The yearly 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 Jul '12 xlsx format of Jul '12 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.