Chevy Volt vs Nissan Leaf

Talk about turning over a new leaf at nissan. OK more than the chevy volt, nissan leaf is an affordable electric car. How will it start on cold mornings? That is my worry. Well, you see, electric cars depend on a chemical reaction from the battery, and do not do well in cold weather, but like warm. Also, where does the energy come from to make the car warm. That could mean a reduction in mpg, or in the case of an electric car, it would be kilowatts/hours per kilometer or so.