The most widely deployed technologies in the geothermal heat pump market for single-family homes (horizontal heat exchangers and vertical geothermal probes).
© Oeil pour Oeil - GRETA - Interreg Alpine Space ERDF
A national objective: large-scale deployment of geothermal energy in all regions
The systematic use of geothermal energy, which is still marginal in the energy mix, would be a major lever for decarbonisation and energy autonomy for buildings, and would therefore reinforce France’s energy sovereignty.
Near-surface geothermal energy (from a maximum depth of 200 m) is available across more than 90% of France and could cover at least 70% of the heating needs for buildings or industrial and agricultural processes. However, it accounts for only 1% of the heat produced today in France! Its large-scale deployment throughout the country would generate around 90 TWh of power per year, within 20 years. An additional 10 TWh could be produced within the same time-frame, by exploiting deep geothermal resources to supply energy for urban heating networks, in particular.
This is the goal of the Government's ambitious action plan presented in February 2023, which BRGM is helping to implement through actions and tools aimed at making both near-surface and deep geothermal energy accessible throughout the country.
A geothermal register for the widespread deployment of near-surface geothermal energy
The government's action plan aims to double the number of geothermal heat pumps installed in private homes each year, up to 2025. These now account for the vast majority of installations, with 195,000 of the 205,000 geothermal systems in France installed in single-family homes. These installations are currently based on two main technologies: horizontal heat exchangers and geothermal probes (see diagram opposite).
With this in mind, BRGM suggested creating a "geothermal cadastre" (land registry map of geothermal potential), based on the model of the solar power cadastre. It could be used to display the geothermal energy potential for a plot of land, and thus determine whether it is worthwhile installing a geothermal heat exchanger fed by a vertical geothermal probe.
Heat production accounts for50.00%of the country's final energy consumption
1.00%of this heat is currently produced by geothermal energy
Subsurface exploration to develop deep geothermal energy in new regions
The other way to develop this energy is by tapping deep geothermal energy – generally down to 2,000 metres – which is more complex to implement and requires a high population density on the surface, i.e. it must cater to significant needs. Currently, this type of energy system is mainly used in the Paris Basin, with some fifty heating networks in the Île-de-France region drawing heat primarily from the Dogger aquifer. However, this type of energy system can be developed in many other catchment areas in mainland France (see map opposite).
The government's plan aims to increase the number of deep geothermal projects by 40% by 2030. To support this ramp-up, BRGM, with the support of the French Ministry for Energy Transition and ADEME, plans to assist project developers by improving their knowledge of the subsurface in order to identify relevant geothermal targets and thus reduce the risk of operations failing.
Geosciences No. 27: Subsurface solutions for the Energy Transition
Geothermal energy, CO2 or heat storage, access to mineral resources and more. This issue of Géosciences looks at the potential of the subsurface for the energy transition.
Associating the subsurface with the energy transition may appear incongruous. Wind turbines, photovoltaic panels, or possibly hydroelectric dams and nuclear power stations come more readily to mind. And yet, the energy and ecological transition that will gradually lead us to develop low-carbon energy will require us to make increasing use of the resources and potential of the subsurface.
Issue 27 of BRGM's Géosciences magazine investigates subsurface solutions: geothermal energy, CO2 storage, heat storage and hybridisation of these different solutions with other sources of renewable energy. It also looks at access to mineral resources, which are vital to the success of the energy transition.