Construction work began this month on the Utah terminal of the 732-mile TransWest Express transmission line, a project designed to carry Wyoming wind energy to the Southwest. 

Civil construction work on the project’s Wyoming terminus started in 2023 and is largely completed, project developers said in a progress report. 

Preparation work is under way on the 100-acre project terminal site in Millard County, Utah, where TransWest Express will connect with the Intermountain Power Agency system. Construction work also is planned this year along the transmission route in Juab and Wasatch counties, Utah; Moffat County, Colo.; and Carbon County, Wyo. 

TransWest Express will consist of a 3,000-MW direct current (DC) segment running from Sinclair, Wyo., to Delta, Utah, where it will be extended with a 1,500-MW alternating current (AC) segment that will run to southern Nevada. Construction is expected to be completed in 2029, according to the TransWest website. 

CAISO Connection

Last month, the Public Utilities Commission of Nevada (PUCN) approved a construction permit for an approximately 1.55-mile, 500-kV transmission line and related facilities to connect TransWest Express to the existing Harry Allen-to-Eldorado (HAE) transmission line, also known as DesertLink. 

LS Power’s DesertLink line, energized in 2020, links NV Energy’s Harry Allen substation with Southern California Edison’s Eldorado substation to the south, which is part of the CAISO system. 

The TransWest to DesertLink interconnection will allow “delivery of wind energy to [CAISO] on the existing HAE transmission line, while enhancing the reliability of the Western Interconnection power grid,” TransWest Express representatives said in a filing with the PUCN. 

Although PUCN approved the TransWest to HAE construction permit, that work will not start in 2025, TransWest Express spokesperson Kara Choquette told RTO Insider. 

In addition to TransWest interconnections with Intermountain Power and CAISO, interconnections are planned with the PacifiCorp system in Wyoming and the NV Energy system in Nevada. 

TransWest Express is a wholly owned subsidiary of Wyoming Renewable Resources, which is a wholly owned subsidiary of The Anschutz Corp., a privately held company, according to TransWest’s filing with the PUCN. 

TransWest Express will transmit wind energy generated by its affiliate, Power Company of Wyoming, to utilities and other wholesale purchasers serving the Desert Southwest, the filing said. TransWest Express said those areas include Arizona, Nevada and Southern California. 

About two-thirds of the project is on federal land, mainly areas administered by the Bureau of Land Management. Federal agencies have issued the needed right-of-way grants and notices to proceed, TransWest said. 

TransWest Express may be among the first transmission facilities to join CAISO under the ISO’s subscriber participating transmission owner (PTO) program, which is open to developers of certain transmission projects not chosen in CAISO’s transmission planning process. (See CAISO Wins FERC Approval for Subscriber-funded Tx Plan.) 

Under the program, the developer can solicit generation-owning customers to subscribe to service on a line designed to deliver energy into California. The project owner then can turn operational authority of the line over to CAISO but won’t be eligible to recover costs through the ISO’s transmission access charge.