Dec. 18, 2014. Arlington, MA.
LED street lights in front of Arlington Town Hall and Town Manager Adam Chapdelaine.
Metropolitan Area Planning Council.
© 2014 Marilyn Humphries
What is Net Zero

Zero to 101

What is Net Zero?

As net zero has grown in popularity, terms to describe it have proliferated. Not only do terms such as “100% Renewable Energy (RE),” “climate neutral,” and “carbon neutral” exist within the same sphere, but net zero can refer to the net accounting of zero energy generated, electricity generated, or greenhouse gas (GHG) emissions generated.

Department of Energy Zero Energy Building (ZEB) Produces enough renewable energy to meet its own annual energy consumption requirements, thereby reducing the use of non-renewable energy in the building sector
Mass Power Forward Net Zero Municipality Produces zero net carbon pollution; community gets as much electricity from renewable sources as it usesAchieved through a combination of energy efficiency improvements, local clean energy production, and purchasing renewable energy
Cambridge Net Zero Taskforce Net Zero Refers to a building or a community of buildings for which, on an annual basis, all greenhouse gas emissions resulting from building operations are offset by carbon-free energy production
World Future Council 100% Renewable Energy (100% RE) All energy needed within the electricity, heat, and transport sector in a particular region is coming from renewable sources
United Nations Carbon Neutral Climate-damaging emissions are reduced where possible and the remaining emissions are netted out through the purchase of carbon offsets

[1] “The Getting to Net Zero Framework.” City of Cambridge. (2015)
[2] “Road to 100% Renewables: Mass Power Forward Campaign Handbook.” Mass Power Forward. (2017)
[3] “How to Achieve 100% Renewable Energy: Policy Handbook.” E3 Analytics & World Future Council. (2014)
[4] “Climate Neutral Now.” United Nations Framework Convention on Climate Change (2017)

In general all of these definitions aim to reduce GHG emissions drastically, but may differ in approach and in scope. These varying definitions demonstrate that many ways exist to achieve GHG emissions reductions and contribute to the worldwide Paris Agreement goal.[5] This work is doable. Net zero work can – and should – seek to align with, complement, and embolden other municipal efforts so that cities and towns can lead, can commit to ambitious mid-century goals, and can set a path to meet them.


Cities within the MAPC region are leading the way. The City of Somerville, the City of Boston, the City of Cambridge, and the Town of Lexington, have already made commitments to become net zero. The Metro Mayors Coalition consists of 14 municipalities in the inner core of Metro Boston that have committed to achieve net zero/carbon-free status as a region by 2050, making the coalition one of the first regions in the country to make such a commitment. The City of Somerville set a goal in 2014 to be Carbon Neutral by 2050.[6] The City of Cambridge has committed to net zero buildings by 2040. The City of Boston has pledged to reduce the City’s GHG emissions 25% by 2020 and become carbon-neutral by 2050.[7] The Town of Lexington has recently adopted a net zero taskforce who will be releasing recommendations for the city to achieve net zero.

Further afield, Burlington, VT, Greensburg, KS, Georgetown, TX, and Aspen, Colorado, among others, have already reached their goal of 100% renewable energy. Cities small and large are working towards this goal around the U.S., including Abita Springs, LA (100% renewable electricity by 2030), Atlanta, GA (100% renewable electricity by 2035), and Columbia, SC (100% renewable electricity by 2036). Outside of the United States, Växjö, Sweden was the first city in the world to commit to becoming fossil-fuel free, setting a 2030 goal back in 1991. As of 2015, the city had decreased CO2 emissions nearly 50% since 1993 while GDP had risen 90%.[8]Much more recently, other cities such as Vancouver, Canada, and the countries of Denmark and Costa Rica have made similar commitments. The current momentum around net zero and the work underway provide municipalities a unique opportunity to build holistic climate plans that accomplish multiple benefits locally and contribute to a climate-smart future.

[5] “The Paris Agreement.” United Nations Framework Convention on Climate Change. (2017)
[6] “SustainaVille: Creating a Resilient & Carbon Neutral Somerville.” City of Somerville. (2017)
[7] “Greenovate Boston: Action Areas.” City of Boston. (2014)
[8] “What Can the World learn from Vaxjo, Europe’s Self-Styled Greenest City?” The Guardian. (2015)