Geothermal energy is the heat contained within the rock and fluid in the earth’s crust. It's a source of clean, renewable energy with a small environmental footprint.
Geothermal energy can be used directly to provide heat or indirectly to produce electricity. Direct uses include heat for buildings, agriculture—such as greenhouse heating—or industrial uses like pulp and paper processing.
Geothermal energy can also be used on a smaller scale by geoexchange (heat pump) systems in buildings and homes. The temperature, depth, and location of the resource, as well as whether fluid and permeability are present, determine the ways in which it can be used.
Range of Applications
- High temperature (above 80°C): Electricity generation from steam and very hot water.
- Medium temperature: Waste water treatment, aquatic centres, space heating, cooling systems.
- Low temperature: Heat pump systems.
Only resources hotter than 80°C when produced at surface through a well are governed by the Geothermal Resources Act.
Geothermal Power Plants
- Binary Power Plant: Uses geothermal water (120 – 180°C) and a second (binary) liquid that boils at a lower temperature to spin turbines. Power is generated in a closed loop and releases no emissions. Binary power plants are the most likely to be used in British Columbia.
- Dry Steam Reservoir: Uses produced dry steam (150°C or greater) to spin turbines.
- Hot Water Reservoir: Uses produced hot water (150 – 370°C) that flashes into steam and spins turbines.
Direct Use Geothermal
Heat used for purposes other than generating electricity is called direct-use geothermal. Medium temperature geothermal energy can be used to provide heat to buildings or for commercial and industrial purposes including:
- Hot spring bathing and health spas
- Pulp and paper processing
- Drying lumber
- Wool or produce
- District heating systems
Geoexchange systems, also known as "geothermal", "geothermal heat pump" or "ground source" heat pumps, are the most efficient means of heating and cooling a building and providing hot water. The earth's surface under the frost line maintains a nearly constant temperature (10 – 16°C), remaining warmer than the air above it in the winter and cooler in the summer. Using low temperature geothermal energy, a geoexchange system transfers heat stored in the earth or in ground water into a building during the winter and transfers it back into the ground during the summer.
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Sedimentary Basin Geothermal Systems
The sedimentary basin in Northeast B.C. contains several aquifer systems that contain warm water. In some locations this may be a viable source of energy for small scale electricity generation or for direct heat uses.
Enhanced Geothermal Systems
Most areas do not have geothermal reservoirs but the subsurface is still very hot. In this case a geothermal reservoir may be created by hydraulic fracturing. Experimental Enhanced Geothermal Systems (EGS) may provide power in the future.
Geothermal Energy in British Columbia
British Columbia is situated on the Pacific Ocean “Ring of Fire” and has several volcanic regions conducive to geothermal energy. Geothermal resources have been identified in several areas of B.C. and more areas are being explored. Geothermal exploration has not yet proceeded to the development of a geothermal power plant.