Geothermal Heating: Environmental Impacts, Optimization, and Remediation

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Reducing reliance on fossil fuels, by increased adoption of renewables, has become a worldwide priority to mitigate climate change and minimize greenhouse gas emissions. In Canada, the use of geothermal heating (or ground source heat pumps) has become a popular option for heating and cooling buildings and it is anticipated that, in the near term, most large buildings will include geothermal heating as part of their climate control strategy. However, very little is known about the environmental impacts of geothermal heating on the subsurface environment. Furthermore, few regulations exist for geothermal installations, groundwater management, and well spacing or depth. Specifications are left to vendors whose goals are to achieve specific heating/cooling objectives; potential impacts on the environment are secondary. ***The proposed research aims to quantify the environmental effects of a large-scale geothermal heating installation on groundwater movement and quality. A new numerical model will be developed that will provide the basis for optimizing geothermal heating for efficiency and impact on groundwater movement. By understanding effects on groundwater flow and quality, the possibility of redeploying geothermal heating as a remediation strategy for sites contaminated by industrial pollutants will be investigated. In this scenario, the rise in subsurface temperature will be leveraged to accelerate the breakdown of harmful compounds. The new model will be critical in this investigation, along with lab-scale experiments that will investigate low temperature effects on contaminant transport and biodegradation. This is the first time that the integration of geothermal heating and subsurface remediation has been investigated. The application is particularly relevant given the large number of developments on brownfield sites across large Canadian urban centres. The proposed research will inform guidelines and help guide Canadian policy on geothermal heating applications.**