- NSTAR
- National Grid
- Unitil
- Western Massachusetts Electric Company
- Ashburnham Municipal Light Plant
- Hudson Municipal Electric Dept
- Belmont Municipal Light Department
- Boylston Municipal Light Department
- Braintree Electric Light Department
- Chester Municipal Electric Light Department
- Chicopee Municipal Lighting Plant
- Concord Municipal Light Plant
- Danvers Electric Division
- Georgetown Municipal Light Department
- Groton Electric Light Department
- Groveland Municipal Light Department
- Hingham Municipal Light Plant
- Holden Municipal Light Department
- Holyoke Gas & Electric Department
- Hudson Light and Power
- Hull Municipal Lighting Plant
- Ipswich Municipal Light Department
- Littleton Electric Light & Water Department
- Mansfield Municipal Electric Department
- Marblehead Municipal Light Department
- Mass Development/Devens Utility
- Mendon Board of Public Affairs
- Merrimac Municipal Light Department
- Middleborough Gas & Electric Department
- Middleton Municipal Light Department
- North Attleborough Electric Department
- Norwood Municipal Light Department
- Paxton Municipal Light Department
- Peabody Municipal Light Plant
- Princeton Municipal Light Department
- Reading Municipal Light Department
- Rowley Municipal Lighting Plant
- Russell Municipal Lighting Company
- Shrewsbury's Electric Light Plant
- South Hadley Electric Light Department
- Sterling Municipal Light Department
- Taunton Municipal Lighting Plant
- Templeton Municipal Lighting Plant
- Wakefield Municipal Light Department
- Wellesley Municipal Light Plant
- West Boylston Municipal Lighting Plant
- Westfield Gas and Electric Light Department
