Tyee Lake Hydroelectric Project

In 2008, the agency's Tyee Lake provided 24,962 MWh of energy or 98% of all City of Wrangell resources.

The Tyee Lake Hydroelectric Project is located in southeast Alaska (approximately 40 miles southeast of the City of Wrangell) and consists primarily of:

1. Tyee Lake, a natural lake used as a storage reservoir with 15 square miles of catchment area, 52,400 acre feet of active storage, and a normal water surface elevation of 1396.0 feet; an 8,300 foot long tunnel; and a powerhouse, switchyard and transmission system.  There is no dam or spillway.  Water from the lake is conducted to the powerhouse through an opening near the lake bottom that connects to the tunnel.  There is a 54-inch diameter penstock that is 1,350 feet long connecting the tunnel to a manifold adjacent to the powerhouse.
    
2. A 122-foot x 38-foot multistory concrete building with two Sulzer Pelton wheel turbines rated 16,700 hp at 1306 foot head, and provision for a third turbine.  The generators are manufactured by Meidensha of Japan and are each rated at12.5 kVA, 13.8 kV, 3 phase.  Governors are manufactured by L&S Electric and are industrial PLCs.  The fenced switchyard has 2 main, 3 phase 138/69 kV, step-up transformers manufactured by Westinghouse that are each rated at 11,250 kVA.  The switchyard also contains three single phase, oil filled, circuit breakers.
    
3. The Tyee transmission line  (designed and built for 138 kV but energized at 69 kV), consists of 68.2 miles of the overhead line and 12.6 miles of submarine cable connecting the Project to the communities of City of Wrangell and Petersburg.  The transmission system includes substations in City of Wrangell and Petersburg.