That's the ultimate advantage of electric cars: independence from any single energy source. Have sunshine? Use solar. Have water? Use hydro. Have uranium? Use fission.
And advances to generation technology increase the efficiency of everything downstream accordingly.
The disadvantage at this point is that our current capacitance technology is less energy dense and slower to replenish than a fossil fuel tank. What happens when your daily commute doesn't fit comfortably within the vehicle's range?
Energy technology should ultimately improve our versatility. Putting batteries in a car doesn't achieve that goal just yet.
For most Americans, todays batteries are more than sufficient to handle the daily commute. For outliers, they can choose to keep their ICEs or opt for hybrids like the Volt. To discount current tech for not being equivalent is just making excuses for the status quo. It's tantamount to simple FUD.
It most certainly is NOT fud. There are real consequences to your suggestion in the form of higher prices for both fuel and hardware. Right now we commute because it makes economic sense to commute, but if the fossil fuel cars and their fuel suddenly make that commute too costly it will negatively impact those who commite, their employers, and probably the communities in which these companies operate.
This all happens because there are a few folks who naively believe that batteries are a clean way to store energy.
How is pointing out that today's batteries are perfectly sufficient for the vast majority of commuters going to cause fossil fuels and the cars that drive them to become too costly?
You've gone from suggesting the batteries are insufficient to suggesting that correcting your misinformation and fear-mongering will itself raise the price of ICEs and their fuel.
You're burning down strawmen of your own imagining.
See Better Place's business model: buy the car, but rent the batteries, and have charging stations where they can be swapped in about as much time as filling your tank.
And by abstracting out of the car, you get to skip re-running acceleration/skid/crash tests, redesigning for the particular size/weight/balance signature of the new tech, retooling the lines to manipulate the thing, rewriting/testing the controller code to drive the damn thing, etc.
And perhaps most importantly: you avoid compromising a technology's best efficiency curve in the quest to meet the demands of the driving model.
e.g. even if you're burning fossil fuel to generate power, for whatever reason, there are vastly more-efficient ways to do it than the way we do in in-car ICEs. Those ways just happen to be ill-suited to the power-demands of personal vehicles.
And advances to generation technology increase the efficiency of everything downstream accordingly.