Controversial Alberta coal mine could soon get green energy makeover

It’s an energy source that helped open the west. But coal mining has left scars on the Alberta landscape: abandoned mines and open pits where energy producers are now prospecting something new.

“Sites like this don’t really exist in a lot of places,” said Blain van Melle, the executive vice president of Alberta business at TransAlta.

“This is really unique. We like to refer to it as a unicorn.”

Metallurgical coal was discovered at Tent Mountain in the early 1900s. Small-scale mining made way for the first open cut pit in 1948.

But operations were suspended in 1983 and coal policy changes in 2021 led owners to rethink the mountain’s potential.

Enter TransAlta. The company was once Canada’s premier provider of coal-fired electricity. Now, it’s partnering with Australian company Montem Resources in a project to turn Tent Mountain’s historic mining operation — and its water-filled mining pits — into a new stream of renewable energy.

“The sheer volume of potential storage that is sitting in that water and the cost to run the pumped hydro facility compared to other facilities, the capital outlay that will need to go into the project up front… is really unique,” said van Melle.

“On a list of pumped hydro projects that you could find around the world, this one ranks near the top.”

Pumped hydro electric storage works a little like a rechargeable battery. When energy demand is low, excess wind and solar power is used to pump water from a lower reservoir and store it in an upper reservoir. When energy demand is high, the system is reversed and gravity does the work. The water then flows through turbines to generate power.

“When you have a lot of wind blowing overnight and nobody really using power, there’s not a lot of ways to store that power,” said van Melle.

“This will allow us, during periods of low demand and high renewable generation, to essentially have a large battery to store that power and then give it back to consumers into the grid during peak periods.”

TransAlta said the project could power up to 400,000 homes in the future.

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Conservationists are pleased that coal mining is no longer part of the plans for Tent Mountain, but are eyeing the project with cautious optimism while it waits to see environmental impact assessments.

“Although a renewable energy complex would be better than a coal mine, it could still have adverse environmental impacts,” Devon Earl with the Alberta Wilderness Association said as part of a statement to Global News.

“Pumped hydro storage generally takes more electricity from the grid than it adds, and we’re concerned about siting industry in alpine areas, which are particularly sensitive to disturbance and difficult to reclaim, so any development could have a really high impact even in preliminary stages.”

It’s still early days. Financing, engineering and regulatory work will continue over the next few years, making way for possible construction by 2026 and what could be Canada’s first pumped hydro plant by 2030.

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