CFG Services, making geothermics simple. A subsidiary of the BRGM.

Job vacancies

What is geothermal energy ?

A renewable energy under the surface of the Earth

The word GEOTHERMAL comes from the Greek “gêo” (earth) and “thermos” (hot). Therefore, it is a renewable energy stored as in the form of heat under the surface of the solid Earth.

Geothermal energy arises from the heat produced by the decay of radioactive elements in the Earth's crust. The produced heat is subsequently carried by underground water.

Geothermal energy is classified according to the enthalpy of the resource, i.e. according to the energy content of the geothermal water :

High enthalpy or high-energy or high temperature resources (temperature above 160°C) and average enthalpy resources (temperature between 90°C and 160°C) can generate electricity by thermoelectric conversion.
Example : The Bouillante (Guadeloupe) geothermal power plant.

Low enthalpy or low energy and low temperature resources (temperature between 30°C and 90°C) allows direct use by heat transfer.
Example : The Paris Basin operations, based on the technique of the geothermal doublet, for which to multiply the calories are transfered to district heating networks by plate heat exchangers.

Very low enthalpy or very low energy or very low temperature resources (temperature below 30 °C) requires the use of thermodynamic systems such as heat pumps to multiply the calories.
Example : Heating a single family home or a building.

Bouillante Geothermal power station, Guadeloupe

Plate heat exchanges in the geothermal plant of Chevilly Larue

In summary...

Geothermal energy is a natural mineable resource, which enables the local production of electricity, heat or cooling, in line with needs a requirement expressed above ground by a network, an installation or an industrial process.

You can find more information, on the site

December 2017

the 13th national meeting of AMORCE

Our Chief Executive Office Eric Lasne was a key note speaker during the 13th national meeting of AMORCE on district heating. The round table dealt with the renewable energy contribution…

more info

3, avenue Claude Guillemin - B.P. 46429 - 45064 Orléans Cedex 2 / France
Tel. 33(0)2 38 64 31 22 - Fax 33(0)2 38 64 32 83