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Green Municipal Aggregation

  • How it Works

    How it Works

  • Participating Communities

    Participating Communities

  • Get Involved

    Get Involved


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.

Participating Communities

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
Bedford 10% Dynegy
Brookline 30% Direct Energy
Dedham 10% Constellation New Energy
Fairhaven 10% Constellation New Energy
Gloucester 10% Constellation New Energy
Hamilton 5% Constellation New Energy
Medford 5% Dynegy
Melrose 5% NextEra
Millis 5% Constellation New Energy n/a
Milton 10% NextEra
Rockland 5% Dynegy
Somerville 10% Direct Energy
Stoneham 5% Constellation New Energy
Waltham 10% Direct Energy
Westford 10% Constellation New Energy
Winchester 10% Dynegy

Get involved

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