Assessment of the geothermal potential of the subsurface as a sustainable energy choice
Diagram of different geothermal heat sources, used for discussion for eco-neighbourhood planning (2011).
Your issues and needs
Given the uncertainty involved in fossil energy prices and the need to reduce its ecological footprint, the integration of renewable energies such as geothermal energy in the energy mix has a promising future.
Defined as the natural heat of the subsurface, it can be exploited sustainably to meet heating, cooling and domestic hot water needs and offers many advantages for socio-economic stakeholders having to control their energy requirements, particularly in areas outside networks that are thus obliged to use energy sources that emit a high level of greenhouse gases (fuel oil, gas, etc.).
Available locally and continuously across a large part of France, geothermal energy can be exploited with minimum impact on the environment. It significantly reduces energy bills and greenhouse gas emissions.
Whether for surface geothermal energy (at a depth of less than 200 m) or deep geothermal energy (beyond 200 m), this mature technology is a well-adapted solution for covering the thermal needs of buildings in all sectors, provided that its actual potential for optimising energy performance is carefully studied beforehand.
Regional map of the energy potential of vertical geothermal heat exchangers. Example of the Centre-Val de Loire region.
Our added value
As a major player in geothermal energy, BRGM, in conjunction with the professional sector, promotes and develops this resource in all its forms.
BRGM is therefore developing various tools (maps, methodologies, etc.) for geothermal energy stakeholders such as contractors, architects, engineering offices, public decision-makers, manufacturers of all sizes, private individuals, etc., to provide them with reliable information to guide their energy strategy by considering the opportunities for deploying geothermal installations.
Its work is based on multi-criteria analyses in order to evaluate the potential productivity in relation to energy needs while ensuring sustainable management of the resource and the installation:
- Characterisation of the resource and its geological (lithology, structures), hydrogeological (permeability, porosity, transmissivity) and geochemical (fluid composition) properties, identification of the aquifers and their geometry,
- Evaluation of the potential productivity of the resource: thickness and depth of access, temperature and flow rate of the fluid,
- Evaluation of the performance of the installation: extractable heat (MWh), Coefficient of Performance (COP: ratio between the energy produced and consumed), annual running time of the Heat Pump,
- Estimation of drilling costs, energy production costs (cost per MWh), environmental gains (carbon content of the heat produced),
- Recommendations as to the type of geothermal energy to be preferred, the power of the heat pump, the sizing of the geothermal exchangers,
- Integration of environmental and social issues (life cycle analysis, social perception, etc.).
This non-exhaustive methodology is adapted to the expectations of stakeholders in order to provide a tailor-made response to their problems at different scales within France (metropolis, municipality, district, network of buildings, study area) and abroad.
Means of analysis
- Feasibility report on the integration of geothermal energy (inventory of available information, degree of interest in using geothermal energy in the study area and expert appraisal),
- Inventory and atlas of surface and deep geothermal resources,
- Techno-economic feasibility study,
- Energy simulation of an operation according to different scenarios and over several years,
- Acquisition of additional data (geophysical exploration campaigns, geometrical and lithological mapping of strata, etc.).
- Géothermies.fr: website containing all the information needed to develop a project (data on the available resource, cartographic illustrations, reports, installation guide, etc.).
- National: Study of a national method for evaluating the geothermal potential on vertical geothermal heat exchangers in the 0-200 m deep section – ADEME-BRGM 2017 project – BRGM/RP-67086-EN
- Regional: Evaluation of the very low enthalpy geothermal potential in the Limousin region – Project of the Nouvelle-Aquitaine Region, ADEME and BRGM 2018 – BRGM/RP-68117-EN
- Metropolis: Atlas of the very low enthalpy geothermal potential of Greater Besançon – Project of Bourgogne-Franche-Comté Region, Greater Besançon Conurbation Community, European Union and BRGM 2017 – BRGM/RP-67001-EN
- Special resource: CLASTIQ: CLAyed sandSTone In Question: research on the geothermal resources of clastic reservoirs in France (Paris basin and Rhine Graben) – ADEME-BRGM project 2008 - BRGM/RP-56626-EN