WAVE Trophy 2018
Here is a nice article about different studies coming to different results about how much cleaner electric cars are, than the ones with combustion engines. It is in German:
I like the sentence towards the end: "People buying a Tesla today invest in a cleaner future for all of us. People buying a fossil car throw the money into the past, which will never lead to clean and sustainable mobility."
Still my favorite study in this field is the Well to wheel. It looks at the energy efficiency from how the propellant is sourced and transported until it powers the wheel. The differences are gigantic. With renewable energy in Switzerland, I expect the number to be above 60.