As early as 1975, concessions could be obtained for exploiting geothermal resources; the regulations for exploiting them were laid down in the Mining Code. With the creation of GEOCHALEUR in 1978 and the French Agency for Energy Management (AFME) in 1982 drilling programmes were undertaken in the Paris and Aquitaine basins.

11 years of research in geothermal energy

In 1983, AFME and BRGM decided to combine their efforts to develop geothermal energy, which involved reorganising BRGM's geothermal energy department by separating its activities into three units under a new energy sub-division. They then established:

• The IMRG (Joint Geothermal Energy Research Institute) to develop new concepts for the use and exploration of geothermal resources (clay and sandstone reservoirs, heat storage, hot dry rocks); 
• The SPG (Public Geothermal Energy Service), whose main role is to disseminate knowledge about geothermal energy resources and to take part in promoting this form of energy; 
• Subsidiary engineering activities, which began in 1985 with CFG (French Geothermal Energy Company), BRGM's first service subsidiary, involving nearly 50 people.

Following the 1986 oil glut, Geothermal energy activities focused on maintaining the facilities and solving corrosion deposit problems that jeopardised the sustainability of existing facilities.

The IMRG took an active part in the AFME General Deep Geothermal Energy Programme, together with its partners Schlumberger, Armines, the Paris VI University and Garchy applied geophysics laboratories and the EDF Materials Studies department. It was also actively involved in research work at the European level.

Overall, the IMRG, hosted by BRGM, operated with the support of ADEME and the European Union from 1983 to 1994.