Canadian hydropower is scheduled to surge into Massachusetts on Friday, marking a major new energy source for the state.
The long-promised and long-delayed transmission line that will carry up to 1,090 megawatts of electricity into the state is set to begin commercial operation after work wrapped up on the project in December, according to a biannual update that developer Avangrid filed with the Maine Public Utilities Commission on Jan. 2.
Gov. Maura Healey said Wednesday that the state estimates it will power about 20% of the electricity in Massachusetts…