2024-11995. Twentymile Pumped Storage, LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting Comments, Motions To Intervene, and Competing Applications

On March 10, 2023, Twentymile Pumped Storage, LLC, filed an application for a preliminary permit, pursuant to section 4(f) of the Federal Power Act (FPA), proposing to study the feasibility of the Twentymile Pumped Storage Project to be located near the town of Oak Creek in Routt County, Colorado. The sole purpose of a preliminary permit, if issued, is to grant the permit holder priority to file a license application during the permit term. A preliminary permit does not authorize the permit holder to perform any land-disturbing activities or otherwise enter upon lands or waters owned by others without the owners' express permission.

The proposed project will have an above ground upper reservoir and an underground lower reservoir. A net hydraulic head of approximately 1,300 feet is expected between the maximum water level in the upper reservoir and minimum water level in the underground lower reservoir. Initial filling of the upper reservoir will use existing available water located currently in the mine. The existing sealed voids of tunnels and galleries at mine sites will become the lower reservoir. The upper surface reservoir will have a surface elevation of approximately 7,600 feet msl and will be connected to the lower reservoir via an underground water conveyance system-penstock, access shafts and tunnels, and ventilation shafts, with a new underground powerhouse containing reversible pump-turbine generator units. The single penstock would be 16 feet in diameter that bifurcates to two units in the powerhouse.

The approximate storage volume of the upper reservoir will be approximately 1,550 acre-feet. The lower reservoir would have a surface elevation of 6,000 feet msl with a storage volume of approximately 1,550 acre-feet. A new, approximately 1.8-mile long 230-kilovolt (kV) overhead interconnection line will extend from the powerhouse to a substation. The powerhouse would contain two turbines and generators, with a generating capacity of 250 megawatts (MW) based on available hydraulic head and water to fill the reservoirs. Each turbine is rated for 133 MW, and each generator is rated for 125 MW. The estimated average annual generation is 547,500 MWh.

Applicant Contact: Ushakar Jha, Twentymile Pumped Storage, LLC, 100 S Olive St., West Palm Beach, Florida 33401; email: [e-mail]; phone: [phone].

FERC Contact: Lee Baker; email: [e-mail]; phone: [phone].

Deadline for filing comments, motions to intervene, competing applications (without notices of intent), or notices of intent to file competing applications: 60 days from the issuance of this notice. Competing applications and notices of intent must meet the requirements of 18 CFR 4.36.

The Commission strongly encourages electronic filing. Please file comments, motions to intervene, notices of intent, and competing applications using the Commission's eFiling system at https://ferconline.ferc.gov/​eFiling.aspx. Commenters can submit brief comments up to 6,000 characters, without prior registration, using the eComment system at https://ferconline.ferc.gov/​QuickComment.aspx. You must include your name and contact information at the end of your comments. For assistance, please contact FERC Online Support. In lieu of electronic filing, you may submit a paper copy. Submissions sent via the U.S. Postal Service must be addressed to: Debbie-Anne A. Reese, Acting Secretary, Federal Energy Regulatory Commission, 888 First Street NE, Room 1A, Washington, DC 20426. Submissions sent via any other carrier must be addressed to: Debbie-Anne A. Reese, Acting Secretary, Federal Energy Regulatory Commission, 12225 Wilkins Avenue, Rockville, Maryland 20852. The first page of any filing should include docket number P-15305-000.

More information about this project, including a copy of the application, can be viewed or printed on the “eLibrary” link of the Commission's website at http://www.ferc.gov/​docs-filing/​elibrary.asp. Enter the docket number (P-15305) in the docket number field to access the document. For assistance, contact FERC Online Support.

Dated: May 24, 2024.

Debbie-Anne A. Reese,

Acting Secretary.