The Mount Cayley volcanic complex seen from the northwest in 2006. Source – Michael Scheltgen, CC SA 2.0.
Scientists are planning a “CAT scan” of a volcano in British Columbia to help harness geothermal energy.
“Canadians are often surprised to know that there are volcanoes in the country,” said Steve Grasby, geologist with Natural Resources Canada, according to CTV News Canada. “But there are active volcanoes.”
Grasby and his crew head about 24 kilometers (15 miles) west of Whistler, British Columbia, to Mount Cayley, which is part of the same mountain range as well-known volcanic peaks such as Mount St. Helens, Washington.
Mount Cayley is an eroded but potentially active stratovolcano. Part of the Garibaldi Volcanic Belt, Mount Cayley was formed by subduction zone volcanism along the western margin of North America.
Eruptive activity began about 4,000,000 years ago and has since gone through three stages of growth, the first two of which built up most of the volcano. The last eruptive period occurred within the past 400,000 years, with lesser activity continuing to the present day.
The volcano dominates the valleys of the Cheakamus and Squamish rivers, where all the peaks rise above 2,000 meters (6,600 feet). Mount Cayley is the highest at 2,385 m (7,825 ft).
The surrounding area has been inhabited by indigenous people for over 7,000 years and geothermal exploration has taken place over the past 40 years. The Geological Survey of Canada (GSC) monitors the volcano and its surroundings.
Cayley’s last lava flow dates back to the 1700s, but there is still plenty of heat left. Near Mount Meager, a well drilled in the 1970s showed temperatures of 250 C at 1.5 kilometers depth.
This amount of heat at such a shallow depth is a great opportunity for geothermal energy, Grasby said. “In terms of temperature, it’s a world-class resource,” Grasby said.
How will they draw this energy?
Geothermal power plants generate electricity from the heat contained in groundwater. Their success depends on drilling wells in the right place to find the most water at the highest temperatures, according to Castanet.
Grasby says that because drilling is so expensive, they look for very high success rates, like 50% or more, unlike oil and gas drillers who only need to be right one in seven times.
So, to get the best possible result for the drill team, Grasby and his team will create a 3D map of Mount Cayley, without using traditional tools like seismic lines.
Part of the map will be drawn through the basic geology. The team will analyze what types of rocks are present to determine their degree of permeability or porosity, and will also locate and map fault systems that may contain hot water.
But here’s something surprising – They will also use methods such as 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 travels through the earth, where it is absorbed and where it passes.
“We have to go all the way around the volcano, so you’re looking at it from all these different angles,” Grasby said.
“You can start developing a 3D image of what’s underground. By collecting these observations all around the volcano, you can begin to see that there is a magma chamber 10 kilometers deep or a reservoir filled with hot fluid two kilometers away.
In other words – Hooray! – we have a CAT scanner.
Canada is the only country in the Pacific that does not have geothermal wells producing energy. It’s not for lack of trying, though. Companies in Saskatchewan and British Columbia have drilled wells and a few others have plans. Alberta recently joined British Columbia in developing a regulatory regime for geothermal development.
The energy source could be a significant carbon-free contributor to Canada’s energy needs, Grasby said. “Until someone sees a geothermal well in production, it’s hard to believe this could be true. You have to see this first,” he said.