The Federal Energy Regulatory Commission on Sept. 18 approved an April application from Clark Canyon Hydro LLC for a preliminary permit to study the feasibility of the proposed Clark Canyon Dam Hydroelectric Project, to be located at the U.S. Bureau of Reclamation’s Clark Canyon Dam on the Beaverhead River, near Dillon in Beaverhead County, Montana.
The proposed project would utilize the existing Clark Canyon Dam and would consist of these new facilities: a steel penstock within the existing concrete conduit, ending in a trifurcation; two penstocks extending from the trifurcation to the powerhouse; a penstock leaving the trifurcation and ending in a cone valve and reducer to control discharge into the existing outlet stilling basin; a reinforced concrete powerhouse containing two vertical Francis-type turbine/generator units rated for 2.35 MW each; two tailrace channels connecting the pump/turbine draft tubes with the existing spillway stilling basin; a 1,100-foot-long, 4.16-kV buried transmission line from the powerhouse to the substation; a substation containing step-up transformers and switchgear; and a 7.9-mile-long, 69-kV transmission line extending from the project substation to the Peterson Flat substation.
The estimated annual generation of the Clark Canyon Dam Project would be 15.4 gigawatt-hours.
Said the Sept. 18 FERC order: “A preliminary permit is issued for the Clark Canyon Dam Hydroelectric Project No. 14677 to Clark Canyon Hydro, LLC, for a period effective the first day of the month in which this permit is issued, and ending either 36 months from the effective date or on the date that a development application submitted by the permittee has been accepted for filing, whichever occurs first.” The company is expected to develop a license application during this 36-month permit period.