Geothermal energy harnesses underground heat at various depths. Applications include heating, cooling, air-conditioning, energy storage, steam production and electricity generation. This offers steady and local supply of efficient, clean energy. However, it represented only a very small share (barely 1% of the total) of final consumption of renewable heat in France in 2021. To address this, the French government has adopted an action plan intended to boost the sector.
One of the means for attaining the 2030 and 2050 targets
Heating currently accounts for over half of energy consumption in France, and is mostly produced from imported fossil fuels which generate high greenhouse gas emissions and are subject to significant price variation. In achieving the dual goals of decarbonisation and energy sovereignty, geothermal energy has a major role to play. Remember that by 2030, renewable energy is intended to cover 38% of energy consumption for heating and cooling in France (up from 22.3% in 2021), and the country aims to be carbon-neutral by 2050.
Different types of geothermal energy
There are two types of geothermal energy: near-surface or very low temperature geothermal energy (below 30°C), and deep geothermal energy at low to medium temperature (between 30°C and 150°C) or high temperature (above 150°C).
Near-surface geothermal energy harnesses heat from the top layers of sub-soil (less than 200 m deep) at low temperature (up to 30°C), using a ground source heat pump coupled with buried sensors, or boreholes that harness heat from shallow aquifers. In 2021, near-surface geothermal energy provided 4.8 TWh of renewable heat in mainland France (representing 0.7% of final consumption of renewable heat), through 207,400 ground source heat pumps. Nearly all (94%) of these heat pumps are installed in individual households, where they cover requirements for heating, domestic hot water, air-conditioning or ‘geothermal cooling’.
Deep geothermal energy taps into water above 30°C in deep aquifers (at depths of over 800 m) and can be used to heat groups of buildings, districts and/or industrial sites, either directly or through a heat network. The 72 facilities of this type currently operating in mainland France produce 2 TWh of renewable heat, representing 0.2% of final consumption of renewable heat. France’s geological features lend themselves well to deep geothermal energy, in particular the Paris Basin (Dogger aquifer), Aquitaine Basin, Southeast Basin, Limagne and Upper Rhine Plain. Most (87%) of these facilities are used for district heating through heat networks (between 50°C and 80°C). The rest are divided between industrial processes, the food industry and thermal spas (between 30°C and 180°C), industrial cooling (100°C), and electricity generation or co-generation (over 150°C) such as in Bouillante in Guadeloupe and Soultz-sous-Forêts in Alsace.
In total therefore, production of geothermal heat in France attained almost 7 TWh in 2021.
Geothermal resources in France
Every part of France lends itself to at least one of the geothermal technologies. As regards near-surface geothermal energy, ground source heat pumps could be installed in 99% of the country. For medium temperature deep geothermal energy, in addition to the Paris Basin and Aquitaine Basin (which currently have 49 and 17 facilities respectively), many other aquifers could be exploited. Finally, for the production of high temperature deep geothermal energy several volcanic regions could be harnessed in addition to Bouillante in Guadeloupe – for example in Martinique, Mayotte and Réunion. A number of rift valleys could also be exploited in addition to the Rhine Valley, such as the Rhône Valley and part of the Massif Central.
Source: ‘Panorama de la chaleur renouvelable et de récupération – Edition 2022’
An action plan to make France a leader in Europe
The action plan adopted by France in February 2023 is intended to speed up the deployment of geothermal energy, focusing particularly on doubling the number of domestic ground source heat pumps by 2025, and increasing by 40% the number of deep geothermal projects by 2030. This comprises six main courses of action: 1) increasing near-surface geothermal borehole capacity to meet demand from the residential and commercial sectors; 2) improving the regulatory framework to encourage the development of near-surface geothermal projects; 3) encouraging the installation of ground source heat pumps in the residential and commercial sectors; 4) identifying and developing under-exploited deep aquifers suitable for the construction of geothermal doublets for heating networks (comprising two boreholes, one for bringing the water up and the other for re-injecting it once used); 5) raising awareness and improving the skills of local actors; 6) stimulating new projects and encouraging new financial arrangements for geothermal energy. According to the Minister for Energy Transition, Agnès Pannier-Runacher, this plan ‘must enable the production of sufficient geothermal heat in 15 to 20 years’ time to save 100 TWh/year of gas, so more than the imports of Russian gas before 2022’.
Geothermal energy and lithium: a promising double act
Geothermal energy is ‘the only renewable energy capable of producing highly energy-efficient heating, cooling, chilling and electricity, available 24/7 in all seasons and irrespective of weather conditions’* but has another benefit of major importance today. Deep geothermal energy offers potential for the co-production of lithium, a resource in great demand for various aspects of the energy transition, such as batteries for electric vehicles, smartphones, laptops, etc. Lithium is found in the geothermal water extracted during the process. As well as recovering the heat, the lithium just needs to be extracted from the water before this is re-injected.
Several companies are already operating in this new field of ‘geothermal lithium’ (or ‘lithium brine’). These include the Eramet group working with Electricité de Strasbourg (the EU project EuGeLi); the young company Geolith, which is developing a specific extraction process (Li-Capt) that can be adapted to any type of brine; the start-up Lithium de France, the first independent operator for geothermal heat and lithium, which raised 44 million euro last March; and the Australian company Vulcan, with which the manufacturer Stellantis signed an agreement at the end of May to supply renewable heat to its site in Mulhouse, while also extracting lithium. It should also be noted that the French Association of Geothermal Professionals (AFPG) has several clusters including specifically: ‘Alliance Lithium’.
* ‘Panorama de la chaleur renouvelable et de récupération – Edition 2022’, AFPG, CIBE, FEDENE, SER, UNICLIMA, with ADEME.
