The U.S. Department of Energy on Jan 11 issued a Finding of No Significant Impact (FONSI) related to a Helena Valley Irrigation District request to the U.S. Bureau of Reclamation to develop the 9.4-MW Sleeping Giant Hydroelectric Project at the existing Helena Valley Pumping Plant site at the Canyon Ferry Dam on the Missouri River near Helena, Montana.
The district has submitted an interconnection request to DOE’s Western Area Power Administration to connect the project to Western’s existing Canyon Ferry-to-Spokane Bench 100-kV transmission line originating at the Canyon Ferry Dam.
Westem’s Upper Great Plains Region is a member of the Southwest Power Pool (SPP) and is subject to the SPP Open Access Transmission Tariff, which is filed with the Federal Energy Regulatory Commission. The SPP Tariff provides for new interconnections to Western’s transmission system by all eligible entities, consistent with and subject to environmental review under the National Environmental Policy Act and other environmental regulations.
Reclamation, with Western participating as a cooperating agency, prepared an environmental assessment (EA) on the project. The final EA is dated November 2015. Westem’s proposed federal action is: to execute an interconnection agreement to connect the proposed project to its system; and to construct and operate a new interconnection tap to which the project would connect.
Westem’s federal action does not include the district’s proposed hydro project itself, which would be constructed, owned, operated, and maintained by the district and is subject to a Lease of Power Privilege (LOPP) between the district and Reclamation as well as Montana’s statewide water appropriator approval. However, the EA analyzed and disclosed the potential environmental impacts of the district’s proposed project including the potential location for the project substation, access roads, and underground and overhead distribution lines. The EA identified no significant impacts to environmental resources resulting from either Western’s federal action or the district’s proposed project.
Western said that preparation of an environmental impact statement is not required and so Western is issuing this finding of no significant impact (FONSl). The final EA is adopted and approved concurrently with this FONSI.
The proposed project would enclose two 4.7-MW variable speed generators directly coupled to the existing turbine runner within the existing steel frame of the Pumping Plant. Proposed operation of the generators would use river flows that otherwise would have been released through the river outlet or spillway gates.
A power line to carry the produced electricity would run underground 850 feet to the northwest adjacent to the service road, and then daylight to cross the river in a 570-foot span. On the east side of the river, a project substation approximately 0.34 acres in size would step the voltage up to 100 kV for injection into Western’s transmission system.