Saint Paul has been ranked the 31st best city in the nation when it comes to building toward a clean-energy future. The annual rankings, released last week by the nonprofit American Council for an Energy-Efficient Economy, scores 75 large cities across five key areas: local government operations, community-wide initiatives, buildings policies, energy and water policies and transportation policies.

Transportation and buildings policies accounted for 30 points each out of the total 100 possible points a city could earn. The scorecards aim to evaluate how city policies and programs save energy, encourage renewable energy and reduce greenhouse gas emissions. Here's how Saint Paul scored in each category:

Total: 35

Local government operations: 3

Community-wide initiatives: 3.5

Buildings policies: 8

Energy and water utilities: 8.5

Transportation policies: 12 Boston retained its position, taking the top spot in the rankings with a score of 77.5. That includes 22.5 and 25.5 points in transportation and buildings policies, respectively. Here are the 10 top ranked large cities and their scores:

Boston — 77.5 San Francisco — 71.5 Seattle — 70 Minneapolis — 69 Washington, D.C. — 68 New York — 67 Los Angeles — 65.5 Denver — 64.5 Austin, Texas — 63 Portland, Oregon — 62.5 The authors highlighted Cincinnati, Hartford and Providence as cities to watch because the trio recently adopted key clean-energy policies and programs. And across the nation, the report said cities have ramped up clean-energy efforts. "Cities are making impressive clean-energy gains — taking big steps to waste less energy and encourage more renewable power," Senior Research Manager David Ribeiro, lead author of the report, said in a news release.

But more work must be done.

Most cities aren't expected to meet their community-wide climate goals at their current pace or are not yet tracking their progress. Cities around the globe account for two-thirds of the world's energy consumption and 70 percent of energy-related carbon dioxide emissions, the report found.