Why did Fort Smith lose power for seven hours?

A “critical issue” behind Fort Smith’s lengthy power outage last week is the ongoing absence of the Taltson hydro plant, the NWT Power Corporation says.

Some Fort Smith residents were without power for seven hours on Friday, January 3. The town opened an emergency warming centre before electricity eventually returned at around 9pm.

Ordinarily, Fort Smith receives its power from the nearby Taltson hydro plant. However, Taltson has been offline since May 2023 for renovation work that is now more than a year behind schedule, meaning diesel generators have powered Fort Smith for more than 18 months.

NWT Power Corporation spokesperson Doug Prendergast said reliance on those generators for so long was “likely” to have been a factor in last week’s power outage.

Prendergast said the generators had been overhauled ahead of work beginning at the Taltson plant, and extra diesel units had been brought in to help, but the units were still “working extra hard” in Taltson’s absence.

“We’ve spoken quite openly about the ageing infrastructure that a number of our communities are facing,” Prendergast said.

“Taltson is really the critical issue, even relating back to Friday’s outage. The best solution to the issues that contribute to that is to get Taltson back online, and we’re working very hard to make sure that happens in the next month or so.”

Why the power went down

In terms of what actually happened on Friday, Prendergast said there are still some uncertainties.

One of four feeder lines distributing power in Fort Smith experienced a fault that damaged one of the town’s generators, meaning the generator had to be taken offline, he said. That incident triggered the initial outage at around 1pm.

After that, Prendergast said a second “issue that we’re still not 100-percent sure of” caused trouble when NTPC tried to return power to its fourth feeder line.

“There were three generators running, and normally they work with one another to make sure the power is evenly spread throughout the community,” he said.

“We were able to get power back on feeder one, feeder two and feeder three relatively quickly – about half an hour or so – but whenever we tried to reconnect feeder four, which included the airport, parts of downtown and Fort Fitzgerald, the system just didn’t want to accept it.

“Through the rest of the day, we kept trying different things to get feeder four back on. That resulted in the secondary outage that went community-wide.”

On Monday, NTPC said some replacement parts were still needed to return all of Fort Smith’s generators to service. Those parts were said to be several days away. Even so, the power corporation said, the town’s power system had “remained stable through the weekend.”

NTPC asked customers to try to use less power when possible, while warmer weather this week was expected to help by reducing demand.

Prendergast said the power corporation plans to improve some of Fort Smith’s electrical infrastructure in the future.

In December, he said, NTPC met with local leaders and “laid out the current status of the electrical system in Fort Smith and area, and talked about our plans to upgrade things over the coming years.”

What happened at Taltson?

The Taltson hydro plant is about 60 years old. When operational, it provides renewable power to most of the South Slave. (The NWT government hopes it can also eventually provide extra power to Yellowknife and the North Slave.)

The refit that begin in May 2023 is designed to keep the plant running for another 40 to 60 years.

However, the work – originally planned to conclude in November 2023 – has been delayed ever since a wildfire tore through the site that summer.

Prendergast said a seven-week evacuation of the site pushed some of the work into the winter, slowing progress, and an “alignment issue” was subsequently discovered when work began to bring the plant back online. That ultimately led to workers dismantling the entire unit and putting it back together, a months-long process.

“We successfully disassembled the unit and reassembled it through the fall into the start of winter. We’re now about to begin what we call the dry commissioning – that’s making sure all of the parts are behaving as they should, without water flowing through the hydro facility,” said Prendergast.

“Once we are comfortable that’s in a good place, we will do wet commissioning, which means we start to allow water back into the hydro unit.

“At this point, we believe that whole commissioning process should be complete by around the end of January, early February, with the unit being back in full service in early February.”

NTPC recently said the project is now expected to cost almost $100 million, up from the $70 million or so initially budgeted.