Canada's remote Northwest Territories Taltson River Twin Gorges hydropower generator has been shut down due to premature failure of the turbine's rotor thrust bearing.

The bearing failure was detected by an out-of-bounds temperature condition detected during September's annual maintenance shutdown and inspection.

Taltson spillway

Although the Northeast Territories Power Corporation (NTPC; 5251R9N7) keeps a replacement thrust bearing available, it is being retested and reinspected prior to installation.

Disassembling the turbine, replacing the bearing and reinstalling the turbine is precision work, requiring equipment which must be flown in to the remote location. Similar repairs normally take 10 to 14 days; however, the turbine has been shut down for over a month and repairs may still drag on for another two or three weeks.

While the Taltson plant is down, businesses and communities served by it -- Hay River, Fort Smith, Fort Resolution and Fort Fitzgerald -- are relying on backup diesel power generators.

Built in 1966, Taltson has been operating at only 10MW of its 18MW capacity since the primary mine it was designed to serve -- the Pine Point lead-zinc mine -- closed in 1987. A project is underway, however, to add another 40MW generator to the Twin Gorges site. Adding power lines, this would allow four additional diamond mines to switch over to hydropower from their current diesel generators, potentially eliminating the environmental impact of the 100 million liters of diesel fuel trucked to and burned every year in their generators.