The scientific question of the month demystifies complex topics with simple, effective answers
With the energy transition in full swing, there’s one question on everyone’s lips: Where can we find more megawatts in Quebec? Answer: In abandoned mines! The King Beaver complex in the Thetford Mines region is a good example. Its geothermal potential could power heating and cooling systems on a large scale. But how?
It all starts with water
Disused open-pit mines contain massive quantities of water. While the surface temperature of the water changes with the seasons, it always remains stable at depth. For example, at the King Beaver complex, it stays at 4.6 °C. If that water is recovered by heat pump systems and piped to buildings, it can be used for air conditioning.
How does it work?
Heat pumps draw heat from the building that needs to be cooled, then sends it to the water in the pit, where it’s naturally kept at a stable temperature. The water in the King Beaver complex is estimated to have a cooling potential of up to 6 megawatts.
Where could this be used?
This system could be used to air-condition buildings near these abandoned mines that have high energy demands, like data centres with servers, greenhouses, and other industrial buildings. Industrial buildings with high process cooling requirements, such as the tailings processing plants being developed in the region, could also benefit from this geothermal potential.
If we can air-condition, can we heat too?
Yes, by reversing the cycle and capturing the cold from a building, we can cool the pumped water from 4.6 °C to 2 °C, releasing heat that can be transferred to the building. King Beaver is estimated to have around 2.5 megawatts of heating power.
But is there actually an advantage to doing this?
Absolutely! Even if the heat pump runs on electricity. Firstly, because transferring heat from a building through water rather than air is more efficient. Secondly, geothermal heating consumes much less energy than heating with electricity or natural gas. What’s more, taking advantage of a former mine doesn’t require any major drilling, and gives a second life to an unused site. At INRS, professors Geneviève Bordeleau and Jasmin Raymond are studying the King Beaver and Carey sites in the Thetford Mines region to evaluate this promising avenue.
