Electric vehicles might soon appear in one of Minnesota’s unlikeliest of places.
The won’t be fancy Teslas or compact cars like the Chevy Volt or Nissan Leaf.
They’ll be trucks — big trucks. Big trucks that carry big rocks.
Deep in the open pit mines of Minnesota's Iron Range, chunks of taconite are loaded into trucks as big as a house. Each one holds up to 240 tons of rock — about 25 times the capacity of a typical dump truck.
Those enormous trucks then carry the ore to a train that hauls it away, or directly to a processing plant.
Those trucks burn a lot of diesel.
So Minnesota Power, a utility company based in Duluth, is pitching a pilot project to study the economics of electrifying some of those huge vehicles. And they're asking the state for approval to try it.
The trucks wouldn't use rechargeable batteries, like the ones in small electric cars.
"What we're looking at is adding some infrastructure in the mine that would allow electricity from the grid to be able to power the truck instead of diesel as it comes out of the mine," said Frank Frederickson, the company’s vice president of customer experience.
Frederickson says battery technology isn't yet advanced enough to power such heavy trucks for long periods of time.
"So the technology that the manufacturers have developed is similar to a trolley system of the past, where there's actually a distribution wire system put in the mine,” Frederickson said. “And the truck has a mechanism that engages the wires of that trolley system as it emerges from the mine."
Electric trolley systems have been used in some mines for decades, mainly in Africa. But recently there's been a surge in interest around the world as mining companies look to reduce their greenhouse gas emissions.
Joe Shoemaker is with the large mining truck manufacturer Komatsu, which wrote a letter of support for Minnesota Power's proposal.
"Due to the focus on emissions today, we've seen an increase in inquiries. There are lots of different mines starting to study it."
Komatsu is working with companies in Canada and Europe on developing new fleets of electric trolley trucks. A copper mine in Sweden that piloted the technology cut its diesel fuel consumption by 20 to 50 percent.
Shoemaker says trucks on trolley lines also run much more quietly, and can operate at double the speed of diesel trucks, which increases a mine’s efficiency.
"It's pretty amazing to see the change when they do move to a trolley line, they just kind of take off, which is pretty neat to watch."
Later this year, Minnesota Power anticipates producing fifty percent of its electricity from renewable sources, mainly from wind. About two thirds of that power is consumed by paper mills and mines in northern Minnesota. Minnesota Power's Frederickson says electrifying heavy industry could benefit the climate, and in the long run, maybe save the mines some money.
"We truly believe it is a win-win, where we can help find a way where not only could we reduce operating costs for the customer, but we could also reduce the environmental impact."
Minnesota Power is currently working to identify which taconite mine in northeastern Minnesota would make the best site for a pilot project.
In a letter of support to state regulators, Chad Asgaard, general manager of United Taconite in Forbes and Eveleth, one of two taconite mines operated in the region by Cleveland-Cliffs, said a mine truck electrification project has “the potential for further operational efficiencies, and added reductions in fossil fuel consumption and greenhouse gas emissions.”
But a spokesperson for Cleveland-Cliffs cautioned that the company has only agreed to evaluate the proposal.
Minnesota Power hopes to file a plan with state regulators next year. The utility said a potential program could include financial support for the replacement or retrofitting of an existing truck fleet, as well as the installation of trolley infrastructure at a mine site.
If it proves cost effective, the goal is to implement it more widely across the Iron Range.