Great Basin Transmission, broke ground on Sept. 3, 2026, in Ely, Nev., on the Southwest Intertie Project-North (SWIP-North), a new 285-mi., 500 kilovolt (kV) transmission line connecting the Midpoint Substation near Twin Falls, Idaho, with the Robinson Summit Substation near Ely.
The project represents a $1 billion-plus investment in power infrastructure that will help strengthen grid reliability, reduce congestion and expand access to diverse power supply resources across the West.
“Reliable power increasingly depends on our ability to move electricity across regions, and that requires major investment in transmission,” LS Power CEO Paul Segal said. “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.”
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 mi., connecting Idaho's Magic Valley near Twin Falls to Nevada's Eldorado Valley south of Las Vegas.
More than 70 percent of SWIP-North will be built in Nevada. Once in service, it will complete a high-voltage transmission corridor stretching from southern Idaho to southern Nevada, building on two earlier phases developed by LS Power: the 231-mi. One Nevada Transmission Line (ON Line), built in partnership with NV Energy and placed in service in 2014, and the 60-mi. DesertLink line, placed in service in 2020.
Together, these transmission paths create a critical link in the regional grid and enhance reliability through their connection to the California Independent System Operator (California ISO).
“Construction of this last phase of the Southwest Intertie Project underscores Nevada's position as a strategic energy hub for the West,” Nevada Gov. Joe Lombardo said. “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.”
Once SWIP-North is energized, the full transmission path will be capable of transmitting more than 2,000 megawatts (MW) of bidirectional electricity — the equivalent of serving more than 1.5 million homes — across the regional grid, including 500 MW of northbound capacity dedicated for Idaho Power customers.
“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,” LS Power President Paul Thessen said.
Specifically, the California ISO, NV Energy and Idaho Power will all share capacity rights on the line. This stems from an agreement between NV Energy and LS Power affiliates whereby NV Energy covers all costs for ON Line; LS Power covers all costs for SWIP-North; and both share capacity across the full path. LS Power has assigned its capacity rights to the California ISO and Idaho Power.
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, with final cost recovery approval in 2024. Idaho Power obtained approval for participation in the project in 2025.
LS Power Senior Vice President of Development Mark Milburn said the project will add approximately 300 construction jobs, generate more than $375 million in regional economic impact from construction-related activity and provide millions in property tax revenue annually. â£
