once you have a petrol car, driving it will result in a pretty constant impact on the environment. With electric cars, we have the future choice, policy allowing, of sourcing our energy cleanly, therefore reducing the emissions for which an electric car is responsible.

But don’t assume that driving an electric car makes your journey environmentally friendly by default. Because it doesn’t.

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