Tyee Lake Hydroelectric Project

 

The Tyee Lake Hydroelectric Project (Project) is located on Tyee Lake and at the head of Bradfield Canal, approximately 40 miles southeast of the community of Wrangell, 70 air miles southeast of Petersburg, and 60 miles northeast of Ketchikan, Alaska. The Project occupies state lands surrounded by the Tongass National Forest.

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Power is transmitted from the powerhouse along transmission lines to Petersburg, Wrangell, and Ketchikan, Alaska. The Project provides power to Wrangell Municipal Light and Power and Petersburg Municipal Power and Light. The Tyee Lake Project contributes approximately 105,800 MWh of electricity annually to the region.

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The Tyee Lake Project features consist of a spillway weir, lake tap intake, power tunnel, penstock, powerhouse, switchyard, and appurtenant structures. The Tyee Lake Project does not include a dam but diverts water to the powerhouse from the naturally impounded Tyee Lake through a lake tap intake. The reservoir is managed between normal pool elevation 1,396 feet mean sea level (msl) and minimum operating pool elevation 1,250 feet msl.

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Water is conducted to the powerhouse through an intake from the lake into a drop shaft, through an 8,300-foot-long unlined power tunnel and a 1,350-foot-long steel penstock, which houses two Pelton-type horizontal-axis generating turbine units. The powerhouse is a reinforced concrete structure located near Bradford Canal; it is 38-feet wide by 122-feet long.

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