A new study appears to be the most thorough yet on the second order pollution impact of electric vehicles. First order effects — actual pollution out of the tail pipe — makes EVs look much cleaner, but getting into things like how the electrical power for them is produced in the first place can make for a very different picture; in areas that use dirty power (from coal, for example), EVs may net out as greater polluters.
This has been speculated about for a long time, but it's not a death knell by any means for the whole idea of electric vehicles. For example, the article notes that electrical energy generation in the US is getting steadily cleaner (recent SCOTUS ruling notwithstanding), and that could easily tip the balance, as could greater improvement in battery efficiency (driven by faster evolution as more EVs come on the market).
It is certainly useful to remember that any comparison of A and B needs to take into account more than just A and B in a vacuum. But by that token, it doesn't appear that the pollution cost of petroleum extraction and refining and transport was considered in the balance sheet of petrol-based cars (at which point the pollution cost of sourcing the fuel for electrical generators also needs to be considered).
It's never simple, and the data is often up to criticism, but it's worthwhile to keep poking at it.
How much do electric cars actually pollute? | Ars Technica
A new assessment suggests more than we think, outside of a few large cities.
To any of you watching, I just tell you. It depends on where the electricity comes from. A renewable wind turbine in your house? Green. Coal plants? Not green. And we're not even talking about manufacturing yet.
Absolutely it depends on how the electricity is being generated — and is, itself, a good argument for therefore looking at greener methods of power generation.
There was a study commissioned on this topic in Cali over 10 years ago and found that even if 100% of the electricity powering EVs was dirty you still are net ahead with EVs replacing combustion engines. This topic seems to come up every 5 years or so and every time it does I'm skeptical.
Seriously, if we had easily affordable EVs and only our current amount of clean energy we would still be net ahead to get combustion cars off the road. How about we add the external costs of dirty energy to the mix? Wars overseas, import spend, dirty energy spills on land and sea, etc.