The Taltson hydro dam is seen in a GNWT inspection photo in May 2022.
The Taltson hydro plant will spend six months offline for refurbishment this year, moving South Slave communities to diesel power between April and October.
The NWT Power Corporation said the work has to happen as parts of Taltson, originally built in 1965 and serving the entire South Slave since 1986, have reached the end of their useful lives.
Electricity in Hay River, the Kátł’odeeche First Nation, Fort Smith, Fort Resolution and Enterprise will come from diesel while the work is carried out.
The expected impact on emissions – an area in which the NWT government is already struggling to reach its posted target – is not clear.
Work to overhaul Taltson should have started earlier but was delayed by Covid-19, the GNWT has previously said.
While no figure for the work was given in a news release last week, the power corporation said in February 2022 regulatory documents that the expected cost is $67 million. Of that, $17.8 million was said to be coming from the federal government and an estimated $48.7 million would be at “cost to rate base,” another term for customers.
Those figures don’t include the cost of generating diesel to replace Taltson while the hydro plant is out of action. In the same documents, NTPC provided figures that suggest the diesel bill will run to more than $6 million.
NTPC said rates would remain the same during the shutdown but suggested an increase could be felt later, stating: “The long-term impact of the overhaul on rates will not be known until NTPC submits its next general rate application to the NWT Public Utilities Board.”
The power corporation has argued in regulatory filings that while rates may have to go up to pay for the overhaul, that’s still cheaper than the same South Slave communities having to cover diesel worth more than $12 million a year if Taltson is “run to failure.”
NTPC also hopes new industrial clients can be found to offset some or all of the cost. In recent months, the power corporation has explored the possibility of providing power to the Pine Point zinc-lead mine if it reopens – an outcome that appears a step closer after the mine secured $100 million in financing last week, though is still years off at best.
Taltson was built in 1965 to power the original Pine Point, with Fort Smith and Fort Resolution also hooked up at roughly the same time. When the mine closed in the 1980s, transmission lines were built that connected Taltson’s 18-megawatt plant to Hay River and other communities instead.
Now, NTPC says, “the turbine and generator as well as other key components have reached their end-of-life and must be replaced.”
“Refurbishment of the Taltson unit will help ensure that electricity customers have access to renewable and reliable hydro power for the next 50 years,” the power corporation concluded.
The overhaul planned this year is not the same as the Taltson hydro expansion, a much more costly and ambitious project that would significantly expand the plant and connect it to the North Slave.
That project, likely to cost more than a billion dollars, remains without significant federal funding, though the federal infrastructure minister says talks are still advancing.