Scientists will perform a ‘CAT scan’ of the BC volcano to locate the best geothermal power spots

Scientists are planning a “CAT scan” of a British Columbia volcano to help harness underground heat that turns rock into magma for renewable energy.

“Canadians are often surprised to learn that there are volcanoes in the country,” said Steve Grasby, a geologist with Natural Resources Canada. “But there are active volcanoes.”

Grasby and his colleagues are heading about 15 miles west of Whistler, BC, to Mount Cayley, part of the same mountain range as the volcanic peaks known as Mount St. Helens in Washington state.

Cayley’s last lava flow was in the 18th century, but there’s still plenty of heat left. At nearby Mount Meager, a well drilled in the 1970s showed temperatures of 250 C at 1.5 kilometers depth.

So much heat at a relatively shallow depth is a huge opportunity for geothermal power, Grasby said. For comparison, underground temperatures in Alberta, where some see geothermal potential in the power wells that dot the province, only rise 50C for every kilometer of depth.

“In terms of temperature, it’s a world-class resource,” Grasby said.

But how do you play it?

Geothermal plants generate energy through the heat contained in groundwater. Their success depends on digging wells in the right place to find the most water at the hottest temperatures.

Grasby said that because the work is so expensive, geothermal drillers need a 50 percent success rate to be viable. Oil and gas drillers, he said, only need to be right once in seven.

He and his colleagues are trying to find ways to help drillers improve their hit rate by building a three-dimensional map of Cayley’s bowels, without using traditional tools like seismic lines.

Part of the map will be drawn through basic geology. The team will analyze what types of rocks are present to find out how permeable or porous they are, or locate and diagram fault systems that may hold hot water.

But they will also use methods like examining how electromagnetic energy moves through the volcano. For example, when lightning strikes, even in a remote part of the world, geologists can examine how that energy moves through the earth, where it is absorbed, and where it passes through.

“We have to go around the volcano, so you look at it from all these different angles,” Grasby said.

“You can start to develop a 3D image of what is underground. By collecting these observations around the volcano, you can begin to see that there is a magma chamber 10 kilometers deep or a reservoir filled with hot liquid two kilometers away.

“You can think of it like a CT scan.”

Drillers could use that alpine scan to determine exactly where to position themselves for the best heat resources.

“Our goal is to reduce that exploration risk,” Grasby said. “You can’t afford to drill a lot of dry holes.”

Canada has some geothermal projects underway.

Companies in Saskatchewan and BC have drilled wells and a couple more have plans. Alberta recently joined BC in developing a regulatory regime for geothermal development.

But no geothermal wells are yet producing power, making Canada the only country in the Pacific Ring of Fire that doesn’t.

The power source could be a major zero-carbon contributor to Canada’s energy needs, Grasby said.

“Until someone sees a geothermal well in production, it’s hard to believe it could be true. You have to see the first one,” she said.

“It’s not going to be the saving grace, but geothermal could be a big contributor, that’s for sure.”

This report from The Canadian Press was first published on August 21, 2022.

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