Green Municipal Aggregation

go green

Also known as community choice aggregation (CCA), this model allows MA & RI communities to take climate action by affordably greening up residents' electricity supply.

Video: Dec 2020 UPDATE on GMA

Watch Q&A with our Renewable Energy Procurement Director, Yaima Braga, as part of our annual Fall Meeting.

What Is GMA

Massachusetts and Rhode Island state laws allow a city or town to choose the electricity supplier for residents and businesses within that municipality. This is called municipal aggregation or community choice aggregation. It allows for important energy decisions to be made at the local level rather than by an investor-owned utility or by a for-profit competitive electricity supplier. 

Green Municipal Aggregation, or GMA, is a model we devised with energy broker Good Energy that adds more Class I or "new" renewable energy to residents' electricity at a competitive price. When a community decides to enact GMA, it goes out to bid for an electricity supplier and secures a long-term price and a cleaner electricity supply. That supplier replaces the utility's Basic Service, offers a more stable price (usually cheaper in the long run, too), and adds more renewable energy than required by state law.

Big progress in Rhode Island

Six RI communities are making significant progress in their quest to implement Green Municipal Aggregation (also referred to as Community Choice Aggregation or CCA).

  • Barrington, Providence, and South Kingstown have followed Central Falls and have filed their plans with the PUC. CCA is one of the program initiatives in Providence's Climate Justice Plan!
  • Portsmouth is filing its plan with the PUC.
  • Newport recently selected their broker and is moving forward with planning.
Watch Providence's excellent videos explaining GMA

Read: Green Municipal Aggregation in MA, 2nd edition, released Feb 2020

Green Energy Consumers' new paper explains the nuts and bolts of GMA and how a growing number of Massachusetts communities are using it to drive demand for new renewable energy sources.

We have worked hard to spread GMA to Rhode Island. As a result of successful changes to state law and concerted outreach and education to cities and towns, we will soon be able to report on big progress. Stay tuned.

Read the Massachusetts report


How do I get my community involved?

If you’re interested in learning more about GMA or want to find out how your community can get started, contact

Here is a list of participating communities:

Name Renewable electricity (added by default) Supplier (what you'll see on your electric bill) Website
Arlington 11% Direct Energy Services
Bedford 5% Dynegy
Brookline 30% Direct Energy Services
Dedham 5% Public Power, LLC
Fairhaven 10% Constellation New Energy
Gloucester 5% Direct Energy Services
Hamilton 5% Constellation New Energy
Medford 5% Dynegy
Melrose 5% NextEra
Millis 5% Constellation New Energy n/a
Rockland 5% Dynegy
Somerville 10% Direct Energy
Stoneham 5% Constellation New Energy
Westport 10% Constellation New Energy
Winchester 10% Dynegy