Reference, completed project

Valeautherm Occitania: developing the geothermal potential of thermal spas

With 28 resorts and 183,290 people (out of a total 576,000 nationally) taking the waters every year, Occitania has more spas than any other region in France. In over half of the resorts, temperatures at the well head exceed 30°C, constituting a natural energy source that remains insufficiently exploited.

12 September 2022

Fontaine sur le site de Saint-Thomas Les Bains à Fontpédrouse (Pyrénées Orientales).

Large sulphur spring (water temperature: 58°C) at the site of Saint-Thomas Les Bains in Fontpédrouse (Pyrénées Orientales).

The need

Led by BRGM with the support of ADEME, the Valeautherm Occitania project was set up to show that better use could be made of the geothermal potential of thermal spas in the Occitania region.

The results

The first step was to list the springs with a temperature of over 30°C, based not only on known thermal spas, but also on the information and data available in the databases (BSS) and in literature. A total of 34 sites were identified in the region (illustration below).

After making a detailed analysis of site characteristics and conducting a survey with the mayors, four sites (Rennes-les-Bains in the Aude, Ax-les-Thermes and Ornolac-Ussat-les-Bains in the Ariège and Bagnères-de-Bigorre in the Hautes-Pyrénées) were selected for a more detailed assessment of their geothermal potential and the practical possibilities for exploitation.

For example, unused resources with an estimated potential of 365 kW have been identified in the municipality of Ax-les-Thermes, where the water emerges naturally at a temperature of over 70°C. Residual energy is also available in the wastewater and could be recovered through a heat network, either a high-temperature system with a heat pump (power >300 kW), or a low-temperature network between 18° and 20°C.

Map of 34 identified sites (spas and other springs) with temperatures above 30°C.

Using the results

For each site, an opportunity analysis was drafted and submitted to the municipality. Each analysis constitutes a preliminary project whose purpose is to illustrate the geothermal potential and the possibilities for exploitation, and to encourage local authorities to pursue the process.