Techno-economic assessment of deep geothermal technologies for district heating systems on the South Shore of Montréal (Québec, Canada)

Geothermal district heating systems with deep boreholes (1.5 to 3.0 km) can be an interesting alternative to electric heating systems powered by hydroelectricity. The techno-economic potential of deep borehole heat exchangers and geothermal doublets (with and without reservoir stimulation) was assessed, and the results suggest that the latter installed in a permeable medium is more economically attractive than deep borehole heat exchangers. The economic analysis also suggests that the former systems can potentially provide energy at a lower cost than Hydro Québec’s minimum electricity selling price of 0.063 $/kWh (Rate D applied to domestic use for the first 40 kWh/day – 1st tier). However, geothermal doublets are a high-risk technology. Further field tests would be needed to fully assess their technological potential. Nevertheless, despite the risk and uncertainty, utilizing deep geothermal energy for district heating systems offers potential long-term benefits that surpass the challenges related to drilling and resource assessment.