The Federal Energy Regulatory Commission on June 8 approved a November 2015 application from the Pyramid Lake Paiute Tribe for a preliminary permit to study the feasibility of the Boca Hydroelectric Project, to be located on the Boca Dam and Reservoir on the Little Truckee River near the town of Truckee in Nevada County, California.
The proposed project would be located entirely on federal land administered by the U.S. Bureau of Reclamation. The project would be located at the existing discharge channel on the downstream side of Boca Dam. It would utilize the existing intake structure in Boca Reservoir and the existing outlet structure of the dam, including two 375-foot-long, 50-inch-diameter steel outlet pipes connecting to two 42-inch-diameter hollow jet valves.
Currently, an existing concrete channel receives the discharge flow from the hollow jet valves and directs it downstream. Under the Tribe’s proposal, the outlet pipes would be modified to remove the hollow jet valves and to add bifurcations that would connect to the proposed new penstocks.
The project would also consist of these new facilities:
- two new penstocks that would use isolation valves to connect the outlet pipes to a new 60-inch-diameter penstock to allow flow to be conveyed to the powerhouse from either or both outlet pipes;
- a 45-foot-long by 45-foot-wide by 40-foot-high powerhouse containing a single Kaplan generating unit rated for 1.6 MW at 60 feet of head;
- a 20 to 40-foot-long tailrace channel that discharges water downstream of the existing outlet channel walls approximately 140 feet from the existing hollow jet valves;
- a channel training wall consisting of either a sheet pile tied-back channel wall or a concrete cantilever-type wall leaving the powerhouse on the landside of the tailrace channel;
- a step-up transformer installed at the powerhouse generator in order to wheel power onto the grid; and
- a new 700-foot-long 12-kV transmission line to interconnect to an existing 12-kV transmission line owned by Liberty Utilities.
The Tribe proposes to develop the proposed project in conformance with the operation of Boca Dam by Reclamation under the terms of the Truckee River Operating Agreement (TROA) and would generate electricity using the existing flow releases under the terms of the TROA. The estimated annual generation of the Boca Hydroelectric Project would be 3.5 gigawatt-hours.
During the course of the permit, the commission expects that the permittee will carry out prefiling consultation and study development leading to the possible development of a license application.