Geologist Antonina Calahorrano is setting up a test well to map the area’s geothermal potential. Scientists are planning a “CAT scan” of a British Columbia volcano to help exploit the 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 head about 24 kilometers west of Whistler, to Mount Cayley, part of the same mountain range as well-known volcanic peaks such as Mount St. Helens in Washington state. Cayley’s last lava flow was back in the 1700s, but plenty of heat remains. At nearby Mount Meager, a well drilled in the 1970s showed temperatures of 250C at a depth of 1.5km. That much heat at such a relatively shallow depth is a big opportunity for geothermal energy, Grasby said. By comparison, underground temperatures in Alberta – where some see geothermal potential in energy wells located in the province – rise by only 50 C for every kilometer of depth. “Temperature-wise, it’s a world-class resource,” Grasby said. But how do you hit it? Geothermal plants generate energy through the heat contained in underground water. Their success depends on sinking wells in the right place to find the most water at the highest temperatures. Grasby said that because labor is so expensive, geothermal drilling needs 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 making a 3D map of Cayley’s guts — without using traditional tools like seismic lines. Part of the map will be drawn through basic geology. The team will analyze what types of rock are present to find out how permeable or porous they are, or to identify and map fault systems that may hold hot water. But they will also use methods like looking at 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. “We have to go around the volcano, so you’re looking at it from all these different angles,” Grasby said. “You can start to develop a 3D picture of what’s underground. Collecting these observations around the volcano, you can begin to see that there is a magma chamber at a depth of 10 kilometers, or a reservoir filled with hot liquid at two kilometers. “You can think of it as a CAT scan.” This alpine scan could be used by drillers to determine exactly where to place to reach 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 a few 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. However, no geothermal wells are producing power yet, making Canada the only country in the Pacific Rim of Fire that does not. The energy source could be a major zero-carbon factor in Canada’s energy needs, Grasby said. “Until you see a geothermal well that’s producing, it’s hard to believe it could be real. You have to see it first,” he said. “It’s not going to be the saving grace, but geothermal could make a big contribution, that’s for sure.” This report by The Canadian Press was first published on August 21, 2022. — Follow Bob Weber on Twitter at @row1960
