Deep Geothermal Heating Potential for the Communities of the Western Canadian Sedimentary Basin (original) (raw)
Related papers
Geothermics, 2020
We examined the potential of geothermal energy to supply power and heat for larger communities (population > 10,000) located over the Alberta Basin in the Western Canadian Sedimentary Basin (WCSB). The major cities and seven towns in Alberta examined, with a combined total population of > 2,500,000 people, were scrutinized for their geothermal potential. Depending on T (°C) and production rate (kg/s) the range of households that are feasible to be heated is in the 100's to 1000's for produced water > 70°C and flow rates of 30−80 kg/s. These are available in most of the deep foreland basin in western Alberta and in most of the larger population centers, outside the shallow and 'cold' parts of the basin in the east. As space heating is the dominant energy demand in Canada, with single households representing ∼80% of energy usage, the geothermal heating transition in Alberta would be the best option for municipalities. Power production is feasible in just a few Alberta communities located over the deeper parts of the basin, still requiring > 140°C temperatures and high production rates (> 80 kg/s) due to low efficiency of power plants (some 10%) and economics of the system. The range of the feasible net power production is assessed between single decimals of MW electrical and up to maximum of 2.7 MW in deep hot high production systems.
The south-eastern territory of the province of Québec (Eastern Canada), a region located along the Saint-Lawrence River Valley, including the Gaspésie Peninsula and the Madeleine and Anticosti Islands, has been identified as an interesting area for the future use of deep geothermal energy several decades from now. This region includes a thick 1-5 km sedimentary rock wedge deepening southwest towards the Appalachian disturbed belt front. The deep part of the sedimentary wedge offers the potential to produce geothermal heating and power from the deep aquifers in the future. Relatively elevated heat flow densities in some thermal anomalous areas (i.e. >60 mW/m 2 ) also result in prospects for temperatures above 120°C at about 4 km in the sedimentary aquifers. Additionally, geothermal power and heat production from hot dry deep granites located below the sedimentary cover can also be considered using Enhanced Geothermal Systems (EGS). On the other hand, Northern Québec, a vast territory covering nearly 1.2 million km 2 of land located north of the 49 th parallel, presents very low mean annual surface temperatures and a relatively low average heat flow density of about 40 mW/m 2 . This area would require deeper drilling for heat mining, i.e. 80°C at a depth of about 4.5 km. In the medium and long terms, geothermal energy could be feasible in the province of Québec with positive future energy and environmental impacts.
Geothermal energy potential in the St-Lawrence River area, Québec
Geothermics, 2012
Previous estimates of geothermal energy potential in Canada give an indication of available heat to be 'farmed' at depth with focus on Western Canadian Cordillera and Western Canadian Sedimentary basin as prime targets. This paper examines in more detail temperature-depth realtionships near large population centres in Québec, in order to provide a first order assesment of enhanced geothermal systems (EGS) potential for electrical and heat generation. Results show areas with significant EGS potential in the St-Lawrence River valley related to high heat flow density and thermal blanketing of thick sedimentary cover. At >120 • C found to be a prospect for several areas in Québec (drilled to depths of over 4.5 km in Trois-Rivières area, near 4.5 km in the Eastern St-Lawrence River (Rimouski, Gaspé and Golf, including Anticosti Island) and just 4 km in Quebec area) the potentially available geothermal power from EGS hydrothermal systems in deep sediments can be of significance.
Resources, 2015
Heat flow of the sedimentary succession of the Eastern Canada Sedimentary Basins varies from 40 mW/m 2 close to the exposed shield in the north to high 60-70 mW/m 2 in the southwest-northeast St. Lawrence corridor. As high fluid flow rates are required for a successful geothermal application, the most important targets are deep existing permeable aquifers rather than hard rock, which would need to be fracked. Unfortunately, the ten most populated Québec urban centers are in the areas where the Grenville (Canadian Shield) is exposed or at shallow depths with sedimentary cover where temperatures are 30 °C or less. The city of Drummondville will be the exception, as the basement deepens sharply southwest, and higher temperatures reaching >120 °C are expected in the deep Cambrian sedimentary aquifers near a 4-5-km depth. Deep under the area where such sediments could be occurring under Appalachian nappes, temperatures significantly higher than 140 °C are predicted. In parts of the deep basin, temperatures as high as 80 °C-120 °C exist at depths of 3-4 km, mainly southeast of the major geological boundary: the Logan line. There is a large amount of heat resource at such depths to be considered in this area for district heating.
2014
Heat flow and geothermal gradient of the sedimentary succession of the Western Canada Sedimentary Basin (WCSB) are mapped based on a large thermal database. Heat flow in the deep part of the basin varies from 30 mW/m 2 in the south to high 100 mW/m 2 in the north. As permeable strata are required for a successful geothermal application, the most important aquifers are discussed and evaluated. Regional temperature distribution within different aquifers is mapped for the first time, enabling a delineation of the most promising areas based on thermal field and aquifer properties. Results of previous regional studies on the geothermal potential of the WCSB are newly evaluated and discussed. In parts of the WCSB temperatures as high as 100-210 °C exist at depths of 3-5 km. Fluids from deep aquifers in these "hot" regions of the WCSB could be used in geothermal power plants to produce electricity. The geothermal resources of the shallower parts of the WCSB (>2 km) could be used for warm water provision (>50 °C) or district heating (>70 °C) in urban areas.
Energies, 2014
Heat flow and geothermal gradient of the sedimentary succession of the Western Canada Sedimentary Basin (WCSB) are mapped based on a large thermal database. Heat flow in the deep part of the basin varies from 30 mW/m 2 in the south to high 100 mW/m 2 in the north. As permeable strata are required for a successful geothermal application, the most important aquifers are discussed and evaluated. Regional temperature distribution within different aquifers is mapped for the first time, enabling a delineation of the most promising areas based on thermal field and aquifer properties. Results of previous regional studies on the geothermal potential of the WCSB are newly evaluated and discussed. In parts of the WCSB temperatures as high as 100-210 °C exist at depths of 3-5 km. Fluids from deep aquifers in these "hot" regions of the WCSB could be used in geothermal power plants to produce electricity. The geothermal resources of the shallower parts of the WCSB (>2 km) could be used for warm water provision (>50 °C) or district heating (>70 °C) in urban areas.
Renewable Energy, 2014
The identification, mapping and evaluation of geothermal resources are an important component of a diversified and resilient energy system. Geothermal resources offer an important series of contributions from direct (low temperature) heat to electric generation (from EGS or Enhanced Geothermal Systems). While not ideal, Alberta has a wide range of subsurface heat resources that are coincident with load and can be developed in the future at reasonable cost. We assess that geothermal energy output from sources at depth for temperature range between 120 and 150 C accessed from 4 to 5 km wells in very western portions of the Alberta basin can be as competitive as gas burning even at these prices. For the 5 km depth and 150 C, the cost of thermal energy can be as low as 2 $ per GJ thermal equivalence for expected EGS flow rates of 5e50 kg/s, with 30 year expected plant life. Replacement of gas heating utilizing EGS systems could form part of a long range target for industry emission reductions. For example, 1000 (2 wells each) heat generating systems across Alberta drawing 100 C from deep wells in deep sedimentary basin or deep granites can save >30 MT CO 2 per year. Oilsands operations generate some >40 MT per year and in Alberta more than 300,000 wells have been drilled by oil and gas industry.
Environmental Earth Sciences, 2015
Northern Québec, a large and cold climate territory located north of the 49th parallel, has low average heat flow density (40 ± 9 mW/m 2) typical of the Canadian Shield. The lack of the thermal blanket otherwise provided by sediments in the platform of southern Québec results in deep drilling requirements for potential mining heat (80°C at some 5 km). Drilling doublet or triplet well systems at such depths into low-enthalpy granitic rocks would be expensive; however, in some cases of heat flow higher by one standard deviation of the mean and fracked permeability allowing flow rates [30 kg/s may make this heat useable in the future. Other options in providing heat are more likely to be applied earlier. These would include shallow geothermal energy use with heat pumps in granites by placement of artificial heat exchanges by directional loop drilling. These systems may have promise in Northern Québec due to its very cold climate and extremely high energy cost based on diesel oil heating for remote communities and mining areas. Findings show that recent industrial age climatic warming increased the mean underground temperatures in the upper circa couple hundred meters. This has resulted in temperature gains and energy ground storage.
Renewable Energy, 2019
Low efficiency of turbines used in geothermal power production, along with large power demand for geothermal fluid pumping, limits use of geothermal resources for power production in the Canadian low to mid enthalpy basins. Much larger areas of Canadian sedimentary basins have potential for geothermal direct heating, but use will be dependent on the amortization period of the installation cost as well as the parasitic power demand to maintain large flow rates in injection and production wells. Maximum exergy (kJ/kg) potential for the most perspective geothermal resources in the deeper parts of Canadian basins (150 kJ/kg (0.15 MJ/kg)), are compared to exergy contained by the intrinsic chemical energy in oil, gas and coal (30-35 MJ/kg) that is required to be replaced in order to reduce carbon emissions. The calculated number of geothermal producing doublet well systems, at very high assumed flows of 0.08 m 3 /s (80 L/s), required to replace an average oil producing well in Alberta-WCSB will be > 10. But, such high exergy is available only in the deepest northern parts of the WCSB.
Geomechanics and Geophysics for Geo-Energy and Geo-Resources
Geothermal resource quantification requires underground temperature and volume information, which can be challenging to accurately assess at the regional scale. The analytical solution for steady-state heat conduction with internal heat generation is often used to calculate temperature at depth, while geological models can provide volume information. Both approaches were originally combined in a single 3D geological model, in which the underground temperature is directly computed, to accurately evaluate geothermal resources suitable for power generation in the St. Lawrence Lowlands sedimentary basin covering 18,000 km 2 in Quebec, Canada, and improve methods for geothermal resource quantification. This approach, used for the first time at such a large scale, allowed to determine the volume of each thermal unit providing a detail assessment of resource depth, temperature and host geological formation. Only 5% of geothermal resources at a temperature above 120°C that is suitable for power generation were shown to be hosted in the Cambro-Ordovician sedimentary rock sequences at a depth of 4 to 6 km, while 95% of the resource is hosted by the underlying Precambrian basement.