This story will be updated. After almost three years of regulatory reviews amid efforts to derail it, the controversial western Maine hydropower corridor received its final major permit and has started construction, the parent of Central Maine Power Co. said Friday. The project received the Presidential Permit from the U.S. Department of Energy for the New England Clean Energy Connect project, which will bring 1,200 megawatts of hydropower through 145 miles of transmission lines from the Canadian border to Lewiston.