Groundwater Use for Residential Geothermal Heating - Approval in the Bow Basin

Groundwater is an increasingly important resource in southern Alberta. Not only is groundwater becoming more important as a water source, but it is also a resource that can supply heat. In January 2008, Alberta Environment issued an "approval" under the Water Act to access the heat energy from groundwater for use in a geothermal heating system at the new Spring Creek Mountain Village development in Canmore. This use of groundwater did not require a water licence; rather it required an "approval" to use the groundwater for its heat and is unlikely to negatively affect the Bow River watershed.

This approval comes after a yearlong wait while Alberta Environment determined if the request for groundwater use in the recently closed Bow River basin was acceptable. Because the Bow sub-basin is closed to new applications for water licences, approval of the non-consumptive use of groundwater as a medium to extract heat energy needed to be examined closely. In this case, the long-term environmental benefit of geothermal systems as an alternative to fossil fuel-based heating systems was a critical factor in the decision to approve the groundwater.

Use of groundwater for geothermal heating in residential developments is non-consumptive (i.e., water is not lost from the system). To ensure that these activities have a minimal negative impact on the local and regional hydrology, Alberta Environment requires special approval under the Water Act. Potential impacts on the aquifer must be assessed to avoid overexploitation and ensure the geothermal heating system will not excessively change aquifer temperature or pollute aquifer systems.

Regulating groundwater for geothermal activities in Alberta

Employing groundwater for geothermal heating in Alberta requires an application to Alberta Environment for an "approval" under the Water Act.

While an approval is not required for groundwater exploration—often used to determine if the local geothermal conditions are appropriate to support a geothermal system—it is mandatory for utilizing groundwater in functioning geothermal energy systems.

This can be confusing because other water "uses" under the Water Act such as irrigation, municipal water demands, and water for cooling in thermal power generation do require a water "licence", which allows for the diversion and use of water (AENV 2003).

An approval under the Water Act is quite different.

"An approval allows the drainage of water for the purpose of subsurface soil drainage for aggregate mining, construction, or groundwater remediation where the water is not needed for any ‘use'. The approval identifies the holder's name and address, legal land location, conditions under which the drainage can take place, and an expiry date (term of the approval), etc." (AENV 2003)

Approvals for employing groundwater in localized geothermal energy systems are required for the activity of "draining" groundwater and extracting the heat energy. This activity does not constitute "use" of water under the Water Act and therefore does not require a licence, unless a significant amount of groundwater being used in a geothermal energy system is being transported long distances (AENV 2003).

Alberta Environment acknowledges the benefits of using geothermal heating as an alternative heating source and reducing dependencies on fossil fuels. Granting approvals for groundwater use in geothermal heating is becoming more common within the department.

If you are interested in learning more about approvals for groundwater for geothermal use please consult Alberta Environment's Groundwater Evaluation Guideline. This guide provides further information on the technical aspects of approvals and requirements for submitting an application under the Water Act.

Geothermal Energy

In a commercial sense, geothermal energy refers to the heat sources contained within the Earth that can, or could, be recovered and exploited by humans.

While temperatures above ground change a lot from day to day and season to season, temperatures in the upper 10 feet of the Earth's surface hold nearly constant. For most areas, this means that soil temperatures are usually warmer than the air in winter and cooler than the air in summer. This geothermal energy gradient (based on the same properties that make any basement cooler in the summer and warmer in the winter) is a considerable energy resource that can be used to heat and cool buildings. Since heat is continuously produced inside the earth, geothermal energy is considered a renewable energy source.

Exploitation of geothermal energy is not a new concept. In fact, it has been used throughout the world for thousands of years. However, growing concerns about the long-term impacts of fossil fuel-based energy have sparked a renewed interest in geothermal power.

Role of groundwater

One of the ways that geothermal heat energy can be extracted from the earth is through groundwater using a "closed loop" system. A closed system works in the following way:

1. Plastic pipes are buried under the ground.
2. Groundwater is placed in the pipe to absorb heat from the surrounding ground around the pipe.
3. The warmed fluid returns to the building, where a heat exchanger transfers the heat from the fluid into warm air or water.
4. A compressor upgrades the heat.
5. The warmed air or water is circulated throughout the building. Air is circulated through ducts and water is circulated in radiators or flooring panels.

The system can be reversed to provide cooling in the summer. The warm air from the building is discharged back into the circulating water, which then dissipates into the ground.

Geothermal heat energy can also be extracted from groundwater in wells using an "open system". The source must be large enough to store sufficient heat. The open system works in the following way:

1. Water is pumped from a deep well or aquifer.
2. The water passes through a heat pump that transfers the heat from the water into warm air or water.
3. A compressor upgrades the heat.
4. The warmed air or water is circulated throughout the building. Air is circulated through ducts and water is circulated in radiators or flooring panels.
5. The cooled water is returned to the original source.

Similar to a closed loop system, an open system can be reversed to provide cooling in the summer.

For more information on geothermal heating check out:

B.C. Ministry of Energy, Mines and Petroleum Resources website outlines the B.C. Geothermal Resources Act and information on exploration.

Geothermal Resources Council (GRC) provides workshops and publications for those involved with the geothermal industry.

Canadian Geothermal Energy Association is a non-profit association promoting the development and use of sustainable geothermal energy in Canada.

Natural Resources Canada presents information on the application of earth and geothermal enerty.

International Geothermal Association offers detailed information on geothermal energy and its uses around the world.

Sources:

Alberta Environment (AEVN), 2003. Groundwater Evaluation Guideline. Information required when submitting an application under the Water Act.

Foubert, Tanya. January 8, 2008. Water licence granted despite ban: Condominium project taps geothermal heat.

Natural Resources Canada (NRC), 2006. Technologies and Applications, Earth Energy and Geothermal Energy.