In the international alliance to fight climate change, the United States is considered the sullen loner. But in the seven years since we rejected Kyoto, changes have begun. Not at the federal level, however. It’s the locals who are making green cities happen.

America’s Top 50 Green CitiesArticle Sponsored by BASF

In everything from emissions control to environmental stewardship, cities across the country are far ahead of the federal government, and they’re achieving their successes with ready-made technology. Austin has pledged to meet 30 percent of its energy needs with renewable sources by 2020, aided by planned wind-power installations that will surpass their predecessors in efficiency. Seattle has retrofitted its municipal heavy-duty diesel vehicles with devices that will reduce particulate pollution by 50 percent. Boulder has enacted the country’s first electricity tax to pay for greenhouse-gas emission reductions. Something about the comparative speed of city government—a city-council member can greenlight a project and be cutting the ribbon a year later—leads to bold action, and as green cities trade ideas, a very positive sort of mimicry is spreading.

The 10 trailblazing civic projects profiled in our list of the top green cities in America are among the most impressive success stories to date—examples of what’s possible when elected officials and local business leaders back up their green visions with scientific know-how, clout and creative funding.

Continue to the next page for the full list. And launch the gallery to see six case studies on how our greenest cities are cleaning up

How the Rankings Work:

We used raw data from the U.S. Census Bureau and the National Geographic Society’s Green Guide, which collected survey data and government statistics for American cities of over 100,000 people in more than 30 categories, including air quality, electricity use and transportation habits. We then compiled these statistics into four broad categories, each scored out of either 5 or 10 possible points. The sum of these four scores determines a city’s place in the rankings. Our categories are:

  • Electricity (E; 10 points): Cities score points for drawing their energy from renewable sources such as wind, solar, biomass and hydroelectric power, as well as for offering incentives for residents to invest in their own power sources, like roof-mounted solar panels.
  • Transportation (T; 10 points): High scores go to cities whose commuters take public transportation or carpool. Air quality also plays a role.
  • Green living (G; 5 points): Cities earn points for the number of buildings certified by the U.S. Green Building Council, as well as for devoting area to green space, such as public parks and nature preserves.
  • Recycling and green perspective (R; 5 points): This measures how comprehensive a city’s recycling program is (if the city collects old electronics, for example) and how important its citizens consider environmental issues.

See the the full list below. Click here to launch the gallery to see six case studies on how our greenest cities are cleaning up

1. Portland, Ore. 23.1

  • Electricity: 7.1 Transportation: 6.4 Green Living: 4.8 Recycling/Perspective: 4.8

America’s top green city has it all: Half its power comes from renewable sources, a quarter of the workforce commutes by bike, carpool or public transportation, and it has 35 buildings certified by the U.S. Green Building Council.

2. San Francisco, Calif. 23.0

  • Electricity: 6.8 Transportation: 8.8 Green Living: 3.5 Recycling/Perspective: 3.9
  • See how San Francisco turns wasted roof space into power, here.

3. Boston, Mass. 22.7

  • Electricity: 5.7 Transportation: 8.7 Green Living: 3.4 Recycling/Perspective: 4.9
  • CASE STUDY: Grass Power
    Boston has preliminary plans for a plant that would turn 50,000 tons of fall color into power and fertilizer. The facility would first separate yard clippings into grass and leaves. Anaerobic bacteria feeding on the grass would make enough methane to power at least 1.5 megawatts’ worth of generators, while heat and agitation would hasten the breakdown of leaves and twigs into compost.

4. Oakland, Calif. 22.5

  • Electricity: 7.0 Transportation: 7.5 Green Living: 3.1 Recycling/Perspective: 4.9
  • See how Oakland’s hydrogen-powered transit helps the city cut pollution, here.

5. Eugene, Ore. 22.4

  • Electricity: 10.0 Transportation: 4.7 Green Living: 2.9 Recycling/Perspective: 4.8
  • CATEGORY LEADER: Electricity
    Much of the wet Pacific Northwest draws its energy from hydroelectric dams. But Eugene draws an additional 9 percent of its municipal electricity from wind farms. It also buys back excess power from residents who install solar panel

6. Cambridge, Mass. 22.2

  • Electricity: 6.1 Transportation: 7.5 Green Living: 3.9 Recycling/Perspective: 4.7

7. Berkeley, Calif. 22.2

  • Electricity: 6.2 Transportation: 8.4 Green Living: 2.9 Recycling/Perspective: 4.7

8. Seattle, Wash. 22.1

  • Electricity: 6.2 Transportation: 7.3 Green Living: 4.7 Recycling/Perspective: 3.9

9. Chicago, Ill. 21.3

  • Electricity: 5.4 Transportation: 7.3 Green Living: 5.0 Recycling/Perspective: 3.6
  • CATEGORY LEADER: Green Space
    In addition to the 12,000 acres Chicago has devoted to public parks and waterfront space, the U.S. Green Building Council has awarded four city projects with a “Platinum” rating, its highest award.
    See how Chicago’s power plants produce twice the energy with a third the carbon, here.

10. Austin, Tex. 21.0

  • Electricity: 6.9 Transportation: 5.9 Green Living: 3.3 Recycling/Perspective: 4.9

11. Minneapolis, Minn. 20.3

  • Electricity: 7.8 Transportation: 7.4 Green Living: 2.8 Recycling/Perspective: 2.3
  • CASE STUDY: Citizen Enviro-Grants
    If you’ve got a world-saving idea, the City of Lakes will give you, your church or your community group the money to get it done. Twenty $1,000 mini-grants and five $10,000 awards were distributed last year to programs ranging from household power-consumption monitors to “block club talks” about global warming. A similar initiative has sprung up in Seattle.

12. St. Paul, Minn. 20.2

  • Electricity: 8.0 Transportation: 4.0 Green Living: 3.5 Recycling/Perspective: 4.7

13. Sunnyvale, Calif. 19.9

  • Electricity: 7.3 Transportation: 6.8 Green Living: 2.2 Recycling/Perspective: 3.6

14. Honolulu, Hawaii 19.9

  • Electricity: 6.0 Transportation: 7.8 Green Living: 2.6 Recycling/Perspective: 3.5

15. Fort Worth, Tex. 19.7

  • Electricity: 8.3 Transportation: 4.6 Green Living: 2.4 Recycling/Perspective: 4.4

16. Albuquerque, N.M. 19.1

  • Electricity: 7.6 Transportation: 5.5 Green Living: 2.4 Recycling/Perspective: 3.6

17. Syracuse, N.Y. 18.9

  • Electricity: 7.0 Transportation: 4.9 Green Living: 2.6 Recycling/Perspective: 4.4

18. Huntsville, Ala. 18.4

  • Electricity: 6.2 Transportation: 4.1 Green Living: 3.6 Recycling/Perspective: 4.5

19. Denver, Colo. 18.2

  • Electricity: 5.9 Transportation: 5.2 Green Living: 3.0 Recycling/Perspective: 4.1
  • CASE STUDY: Green Concrete
    Fly ash, a by-product of coal-burning power plants, usually ends up in landfills. Researchers at the University of Colorado Denver found a way to reuse this industrial by-product. They add it at concentrations of about 20 percent to a new green concrete mix. The addition of fly ash also reduces the amount of sulfur- and carbon-spewing concrete production needed to finish a job. The mayor has signed an executive order requiring the use of green concrete in new city projects, and a $550-million infrastructure bond makes demand for the mix likely to grow.

20. New York, N.Y. 18.2

  • Electricity: 2.8 Transportation: 10.0 Green Living: 3.4 Recycling/Perspective: 2.0
  • CATEGORY LEADER: Transportation
    More than 54 percent of New Yorkers take public transportation to work, beating the next-best metropolis, Washington, D.C., by 17 percent.
    See how New York City turns its tides into electricity, here.

21. Irvine, Calif. 18.1

  • Electricity: 4.2 Transportation: 6.8 Green Living: 2.9 Recycling/Perspective: 4.2

22. Milwaukee, Wis. 17.3

  • Electricity: 5.0 Transportation: 4.9 Green Living: 3.1 Recycling/Perspective: 4.3

23. Santa Rosa, Calif. 17.2

  • Electricity: 7.0 Transportation: 3.4 Green Living: 2.4 Recycling/Perspective: 4.4
  • See how Santa Rosa taps geysers for watts, here.

24. Ann Arbor, Mich. 17.2

  • Electricity: 4.6 Transportation: 4.8 Green Living: 2.9 Recycling/Perspective: 4.9

25. Lexington, Ky. 16.8

  • Electricity: 5.9 Transportation: 3.6 Green Living: 2.3 Recycling/Perspective: 5.0
  • CATEGORY LEADER: Recycling and green perspective
    Lexingtonians recycle everything from surplus electronics to scrap metal, and they listed the environment as their third most important concern (behind only employment and public safety)—the highest ranking in our survey.

26. Tulsa, Okla. 16.7

  • Electricity: 5.0 Transportation: 3.9 Green Living: 3.4 Recycling/Perspective: 4.4

27. Rochester, N.Y. 16.1

  • Electricity: 4.5 Transportation: 4.4 Green Living: 3.1 Recycling/Perspective: 4.1

28. Riverside, Calif. 16.0

  • Electricity: 7.5 Transportation: 3.1 Green Living: 2.1 Recycling/Perspective: 3.3

29. Springfield, Ill. 15.7

  • Electricity: 5.3 Transportation: 3.0 Green Living: 3.2 Recycling/Perspective: 4.2

30. Alexandria, Va. 15.7

  • Electricity: 2.7 Transportation: 6.3 Green Living: 3.1 Recycling/Perspective: 3.6

31. St. Louis, Mo. 15.0

  • Electricity: 2.7 Transportation: 5.0 Green Living: 3.7 Recycling/Perspective: 3.6

32. Anchorage, Alaska 14.4

  • Electricity: 2.7 Transportation: 4.7 Green Living: 2.1 Recycling/Perspective: 4.9
  • CASE STUDY: Power-Saving Streetlights
    Since Anchorage spends a good part of the year buried under highly reflective snow, it doesn’t make sense to keep the street lamps at full bore when moonlight can do the job. The fix? Install citywide dimmers. On top of that, the city is planning to upgrade its 16,000 streetlamps to either LED or induction bulbs, depending on the results of computer simulations designed to find the type of light that helps humans see best and disturbs wildlife the least. The swap should be complete by year’s end, and the initial $5-million investment is expected to save up to $3 million in energy costs annually.

33. Athens-Clarke, Ga. 14.1

  • Electricity: 2.4 Transportation: 4.7 Green Living: 3.2 Recycling/Perspective: 3.8

34. Amarillo, Tex. 14.0

  • Electricity: 5.2 Transportation: 2.9 Green Living: 2.3 Recycling/Perspective: 3.6

35. Kansas City, Mo. 13.8

  • Electricity: 2.7 Transportation: 3.7 Green Living: 2.7 Recycling/Perspective: 4.7

36. Salt Lake City, Utah 13.5

  • Electricity: 3.6 Transportation: 4.1 Green Living: 2.3 Recycling/Perspective: 3.5
  • See how Salt Lake City heats homes from waste, here.

37. Pasadena, Calif. 13.2

  • Electricity: 5.8 Transportation: 3.1 Green Living: 1.8 Recycling/Perspective: 2.5

38. Norwalk, Calif. 13.0

  • Electricity: 3.5 Transportation: 3.1 Green Living: 2.5 Recycling/Perspective: 3.9

39. Laredo, Tex. 12.9

  • Electricity: 4.4 Transportation: 2.5 Green Living: 1.7 Recycling/Perspective: 4.3

40. Joliet, Ill. 12.0

  • Electricity: 1.3 Transportation: 4.3 Green Living: 2.6 Recycling/Perspective: 3.8

41. Newport News, Va. 11.9

  • Electricity: 2.7 Transportation: 2.7 Green Living: 2.7 Recycling/Perspective: 3.8

42. Louisville, Ky. 11.9

  • Electricity: 1.3 Transportation: 4.0 Green Living: 2.5 Recycling/Perspective: 4.1

43. Concord, Calif. 11.9

  • Electricity: 3.0 Transportation: 3.2 Green Living: 2.2 Recycling/Perspective: 3.5

44. Fremont, Calif. 11.3

  • Electricity: 3.0 Transportation: 3.0 Green Living: 1.5 Recycling/Perspective: 3.8

45. Elizabeth, N.J. 10.5

  • Electricity: 2.6 Transportation: 2.8 Green Living: 1.8 Recycling/Perspective: 3.3

46. Livonia, Mich. 10.2

  • Electricity: 2.7 Transportation: 2.1 Green Living: 1.8 Recycling/Perspective: 3.6

47. San Bernardino, Calif. 10.2

  • Electricity: 2.8 Transportation: 2.3 Green Living: 1.6 Recycling/Perspective: 3.5

48. Thousand Oaks, Calif. 10.2

  • Electricity: 2.9 Transportation: 2.9 Green Living: 1.6 Recycling/Perspective: 2.8

49. Stockton, Calif. 10.1

  • Electricity: 2.8 Transportation: 2.5 Green Living: 1.0 Recycling/Perspective: 3.8

50. Greensboro, N.C. 10.0

  • Electricity: 2.0 Transportation: 2.0 Green Living: 2.1 Recycling/Perspective: 3.9

For more on six cities’ green case studies, click here to launch the gallery

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The East Bay cuts pollution with hydrogen-powered transit The buses are 40-foot-long behemoths, but they glide along downtown streets as silently as sleds coasting over snow; passersby barely turn their heads. The local AC Transit agency, which serves Oakland, Berkeley and other East Bay cities, hopes its fleet of three hydrogen-powered busesa€”the largest in the nationa€”will help to leave the environment just as undisturbed. Jaimie Levin, AC Transit’s director of alternative-fuels policy, had his conversion experience in 1999 when he attended a demonstration. a€œI couldn’t believe the potential for addressing environmental-health issues,a€ he says. a€œThe only emission from this bus was water vapor.a€ When the California Air Resources Board passed a regulation in 2000 requiring transit agencies to switch to cleaner buses, AC Transit had the impetus it needed to start a project. Over the next few years, it amassed more than $12 million in grants and forged partnerships with multiple companies that helped them design the hydrogen-powered buses. The first buses took to the streets in 2005, and the fleet should grow to eight in 2009. Although the buses substantially reduce transit pollution (diesel buses emit 130 tons of carbon dioxide per year), initiatives like AC Transit’s remain largely showcase projects. Custom components drive the price of each bus to $2 million, more than five times the cost of diesel buses. Levin believes this will change if U.S. authorities throw their full political and financial weight behind hydrogena€”which seems a more feasible goal now that the Federal Transit Administration has started parceling out $49 million in research grants for fuel-cell buses. a€œUltimately, this becomes a public-policy decision,a€ he says. a€œWe can bring costs down by building the buses on a large scale, and local governments can help accelerate that.a€

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Chicago produces twice the energy with a third the carbon A typical fuel-burning power plant is wasteful in two ways: It produces harmful emissions, and it squanders two thirds of the energy it generates. The primary reason? Heat, the natural by-product of fuel combustion, dissipates into the atmosphere unused. Chicago is among the first cities to confront energy loss head-on. The city government has invested in cogeneration, the simultaneous production of heat and electricity, which is twice as efficient as conventional fuel-burning power production. The strategy is also a potent means of reducing greenhouse-gas emissions. A cogeneration plant produces only one third the CO2 of a coal-fired power plant. In its most recent energy plan, Chicago committed to producing 1.5 billion kilowatt-hours of electricity from cogeneration by 2010a€”25 percent of the city’s increased energy needs from 2000 to 2010. Rather than allowing accumulated heat to escape through exhaust vents, a cogeneration facility collects the hot steam exhaust produced by natural gas combustion and channels it into a network of pipes that distributes it throughout the building. a€œYou can take steam and use it directly for heating the building, cooking, and hot water,a€ says John Kelly of Illinois-based Endurant Energy. a€œThat’s huge.a€ Chicago’s famed Museum of Science and Industry developed a cogeneration plant in 2003, and in recent years other city institutions, such as the Jesse Brown VA Medical Center, have followed suit. Kelly thinks the cogeneration meme will soon spread. a€œManhattan is anticipating a power shortfall of 1,000 megawatts,a€ he points out. a€œIt’s a perfect candidate.a€ HOW IT WORKS Cogeneration starts when a generator burns natural gas [A] to produce electricity. The hot exhaust from that combustion boils water [B], and that steam powers a turbine [C] connected to a second generator [D], producing another shot of electricity. Any leftover waste steam heats the building.

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San Francisco turns wasted roof space into power Travelers flying over San Francisco’s Moscone convention center could easily mistake the roof for a parking lot. But the 60,000-square-foot expanse of black atop the building isn’t asphalta€”it’s an intricate honeycomb of photovoltaic cells. When San Francisco’s Public Utilities Commission teamed up with PowerLight Corporation to cover the convention center’s roof in solar panels, some observers scoffed. a€œThe tongue-in-cheek remarks were, a€˜Oh, Fog City,’ a€ says Susan DeVico, then a spokeswoman for PowerLight. a€œBut photovoltaic doesn’t need to have strong sun.a€ The installation has defied critics since its unveiling in 2004, delivering enough juice to supply the Moscone Center during events, and more than 180 homes when the center is dark. The solar cells that stud the roof contain silicon semiconductors that absorb photons from sunlight, setting a procession of electrons in motion to create a current. Now the city is staking its renewable future on letting the sun in. Moscone is just the first stepa€”officials are blanketing the city with solar cells, installing solar arrays on municipal buildings, including ports and libraries, and a $2.2-million solar rooftop on a wastewater-treatment facility.

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Free steam outside Santa Rosa creates 850 megawatts of power Most people associate geothermal energy with countries like Iceland, where the thin crust creates lakes the temperature of hot tubs. But the U.S. actually harvests more electricity from the earth’s natural heat than any other nationa€”and the simmering underground steam reservoir called the Geysers, in the redwood-studded wilderness outside Santa Rosa, is the world’s largest such geothermal installation. For every Vesuvius that erupts on our planet, far more magma remains underground, heating pockets of water and yielding vast amounts of steam. Mining these veins of vapor is a€œjust like drilling for oil or gas,a€ says Dennis Gilles, a senior vice president of Calpine, the company that owns and manages 19 of the 22 power plants at the Geysers. a€œBut you’re sending the drill down into a reservoir of hot steam instead.a€ At the Geysers, pipes send the steam from the drilled wells to central collection facilities, where it is used to power 31 steam turbines. The system generates more than 850 megawatts of electricity, enough to power about 850,000 homes on the California grid. Santa Rosa’s relationship with the Geysers dates to the 1920s, when entrepreneurs installed enough steam piping and turbines to light the buildings of a nearby resort. By the 1990s, however, as the plumes of steam thinned, it was clear that after many years of use, the famed steam fields were almost tapped out. In 1998, the city approved a plan to replenish the Geysers. A $187-million municipal initiative funded the construction of a four-foot-wide, 41-mile-long pipeline that routes 12 million gallons of the city’s wastewater per day back to the steam fields. Since the pipeline’s inauguration in 2004, it has consistently boosted the Geysers’s electrical output by about 85 megawatts, replacing conventional processes that would have released 570 million pounds of carbon dioxide into the atmosphere every year.

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Salt Lake City saves eight tons of carbon dioxide with the warmth of sewage When Salt Lake City attorneys Jon and Phillip Lear decided to set up offices in the Major George Downey mansion downtown in 2005, gas prices had spiked after Hurricane Katrina, and they started brainstorming alternative heating and cooling systems. a€œAlternativea€ is the word for what the brothers came up with. The system they designed, with help from engineers at Utah’s Sound Geothermal Corporation, pulls heat from warm sewage water. A secondary network of pipes surrounding a sewage pipe carries a water-based glycol that enables a heat exchangea€”since it is cool relative to the sewage water, it rapidly absorbs heat. The pipes carry the warmed glycol back into the house, where the accumulated heat energy radiates from vents. On hot summer days, the glycol absorbs heat from inside the house and releases it underground. The entire setup uses about 40 percent less energy than a conventional heating and cooling system would, reducing carbon dioxide emissions by eight tons a year. The Lears moved their offices there permanently in January. Public-utilities director Jeff Niermeyer hopes to install similar systems in other public buildings within the next few years. a€œWith any wastewater system, there’s a lot of heat that you’ve already put in for other purposes,a€ he says.

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New York City hopes to generate enough power for 8,000 homes with underwater turbines Traditionally, New Yorkers have considered the East Rivera€”alongside pigeons and trasha€”an indelible part of the landscape, better off overlooked. But the city and state have partnered with Verdant Power to install a fleet of submerged turbines near Roosevelt Island, a few hundred feet east of Manhattan, that will transform the river into a valuable power source. New York is already one of the world’s most energy-efficient citiesa€”an average New Yorker uses about half the electricity an average San Franciscan does. Yet an anticipated influx of new residents will further strain existing energy sources, so city and state officials gave Verdant about $3 million to harness power from the river’s strong tidal currents. Verdant’s turbines resemble their wind-farm cousins, with triple-bladed rotors that generate electricity from kinetic energy. The East River’s tides turn the rotors only about once every two seconds. But since water currents are about 1,000 times as dense as wind currents, each turbine sends up to 36 kilowatts into the Roosevelt Island grid. When all 300 planned turbines are installeda€”in the next decade, if all goes as planneda€”the underwater field will produce 10 megawatts of power, enough electricity for 8,000 homes. But hydropower is tricky. During initial tests last summer, tides were 20 percent more powerful than anticipated, and the currents simply snapped the blades off the turbines. Verdant says it can solve the problem with reinforced turbines; the replacements should be ready for East River testing this year. The company is also in talks to install similar systems in the St. Lawrence River in Ontario and in Seattle’s Puget Sound.