According to a new ranking by the American Council for an Energy-Efficient Economy, many of the nation's cities are instituting a variety of energy-saving measures such as requiring more efficient building designs, building electric vehicle charging stations, and promoting bike sharing. (See related story: "Bike-Share Schemes Shift Into High Gear.")

Boston achieved the highest score overall, with 76.75 out of a possible 100 points on a scorecard devised by ACEEE, on which cities received points for their energy-saving initiatives. Portland, New York City, San Francisco, Seattle, and Austin also received scores of more than 60 points. (Here's a graphic showing some of the cities' scores in specific areas.)

"I always believed that mayors have a responsibility to push