This link provides a starting point: https://www.mass.gov/info-details/power-outages#historic-power-outages-

Notes:

The historic power outage information can be found in the initial filings (generally the filing with the oldest date) and includes information such as:
- city or town where the outage occurred
- number of customers affected
- outage duration
- time the outage occurred
- reason for outage

We are apparently supposed to go to the Massachusetts government online file room, which will give us access to a spreadsheet.

Eversource and National Grid are the two major providers of power in Massachusetts. We use National Grid south of Boston (Quincy, Hingham, etc.).