Tesla's supercharger stations are designed specifically to address this 5%. He quotes studies about driving that show that most people stop for approximately 30-60 minutes every 200 miles or so. The Supercharger stations are supposed to be able to charge to 160 miles of usage in 30 minutes, enough time to get a bite to eat.
The specs for the Model S (options section of the site, actually) state the single plug charger replenished 31 miles of ranger per hour of charge, and the optional dual plug charger replenishes 62 miles of ranger per hour of charge.
That doesn't address power grid problems if there is a large influx of demand because of electric vehicles, but at least it's at night, when there's less demand on the system from other sources. Ideally, that would spur more power grid development, but I'm not going to make predictions on such sparse and tenuous assumptions (even if they come from myself).
