The U.S. Department of Energy's Bonneville Power Administration (BPA) developed this statement to evaluate the environmental impacts of constructing between 254 and 271 miles of 500-kilovolt transmission line across western Montana and northern Idaho to the Spokane area in order to reinforce a section of the BPA electric power grid and to permit reliable integration of 1,240 megawatts of power produced by Colstrip Units 3 and 4, for use in Montana and throughout the Northwest.