Geothermal power plants use the heat from subsurface water to produce electricity. Their effectiveness depends on placing wells precisely where the most water at the highest temperatures will be found. To help capture the subterranean heat that transforms rock into magma for renewable energy, scientists are preparing to conduct a “CAT scan” of a volcano in British Columbia.
“Canadians are often surprised to know there’s volcanoes in the country,” said Steve Grasby, a geologist with Natural Resources Canada. “But there are active volcanoes.”
In order to reach Mount Cayley, which is a part of the same mountain range as well-known volcanic peaks like Mount St. Helens in Washington State, Grasby and his colleagues are traveling roughly 24 kilometers west of Whistler, British Columbia.
There is still a lot of heat in Cayley, even though the last lava flow occurred in the 1700s. A borehole drilled in the 1970s near Mount Meager revealed temperatures of 250°C at a depth of 1.5 kilometers.
Geothermal energy has a strong possibility with that much heat at such a shallow depth, according to Grasby. For example, the temperature underground in Alberta only increases by 50°C for every kilometer of depth, despite the fact that some believe the energy wells scattered throughout the province have geothermal potential.
“In terms of temperature, it’s a world-class resource,” Grasby said.
How do you tap it, though?
Groundwater heat is used in geothermal power plants to produce energy. The key to their success is placing wells where they will locate the most water at the warmest temperature.
Geothermal excavators need to have a 50% success rate in order to be profitable, according to Grasby, because the work is so expensive. Only one out of seven times, he claimed, must an oil and gas prospector be correct.
By making 3D maps of Cayley’s interior without the aid of conventional instruments like survey lines, he and his colleagues are attempting to identify ways to increase the excavator hit rates.
The map is drawn in part using simple geology. The team will detect and map fault networks that might contain hydrothermal fluids as well as assess the sorts of rocks in the area to determine how porous or permeable they are increasing.
However, it also employs techniques like investigating the path electromagnetic energy takes through volcanoes in BC. Geologists can, for instance, analyze how lightning strikes the Earth, where its energy is absorbed, and where it goes through, even if they occur in remote regions of the planet.
“You have to circle the volcano, so you have to look at it from different angles,” says Glasby.
“You can start to develop a 3-D image of what’s underground. By collecting these observations all around the volcano, you can start to see there’s a magma chamber at 10 kilometres depth or a hot fluid-filled reservoir at two kilometres.”
“You can think of it as a CAT scan.”
Drillers may utilize that alpine scan to pinpoint exactly where to stand to access the finest heat sources.
“Our goal is to reduce that exploration risk,” Glasby said. “I can’t afford to drill a lot of dry holes.”
In Canada, a number of geothermal projects are in progress.
Companies are drilling wells in Saskatchewan and British Columbia, and more are preparing. Recently, Alberta and BC joined together to create a regulatory framework for geothermal development.
Canada is the only nation in the Pacific Rim without energy production, as there are still no geothermal wells that can provide it.
“The energy source could become a significant carbon-free contributor to Canada’s energy needs”, Glasby said.
“It’s hard to believe it’s true until you see someone producing a geothermal well. We have to see the first one,” he said.
“It’s not helping, but it’s certainly possible that geothermal could make a big contribution.”
With efforts to find geothermal energy at the BC volcano, hopefully scientists will have the next new step.