The top 10 cleanest U.S. cities progressing toward zero carbon

Our cleanest cities provide powerful lessons in how to transition to clean energy, while growing a city economy and providing better services to citizens. All of these cities improved their renewable energy generation, energy-efficient buildings, government, equitable communities and transportation. The success of these cities, and the ranking of all major U.S. cities is detailed by American Council for an Energy-Efficient Economy (ACEEE). The highest ranking U.S. cities are:

  1. Boston
  2. San Francisco
  3. Seattle
  4. Minneapolis
  5. Washington, D.C.
  6. New York
  7. Los Angeles
  8. Denver
  9. Austin
  10. Portland

Getting to 100 percent renewable electricity, however, does not cut even half of a city’s GHG emissions. Buildings typically use natural gas (methane) for heating, cooling, hot water and cooking. Vehicles spew emissions by burning gasoline, diesel, natural gas and other fossil fuels. To take advantage of renewable electricity, buildings and transportation will need to be all electric and efficient.


Boston outranked all other U.S. cities in the scorecard. Boston plans to be carbon neutral by 2050. Boston buildings are far more energy efficient than most. The Massachusetts Stretch Energy Code mandates efficiency. Buildings greater than 50,000 square feet must report annually on energy use and efficiency progress, such as achieving LEED or Energy Star certification. There are over 800 green buildings with LEED certification. All use efficient lighting, insulation, heating and cooling. Many are mixed use near transit. Some are unique, such as the Boston Public Market, which showcases local sustainable food. 

The city partners with Mass Save to fund training for builders, contractors and inspectors.

Because 67 percent of Massachusetts energy is from gas (methane), Boston is challenged to become carbon neutral. Offshore wind will play a major role. 

Utilities promote electricity and gas efficiency. Low-income and multifamily programs are promoted to help with low-cost and free LED light bulbs, thermostats, energy audits and building insulation with financing. Renters, homeowners and landlords can all apply for help. Boston Seniors Save Program helps lower income seniors replace old systems with efficient heating.

Boston outranks most cities in using electric and hybrid vehicles in its government fleet. To encourage citizens to switch to electric cars, all parking structures must equip 5 percent of spaces with EV charging, and have an added 10 percent wired to be EV ready. The compact city of 48 square miles (of land) makes it easy to get everywhere by walking and using transit.

San Francisco

San Francisco was No. 2 on the scorecard and No. 1 in transportation. San Francisco promotes 0-80-100-Roots Climate Action: zero waste by 2020, 80 percent of trips made sustainably by 2030 and 100 percent of electricity from renewables by 2030. Five thousand tech companies have driven growth in the San Francisco Bay area, yet San Francisco’s emissions are 30 percent less than in 1990.

Urban density helps. In equal square miles of land to Boston, most places in San Francisco can be reached by walking, buses and commuter rail. San Francisco is home to Uber, Lyft and a variety of last-mile solution providers offering shuttles, e-bike and scooter sharing. San Francisco fast-track approves mixed-use buildings near transit by establishing Priority Development Areas (PDA) where fewer development approvals are needed. Endless reviews, which stretched to eight years added cost and uncertainty to developments, are streamlined to less than two years. To help address its crisis of expensive housing and homeless, no parking spaces are required. San Fransisco is a leading city in transportation mode shifting, rather than only driving.

San Francisco is likely to achieve its goal of 100 percent renewable energy within 10 years. It has long promoted solar roofs and energy efficiency. Community choice aggregator CleanPowerSF makes it easy for customers to elect electricity generation from 100 percent renewables. Major utility PG&E generates 40 percent of electricity from renewables. In September, the San Francisco Board of Supervisors approved breakthrough legislation: By 2022, large commercial buildings must use 100 percent renewables; by 2030, commercial buildings over 50,000 square feet must use 100 percent.


Seattle generates virtually all electricity with renewables thanks to its leading utility, carbon-neutral Seattle City Light, and thanks to having 8,000 solar buildings. Like many great cities, Seattle is leading, not waiting for the federal government, to deal with climate change. In August, the Seattle mayor and city council resolved to reduce GHG emissions 100 percent by 2030 with a Seattle Green New Deal.

Seattle City Light offers programs for low-income customers such as weatherization, refrigerator replacement, energy efficiency and heat pump installation. Seattle City Light’s Multifamily Program offers property rebates on lighting, windows and heating, ventilation and cooling updates. In 2017, Seattle also formed the Environmental Justice Committee and encouraged those most affected to have a voice in environmental planning.

Amazon, Seattle’s largest employer, announced plans to order 100,000 electric delivery trucks, making home delivery far lower in carbon emissions than individuals driving to stores to pick up goods. Amazon has committed to meet the Paris Agreement 10 years early. It has over 50 solar rooftops and is a major buyer of wind, solar and other renewable power globally.

Seattle is home to the Bullitt Foundation whose president Denis Hayes states, “Tomorrow’s cities will consist of ‘living buildings’ inside vibrant, resilient neighborhoods all connected by super-efficient transportation links. Today’s living buildings, like the Bullitt Center, represent efforts to learn from nature how to exist comfortably and productively in a particular environment, making the least possible demand on resources.” The Bullitt Center helps organizations globally go beyond net zero. Its six-story headquarters building with integrated solar generates 60 percent more energy than it uses.

Read more about Sustainable Seattle.

Efficiency is a key to shifting to renewables, improving buildings, mobility and city living.

Photograph from ShutterstockVDB Photos

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