Great Basin Transmission, an affiliate of LS Power, is beginning construction on the Southwest Intertie Project-North (SWIP-North), a 285-mile, 500-kilovolt (kV) transmission line connecting the Midpoint Substation near Twin Falls, Idaho, with the Robinson Summit Substation near Ely, Nevada.

A groundbreaking ceremony was held on September 3 in Ely, Nevada, to mark the start of construction. The project represents an investment of more than $1 billion in transmission infrastructure and is intended to increase transmission capacity, reduce congestion and expand access to power resources across the Western grid.

LS Power CEO Paul Segal said, "Reliable power increasingly depends on our ability to move electricity across regions, and that requires major investment in transmission. SWIP-North will complete an important new pathway between the Pacific Northwest and the Desert Southwest, improving reliability and giving the Western grid greater flexibility. Projects of this scale take persistence, and we're proud to have spent more than two decades advancing this corridor to construction."

Background

SWIP-North is the final segment of the Southwest Intertie Project, a transmission corridor first conceived in the 1980s and advanced by LS Power since it acquired development rights in 2005. Once complete, the corridor will span 576 miles, connecting Idaho's Magic Valley near Twin Falls to Nevada's Eldorado Valley south of Las Vegas.

More than 70% of SWIP-North will be built in Nevada. The project will complete a high-voltage transmission corridor extending from southern Idaho to southern Nevada, building on two earlier phases developed by LS Power: the 231-mile One Nevada Transmission Line (ON Line), built in partnership with NV Energy and placed in service in 2014, and the 60-mile DesertLink line, placed in service in 2020.

Together, the transmission paths connect to the California Independent System Operator (California ISO) and provide a link between portions of the regional grid.

Nevada Governor Joe Lombardo said, "Construction of this last phase of the Southwest Intertie Project underscores Nevada's position as a strategic energy hub for the West. SWIP-North will provide benefits for Nevadans, including additional transmission capacity, new energy import and export opportunities, increased energy reliability for residents and businesses, and enhanced resiliency against extreme weather events and wildfires."

Project Details

Once SWIP-North is energized, the full transmission path will be capable of transmitting more than 2,000 megawatts (MW) of bidirectional electricity, equivalent to serving more than 1.5 million homes. The project will also include 500 MW of northbound capacity dedicated to Idaho Power customers.

LS Power President Paul Thessen said, "SWIP-North represents a unique cooperation between multiple regions, states and utilities — and a great example of innovation and collaboration between a private developer, LS Power; Western electric utilities, NV Energy and Idaho Power; and a regional grid operator, the California ISO, to balance cost allocation, capacity sharing and benefits."

The California ISO, NV Energy and Idaho Power will share capacity rights on the line. Under an agreement between NV Energy and LS Power affiliates, NV Energy covers the costs for ON Line, while LS Power covers the costs for SWIP-North. The two companies share capacity across the full transmission path. LS Power has assigned its capacity rights to the California ISO and Idaho Power.

California ISO President and CEO Elliot Mainzer said, "Major transmission investments like SWIP-North are essential to building a more reliable, resilient and efficient Western grid. By creating a stronger connection across the West, this line will give grid operators greater flexibility to move power where it is needed most, improve access to diverse energy resources, and enhance our ability to respond to changing system conditions and extreme weather events."

Idaho Power Vice President of Planning, Engineering and Construction Mitch Colburn said, "Keeping energy costs affordable for our customers is one of our top priorities. SWIP-North will help Idaho Power meet growing energy demands and reduce costs for our customers by connecting Idaho Power to the Desert Southwest's low-cost energy resources."

Timeline and Benefits

Construction on SWIP-North began in summer 2026 and is expected to be completed in 2028.

Great Basin Transmission was selected by the California ISO in 2023 to develop, permit, finance, construct, own, operate and maintain the SWIP-North Project. Final cost recovery approval was granted in 2024, and Idaho Power received approval to participate in the project in 2025.

LS Power Senior Vice President of Development Mark Milburn added, "Beyond the increased electrical capacity that the project will bring to the Western grid, SWIP-North will bring measurable economic benefits to Nevada and Idaho during construction and beyond. We estimate the project will add around 300 construction jobs, generate over $375 million in regional economic impact from construction-related activity and provide millions in property tax revenue each year to help fund essential local services."