That's outside the car makers' control. The public charging stations in my town (in Germany) are powered (hooked up to our common electricity network, but in t

That's outside the car makers' control. The public charging stations in my town (in Germany) are powered (hooked up to our common electricity network, but in terms of energy bought for them) using hydro power from a nearby river. Any car owner could use their own generator using coal or oil to power their private charging point though. Generally speaking the only remedy to that is to make CO2 intensive power cost prohibitive. Our government decided just today to attach a CO2 tax to sales of energy sources with CO2 residues, so let's see how that develops.