Dr Catherine Hickson is CEO of Terrapin Geothermics (https://www.terrapingeo.com/) and the proponent for the Alberta No. 1 geothermal proposed project (https://www.albertano1.ca/) involving hot fluids at 4 km depth and perhaps co-sequestration of carbon dioxide. Her slide deck presented recently in Yellowknife outlines a vision of using the Earth as a source of heat – a highly valuable commodity in our Great White North.
I am adding a few comments here for context, please look at her slides here.
Energy in the North (isolated, generally small communities, no local oil and gas)
Hydro is generally not available except in southwestern parts of NWT and some YK locations. Furthermore, the large investments needed for hydro mean it is suitable in a very limited way. Tidal and “run-of-river” hydro are not options.
Solar energy is too seasonal for direct photovoltaic electricity to be used
In many communities, mild winds in the winter also disqualify wind power year-round use
Renewable energy cannot be stored seasonally in any form except converting it to a fuel (e.g., H2) or in a heat repository in the rock mass large enough so that the heat losses are small compared to the amount of heat stored seasonally. H2 or other fuel technology in the north is a distant possibility at best, for many reasons.
Small modular nuclear reactor technology for communities less than 10,000 persons is at least a full generation away, likely much more, and it has its own challenges such as wastes and very high costs for small power applications (0.25 – 10 MW).
So, this leaves us looking at exploiting the heat in the Earth (geothermal heat), or using the subsurface to store waste low-grade heat or other sources of heat for later extraction using ground-source heat pump technology. A few comments…
Except for regions in YK and a “hot spot” that lies in the SW corner of NWT and incorporates small areas of AB and BC, there is no high-grade geothermal resource possible
Direct exploitation of low-grade Earth heat for habitat heating (no electrical power generated) requires a temperature of at least 40-50°C.
The thermal gradients in the North are low: ~15°C/km
This means a minimum of two boreholes at least 3 km deep, hydraulicly stimulated, to circulate a fluid to extract the heat from the rock mass ($$)
For a community, a shallow seasonal heat repository needs to be at least 50-55 m on each side to keep heat losses at a reasonable level annually (the bigger the cup of coffee, the longer it stays hot).
Nonetheless, despite these challenges, there remains merit in looking at geothermal exploitation and heat storage to reduce the use of fuel oil and propane in providing winter heat. Some of the things we need to do this are:
Cheap and easily deployed drilling capabilities to depths of 4-5 km for deep geothermal heat, or to depths of 200-400 m for borehole heat exchanger arrays for a shallow thermal repository.
In granites, this repository has to be accessed by an array of borehole heat exchangers to emplace and withdraw low grade heat (<50°C).
Probably, 50-80 vertical borehole heat exchangers would be needed for a 60x60x60 repository at a depth of 150-200 m.
Modular, robust and reliable heat pump systems designed for climates that do not need air conditioning but need to store heat in the summer for winter use.
Highly mobile installation equipment and procedures suited for remote and distant communities.
Training of local persons to manage systems.
Community design (and retrofits) for direct heat provision to homes.
…and a few other things.
This won’t be cheap, but the current true costs of electrical power anywhere in the North are at least several times the true cost in the south (in excess of $1.00/kWh in the more remote communities), and there are no alternatives but diesel generated electrical power and fuel oil heat.
So why pursue non-fossil fuel energy sources like geothermal??
Decarbonization of energy – related to climate change concerns
Direct heat use is far more efficient than electrical power use for low-grade heat sources, and we can store heat as well
Reduction of logistics challenges (4000 km by boat for diesel in some communities)
Elimination of fire concerns (fuel oil), environmental risks (boat accidents, spills contaminating water supplies…), health issues (particulates, fumes, poor combustion…)
Energy systems become local issues, not systems that remain umbilically tied to distant suppliers, so local communities can make decisions affecting them
We need technology development. We need agencies like the Department of Defence to come forward and assess needs for their northern presence which is likely to be enhanced in the near future, and equipment and personnel must be kept warm and cozy. We need interaction with northern communities to “bridge the divide”. We need “made in Canada” solutions to meet the particular challenges that face us in the North and in the northern sections of many Provinces.
Heat is existential in the North: the more reliable and robust we can make the systems, the better off communities will be. And, I have no doubt that technologies that are developed for the north will become highly useful in much of the rest of Canada.