From Euan Mearns’s Energy Matters site: http://euanmearns.com/co2-intensity-of-electric-cars/
CO2 Intensity of Electric Cars
Electric cars (or EVs) are more expensive than internal combustion engine (ICE) equivalents and return little tax revenue on their fuel use in the UK.
In the UK electric cars are subsidised to the tune of £4,500 and in the USA by $10,000+. These subsidies are paid in the belief that reducing CO2 emissions is worth paying for and it is alleged that EVs have low to zero CO2 emissions.
Analysis of the CO2 emissions embedded in their manufacture and in the fuel mix used to generate electricity suggests that electric cars produce
at least almost as much CO2 as diesel equivalents and perhaps twice as much 50% more CO2 in high coal countries like India.
[Correction added 12:30 17 July: Commenter Ingenergia noted that I had overlooked to include the CO2 embedded in ICE car manufacture in my numbers and that is a pretty serious oversight for my part. So much so that I considered taking the post down. This moves the goal posts a little and I have elected to correct the text where appropriate instead. Electric cars do have lower CO2 emissions compared to diesels, but only marginally so. For example the UK 189/219 = 86% or a 14% reduction. No where like enough to warrant a £4,500 subsidy in my opinion.]