Geothermal energy draws hot water from below ground to produce heating and/or electricity before reinjecting the water back into the subsoil.

The hot water that comes out of the ground flows through a closed loop and releases its heat via a heat exchanger to another network, which then takes the hot water to radiators. A backup boiler system can provide additional heating when needed and can be used in cases where geothermal energy is unavailable.

Three types of geothermal energy

There are three types of geothermal energy, based on depth:

The benefits of geothermal energy

The French environment and energy management agency (ADEME) and the country's geological survey* (BRGM) see geothermal power as an "outstanding energy source" since it offers a whole array of advantages with virtually no drawbacks.

Geothermal energy in France

Geothermal is now France's third-largest source of renewable energy, and its leading source in Ile-de-France. It appears to have a bright future: the Grenelle Environment Forum has forecast a sixfold increase in geothermal production by 2020! However, geothermal energy, especially at greater depths, requires extremely specialised technology and expertise, which can only be provided by established professionals and specialists. This applies to the entire project chain, including operation and maintenance. Dalkia can handle every aspect of this complex approach and has established itself as France's leading name in geothermal solutions.

*Les Enjeux des Géosciences. La Géothermie - December 2004.


Dalkia manages 27 geothermal facilities in France


The Grenelle Environment Forum has forecast a sixfold increase in geothermal production by 2020

Learning about geothermal energy

Geothermal energy is a renewable resource produced from “the earth’s heat" and is especially suited to meeting heating needs.

The assets of geothermal energy

The Bagneux geothermal heating network…The energy we need, underneath our feet !

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