Today, the majority of countries obtain their electricity from carbon sources, and yet there is a proven technology that, by absorbing energy from the subsoil, makes it possible to avoid using electricity, coal, and even natural gas, to generate heat.

Geothermal energy is very clean and does not lack advantages in the energy transition. It is renewable, on the scale of humanity. It is an ecologically sustainable solution. Geothermal energy lies in the exploitation of the thermal energy of this immense reservoir that is the Earth. Each kWh recovered helps limit greenhouse gas (GHG) emissions. Also, the kilowatt-hours (kWh) that we take from the basement would be dissipated anyway. The only difference is that by taking them in a controlled way, we can put them to good use for the environment.

All you have to do is dig a well in a body of naturally hot water and pump out the liquid, before reinjecting it once its calories have been consumed. The "free" heat from the subsoil can thus be used either to produce electricity or, which is often the most practical, as a source of heat to supply district heating networks.

Crédit image © par Getty image, Aerial view of thermal power generation and solar power plant.

"It's one of the most energy-efficient sources of heating and cooling energy," explains Philippe Pasquier, professor at Polytechnique Montréal and holder of the Geothermal Research Chair on the integration of permanent column wells in institutional buildings. However, less than 1% of the population invests in geothermal energy. On a large scale, deep geothermal energy, which consists of drilling several hundred meters to reach the heat-carrying layers, makes it possible to obtain industrial quantities of heat.

Greenhouse gas (GHG) emissions from buildings total 17% of emissions in Canada, mainly due to the use of fossil fuels for heating. Geothermal energy, on the other hand, does not emit GHGs…

The urgency of the energy transition is pushing more and more countries to review their position vis-à-vis this source of energy. In France, its use is even on an upward slope, as shown by the figures from the Ministry of Ecological Transition: in barely ten years, the quantity of energy recovered from the subsoil has increased by +100%.

Image credit © by polymtl.ca, Philippe Pasquier, associate professor in the Department of Civil, Geological, and Mining Engineering at Polytechnique Montréal, in front of the geothermal research unit.

Also, geothermal energy is entering the era of modern drilling by adopting smart drilling. Utilities have applied the multi-drain drilling method enabling the emergence of a major technological innovation that is expected to increase yields. In concrete terms, this involves creating several heat circulation networks within the heat-carrying layer, increasing the exchange surface with the energy reservoir that is our subsoil, each installation thus increasing its efficiency.

At the end of 2021, the technique was tested in a deep geothermal project in Vélizy-Villacoublay in France. The results showed an improvement in drilling leading to a doubling of the well's production rate, bringing it to 400 m3/hour. Multiplying the energy recovered at each site by two or more improves the acceptability of the technology and will reduce its costs accordingly.

At the same time, in Montreal, Philippe Pasquier with a team made up of specialists from Polytechnique Montreal, Hydro-Quebec, and school service centers launched demonstration projects in three Quebec schools "We are going to drill a hole that can reach 500 meters depth. The idea is to exchange heat with the basement to heat or cool a building at a lower cost”. The construction of the first permanent column wells at the Clé-des-Champs elementary school in Mirabel was to begin in the summer of 2021.

Image credit © by Franceinfo, The adoption of the Paris Agreement on 12 December 2015 in Le Bourget (Seine-Saint-Denis). (ESPECIAL/ NOTIMEX/ AFP).

At a time when each kWh of renewable origin represents an improvement in the trade balance of each signatory country to the Paris Agreement aimed at reducing GHG emissions (2015), there is no doubt that the use of geothermal energy will accelerate.

Our insatiable energy needs force us to look for innovative solutions and geothermal energy, which remains one of the cleanest sources of energy, could be one of the possible solutions for the future of nations.