Project
Green Line is a high voltage direct current (HVDC) system that will transfer electric energy from the Maine Yankee 345 kilovolt (kV) substation in Wiscasset, Maine to the K Street 345 kV substation in Boston, Massachusetts, with the potential to be extended further south. A submarine cable of approximately 140 miles will connect HVDC converter stations located in Wiscasset and Boston. The stations convert AC power to DC power before moving it through the DC cable. The system is initially proposed as a 500 kV line that would move 660 megawatts (MW) of energy, but the system could be expanded to twice that size if needed to meet fast-growing environmental needs for clean energy in New England. The system uses proven electric grid technology that has minimal environmental impacts. The cable will rest beneath the sea, where its small footprint and careful installation make it the most environmentally sensitive transmission technology available.