Hydroelectric Plants in Alaska
Operator: Homer Electric Association
Configuration: 2 X 63 MW Pelton
T/G supplier: Fuji
EPC: Stone & Webster, Enserch Corp, Losinger
Quick facts: Bradley Lake was constructed by the Alaska Power Authority on the Kenai Peninsula near Homer. The state legislature appropriated $168mn for what was initially estimated to be a $245mn project. The final cost was over $300mn. The project comprises a 610ft long, 125ft tall concrete-faced and rock-filled gravity dam, a 3.5mn power tunnel, and a steel-lined penstock. The project transmits power to the state’s main grid via two parallel 20mi transmission lines. Homer Electric Association operates the plan under contract with AEA . Bradley Lake serves Alaska’s Railbelt from Homer to Fairbanks as well as the Delta Junction area.
Photograph courtesy of Alaska Center for Energy and Power
Operator: Atka Utilities
Configuration: 1 X 238 kW crossflow
T/G supplier: Ossberger
EPC: Polar Consult, Marsh Creek LLC
Quick facts: This run-of-river minihydro replaces diesel-electric power for the village of Atka in the Aleutian Islands. The $5mn project has a small concrete dam and a 1,000ft HDPE penstock to the powerhouse. Construction of the powerhouse building and foundation and construction of the acess road to the powerhouse and the dam were completed in 2005 with funding from the Denali Commission and the RUS. The cross flow turbine for the project was purchased in 2005 through funding from Aleutian Pribilof Island Community Development Association (APICDA). Operation began on 23 Dec 2012 after 20+ years of planning and development.
Photograph courtesy of Polar Consult
Operator: Inside Passage Electric Cooperative Inc
Configuration: 1 X 455 kW crossflow
T/G supplier: Ossberger
Quick facts: This small storage project was licensed in Jan 2013. It supplies about 30% of Hoonah's electricity delivered via a 4.5mi transmission line. A 14ft tall, 54ft long concrete diversion dam was built on Gartina Creek creating a 17ac reservoir. Water passes through the intake chamber to the project penstock. The SHP went online in Aug 2015 and cost about $8.2mn
Photograph courtesy of www.alaskapublic.org
Operator: Cordova Electric Coop
Configuration: 2 X 500 kW Francis, 1 X 250 kW Turgo
T/G supplier: Dependable, Kato
EPC: J F White Contracting Co
Quick facts: The Humpback Creek SHP has a 35ft concrete diversion dam that ponds water at 174ft elevation and a 1,900ft pipeline to the powerhouse. A 17,000ft underground and submarine 12.5kV transmission line connects to a substation near Orca Adventure Lodge at the northern limit of the Cordova road system. In 2006, heavy floods wiped out transformers, power lines and disabled the plant. After a $21mn rebuilding effort, the plant was reactivated in Jun 2011.
Photograph courtesy of Cordova Electric Coop
Operator: Alaska Electric Light & Power
Configuration: 2 X 23.5 MW, 1 X 31 MW Francis
T/G supplier: MHI, GE, Dominion Bridge Sulzer, Siemens-Allis
Quick facts: Snettisham was the Corps of Engineers' first lake tap project nationwide and has the Corps' only underground powerhouse and one of the few Corps-built transmission lines in the country. The project supplies power to Juneau and was transferred to the Alaska Power Administration in 1997. APA subsequently turned the project over to the State of Alaska. The project's first phase tapped Long Lake, a high mountain perched lake for an underground power house with two turbines. The second phase tapped Crater Lake, another perched lake, and added a third turbine. The Snettisham project features include an 8,230ft power tunnel and a 1,400ft penstock tunnel to Long Lake, a 7,118ft power tunnel and a 1,540ft penstock tunnel to Crater Lake, and a 45mile transmission line. The scheme cost about $100mn.
Photograph courtesy of USACE
Operator: Ketchikan Public Utilities
Configuration: 2 X 11.3 MW Francis
T/G supplier: Litostroj, Siemens
EPC: R W Beck
Quick facts: The Swan Lake scheme includes a 174ft tall, 430ft long concrete arch dam 3/4 mile downstream from the mouth of the original Swan Lake, a 2,200ft, 11ft diameter power tunnel to the powerhouse, two 5.5ft diameter steel-lined penstocks, a 13.8/115-kV substation, and a 30.5mi, 115kV transmission line to the S W Bailey in Ketchikan. SEAPA is owned by the cities of Ketchikan, Petersburg, and Wrangell.
Photograph courtesy of Southeast Alaska Power Agency
Operator: Kodiak Electric Association Inc
Configuration: 3 X 11.25 MW Pelton
T/G supplier: Fuji, Andritz, Melco, Ideal
EPC: Ebasco, NAES
Quick facts: The Terror Lake HPP is adjacent to Kizhuyak River on Kodiak Island, 25mi southwest of the City of Kodiak. The project components include a 156ft high, 2,100ft log concrete-faced rockfill dam with 600ft spillway and a 5mi long, 10ft diameter power tunnel from an inlet 143ft below the nominal surface of the lake to the penstock. The steel-line penstock runs 3,400ft and varies from 56 to 96in in diameter. A 17mi private road was built between the barge landing site at the head of Kizhuyak Bay to the powerhouse. A 17mi , 138kV transmission line runs to a substation at the City of Kodiak. The project was initially constructed by the State of Alaska and cost $230mn. In addition to Kodiak, power is supplied to US Coast Guard Support Center, and the communities of Chiniak, Pasagshak, and Port Lions. In the original construction, provision was made for a third set and this was installed in 2013. Terror Lake was purchased by KEA in 2009 from the Southeast Alaska Power Agency.
Photograph courtesy of Kodiak Electric Association Inc
Operator: Southeast Alaska Power Agency
Configuration: 2 X 12 MW Pelton
T/G supplier: Sulzer, Meidensha
Quick facts: Tyee Lake project is in southeast Alaska 40mi southeast of Wrangell. Project components are Tyee Lake, a natural lake used as a storage reservoir, a lake-bottom tap, an 8,300ft power tunnel, a 54in, 1,350ft penstock and a powerhouse, switchyard and transmission system. The project transmission line was designed and built for 138kv but operates at 69Kv. It consists of 68mn of overhead line and 13mi of submarine cable connecting to substations in Wrangell and in Petersburg.
Photograph by Greg Knight and courtesy of www.wrangellsentinel.com
Data: industcards, Platts UDI World Electric Power Plants Data BaseUpdated 31-Oct-2015