Geological, Economical and Environmental Assessment of Combined Geothermal Power and Heat Generation in Québec, Canada

Abstract

The south-eastern territory of the province of Québec (Eastern Canada), a region located along the Saint-Lawrence River Valley, including the Gaspésie and the Madeleine and Anticosti Islands, has been identified as an interesting area for the future use of deep geothermal energy several decades from now. This region includes a thick 1-5 km sedimentary rock wedge deepening southwest towards the Appalachian disturbed belt front. The deep part of the sedimentary wedge offers the potential to produce geothermal heating and power from the deep aquifers in the future. Relatively elevated heat flow densities in some thermal anomalous areas (i.e. more than 60 mW/m2) also result in prospects for temperatures above 120°C at about 4 km in the sedimentary aquifers. Additionally, geothermal power and heat production from hot dry deep granites located below the sedimentary cover can also be considered using Enhanced Geothermal Systems (EGS). On the other hand, Northern Québec, a vast territory covering nearly 1.2 million km2 of land located north of the 49th parallel, presents very low mean annual surface temperatures and a relatively low average heat flow density of about 40 mW/m2. This area would require deeper drilling for heat mining, i.e. 80°C at a depth of about 4.5 km. In the medium and long terms, geothermal energy could be feasible in the province of Québec with positive future energy and environmental impacts.