Note - CO2e is greenhouse gas equivalent as CO2 - i.e. the amount of CO2 that would produce the same amount of greenhouse warming/climate change as the actual gases released (because many processes release other more potent greenhouse gases like methane).Until we stop using fossil fuels to generate power then no transport system or industrial process is “green”. Every additional process using power is adding to demand. If you build your own wind farm that is still power that could be fed to the grid, it is just displacement. At the moment we are burning coal for power (double the emissions of gas per kW.hr), so every new electric car is coal fired.
I can’t be bothered with the maths (have to paint), but I somehow doubt that the emissions per mile of an electric car power by coal are better than a petrol/hybrid car by the time you add up the efficiency losses. I already thought gas fired was suspect, and that has many decades to go at this rate.
In 2010 electricity has a greenhouse gas equivalent of 482g CO2e per kWh. In 2020 it was only 242g CO2e per kWh (it went up slightly to 265g CO2e per kWh in 2021). I assume those figures include transmission losses, but even if they don't that's only 9% loss. So electricity has been partly decarbonised and continues to be decarbonised.
Carbon intensity of electricity
Carbon intensity is measured in grams of carbon dioxide-equivalents emitted per kilowatt-hour of electricity.
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1049346/2021-ghg-conversion-factors-methodology.pdfwhich quotes 235g CO2e per kWh for 2019 UK generation at the point of consumption (i.e. including transmission losses) - 231g CO2e per kWh if you include imports. That doesn't include emissions before generation though e.g. in mining/transport.
An electric car will typically use 15 kWh per 100km. A petrol car will typically need 5.5l of petrol per 100 km.
Cost Comparison: Electric Car vs. Petrol (TCO analysis)
Which car pays off? - A cost comparison between the Hyunday IONIQ Electro and the Hyundai i30 1.4 T-GDI.
Petrol releases about 2.3 kg CO2 per litre burnt, so our 5.5l of petrol will release 12.65 kg of CO2 for that 100km drive.
The electric car, running off 265g CO2e per kWh UK electricity, releases 3.98kg CO2e.
That's massively less CO2, and looking at the trend of UK electricity carbon impact over the last 10 years (i.e. steeply decreasing) suggests that driving an electric car is better right now for the planet and will get even better in the future.