Not everywhere. My car charges off an average of 80% renewables (mostly hydro and geothermal), right now it's 95%.
But it is definitely something you need to take in to account when purchasing, an EV isn't right for everyone.
Whenever you do the real world calculation for what an electric cars CO2 profile looks like it turns out to be the same as a gasoline car unless your country is majority nuclear.
Not at all true: https://www.carboncounter.com/
US-specific but you can even pick a state and it will use the generation mix of that state
At night the sun doesn't shine.
The mix is mostly coal or if you're lucky mostly gas.
This is the type of bullshit I mean by doing real world calculations.