Charging your electric car at night could save the world

An employee prepares to attach an electric charging cable to a Mercedes-Benz B class electric automobile, produced by Daimler AG, at the 65th Frankfurt International Motor Show in Frankfurt, Germany, on Wednesday, Sept. 11, 2013. The 65th Frankfurt International Motor Show, Europe's biggest auto event, will open to the public on Sept. 12 and showcase the industry's latest models. Photographer: Jason Alden/Bloomberg
An employee prepares to attach an electric charging cable to a Mercedes-Benz B class electric automobile, produced by Daimler AG, at the 65th Frankfurt International Motor Show in Frankfurt, Germany, on Wednesday, Sept. 11, 2013. The 65th Frankfurt International Motor Show, Europe's biggest auto event, will open to the public on Sept. 12 and showcase the industry's latest models. Photographer: Jason Alden/Bloomberg