A transmission corridor conceived in the 1980s finally reached notice to proceed. LS Power’s Great Basin Transmission broke ground September 3 in Ely, Nevada on the Southwest Intertie Project-North, a 285-mile, 500 kV line running from the Midpoint Substation near Twin Falls, Idaho to Robinson Summit near Ely. Investment is stated at more than $1 billion, with completion expected in 2028.
The last 285 miles of a 576-mile path
SWIP-North is the final segment. Once it’s energized the completed corridor runs 576 miles, from Idaho’s Magic Valley down to Nevada’s Eldorado Valley south of Las Vegas. More than 70% of the new route sits in Nevada. Construction actually began in summer 2026; September 3 was the ceremony.
The earlier phases are already in service: the 231-mile ON Line, built with NV Energy and energized in 2014, and the 60-mile DesertLink, in service since 2020. LS Power acquired development rights in 2005, which means this line took 21 years from acquisition to construction start on the last piece, and roughly four decades from concept.
At full path the system moves more than 2,000 MW bidirectionally, including 500 MW of northbound capacity dedicated to Idaho Power customers. Great Basin estimates about 300 construction jobs and more than $375 million in regional economic impact from construction activity, plus annual property tax revenue. Those are developer figures.
The cost allocation is the part other developers will copy
Capacity rights are shared among the California ISO, NV Energy and Idaho Power. Under the NV Energy agreement, NV Energy pays all ON Line costs and LS Power pays all SWIP-North costs, with both sharing capacity across the full path. LS Power then assigned its rights to CAISO and Idaho Power. CAISO selected Great Basin in 2023 to develop, permit, finance, build, own and operate the line; final cost recovery approval came in 2024 and Idaho Power’s participation was approved in 2025.
That structure, a private developer financing a line and assigning capacity rights to a grid operator and a vertically integrated utility, is the template merchant transmission developers have been trying to make bankable for a decade. It works here partly because the corridor already had two energized segments proving the path.
Two decades of permitting, and what that costs
The interesting number isn’t the billion dollars. It’s 21 years. Western load growth is transmission-constrained right now and every interconnection queue in the region reflects it, but the projects that relieve that constraint were started by people who are mostly retired.
Megaprojects that survive long enough to get built also absorb whatever happens in the intervening years, and that isn’t free. BHP’s Jansen potash mine in Saskatchewan was sanctioned in 2021 at US$5.7 billion and re-estimated in January 2026 at US$8.4 billion, a 47% increase on a fully engineered project in under five years. SWIP-North had four decades to accumulate that kind of drift and is only now exposed to construction-period escalation.
No EPC or construction contractor has been named in the release or in secondary coverage, which is worth watching. A 285-mile 500 kV line through Nevada high desert is a specialized bid list, and the ironworker manpower question is live: the Iron Workers named energy and infrastructure among their target markets at their convention the day before. Named at the groundbreaking were Paul Segal, Paul Thessen and Mark Milburn of LS Power, CAISO’s Elliot Mainzer, and Idaho Power’s Mitch Colburn. The announcement has the rest.