B.C. volcano to get ‘CAT scan’ to locate best geothermal energy spots

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Scientists plan to “CAT scan” a volcano in British Columbia to harness the subterranean heat that converts rock into magma for renewable energy.

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

Grasby and his colleagues drive about 15 miles west of Whistler to Mount Cayley, which is part of the same mountain range as well-known volcanic peaks like Mount St. Helens in Washington state.

Cayley’s last lava flow was in the 17th century, but much heat remains. At nearby Mount Meager, a well drilled in the 1970s showed temperatures of 250°C at a depth of 1.5 km.

So much heat at such a relatively shallow depth is a huge opportunity for geothermal energy, Grasby said. For comparison, underground temperatures in Alberta — where some see geothermal potential in the province’s energy sources — are rising at only 50°C per kilometer of depth.

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

But how do you tap it?

Geothermal systems generate electricity from the heat contained in the groundwater. Your success depends on drilling wells in just the right spot to find the most water at the highest temperatures.

Grasby said because the labor is so expensive, geothermal drills need a 50 percent success rate to be profitable. Oil and gas drillers, he said, only have to be right about one in seven.

He and his colleagues are trying to find ways to help drillers improve their hit rate by creating a 3-D map of Cayley’s innards — without using traditional tools like seismic lines.

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

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But they will also use methods to study, for example, how electromagnetic energy moves through the volcano. For example, when lightning strikes—even in a remote part of the world—geologists can study how that energy moves through the Earth, where it’s absorbed, and where it permeates.

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

“You can start developing a 3-D image of what’s underground. Collecting these observations around the volcano, you can begin to see a magma chamber 10 kilometers down, or a reservoir filled with hot liquid two kilometers down.

“You can think of it like a CAT scan.”

This alpine scan could be used by drillers to determine exactly where to position themselves to get to the best heat resources.

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“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 few more have plans. Alberta recently joined BC in developing a regulatory regime for geothermal development.

But no geothermal sources are producing energy yet, making Canada the only country in the Pacific Rim that isn’t.

The energy source could make a significant zero-carbon contribution to Canada’s energy needs, Grasby said.

“Until someone sees a producing geothermal well, it’s hard to believe that could be true. You have to see that first,” he said.

“It won’t be the salvation, but geothermal could make a big contribution, that’s for sure.”

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