The energy problem isn't so much with the infrastructure itself, or how much power it produces, but with the amount of demand placed upon it. It's not so much necessary to produce more electricity as it is to reduce how much electricity is used. Often enough I see and hear messages on TV and radio about conserving energy, switching to energy efficient lights, appliances, heating/cooling systems for air and water, etc. I wonder how much energy could be saved if enough people actually took the initiative and did all they could to reduce energy consumption both at home and at work, especially as the cost of energy efficient appliances and equipment falls as they become more common.
Dean Kamen himself is a prime example. There was an
article on MSNBC a few years ago highlighting his island's energy independence. The article states that just by switching the island's lighting to LEDs, the electrical use dropped by at least half. Granted LED lighting fixtures aren't the cheapest things on the market at the moment, but as they become more prevalent costs will drop. If LED lights were to replace the majority of incandescent, and even CFL bulbs, the demand on the electric infrastructure would fall by a noticeable amount, opening up capacity to charge electric vehicles.
Something else that caught my eye on Slashdot this morning was a
Caltech press release stating they've been able to produce flexible solar cells that are 85% efficient in sunlight. Build them into the frames of electric vehicles, or panel a building's roof with them, and you're offsetting your demand from the grid, again opening up capacity to charge electric vehicles.
As for the range of pure electric vehicles, I personally drive 13 miles to work, and 13 miles home every day. 40 miles is plenty of range for my needs, and enough for many people I know to get to work and back home without the need to charge during the day.