Suitable Regions for a Geothermal Energy Facility in Alberta, Canada Ana Andrijevic, Rodrigo Narro Perez and Victoria Tweedie McMaster University, Advanced Raster GIS
Background and Purpose
Greenhouse gas emissions are a prevalent concern. High emissions and costs from non-renewable energy resources have sparked increased research into Canada’s potential for cleaner and more sustainable energy sources5. In particular, geothermal, a method of harnessing thermal energy from the Earth’s interior as electrical energy demonstrates the potential to be a suitable renewable source of energy for various parts of Canada2,7.
A geothermal plant is essential to assist with Alberta’s rising demand for energy. Based on the outcomes of this model it is recommended that Alberta explore the very high suitability regions of Peace River as potential locations for a geothermal facility.
Study Area Currently, Alberta produces 90% of its electricity (13,898 MW), using fossil fuels1. The adoption of geothermal energy as a renewable energy resource, could help to dramatically reduce fossil fuel emissions and foster electrical sustainability within the province. Geothermal temperatures greater than 80°C are used primarily for electrical generation, however Alberta contains regions of varying interior temperatures (Figure 1), and is capable of supporting geothermal systems with lower surface temperatures3.
Figure 1: Alberta’s geothermal potential at 5500m depth.
Decision Criteria Weighted Decision Criteria Decision Criteria Geothermal Potential Slope Proximity to Transmission Lines
Criteria The warmer the better The lower the better The closer the better
The closer to 2.4-2.6 km the Proximity to Water Bodies better Proximity to The closer the Road Networks better
The lower the better
Rational Higher geothermal temperatures ideal for medium and high geothermal systems Lower slopes are easier to set up an energy plant on Minimize costs associated with constructing additions to transmission lines Anything farther away or closer could either increase risk of water contamination or decrease access to water supplies. Minimize costs associated with transportation Lower elevations reduce the amount of transport and increase accessibility
Weight Ratio Pairwise Estimation Comparison
Straight Rank Rank Sum 1
Decision Constraints Decision Constraint
Not on a body of water
Only in open area
Higher geothermal temperatures ideal for medium and high geothermal systems Avoid controversy of constructing the facility on lands previously in use (ie. Commercial, residential, industrial)
Region must be greater than 1km2
1km2 is the minimum suitable area for a geothermal facility6
Figure 2: Suitable sites for a geothermal facility in Alberta, Canada. Different colours establish ranked regions of preferred suitability, among those that are suitable. The selected Peace River region contains several very high, and medium-high suitable sites. The weighted decision criteria, pairwise weighting, and constraints were applied to study area in order to determine suitable locations for a geothermal facility. The most suitable regions appeared to be located in the South-Central and Western portion of the province (Figure 2). The selected region was chosen because it contains a variety of very high and high suitability locations for a geothermal facility, in addition to it’s proximity to the small community of Peace River, which could be sustained by this renewable energy source.
Sensitivity Analysis Sensitivity analysis was performed (a) (b) using rank sum and ratio estimation. While rank sum assumes that factors are weighted at equal intervals from one another, ratio estimation provides a fairly subjective and arbitrary estimation. The two approaches both contain the same regions within their maps, however the rank sum appears to have more intermittent patches with different suitability ranks, whereas the ratio estimation displays a more clumped style. Both the rank sum and ratio estimation approach displayed the same sections of the Peace River Figure 3: Sensitivity analysis of pairwise comparison region to be of very high suitability and model (a) ranking approach using rank sum; (b) rating medium-high suitability. These two approach using ratio estimation weighting approaches provided similar results to that of pairwise comparison, suggesting that the weighting approach selected has a small influence on the regions identified by the factors and constraints.
The first method of improvement might be to decrease the cell size in order to raise the data resolution and present more accurate findings, however that of the data obtained limits this resolution. Next, the land use constraint might have been fairly limiting. While open areas are the most ideal regions, other land types such as residential, commercial, industrial, and parks are also possible realistic locations. In this model the geothermal temperature selected was at a depth of 5500m, however there exists data for depths between 500 and 5500m at 1000m increments. Combining this data a geothermal gradient could be attained and applied in order to determine the regions with the most suitable geothermal temperatures. Additionally, when selecting geothermal plant locations, rock substrate is important. To attempt to use geothermal gradient and rock lithology, complex 3D models would be required. With the addition of this improvements, better suitable regions could be attain determine the most appropriate site for a geothermal plant.
Data Sources Natural Resources Canada Geobase – Digital Elevation Model, Road Networks Statistics Canada - Census Boundary DMTI Spatial Inc. – Water Bodies, Transmission Lines, Land Use Canadian Geothermal Energy Association (CanGEA) – Geothermal Gradient
1. Alberta Energy, 2013. Alberta Electricity Facts. Retrieved from http://www.energy.alberta.ca/Electricity/681.asp. 2. Grasby, S.E., et al., 2012. Geothermal Energy Resource Potential of Canada, Geological Survey of Canada, 322 p. doi: 10.4095/291488. 3. Grobe, M., & Bechtel, D., 2010. Geothermal Energy in Alberta - Opportunities and Challenges. Canadian Society of Petroleum Geologists. Retrieved from: http://www.cspg.org/documents/Conventions/Archives/Annual/ 2010/0925_GC2010_Geothermal_Energy_in_Alberta.pdf 4. Kagel, A., 2008. The State of Geothermal Technology - Part II: Surface Technology. Washington, DC: Geothermal Association for the US Department of Energy. 5. Majorowicz, J, Grasby, SE, Skinner, WR 2009. Estimation of Shallow Geothermal Energy Resource in Canada: Heat Gain & Heat Sink, Natural Resources Research, vol. 18, no. 2. 6. Northwest Territories Environment and Natural Resources (NWTENR), 2010. Geothermal Favourability Map Northwest Territories. Retrieved from: http://www.enr.gov.nt.ca/_live/documents/content/ Geothermal_Favorability_Report.pdf. 7. Rybach, L., 2010. CO2 Emission Mitigation by Geothermal Development – Especially with Geothermal Heat Pumps. Proceedings World Geothermal Congress 2010, Bali, Indonesia, 25 -29, April 2010.