A file photo of the NTPC's Snare Falls hydro facility.
An ongoing drought in the NWT has left hydro facilities with unusually low water levels for generating electricity, according to the territory’s power corporation.
“The volume of water available for hydro is as low as it’s ever been,” said Doug Prendergast, a spokesperson for the NWT Power Corporation, or NTPC.
Although low water events typically happen every eight to 10 years, Prendergast said the current state of affairs “appears to be about as dire a situation as we’ve seen, at least according to our records.”
The territory has experienced unrelenting dry conditions since the summer and fall of 2022, scientists at the territorial government said this month. Several lakes and rivers – including Great Slave Lake, portions of the Mackenzie River and the Snare River – are now at record-low water levels for this time of year.
That means less water is available at hydroelectric power stations to produce electricity.
Prendergast said the situation at hydro facilities might not look all that different to a non-expert, but less water is flowing through the systems and it’s moving at a slower pace, which has implications for power output.
“You need certain flow volumes in order for those hydro units to operate at their maximum efficiency,” he said.
With low water levels, the power corporation is not able to produce as much hydroelectricity as it normally would, as the CBC reported earlier this summer.
Usually, hydro facilities supply Yellowknife, Behchokǫ̀ and Dettah with most of their electricity. Over the course of a typical year, roughly 95 to 98 percent of electricity in the North Slave comes from hydro.
This year, that contribution has dropped closer to 45 to 55 percent, according to Prendergast, with diesel generation making up the rest.
The electricity North Slave residents are currently using adheres to this mix, with roughly half coming from hydro and half from diesel.
Other than during the recent wildfire-triggered evacuations, when electricity demand dropped, Prendergast said the breakdown of power sources has remained roughly consistent since July.
NTPC’s struggles with low water levels go back further than that, however. As NNSL reported in July, diesel generators at the Jackfish power plant in Yellowknife have been running since the summer of 2022.
“We’ve had to run diesel consistently for months,” Prendergast said.
Residents of the South Slave are currently relying on diesel, too, as the Taltson hydro dam has been offline since May for scheduled refurbishment work. The dam usually supplies electricity to Fort Smith, Hay River, the Kátł’odeeche First Nation, Fort Resolution and Enterprise.
In a typical year, hydro supplies about 75 percent of electricity territory-wide, Prendergast said.
Although he didn’t have the figures for this year, he said hydro’s contribution in 2023 will be considerably lower.
Hydro expected to dip even lower this winter
Heading into the winter, forecasts suggest there is little relief in sight.
Prendergast said low water levels are projected to continue into next year and further declines in hydro generation are expected this winter.
Prendergast explained that hydro facilities have reservoirs, where water is stored and released as needed when water levels are low. But with continued dry conditions, water in the reservoirs hasn’t been replenished over the course of the year, he said. After freeze-up, operators will only have access to whatever was stored up to that point, in addition to natural streamflow.
It’s too soon to tell the extent to which hydro generation will drop this winter, Prendergast said, adding that rain in the coming fall could lessen the scale of the problem.
Nonetheless, more electricity coming from diesel means increased greenhouse gas emissions and higher costs to produce electricity.
Asked if electricity rates are expected to increase as a result of heightened diesel generation, Prendergast said: “We’re looking at a number of different options, working with our board of directors, working with the Government of the Northwest Territories.”