Since 2010, France has doubled its installed capacity in deep geothermal energy. Today, it is Europe’s second-largest producer of deep geothermal heat. To meet its ambitions in terms of renewable energy, France wants to give a boost to this local, high-performance, low-carbon energy source. Several exploration projects are currently underway, notably in the western Paris region and the southeast of the country.
THE ESSENTIAL
- 78 deep geothermal installations in France
- Most produce heat (total: 2.1 TWh)
- Two, including one at Bouillante in Guadeloupe, generateelectricity (total: 0.1 TWh)
- France is Europe’s2nd largest producer of deep geothermal heat, behind Italy.
They criss-crossed the roads and towns of Val-d’Oise, Hauts de Seine, Essonne and Yvelines over 40 days in March and April 2024.
“They? The vibrating trucks of the“Géoscan Île-de-France” project. These were tasked with scanning the subsoils of almost 100 communes in the south and west of the region to produce a map – a veritable echography of the subsoil – aimed at assessing their geothermal potential.
The aim is to help local authorities make the most of renewable energies by setting up deep geothermal operations to green their heating networks or create new ones.
What is deep geothermal energy?
This involves harnessing the renewable energy contained in geothermal fluids at depths of between 200 and 3,000 meters, at temperatures generally ranging from 30 to 90°C. It is used to supply urban heating networks and generate electricity.
Geothermal energy has many advantages. It is :
- renewable,
- low-carbon,
- efficient (1 kWh consumed in the well produces 20 kWh of heat)
- price stable,
- local (no transport),
- discreet (very little impact on the landscape),
- independent of weather conditions,
- long-life (geothermal power plants built in the 1980s are still in operation today).
Accelerating
Supported by the French Agency for Ecological Transition (ADEME), the French Directorate-General for Energy and Climate (DGEC) and the French National Geological Survey (BRGM), this exploration project in the Paris sedimentary basin is one concrete example of France’s commitment to geothermal energy.
The Pluriannual Energy Program (PPE) plans to double the use of geothermal resources by 2028. Today, geothermal energy is seen not only as a fundamental lever in the fight against global warming and rising energy prices, but also as a means of strengthening France’s energy sovereignty.
Another campaign of this type, this time called“Géoscan Arc”, isdue to start shortly in south-east France, around the Etang de Berre (Arc syncline). The area covered this time extends from Fos (in the west) to Aix en Provence (in the east), via Sausset les Pins (in the south) and Lançons de Provence (in the north). An initial information meeting was held on May 22, and the first explorations in the communes should begin later this year.
Many installations already in place
Seventy-eight deep geothermal geothermale deep geothermal power plants are already operating in mainland France, producing a total of 2TWH of heat.
Fifty-four of these are located in the eastern part of the Paris region (Seine Saint Denis, Val-de-Marne, Seine-et-Marne), home to the largest concentration of deep geothermal installations in the world. Today, they provide heating for one million people, and avoid the emission of over 400,000 tonnes ofCO2 per year compared with gas-fired heating systems.
The south-western quarter of France is home to around a quarter of France’s 78 geothermal power plants (see map below).
To the northeast, in the Bas-Rhin region, the Rittershoffen power plant, inaugurated in 2016, supplies a corn starch factory using water at 170°C drawn from an altitude of 2,500 meters. It is the only concession in France to produce heat for industrial use. A project is also underway at Illkirch-Graffenstaden, south of Strasbourg, under an exclusive exploration permit. However, the Vendenheim project, which was intended to co-produce heat and electricity, is currently suspended by prefectoral decree following the earthquakes north of Strasbourg in 2019.
Source: BRGM
As far as geothermal power generation is concerned, only two sites currently exist.
In the Bas-Rhin region, the Soultz-sous-Forêts sitesite, commissioned in 2008, comprises three boreholes at a depth of 5,000 meters. It generates 1.5 MW of electricity by harnessing the geothermal heat in the rocks.
Finally, in the French overseas territories, the centralale de Bouillante in Guadeloupelocated in a volcanic zone and commissioned in 1986, produces heat and electricity in cogeneration, thanks to a 1000-meter borehole. It is the first power plant in France to produce electricity.
This interactive map shows the location of all geothermal projects in France, including deep geothermal projects.
Plenty of potential to exploit
There are many areas in mainland France that could be explored in the same way as Géoscan’s, as the subsoil of mainland France has many untapped deep aquifer geothermal resources: Aquitaine Basin, Rhine Graben, Rhone and Bresse Corridors, Massif Central…
Potential areas for power generation in volcanic zones (cogeneration) have been identified in Martinique and Réunion, as well as in the Massif Central and Languedoc-Roussillon. Some are currently under investigation.
In addition to volcanic zones and sedimentary rocks, collapse trenches, such as those in the Rhine and Rhône valleys and in the Massif Central (Limagne), could also be favorable zones for deep geothermal energy, with temperatures reaching 110°C above a depth of 2,500 meters.
To be continued…