Answering Your Top 3 Questions on Geothermal Energy Development in Alberta
Terrapin • March 30, 2021
4 minute read
Since we announced our collaboration with Akita Drilling for the Alberta No. 1 exploration well, Terrapin has received numerous questions about the project, geothermal energy, and the bridges between geothermal and oil and gas. We wanted to dive deeper into the three most pressing questions we have seen recently echoed by Albertans.
Why drill new wells for geothermal energy when we have hundreds of orphaned wells?
Only a small percentage of oil and gas wells are suitable for drilling for geothermal energy. Generally, geothermal wells require
Wellbores larger in diameter and are drilled deeper than oil and gas wells
High fluid flow rates (greater than 30 litres per second)
Higher temperature in order to be economical for power generation (greater than 110°C).
There is the possibility of using some existing drilled wells for direct-use applications or as monitoring wells. For direct-use, fluid flow rate requirements are lower, and fluids as cool at 40°C can be put to useful work. However, location is an important factor; direct-use wells must be relatively close to a load, or a space to receive and utilize the heat, as heat can only be transported a limited distance – around 10 to 15 kilometres.
Another concern with using existing wells is “well integrity.” This refers to the condition of the well – what shape is it in? How many years has it been in use, and what types of corrosion or scaling might the well bore have been subjected to? Safety and liability are critical factors when contemplating the repurposing of wells.
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That being said, existing oil and gas wells are still a valuable asset for geothermal energy development in the province as they provide extremely useful information about the subsurface; the regional study conducted for the Alberta No. 1 project alone did detailed evaluation of over 4,000 wells to date. These wells provide an extensive database that help the Alberta No. 1 project team understand the temperature range, stratigraphy, and formation properties of the location to be drilled.
Orphaned wells have other uses as well – check out the work that Regenerate Alberta has done to convert these wells into valuable resources.
In addition to the wellbores, there is a significant potential benefit from the use of previously disturbed infrastructure. Alberta No. 1 is taking advantage of already disturbed sites rather than building new roads and pads, further reducing the environmental impacts of clean energy development.
Located in the Municipal District of Greenview, Alberta No. 1 utilizes the data from existing oil and gas wells and previously disturbed infrastructure, reducing its impact on land use. (Photo: M.D. of Greenview)
How else does oil and gas drilling and geothermal drilling compare?
Geothermal drilling has always “borrowed” from the oil and gas world but has also had to adapt techniques and equipment for some of the unique aspects of drilling and production of geothermal energy. Alberta is advantageously positioned in the Western Canadian Sedimentary Basin (WCSB), which is a low-temperature system, allowing for more synergies between geothermal and oil and gas drilling than that of a higher temperature system (e.g., Iceland).
The key difference between the two drilling techniques is the size of the wells required for geothermal power production. Due to the low temperatures of the fluids in the WCSB, large amounts of fluid need to be flowed to produce electricity. A geothermal power plant producing 5 MWe (net) at 120 degrees Celsius requires 300 litres per second of fluid. This is achieved through wide diameter bore holes and large electrical submersible pumps (ESPs).
Preparing equipment to log HS Orka injection well RN30. Drilled by Iceland Drilling rig Odinn at the Reykjanes high temperature geothermal field. (Photo: Catherine Hickson)
Geothermal wells at least 2000 metres deep, with pipe diameters of greater than 7 inches wide, are needed to handle the large flows required for power production. These large geothermal wells must also be designed to last. Geothermal production wells must withstand decades of hot, corrosive fluids, whereas oil and gas resource extraction wells typically lasts 5 to 15 years.
How does geothermal energy compare to other renewable/alternative resources?
Geothermal is the only renewable resource that can provide clean electricity while simultaneously providing heat on a massive scale. This thermal resource is also baseload, meaning it is available 24/7, 365 days a year. Considering how over 60% of Canada’s energy needs are for heating, the importance of reliable, renewable heat cannot be understated.
Geothermal energy can be provided to industries and facilities that require large amounts of heat and power, like commercial greenhouses. (Photo: Getty Images)
Geothermal energy production also takes up the least amount of surface area per megawatt compared to any other energy source, which further speaks to its minimal environmental footprint. According to the Massachusetts Institute of Technology, producing a single megawatt of geothermal energy requires 1,500 square metres of land. This is compared to the
10,000 square metres needed for a megawatt of nuclear energy
16,000 square metres needed for a megawatt of wind energy
40,000 square metres needed for a megawatt of coal-fired energy, and
66,000 square metres needed for a megawatt of solar PV-produced energy.
Compared to other renewable energy sectors, however, the geothermal energy industry in Alberta is at its infancy. Despite this, Terrapin believes Alberta has demonstrated capacity for delivering commercial-scale energy solutions and sits on top of a sedimentary basin with great potential for geothermal energy development. Combined with proven Albertan talent and a line of sight for a stable regulatory environment, the stage is set to produce homegrown sustainability stories with the heat beneath our feet.
Although we are delighted in the geothermal interest so far from the masses, we encourage clarification and transparency in the regulatory regime in order to provide a stable investment opportunity. Private companies and governments will continue to need to work hand-in-hand to really get this show on the road.