This article was written by Kristy Dyer - Sep 3, 2024 for Castanet.
To begin, you have to understand there are two kinds of geothermal energy.
There is geothermal energy based on the simple fact that the ground 30 metres down doesn’t change temperature during the year. In B.C., during the summer the ground is 12 C, even as temperatures push 35 C at the surface. In the winter it can be as cold as -30 C at the surface but the ground temperature is still an even 12 C.
If you run pipes underground you can use that even, year-round temperature to pre-cool or pre-heat. Better than that, a heat pump allows you to exchange temperatures, pulling either heat or cooling from that stable temperature layer.
Many university campuses are installing geothermal heat pumps, including McMaster University and University of Toronto. If you think of a typical campus, there are large buildings requiring heat and cooling and large areas of grass between them. Universities dig up the grass, install the geothermal piping and replant the landscaping. That allows them to switch from expensive and polluting fossil fuels to a more efficient geothermal heat pump.
Then there is another form of geothermal energy. The earth’s core is a whopping 5,430 C. You do not have to dig all the way to the core to find the heat however. Depending on the geology of the region you live in, there may be heat at the surface (such as the Revelstoke hot springs or demonstrated spectacularly at Yellowstone National Park in the U.S.). B.C. has the best geothermal resources in Canada with hot dry rock in the southern Interior (including the Okanagan) and volcanic hot water in the coastal regions.
In places where the heat doesn’t make it to the surface you may be able to find it by digging 100 metres to 1,000 metres down.
The powerful thing about geothermal energy is it runs 24 hours a day. Because of decades of investment, costs for wind and solar have come down, making them the cheapest option. However, solar only produces power during the day and wind can be intermittent.
Before renewables, coal power plants ran 24/7 producing baseline power and natural gas “peaker” plants met high demand, in particular during the the 5 p.m. to 8 p.m. peak period when people come home from work turn on lights, run laundry and dishwashers.
Now we can produce much of our energy from solar and wind but we lack a clean source of baseline power and dispatchable power to meet peak use. In some locations nuclear and hydro power can supply baseload energy but no one is building new nuclear plants and hydro is limited to regions with the right geography. Geothermal energy could fill that gap.
Canada has one operating geothermal power plant, the Swan Hills in Alberta. Swan Hills was one of the largest oil and gas reserves in Alberta. As the oil and gas were depleted, the site switched to “fresh water enhanced oil recovery” where 95 to 98 percent of the fluid was water. However, that water was hot, more than 100 C.
Now Swan Hills runs a combined natural gas and geothermal plant, selling electricity into the grid in Alberta. The U.S. has geothermal power plants in seven states. Ten percent of Nevada’s electricity is produced by geothermal.
The “shale revolution” in drilling for oil and gas, has provided North America with cheap natural gas over the past 20 years. From an environmental standpoint that has been bad news. While natural gas is slightly less carbon intensive than oil, it is still a major contributor to climate change.
Human psychology drives the switch from carbon intensive to low carbon technology. Many people switch because low carbon technology is better for the climate, but a large driver is the long-term savings and inexpensive natural gas has slowed the change.
However, there may be a climate upside to the shale revolution. The revolution consists of advances in horizontal drilling, fracking and magnetic sensing. Using these advanced drilling techniques, geothermal power plants could be located on a much wider range of sites.
One technique involves drilling parallel wells 300 to 1,000 metres down and then horizontally, using fracking. Water is injected in one well and seeps into the parallel well, now hot from the surrounding rocks.
Up until now, geothermal plants have only been located in places where geology brings heat up near to the surface but fracking and horizontal drilling mean many more sites are potential locations for geothermal power plants. There is a vision that coal-fired power plants could be repurposed by drilling onsite for geothermal energy, replacing the coal-generated steam with steam from geothermal.
Wind and solar generated power lead the charge in renewables because, after decades of investment and development, they are now mature technologies. While the drilling technology behind geothermal is well developed, geothermal power stations are a new breed.
Investment in geothermal, combined with technology transfer from oil and gas drilling, will reduce risk and bring the cost of geothermal down.
Natural Resources Canada has made a $5-million investment in Novus Earth to carry out a study for Latitude 53 in Hinton, Alberta. The Canada Growth Fund has made a $90 million investment in Eavor Technologies Alberta Drilling Accelerator. The 2023 federal budget extended the clean tax created to geothermal drilling.
Unlimited supplies of power are literally right beneath our feet, if we can make the investments.