By the time batteries become mainstream, the subsidies for EVs will probably disappear as well.

I suspect they'll still have some sort of "not a gas guzzler or CO2 producer" subsidy, though it'd likely be very mild.

If you don't have solar panels on your roof, chances are it's still coming from fossil fuels. Generation/transmission efficiency for taking energy from fossil fuels and getting it to your house is around 30%. Electric cars are part of a solution to CO2 emissions, but they aren't one on their own.

I was under the impression that coal plants, et cetera, were quite a bit higher efficiency than ICEs?

And I'm sure we'll continue to bulk up non-CO2 methods of power generation. Hydro power is commonplace, solar panels are a growth area, and likewise wind turbines...

(Lastly, since I live in BC, my power is 86% hydroelectric already, but I'm speaking generally. :) http://www.energybc.ca/map/bcenergymap.html)

Hmm, wikipedia says ICEs in cars are up to 25-30% efficient. Then there's additional losses from the rest of the car. But the electric car has its own losses from the battery charge/discharge and the motors and whatnot, so it seems like they're at least roughly in the same ballpark. Electric cars certainly have more room for improvement though, since fossil fuels aren't the only way to run the electric grid.

That's when it flips to become a tax on non-EVs.