YELLOWTAIL POWERPLANT
Yellowtail Dam and Powerplant
| Plant Contact: | Dan Jewell |
| Telephone Numbers: | Phone: (406) 247-7325 Fax: (406) 247-7338 |
| E-Mail Address: | ttauscher@gp.usbr.gov |
| Reclamation Region: | Great Plains |
| NERC Region: | Western Electricity Coordinating Council, Rocky Mountain Power Area and Mid-Continent Area Power Pool |
| PMA Service Area: | Western Area Power Administration, Rocky Mountain Region and Upper Great Plains Region |
| Project Authorization: | Construction of the Yellowtail Unit, part of the Pick-Sloan Missouri Basin Project Eastern and Western Divisions, was authorized by the Flood Control Act of December 22, 1944, Public Law 534, which approved the general comprehensive plan set forth in Senate document 191, as revised by Senate Document 247, 78 th Congress. |
| Project Purposes: | The Yellowtail Unit is a multi-purpose project which provides low cost power generation and makes an important contribution to the flood control, irrigation, and power supply in the Missouri Basin . |
| Plant Purpose: | Yellowtail Powerplant, with an installed capacity of 250,000 kilowatts, provides low cost power and supplies expanding power needs for residential and commercial use in a wide surrounding area. The widely varying releases from the powerplant are regulated by the Yellowtail Afterbay Dam, constructed 2.2 miles downstream. The afterbay, with a capacity of 3140 acre-feet, minimizes downstream fluctuations in the Bighorn River by providing a uniform daily flow, leveling the peaking power discharges from the powerplant. |
| Plant Facts: | Yellowtail Powerplant is located at the downstream toe of the dam on the right abutment. Four 12-foot diameter penstocks embedded in the dam supply water to four 87,500 horsepower, vertical-shaft, Francis-type hydraulic turbines each driving a 62,500-kilowatt generator. Yellowtail’s annual power generation over the last 10-years has averaged 974,400,000 kilowatt-hours. Yellowtail Dam, at the mouth of Bighorn Canyon, is a concrete structure rising 525 feet above the rock foundation and impounds flows of the Bighorn River for multi-purpose use. Bighorn Lake is about 72 miles long with a total capacity of 1,328,360 acre feet. |
| Plant History: | Construction on Yellowtail Dam and Powerplant began in May 1961 and was completed in December 1967; construction of Yellowtail Afterbay Dam was started in April 1964 and was completed in November 1966. Operation of Units 3 and 4 began in August 1966, followed by Unit 2 in October 1966, and Unit 1 in November 1966. Units 1 and 2 (115-kV) are part of the Western Division of Pick-Sloan Missouri Basin Program, and Units 3 and 4 (230-kV) are part of the Eastern Division. |
| Present Activities: | FY-2004 activities included high-pressure air compressors and receiver tanks replacement; powerplant roof replacement; extensive cavitation weld repairs and coating of the upper portion of Units 3 and 4 draft tubes; spillway tunnel liner repairs; and spillway stilling basin de-watering, inspection, and cleaning. |
| Future Activities: | Major activities planned in the near future included generator brake air compressor replacement; draft tube and spillway stilling basin stoplogs refurbishment; afterbay control system upgrade; powerplant 480 Vac distribution center replacement; afterbay gate actuators replacement; powerplant and dam elevators modernization; powerplant station service standby engine-generator; spillway radial gate stoplog system addition; and conversion to narrowband radio system. |
| Special Issues: | The Bighorn River Basin experienced its fifth consecutive year of drought conditions, resulting in below average power generation in FY2000 through FY2004. Responsibilities, in addition to the 250,000-kilowatt powerplant, also include the operation and maintenance of two dams, two reservoirs, two switchyards, a Government camp and residential housing, two water and sewage systems, the Bighorn Canal headworks, and miles of road and fences. |
| River: | Bighorn River |
| Plant Type: | Conventional |
| Powerhouse Type: | Above Ground |
| Turbine Type: | Francis |
| Original Nameplate Capacity: | 250,000 kW |
| Installed Capacity: | 250,000 kW |
| Year of Initial Operation: | 1966 |
| Age: | 39 years |
| Net Generation: (FY 2005) |
510,564,280 kWh |
| Rated Design Head: | 440 feet |
| Plant Factor: (FY 2005) |
23.46 percent |
| Remotely Operated: | Yes |
| Production Mode: | Peaking |
Click here for graphs and charts of Yellowtail Powerplant performance.
Click here for information on the Yellowtail Dam.
Click here for information on the Pick-Sloan Missouri Basin Project - Yellowtail Unit.
Revised December 29, 2005 Hydropower Site Map Help