Project
Green Line is a high voltage direct current (HVDC) system that will transfer electric energy from Houlton, Maine to Boston or Salem, Massachusetts. The full route is via a combination of terrestrial and submarine transmission lines. The converter stations at each end of the transmission line convert alternating current (AC), like that used in the typical household, to direct current (DC). DC is the most efficient way to move electricity long distances. It also provides great flexibility and near instantaneous control over how much and in which direction power flows, thus proving many reliability benefits to the larger electric grid. The system is initially proposed as a +/-300 kV line that would move 800 megawatts (MW) of energy between Maine and Massachusetts.
