OK, I'll take the loser's position on this one. From an engineering point of view, electric cars are very cool. For most of us, it has nothing to do with the environment. They can out accelerate anything on the road. They are quite. And, there just plain different. Plus, for the tesla it cost like $3.25 to fill it up, for a 250 mile trip (tesla). It could save you several thousand dollars a year in gas bills.
The good thing about electric cars is that if worst comes to worse, we don't have to walk. It might be possible to drive, without gasoline.
As for brownouts, the Ruffy's eluding to the power potential of all those batteries sitting out there. So, if you have tens of millions of batteries hooked up in the parking lots, and suddenly, you get a brown out. Someone came up with this idea to suck some of the power back out of the batteries, and put it back on the grid. Think of it as distributed load balancing.
As for batteries. Batteries are made of metals of some type. Lead being a principle one. Yep, it's bad for the environment, no doubt. Most can be recycled, but it's not good for the health of the workers that do it. Also, some of the cooler batteries, have materials, which are in short supply, and some have nasty metals in them. (cadmium for example) Batteries will also go bad, and need to be replaced. But, as far as I know, there's no such thing as a car where the batteries can't be replaced. Even tesla was showing off their new battery pack the other day. Big plastic box, that sits behind the seat. It's a $30,000 box though. Your average car will cost a lot less.
As for the pollution. You should be able to produce power with less pollution, than what a average car produces. But, just like ethanol did to corn supplies, cars will quickly tax the electrical grid, and power prices will sore. So, expect a huge power infrastructure build up. Nancy Pelosi, won't say shet when her voters are sitting in the dark.
Oh, and don't overlook the political aspect of electric cars. The government will use it to control you. And, instead of getting oil from lots of different places, you'll be getting it from regulated facilities. Hard to imagine how it could play out for personal freedoms over many decades. The greenies will figure out a way to profit off it for sure.
Personally, I'd love to build a electric car for myself. And, I aint no greenie.