energies Article Deep Geothermal Heating Potential for the Communities of the Western Canadian Sedimentary Basin Jacek Majorowicz 1,2,* and Stephen E. Grasby 3 1 Northern Geothermal Cons, Edmonton, AB T6R2J8, Canada 2 Department of Physics, University of Alberta, 11322-89 Ave., Edmonton, AB T6G 2G7, Canada 3 Geological Survey of Canada, 3303 33 St NW, Calgary, AB T2L 2A7, Canada; [email protected] * Correspondence: [email protected] or [email protected] Abstract: We summarize the feasibility of using geothermal energy from the Western Canada Sed- imentary Basin (WCSB) to support communities with populations >3000 people, including those in northeastern British Columbia, southwestern part of Northwest Territories (NWT), southern Saskatchewan, and southeastern Manitoba, along with previously studied communities in Alberta. The geothermal energy potential of the WCSB is largely determined by the basin’s geometry; the sediments start at 0 m thickness adjacent to the Canadian shield in the east and thicken to >6 km to the west, and over 3 km in the Williston sub-basin to the south. Direct heat use is most promising in the western and southern parts of the WCSB where sediment thickness exceeds 2–3 km. Geother- mal potential is also dependent on the local geothermal gradient. Aquifers suitable for heating systems occur in western-northwestern Alberta, northeastern British Columbia, and southwestern Saskatchewan. Electrical power production is limited to the deepest parts of the WCSB, where aquifers >120 ◦C and fluid production rates >80 kg/s occur (southwestern Northwest Territories, northwestern Alberta, northeastern British Columbia, and southeastern Saskatchewan. For the west- ern regions with the thickest sediments, the foreland basin east of the Rocky Mountains, estimates indicate that geothermal power up to 2 MWel. (electrical), and up to 10 times higher for heating in Citation: Majorowicz, J.; Grasby, S.E. MWth. (thermal), are possible. Deep Geothermal Heating Potential for the Communities of the Western Keywords: heat flow; deep geothermal heat; foreland basin; WCSB; energy transfer Canadian Sedimentary Basin. Energies 2021, 14, 706. https:// doi.org/10.3390/en14030706 1. Introduction Academic Editor: Stefano Mazzoli Direct heating with geothermal energy could provide an important energy resource Received: 27 December 2020 in cold climate regions, such as the Canadian prairie provinces where heating accounts Accepted: 27 January 2021 Published: 30 January 2021 for 80% of the total energy demand. Sedimentary basins, such as the Western Canadian Sedimentary basin (WCSB), hold significant heat that could be used to support communities Publisher’s Note: overlying the basin. Direct use geothermal energy is commonly used for district heating MDPI stays neutral ◦ with regard to jurisdictional claims in systems [1–4]. Typically, district heating systems require temperatures >60 C and fluid published maps and institutional affil- production rates >30 kg/s, using two or more geothermal wells with at least one production iations. well and one injection well [5]. District heating systems could significantly reduce CO2 emissions by replacing gas and oil combustion with renewable energy resources [6–11]. The WCSB contains large geothermal energy reserves, with temperatures reaching over 160 ◦C. About half of the basin area is >2 km deep, with measured temperatures >60 ◦C[11–16]. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. Previous studies of the WCSB examined both direct heating energy, in GJ per year, This article is an open access article and potential electrical power generation (MW electrical), but for only the province of distributed under the terms and Alberta [17]. We expand on this previous work by examining geothermal potential for all conditions of the Creative Commons communities with populations >3000 people that overly the WCSB, adding geothermal Attribution (CC BY) license (https:// energy calculations for northeastern British Columbia, Saskatchewan, southern Manitoba, creativecommons.org/licenses/by/ and southwestern NWT (see location of the study area in Figure1 and location of the 4.0/). municipalities in Figure2). Maps specific to these new assessment areas are presented Energies 2021, 14, 706. https://doi.org/10.3390/en14030706 https://www.mdpi.com/journal/energies Energies 2021, 14, x FOR PEER REVIEW 2 of 51 Energies 2021, 14, 706 2 of 37 municipalities in Figure 2). Maps specific to these new assessment areas are presented in Appendixes A–B, while combined maps for the entire WCSB are presented here. Calcu- in AppendicesA andB, while combined maps for the entire WCSB are presented here. lated geothermal Calculatedpotential for geothermal specific potential communities for specific are communities in tables in are Appendix in tables in C Appendix. These C. tables include geothermalThese tables energy include geothermalavailable assuming energy available an average assuming energy an average use energy of 130 use of GJ/year, enthalpy,130 calculated GJ/year, enthalpy,formation calculated temperature formation, and temperature, the drill anddepth the drillrequired depth requiredfor cal- for culated temperatures.calculated temperatures. FigureFigure 1. Map 1. ofMap Canada of Canada showing showing the study area the (rectangle).study area Provinces (rectangle). and territories Provinces that and are considered territories in that the study are are indicatedconsidered along with in the the outlinestudy ofare the indicated Western Canada along Sedimentary with the outline Basin (WCSB). of the BCWestern = British Canada Columbia, Sedimentary NWT = North- westBasin Territories, (WCSB Sask.). BC = Saskatchewan, = British Columbia, Man. = Manitoba. NWT = TheNorthwest red line depicts Territories, the western Sask margin. = Saskatchewan, of the WCSB which Man. is = definedManitoba. by the deformation The red line front depicts of theCanadian the western Rocky margin Mountains. of the The WCSB black line which shows is thedefined eastern by edge the of defor- our study definedmation by 1 kmfront sedimentary of the Canadian thickness. Rocky Mountains. The black line shows the eastern edge of our study defined by 1 km sedimentary thickness. Energies 2021, 14, 706 3 of 37 Energies 2021, 14, x FOR PEER REVIEW 3 of 51 Figure 2. Location map of the Western Canadian Sedimentary Basin (WCSB) with provincial boundaries and locations of Figure 2. Location map of the Western Canadian Sedimentary Basin (WCSB) with provincial boundaries and locations of municipalities with populations >3k. The red line depicts the western margin of the WCSB defined by the deformation municipalities with populations >3 k. The red line depicts the western margin of the WCSB defined by the deformation front of the Canadian Rocky Mountains. front of the Canadian Rocky Mountains. 2. Background 2. Background Geothermal production of electrical power, through the Organic Rankin (ORC) or KalinaGeothermal cycle (KC), production needs to be of in electrical the vicinity power, of an through existing the power Organic grid Rankinto be economical. (ORC) or KalinaSuch infrastructure cycle (KC), needs is available to be in in the some vicinity remote of an areas existing as already power shown grid to by be economical.wind-based Suchpower infrastructure production in is Alberta. available However, in some remotethe low areas~10% asefficiency already of shown ORC byand wind-based KC power powerplants is production a limiting infactor, Alberta. making However, only high the enthalpy low ~10% regions efficiency of interest of ORC for and electrical KC power po- plantstential, is such a limiting as the deepest factor, making parts of only the WCSB high enthalpy in Alberta regions and southern of interest Saskatchewan for electrical [11] po-. tential,However, such “The as the Alberta deepest Climate partsof Leadership the WCSB Plan” in Alberta goal andof replacing southern 5000 Saskatchewan megawatts [11 of]. However, “The Alberta Climate Leadership Plan” goal of replacing 5000 megawatts of coal-generated electricity with power coming from renewable sources by the year 2030 is coal-generated electricity with power coming from renewable sources by the year 2030 is daunting. Electrical power from geothermal sources would require thousands of geother- daunting. Electrical power from geothermal sources would require thousands of geother- mal doublet well installations, while two well systems with 1–2 MW potential is feasible mal doublet well installations, while two well systems with 1–2 MW potential is feasible in only limited areas (see Tables in Appendix C). The cost of geothermal wells to produce in only limited areas (see Tables in AppendixC). The cost of geothermal wells to produce sufficient electricity would be upwards of $50 billion dollars for 1000 systems [7]. District sufficient electricity would be upwards of $50 billion dollars for 1000 systems [7]. District heating (DH) may therefore be the most feasible use of geothermal resources in cold cli- heating (DH) may therefore be the most feasible use of geothermal resources in cold climate mate regions such as the Canadian prairie provinces. This also comes with challenges regions such as the Canadian prairie provinces. This also comes with challenges though. though. Transmitting hot fluids over large distances comes with significant energy loss, which Transmitting hot fluids over large distances comes with significant energy loss, means that to be useful, DH projects must be as close to a community