Subsurface potential for the energy transition
The partner interview
Sophie Mourlon French Director-General for Energy and Climate
Why has the DGEC decided to work with BRGM?
Sophie Mourlon — The task of the General Directorate for Energy and Climate (DGEC) is to draw up and implement policy on energy, energy raw materials and the fight against global warming and atmospheric pollution.
With respect to the subsurface, the DGEC is working in particular to develop the geothermal sector, which has major potential for decarbonising heat production. The objectives of France's next energy and climate strategy call for a sharp increase in the pace of deep and near-surface geothermal energy projects. To accelerate this development, the government launched a national action plan in February 2023, which was then updated in December 2023.
What work is BRGM carrying out in this framework?
S.M. — To implement the plan, BRGM is working to improve knowledge of the subsurface and thus encourage the launch of deep and near-surface geothermal energy projects. For near-surface geothermal energy, the first step is to map the thermal properties of the ground so that vertical geothermal probes can be installed. For deep geothermal energy, the work requires identifying and analysing sufficiently recent geological data (boreholes, seismic lines), particularly in regions that are likely to be able to exploit the resources identified in the short term (presence of a significant number of heating networks to be decarbonised, prospects for the deployment of new heating networks, etc.).
What role does deep geothermal energy play in overseas France?
S.M. — Overseas territories such as Réunion, Mayotte, Martinique and Guadeloupe are all located in active volcanic island regions, making them ideal for the development of geothermal energy, which is non-intermittent and carbon-free, particularly for generating electricity. To date, only Guadeloupe has a geothermal power plant in operation.
In the wake of the Act to accelerate the development of renewable energies, BRGM is preparing a report on the potential for geothermal energy in areas that are not connected to the French mainland grid, in particular La Réunion, which will be submitted to Parliament and made public. The geothermal potential of most of these islands is real, even though it needs to be confirmed by costly exploratory drilling (several million euros).
