First pumped-storage project planned for Wyoming, USA

RPlus Hydro has submitted a Draft Licence Application for the Seminoe pumped-storage project, near Raw­lins in the northwestern US state of Wyoming.

“The submission is a significant achievement in RPlus Hydro’s work to bring pumped storage to Wyoming and to contribute to the reliability of renewable energy sources that the state has to offer”, the developer announced on 6 June.

Seminoe would be Wyoming’s first pumped-storage project and will facilitate up to 900 MW of flexible, long-duration, generating capacity. With an estimated construction cost of approximately US$ 2.5 billion, this project represents a substantial investment in Wyoming’s clean energy infrastructure, the company ad­ded.

The project will create up to 500 high-skilled construction jobs over three to five years, and once operational will provide an estimated 35 full-time skilled positions and generate more than $10 million in additional annual tax revenue for state and local governments.

The submission of the Draft Licence Application to Wyoming and Federal agencies is part of a multi-year study and approval process, which includes detailed engineering designs, environmental assess­ments, and community eng­agement. After a 90-day review process, rPlus Hydro would then submit a final licence application to the Federal Energy Regulatory Com­mission (FERC).

Construction is expected to begin as early as 2025, pending timely issuance of FERC and other approvals, and would take approximately four years, the developer has said. Stantec was contracted by rPlus Hydro in October 2021 to conduct a detailed feasibility study for the project (see H&D Issue 6, 2021). The proposed project, which is designed as a closed-loop station, will make use of the existing Seminoe reservoir as the lower basin.

The Seminoe dam, on the North Platte river, is a multipurpose structure providing water for irrigation, power, and flood control. The 90 m-high concrete gravity arched dam impounds a reservoir with a total storage capacity of 1.25 ×109 m3. The project will entail the construction of an upper reservoir, underground tunnels and an underground powerhouse, an intake-outlet structure in the Seminoe reservoir, and a new transmission line. It is the second Draft Licence Application filed for a pumped-storage scheme by rPlus Hydro this year. In February it submitted an application for the 1000 MW White Pine project, located near Ely in the western US state of Nevada.