BLM Authorizes Routes for Final Segments of Gateway West Transmission Line

BOISE, ID – The Bureau of Land Management (BLM) has signed a Record of Decision to authorize routes for the final two segments of the Gateway West transmission line project, which connects the Hemingway substation in southwest Idaho with power generation facilities in central Wyoming.  The project will address congestion problems within the Western electrical grid, facilitate the renewable energy market, especially wind energy in Idaho and Wyoming, and aid in delivering that energy to the region. 

The authorization grants rights-of-way (ROWs) to Idaho Power and Rocky Mountain Power to build and operate 321 miles of 500-kilovolt transmission lines on BLM-managed public lands in Gooding, Elmore, Owyhee, Cassia, and Twin Falls counties in Idaho.  

“Gateway West has been an Administration priority project to transform our electric power grid and spur development of renewable energy,” said BLM Director Neil Kornze.  “Today’s decision authorizes the routes with the least impact on private property, farmland, historic trails and cultural resources, visual resources, wetlands, sage grouse habitat, and the Birds of Prey National Conservation Area." 

The lines will cross 17.6 miles of public land in the National Conservation Area (NCA)—8.8 miles per line, separated by 250 feet in a 500-foot-wide ROW—and are routed to avoid all Priority Habitat Management Areas for Greater Sage-grouse identified in the 2015 Great Basin resource management plan amendments for Idaho.  

The Decision requires compensatory mitigation for impacts to NCA resources.  The mitigation will result in enhancement of those resources.  Mitigation for affected sage-grouse habitat must result in a net conservation gain for the species.  Required measures to mitigate effects to other important, scarce, or sensitive resources, such as the Oregon-California National Historic Trail, Class I visual resources, and habitat for migratory birds will result in a minimum of no net loss or a net benefit, depending on the circumstances. 

Environmental effects analysis and public involvement 

After detailed environmental review under the National Environmental Policy Act (NEPA), the BLM approved eight of the ten segments (Segments 1 through 7 and 10) for the larger Gateway West transmission line in November 2013, but the BLM later determined that new information on Segments 8 and 9 required supplemental environmental analysis prior to approval.  

In October 2016, after extensive public involvement and comment, the BLM published a Final Supplemental Environmental Impact Statement together with cooperating agencies including the State of Idaho, the U.S. Fish and Wildlife Service, and the Federal Energy Regulatory Commission.  The environmental review identified the routes authorized in today’s Decision as the agency’s preferred alternative, and it outlined mitigation requirements that will become stipulations or terms and conditions for the ROW grants.  

About the Gateway West Transmission Project 

The Gateway West Project is a national-level priority and an important component of President Obama’s initiative to transform the Nation’s power grid and spur development of renewable energy. Idaho Power and Rocky Mountain Power jointly proposed the line as 10 segments originating at the Windstar substation near Glenrock, Wyoming and terminating at the Hemingway substation, 20 miles southwest of Boise, Idaho, to deliver up to 1,500 megawatts of transmission capacity in southern Wyoming and southern Idaho – enough to power 975,000 homes.  

This year, we invite everyone to reimagine your public lands as we celebrate 75 years of the BLM’s stewardship and service to the American people. The BLM manages approximately 245 million acres of public land located primarily in 12 Western states, including Alaska. The BLM also administers 700 million acres of sub-surface mineral estate throughout the nation. The agency’s mission is to sustain the health, diversity, and productivity of America’s public lands for the use and enjoyment of present and future generations. 

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Bureau of Land Management


Idaho State Office


Heather Feeney