Experts say smaller-scale geothermal has a future in the NWT
The NWT has high geothermal potential but projects have struggled to get off the ground. Taking advantage of the resource may call for a more cautious, scaled-down approach.
On a geothermal map of Canada, a blotch of deep red covers the southwestern portion of the Northwest Territories. Although the colour-coding represents a specific geologic measure, the message is clear: There is a lot of heat underground.
If you were to tunnel 10 kilometres into the earth and measure the temperature at various spots throughout Canada, you would find some of the highest temperatures in the southern part of the NWT, according to John Ketchum, director of the Northwest Territories Geological Survey (NTGS).
“There is heat down there,” he said. “And that’s a good-news story.”
Despite this potential, the territory has little to show for it. Much like the rest of Canada, the NWT has been slow to develop geothermal, and past attempts at geothermal projects have fallen through. In 2011, Yellowknife residents voted against a plan to use geothermal energy from Con Mine to heat buildings downtown. And in 2013, a proposed geothermal power plant in Fort Liard was cancelled when a corporation working on the project couldn’t reach a power purchasing agreement with the territorial power corporation.
With the cost of fuel continuing to rise, the price of carbon adding to it, and the territory looking to cut carbon emissions by 2030, geothermal may be worth reconsidering.
“Things have changed radically in the last year,” said Catherine Hickson, president of Geothermal Canada, an organization that works to advance and promote geothermal in Canada, and chief geoscientist at Terrapin Geothermics. In a presentation at the Yellowknife Geoscience Forum last month, Hickson made the case that geothermal may be well-suited to meet the NWT’s energy needs, particularly those related to heating.
“In all of Canada, [the NWT] is the jurisdiction that has the most to gain from geothermal,” she said in an interview with Cabin Radio.
At the same time, scientists and developers are taking steps to address challenges faced in the past. They are proposing smaller-scale projects, which have a lower price tag and may be better-suited to northern communities. They’re also conducting research to better understand the resource, which may help developers make more informed decisions.
“It’s early days for geothermal development of any kind in the Northwest Territories,” Ketchum said.
The path forward, however, may involve projects that are smaller and slower to develop than what’s been promised in the past.
Geothermal energy comes from the decay of naturally occurring radioactive elements deep in the Earth’s crust. As these elements decay, they release a lot of heat. In fact, the Earth’s core is roughly the same temperature as the surface of the Sun, according to Vox. Harnessing this heat, either where it comes to the surface or by drilling into the ground, can provide a renewable, continuous energy source.
Countries such as Iceland, the United States and the Philippines have been using geothermal for decades. In other cases, very little has come out of proposed developments.
“Geothermal has a bad name,” Hickson said. Projects are notoriously expensive and securing capital is a challenge. “There have been some spectacular failures,” she said.
Hickson acknowledges that making electricity with geothermal carries a big price tag. That’s because generating electricity requires temperatures of around 120C. To reach that level of heat, developers have to drill several kilometres into the Earth.
But communities in the NWT don’t necessarily need the amount of electricity that a geothermal plant would produce, according to Hickson. She said a geothermal power project can produce 100 megawatts of electricity. In comparison, the NWT’s entire generating capacity is estimated at 217 megawatts. Investing in geothermal power generation would be overkill, she said.
A more appropriate system for a community of 200 to 500 people might involve harnessing heat at a lower temperature, she said. Temperatures of 40 to 70 degrees can efficiently be used to heat buildings, and accessing these temperatures requires less drilling. “The shallower we go, then the cheaper it is,” she said.
In practice, a small-scale, heat-focused system would involve drilling two wells, according to Hickson. Naturally occurring, hot brine would be pumped up from underground and travel through a heat exchanger, a system used to transfer heat between two fluids. The heat from the brine would be transferred to water, which could then be piped to homes throughout the community. With the heat transferred, the now-cooled brine would be returned to the ground in the second well.
The cost of this type of system would vary depending on the community, but Hickson estimates the price to be less than $10 million. That’s still a lot of money but it’s a fraction of a power generation project’s cost, she said.
Proceed with caution
Community-scale geothermal is an attractive option, according to Ketchum. Not only is it less expensive, it’s also more inclusive. By targeting lower temperatures, more communities may have the option of pursuing geothermal projects.
“It is more viable than other forms of geothermal development,” Ketchum said. However, he points out that “it’s not a straightforward proposition to just drill a hole and produce heat.”
Cost isn’t the only barrier that has hindered geothermal development. Several technical barriers still need to be addressed, Ketchum said. Hot fluids pumped up from the ground contain a lot of dissolved constituents that can cause reservoirs to plug themselves up over time. The process of extracting hot steam from underground has also been known to trigger earthquakes.
Mostly, though, developers need to know that they will be able to extract heat successfully and sustainably.
Underground heat is only one of three components that make up a good geothermal resource, according Jasmin Raymond, a professor who studies geothermal energy at the Institut National de la Recherche Scientifique in Quebec. To access geothermal energy, you also need water and permeable rock.
Some regions in the NWT have a high geothermal gradient — meaning temperature rises quickly with increasing depth. These areas also likely contain water, Raymond said, but finding permeable rock is complex.
Working with the NTGS, Raymond has been examining drill cores from oil and gas wells to assess the porosity and permeability of rock formations around Nahanni Butte and Fort Liard.
So far, preliminary results suggest that porosity and permeability are not that high, according to Raymond. “We would expect higher values for a good reservoir,” he said. Additional work may reveal higher values, however. The team hasn’t yet assessed fractures within the rock that might allow water to flow, he said. Other types of rock in the region also have yet to be studied.
Ultimately, the aim of the research is to gain a better understanding of the geothermal resource and what’s possible, Ketchum said. The information could help experts make decisions and assess the risk involved in developing a project, thereby increasing the chances of success, he said.
According to Raymond, expectations about geothermal energy may have been overly high in the past. Although the resource is promising and could offer a path to decreasing reliance on fossil fuels, he said, any development will likely take years.
In the Dehcho region, Nahanni Butte is one community currently in the early stages of considering small-scale geothermal.
As of 2018, roughly a third of the community’s energy use goes toward heating, according to the Arctic Energy Alliance. The bulk of this heat is provided by oil or firewood.
The community is focused on taking on innovative projects and its approach to energy is no different, according to Soham Srimani, Nahanni Butte’s band manager. Leadership has always wanted to do something that would be beneficial to nature, apart from traditional sources of energy, he said.
That’s why, for the past few years, the Nahɂą Dehé Dene Band in Nahanni Butte has been working with Jason Collard, chief executive of Gonezu Energy, to better understand the community’s energy needs and its options for a district heating system. Terrapin Geothermics is also involved in the assessment.
Alternatives being explored include a small-scale geothermal project and a geoexchange system, which would involve storing excess heat in the ground for later use. Options that would make use of biomass or waste heat from existing diesel generators are on the table too.
Several factors have made geothermal more appealing in recent years, according to Collard, including the fact that other projects are gaining footing in Canada. A geothermal power plant owned by the Fort Nelson First Nation is poised to be the first in British Columbia and a project under way in central Alberta is set to be the province’s first conventional geothermal energy facility. “We’re starting to see some traction,” he said.
Collard also highlights that a key benefit of a geothermal project in Nahanni Butte would be to give an Indigenous government ownership of critical energy infrastructure, enabling self-determination and self-reliance.
The community’s energy assessment is still in progress, however, and nothing has yet been decided on how to move forward.
According to Srimani, any decisions on next steps will depend on the results of the assessment. Although there is community support for geothermal, feasibility and funding will be the deciding factors, he said.
“It’s a very nascent stage right now,” Srimani said. “But we are at least starting somewhere.”