The Federal Energy Regulatory Commission on Aug. 1 issued an original license to the Copper Valley Electric Association for a 6.5-MW hydroelectric project in Alaska.
In August 2011, Copper Valley had filed an application for an original license to construct, operate, and maintain the proposed Allison Creek Hydroelectric Project No. 13124. The 6.5-MW project will be located on Allison Creek near the city of Valdez, Alaska. The project will not occupy any federal lands.
Allison Creek basin is located within the coastal Chugach Mountain Range, which intercepts moisture from the Gulf of Alaska and hosts numerous glaciers as a result of heavy, wet snows. The basin is about 6 miles in length and up to around 1.4 miles wide, and includes Allison Lake which is the headwater of Allison Creek.
The project will consist of the following new features:
- a 16-foot-high, 130-foot-wide diversion structure with an integrated spillway located about 1.9 miles upstream of the mouth of Allison Creek and 2,350 feet downstream from the outlet of Allison Lake;
- a Coanda screened intake at the spillway conveying flows to the powerhouse;
- a 42-inch-diameter, 500-foot-long buried and 7,200-foot-long above-ground steel penstock traversing the existing grade;
- a powerhouse containing two Pelton-type, horizontal access turbine generator units with a total installed capacity of 6.5 MW;
- a 120-foot-long tailrace extending from the west side of the powerhouse to Allison Creek via a concrete channel and the existing creek bed;
- a 550-foot-long access road; and
- a 3.8-mile-long, 34.5-kV transmission line interconnecting to an existing substation.
The project will be operated in a run-of-river mode and bypass about 7,500 feet of Allison Creek. The project would have a minimum and maximum hydraulic capacity of 4 cubic feet per second (cfs) and 80 cfs, respectively. All flows greater than the maximum hydraulic capacity will spill over the spillway section. Minimum flow releases will be made at the diversion dam. The estimated annual generation for the project is 23,300 megawatt-hours (MWh).