National Grid has proposed a $1-billion transmission line capable of moving up to 1,200 MW of power into New England. The first 58-mile leg of the Granite State Power Link would be an overhead direct-current line from Norton, Vt., on the Canadian border, to Monroe, N.H.; it would run alongside an existing DC line. Most of the second, 110-mile leg, from Monroe to Londonderry, N.H., would use upgraded transmission towers on an existing right-of-way. There are at least six other transmission projects vying to bring renewable resources, mostly hydropower, into New England from Canada. National Grid Massachusetts hopes to have the line in service by 2022.