I think this misses the point. With that thinking virtually everything produces carbon emissions - the question is how much, and what is it a function of. Hydro

I think this misses the point. With that thinking virtually everything produces carbon emissions - the question is how much, and what is it a function of. Hydroelectric (which doesn't just include dams btw.) may have a positive CO2 balance, but it doesn't scale linearly with the amount of electricity you produce from it. The same goes for all other renewables. Battery manufacturing is trickier - it does scale its footprint with number of miles driven (because it has a limited service life), but I'd assume the term has a fairly low multiplier compared to directly burning gasoline to get ahead. So my point is: The devil is in the details, blanket claims like "X is bad because CO2" doesn't really help. "Zero emission" may be a bad approximation, but I'd postulate that if you live in a place with very low fossil energy mix and use a car that has negligible direct and indirect emissions for each mile driven, you can claim "Zero emission" - otherwise the term becomes rather useless.