THEBACHA/FORT SMITH - The Taltson River hydroelectric plant is back in service after being out of commission for 54 days.

Power began to flow once again on Oct. 31.

The Taltson River hydroelectric plant resumed generating electricity on Oct. 31. - photo courtesy of Deze Energy Corporation

The prolonged outage began on Sept. 9 as an annual scheduled maintenance shutdown.

However, during startup testing on Sept. 18, inordinately high bearing temperatures were recorded and a turbine was shut down.

It was determined the thrust bearing at the head of the turbine had failed, rendering the unit inoperable.

A back-up bearing was installed to bring the unit back into service.

While the repairs were being made, the five South Slave communities served by Taltson - Fort Smith, Hay River, the Hay River Reserve, Fort Resolution and Enterprise - were switched to diesel generation.

Mike Bradshaw, director of communications with the NWT Power Corporation, said it is uncertain how much the repair work cost.

"We don't know yet," he said. "We'll have to wait and get invoices from contractors and the like."

However, he estimated the cost of running diesel generators in Fort Smith and Fort Resolution during the Taltson outage at about $500,000.

Some of the expenses will be recovered by insurance and the rest from a reserve fund for such incidents.

Bradshaw said there will be no impact on consumers' bills.

As for why it took as long as it did to make repairs, Bradshaw said it was a large and complex project.

"You have to dismantle the entire hydro generator," he said, adding the work required special scaffolding, equipment and skills.

Bradshaw said people were working on the repairs every day, including weekends.

The 18-megawatt hydro plant is located 64 km north of Fort Smith on the Taltson River.

The diesel generation for Hay River, the Hay River Reserve and Enterprise was the responsibility of Northland Utilities (NWT) Ltd., which distributes Taltson power in those communities.

"It did have a profound impact on Northland Utilities," said manager Duane Morgan about the Taltson outage.

Morgan said Northland is still determining the cost of diesel, labour and maintenance of the generators during the outage.

Over the 54 days, he said Northland burned about $840,000 worth of diesel.

During the outage, Northland Utilities' main 2.5-megawatt generator in Hay River also failed on Sept. 28, causing rotating blackouts over three days.

Northland was required to bring in a mobile generator from Edmonton - at a cost of about $75,000 just for transportation - to supplement the smaller generators in Hay River.

Morgan said the costs will be covered by a reserve fund and Northland will also be making an insurance claim.

The company will not make an extraordinary application to the Public Utilities Board (PUB) to help recover costs.

However, Morgan said the costs will be included in future submissions to the PUB, which will take them and all other expenses into account when setting rates.

The only other major problem in a community during the Taltson outage was a seven-hour outage in Fort Resolution on Oct. 19.

That outage was caused by a mechanical fault in the community's diesel generator.