Plugged into a socket, an electric car can draw as much power as a small house.
The surge in demand could knock out power to a home, or even a neighborhood.
That has utilities in parts of California, Texas and North Carolina scrambling to upgrade transformers and other equipment in neighborhoods where the Nissan Leaf (seen here) and Chevrolet Volt are expected to be in high demand.
Not since air conditioning spread across the country in the 1950s and 1960s has the power industry faced such a growth opportunity. Last year, Americans spent $325 billion on gasoline, and utilities would love even a small piece of that market.