Deep Geothermal Energy
Geothermal heat comes from the interior of our planet as the earth cools. Radioactive decay within the crust also contributes to this heat flow.
In regions close to volcanoes, or where the earth’s crust is being stretched (e.g. Iceland, Philippines, Mexico, and the western United States), large amounts of geothermal energy can be extracted and used to generate electricity with low emission of greenhouse gasses. In these locations, hot water is naturally present in the upper 1 to 2 km of the earth, and natural fractures allow the hot water to be extracted, carrying heat to the surface.
In other locations, hot rocks can be found at depths of 3 to 10 km, but there is no water or fracture network to bring the heat to the surface. To extract the heat, a network of fractures must be artificially created in the rocks and then water is pumped through the rocks to extract the heat. This is called an Engineered Geothermal System (EGS).
Even if subsurface temperatures are not high enough to generate electricity, geothermal energy can still be extracted for direct use in heating.
Why Is this Research Important?
Vast amounts of natural gas are currently burned to produce the hot water needed for oilsands processing (about 6% of Canadian consumption). Our research explores whether geothermal energy—a renewable source of energy with a low environmental impact—could be used to heat this water. Geothermal energy may be a cost-effective heat source for oilsands processing and for reducing the amount of natural gas currently burned (in this way lowering greenhouse gas emissions).
This project concentrates on the areas around Fort McMurray and Peace River in Alberta, where there is a demand for hot water. We will be determining the best locations and techniques for this type of geo thermal development in Alberta and laying the groundwork for potential future investment.
Our research uses the following approaches:
- Revising the database of subsurface temperatures to find places with the highest temperatures close to the surface
- Combining geological and geophysical imaging to determine the properties of the rocks beneath northern Alberta, including seismic and electromagnetic imaging methods
- Determining the best locations/directions to artificially fracture the rocks, so that fluids can be made to flow through the rock and extract heat
- Using computer simulations to determine how best to extract heat from the rock
- Assessing the economics of this process
Dr Ernst Huenges
Professor and Head, International Centre for Geothermal Research IGC
Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Dr Martyn Unsworth
Department of Physics/Department of Earth and Atmospheric Sciences
University of Alberta
Edmonton, Alberta, Canada