The data tables below illustrate the migration of electric power customers in Massachusetts from incumbent generation sources to competitive generation sources. You can also download Excel spreadsheets of the tables (by month), which also include migration data broken down by distribution company:

Notes and definitions:

All data were collected from investor-owned distribution companies, who reported data by their respective rate classes. Each company reported two data elements each for both incumbent and competitive generation service: (1) the number of customers on the last day of the month, and (2) the kilowatt  hours (kWh) used during the entire month.

Data for residential, farm, and street-lights rate classes are shown as reported by the distribution companies. The remaining rate-class data were aggregated by DOER as follows: small commercial and industrial (C&I) includes rate classes with average monthly usage levels below or equal to 3,000 kWh/month; medium C&I includes rate classes with average monthly usage levels greater than 3,000 kWh/month but less than or equal to 120,000 kWh/month; large C&I includes rate classes with average monthly usage levels greater than 120,000 kWh/month. DOER chose this particular aggregation scheme to simplify the reported data. DOER does not endorse any particular conclusions or findings that may result from the data.

Further questions can be directed to DOER Energy Markets 617-626-7329 or 617-626-7348, email

April 2015 Customer Migration Data table


Competitive Supply 2014/2015


Jan '15  pdf format of Jan '15
xlsx format of                             Jan '15                Feb '15  pdf format of Feb '15
xlsx format of                             Feb '15                Mar '15  pdf format of Mar '15
xlsx format of                             Mar '15
Apr '15  pdf format of Apr '15
xlsx format of                             Apr '15                May '15  pdf format of May '15
xlsx format of                             May '15                June '15 pdf format of June '15
xlsx format of                             June '15