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Carbon Free Boston project update

After meeting with key experts, the Carbon Free Boston research team has started to model how different policy options could affect Boston’s future carbon emissions. This analysis will help us understand all our options to reach our goal of becoming carbon neutral by 2050.


Our research team recently met with City and state representatives, energy experts, and equity advisers. The group discussed the electric grid’s current energy mix and how a new state law affects Boston’s path to carbon neutrality.

What we've learned so far

For Boston to become carbon neutral, the electric grid needs to switch to clean energy. In its future scenario, the team assumes that Boston’s transportation and building sectors will switch to electricity. For example, homes that use oil-fired furnaces will switch to electric heat pumps. But electricity is currently Boston’s largest source of energy emissions. That’s because Boston gets its electricity from the New England grid, which still relies on natural gas. In 2016, the New England grid only generated 10% of its electricity from renewable energy. For Boston to both electrify and decarbonize, the electric grid needs to get cleaner too. 

In August 2017, the Commonwealth of Massachusetts passed the Clean Energy Standard. This new law requires the Massachusetts electric grid to run on 80% clean energy by 2050. 

But Boston needs to go further. Under the new law, in 2050, one-fifth of its electricity will still come from fossil fuels. And Boston still burns natural gas and oil to heat buildings and power vehicles.

Where we're headed next
The project team is considering various energy policy options to help Boston go carbon neutral, including:
  • investing in new district heating and cooling systems
  • converting district energy systems to run on clean energy
  • investing in micro-grids to boost resilient local electricity generation capacity
  • encouraging or requiring rooftop solar panel installations, and
  • increasing locally-produced and community-owned renewable power.

You can learn more about the energy policy options that we’re evaluating.


What we've learned so far
The Carbon Free Boston team has been assessing Boston’s building stock. Their initial findings show that:
  • Boston has nearly 86,600 buildings, representing more than 633 million square feet.
  • Boston’s building stock is old. More than four out of five buildings were built before 1950. These pre-1950 buildings account for 61% Boston’s total square footage.
  • 92% of Boston’s buildings are residential, most of which were built before 1950. But residential buildings only represent 56% of Boston’s total square footage.
  • Offices represent 18% of Boston’s total square footage. Offices larger than 500,000 square feet tend to have been built after 1950, when the first modern building code went into effect.
  • Most of the structures built since 1950 are large residences and commercial projects larger than 100,000 square feet.
Where we're headed next
The team is studying strategies to reduce emissions from both new and existing buildings, including:
  • requiring new construction to have net zero emissions or net positive energy
  • placing a cap on energy consumption or greenhouse gas emissions
  • encouraging building envelope retrofits, like glazing and window replacements or increased insulation
  • mandating that more buildings disclose their energy use
  • requiring building owners to undertake fossil fuel free retrofits or Passive House retrofits, and
  • calling for higher standards for energy efficiency of appliances and building equipment.

The team is also studying how electric vehicle charging and district energy systems will affect building sector emissions. You can view a comprehensive list of building policy options.


What we've learned so far

During another recent meeting, the research team shared some findings related to transportation. They have found that, in 2016:

  • Boston held approximately one-tenth of the state’s population and one-fifth of its jobs
  • passenger vehicles accounted for 79% of transportation greenhouse gas emissions, and
  • fuel used by private vehicles accounted for more than 90% of transportation emissions.

The team also identified key national trends that will influence transportation through 2050:

  • Passenger vehicles will travel 20% more miles by 2050. But fuel efficiency improvements will help cut energy use by 25-35% by 2030.
  • Trucks will travel 50% more miles by 2050. The amount of energy used will not change, thanks to improved fuel efficiency.
  • Electric vehicle sales will increase until they represent about 15% of all vehicles. But most vehicles will still run on diesel and gasoline.
  • The project team is also testing different assumptions. These include more electric vehicles, less driving, and smart mobility.
Where we're headed next

Here are some of the transportation policy options the team will be looking at:

  • Giving clean vehicles preferential parking or lane access.
  • Encouraging or requiring electric vehicle charging stations.
  • Concentrating jobs and homes around transit hubs to reduce demand for personal vehicles.
  • Deploying transit signal priority systems, which allow buses or trains to bypass traffic.
  • Charging road users during rush hour or traveling within a certain zone.
  • Charging for vehicle parking, road use, fuel use, or carbon emissions.

You can learn more about the transportation policy options under study.


What we've learned so far

The Carbon Free Boston team is coordinating with the ongoing Zero Waste Boston planning initiative. The Zero Waste Boston advisory committee recently had its second meeting. 

The meeting introduced the zero waste concept and reviewed Boston’s waste generation, noting:
  • Boston residences generate an estimated 240,000 tons of waste. One-fifth of residential waste is recycled; the rest is incinerated to produce energy that powers the region.
  • Business and institutions produce an estimated 915,000 tons of waste. One-quarter of that waste is recycled and the rest is incinerated to produce energy.

The committee broke out into two groups to discuss potential zero waste initiatives. One group focused on residential waste. The other group focused on waste from Boston's institutional, commercial and industrial sectors.

Where we're headed next
Here are some of the ideas that the team will continue to study:
  • Expand organics collection to include food scraps and compostable paper.
  • Change collection rate structure incentives or trash limits.
  • Improve outreach and technical assistance to address issues and increase participation.
  • Adopt an ordinance to require deconstruction and recycling of construction and demolition debris.
  • Collect waste data to better target outreach efforts and design better recycling programs.

For more information on the Zero Waste Boston initiative, please visit our Zero Waste Boston page.

Share your thoughts

Do you see something missing? Carbon Free Boston is an ongoing initiative, and we’re always listening for ideas to reach Boston’s climate goals. If you have any suggestions or questions on the work we’re doing, please email us at

Greenovate Boston is Mayor Walsh’s initiative to get all Bostonians involved in eliminating the pollution that causes global climate change, while continuing to make Boston a healthy, thriving, and innovative city. Greenovate works with the broader community to implement the City’s Climate Action Plan, which is a roadmap to become carbon neutral by 2050.

What's Next?

Over the next couple months, the research team is going to be modeling greenhouse gas  emission scenarios. They will quantify how various policy options could affect Boston’s future carbon emissions. Through this work, the Carbon Free Boston team will identify the benefits and costs of the possible strategies. The research team will also address equity issues in its analysis. The final report results will help the City to make informed choices as we update our Climate Action Plan over the upcoming year.

ABOUT Our climate goals

Boston is committed to becoming carbon neutral by 2050. Climate change poses a serious threat, for both Boston and the world. If we don't take action now, sea level rise over the next century could leave more than 30% of Boston underwater. Going carbon neutral means we have to start making tough decisions to cut our emissions and do our part to help prevent the worst effects of climate change.

Last year, Mayor Martin J. Walsh launched a new initiative, Carbon Free Boston, to help us reach our carbon neutrality goal. Our first step is to study how different policies and technologies can help us meet our goal of reaching carbon neutrality by 2050. The ongoing Carbon Free Boston research project focuses on four key sectors: energy, buildings, transportation, and waste. Its findings will inform the next update to Boston’s Climate Action Plan.

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  • Sign Up for Updates

    To be the first to learn about updates on Carbon Free Boston, including upcoming events, sign up at Greenovate Boston

  • Any questions?

    We've provided answers to common questions at this page.

  • Other questions or comments?

    Ask us a question, leave a comment, or suggest an option you'd like us to consider.

     submit your comment 

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