Results

The first scheme emphasizes geothermal potential in terms of heat content. Gradient temperature and heat flow have the highest weights due to these factors being a direct indicator of the quality of the heat content. The weighing scheme is shown below the map, and has a consistency ratio of zero. The sites with the highest predicted potential are distributed in the southern part of BC, particularly in south-west BC, although there are some areas with moderate geothermal potential in the north and mid west part of BC. This map should be used in the scenario that having sufficient temperatures is your main concern.

The second scheme emphasizes geothermal potential in terms of permeability. The weighing scheme is shown below the map, and has a consistency ratio of 0.012. Due to the presence of faults in most of BC, the predicted geothermal potential in most of BC is at least moderate, although once again, the south part of BC has the areas with the highest predicted geothermal potential, especially in south-west BC. The mid-west part of BC also has moderate predicted geothermal potential. This map should be used in the scenario that you want to use hydrothermal resources with high temperatures, which is currently the most cost effective situation a geothermal power plant can be set up. This is also a good map to use for to locate areas with sufficient permeability to set up binary cycle geothermal plants, which require sufficient permeability but not extremely high temperatures.

The equal weight scheme emphasizes all factors equally, and the weighing scheme is shown below the map. Two randomly chosen factors were given a weight of 16 instead of 17 to ensure total weight added up to 100. Considering all factors, the areas with a more predicted favourable geothermal potential are in the south part of BC and in the middle of BC.

Discussion

In all three generated maps, the southern part of BC had areas with the highest geothermal potential. There was also one area in south-west that had the highest predicted geothermal potential in all of BC, which actually corresponds to the location of Mount Meager, which is the most northern volcano in the cascade mountain range (Allen et al 2000). The area around Mount Meager is known to have high geothermal potential due to high volcanic activity, and has been explored since 1980, with test drilling starting in 2003 (Allen et al 2000). Mount Meager was projected to start producing power in early 2010 but has faced some recent setbacks.

Overall, the results from the three generated maps do not match up very well with the estimated geothermal potential in the “Geothermal Resources of British Columbia” map by Fairbank & Faulkner (1992). Only the southern and north-west parts of the three maps match with the “Geothermal Resources of British Columbia”. This may be because the “Geothermal Resources of British Columbia” map uses much more information that is not available in digitized format, such as more detailed information about local environments and geology.

The results from the three generated maps do have a somewhat decent match with the “Resource Factor Map” in Sarah Kimball’s thesis (2010), which has a weight of 80% for factors affecting temperature and a weight of 20% for factors affecting permeability. This is partially due to similar data sources being used, although the maps in Sarah Kimball’s thesis have more factors taken into consideration.

Using continuous classes (rasters) to map geothermal potential does provide more resolution locally, and does not seem to affect the overall results too greatly, as the trends observed in the three generated maps have similar trends as Sarah Kimball’s “Resource Factor Map” map. Whether the accuracy of our data is high enough to warrant the resolution of the generated result is not clear, as we do not know if the data gathered was meant to be used with such precision. With reliable data sources, using continuous classes to map geothermal potential can provide better results.

Improvements that could be made for this project include incorporating more data sources and having more concrete guidelines for the relationships between factors that many affect geothermal potential and geothermal potential. The maps generated from this project have achieved their purpose of providing a guideline for potential areas that can be further explored and surveyed to determine geothermal potential. Most geothermal sites, such as the Mount Meager site, require much further local exploration even after being discovered, and GIS mapping may also be useful for mapping at more local scales for geothermal potential.