Diavik mine’s wind-driven power saves $5 million a year in diesel costs

Chris Bertoli, superintendent of electrical and instrumentation for the Diavik diamond mine, chats with a delegate at the Nunavut Mining Symposium in Iqaluit, April 10, where he described the success of the mine’s wind turbine power-generation project. (PHOTO BY PETER VARGA)

Diavik Diamond Mines’ wind turbines tower over the landscape at the Lac des Gras mine site in the Northwest Territories, to a height of 100 metres. Four of these turbines have cut back the mine’s reliance on diesel fuel by 10 per cent. (PHOTO COURTESY OF THE DIAVIK DIAMOND MINE)

Powering an Arctic mine on anything other than diesel fuel — flown or shipped in via supply lines thousands of kilometres long — once seemed unthinkable, but Diavik Diamond Mines recently proved it can be done.

Diavik’s diamond mine on Lac des Gras in the Northwest Territories, near the Nunavut border, found its answer locally, by tapping into the strong winds blowing right over the mine site.

Located some 300 kilometres northeast of Yellowknife and about 400 kilometres southeast of Kugluktuk, the Diavik diamond mine takes up about 10 square kilometres of land, just above the tree line.

Diavik’s installation of four wind turbines on the site has cut down the mine’s consumption of diesel by almost 10 per cent.

It now consumes about four million fewer litres of diesel fuel per year than it did in 2012, just before the company installed the turbines.

That amounts to more than $5 million per year in savings, says Chris Bertoli, electrical and instrumentation superintendent for Diavik.

“There were a lot of naysayers,” he told an audience at the Nunavut Mining Symposium in Iqaluit, April 10. “Back in 2012, I was a naysayer.”

There were other naysayers in 2012.

The mining symposium that year featured a talk from Peter Mackey, then president and CEO of Qulliq Energy, who said Qulliq favoured hydroelectric power over wind.

Mackey said the technology is finicky in cold weather, that it would require repair and maintenance from specialized technicians and that pilot projects in Kugluktuk, Cambridge Bay and Rankin Inlet were unsustainable.

But at least some of those obstacles seem to have been overcome at Diavik.

Installation costs at Diavik amounted to $31 million, a full million under budget.

Purchased from German wind turbine manufacturer Enercon, the four turbines experienced some complications from extreme temperatures in the winter of 2013, Bertoli said, but his doubts receded once the troubles were fixed. The equipment is set to provide power for the mine’s full lifespan, through to 2023.

“In 2013, definitely, after the fixes, I’m on board with what the wind can provide,” he said.

“This demonstrates that wind is a better overall option for the North.”

South Baffin’s near-persistent wind seems to make it an ideal place to take on wind turbine power-generation.

“I hope that communities will take our success, and run with it,” Bertoli told his audience. “When I stepped off the plane here in Iqaluit, I could see this is definitely a place that could use wind.”

Gusts in the territorial capital topped 50 kilometres per hour during the week of the mining symposium. That speed is about as fast as winds blow at Diavik.

The mine’s four turbines typically turn to winds averaging about 25 kilometres per hour, Bertoli said, and have been powered by speeds as high as 54 kilometres an hour.

Before 2013, Diavik mine relied completely on diesel fuel for power, amounting to about 40 million litres per year.

Fuel is trucked in via a 550-km ice road, which is only open eight weeks of the year, in late-winter. Diavik and two other diamond-mining companies, also in operation above the tree line northwest of Yellowknife, run the ice road as a joint venture.

Success of the ice road trucking season depends on the weather, and climate change has caused a high level of risk, Bertoli said.

“We had a large scare in 2006,” he said, recalling the shortest trucking season in the mine’s 11 years of operation.

“We had to fly in fuel, which was a high cost. We definitely need something to offset the fuel prices. So wind was our option.”

Diavik had considered tapping into hydro power, solar and geothermal energy, Bertoli said, but none proved to be profitable.

A three-year feasibility study proved the mine site had a strong wind source. The four turbines went up quickly in the summer of 2012, after all material had been shipped up the ice road that winter.

Customized trailers carried 60 loads of material to the site, including 33-metre-long turbine blades, which Diavik touted as “the longest loads ever hauled up the road.”

The four turbines are located at the site of the mine, which includes open-pit and underground operations. Each can produce 2.3 megawatts of power, for a combined total of 9.2 megawatts.

This supplies up to 10 per cent of the mine’s power needs per year, Bertoli said. This represents about 1.9 gigawatt hours of power out of the total 17.3 gigawatt hours needed to run the mine each year.

“If the wind’s there, then we’ll capitalize on it,” he said. “We’re getting what we paid for.”

In fact, results have been better than expected. Bertoli said Diavik is on track towards paying off its investment within eight years.

“I envision it could be even in six years that we pay it off,” he said. “It all depends on mother nature.”

Diavik has decommissioned two of its four diesel fuel tanks since the turbines proved themselves — down to a capacity of 80 million litres from 120 million in 2012.