416-mile ‘Gateway South’ transmission project breaking ground Monday could support Wyoming nuclear, carbon capture


GILLETTE, Wyo. — PacifiCorp/Rocky Mountain Power will break ground on its 416-mile “Gateway South” transmission project that will cross through Wyoming, Colorado and Utah on Monday, June 27.

The project involves extending transmission lines from the Aelous Substation near Medicine Bow, Wyoming to the Clover Substation near Mona, Utah. Rocky Mountain Power also plans to begin work on a 75-mile transmission project connecting the Windstar Substation in eastern Wyoming to the Aelous Substation in August. Both transmission lines are expected to be in service in late 2024.

The Wyoming Public Service Commission and the Public Service Commission of Utah granted approval this spring needed for the transmission projects to proceed, according to Rocky Mountain Power. The projects are expected to improve reliability of the transmission network in Wyoming and will enable interconnection of more power generation resources to serve PacifiCorp/Rocky Mountain Power customers in six states, according to the company.

“Transmission additions allow the interconnection of the additional generation resources our customers will need in the coming years—including the evaluation of potential carbon-capture projects that Wyoming officials have requested; and pursuing advanced nuclear and energy storage with TerraPower, among other technologies in our diversified clean energy strategy,” Gary Hoogeveen, president and CEO of Rocky Mountain Power, said in a press release.

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PacifiCorp’s 2021 Integrated Resource Plan found generation capacity need would grow to over 6,600 megawatts by 2040.

“In 2025, the first full year that the transmission projects will be online, the capacity need is expected to be 1,627 megawatts,” the company’s press release said. “Over the current 20-year planning horizon, the resource portfolio that includes the Gateway South and Gateway West segments is $260 million lower in cost than the comparable portfolio without the projects.”

Wyoming Governor Mark Gordon, Wyoming’s U.S. Sen. John Barrasso and other state and local leaders will join the groundbreaking ceremony that will begin at 10 a.m. Monday one mile north of 1007 County Road 121 near Medicine Bow.