Rueil-Malmaison entrusts its geothermal energy to ENGIE Solutions through GéoRueil, a dedicated ‘Renewable Energy’ company

Fully committed to its territory’s energy transition, the town of Rueil-Malmaison has entrusted ENGIE Solutions teams with the construction and development of a geothermal energy system in the town. To supply geothermal energy to the future heating network, the selected tender for which will be announced in spring, the town council and ENGIE Solutions have announced the creation of a renewable energy company called GéoRueil. A major step in the greening of resources to heat Rueil-Malmaison’s inhabitants.


A local, renewable resource for the future Rueil-Malmaison network

The town of Rueil-Malmaison has announced that it has chosen geothermal energy, the 3rd renewable energy source in France, to supply its future heating network.

The development of geothermal energy in the Rueil-Malmaison territory is reflected in the creation of a dedicated REn SAS (Renewable Energy joint stock company), GéoRueil. The new company dedicated to this major energy project is the result of the local partnership between ENGIE Solutions, an 88.5% shareholder, and the town of Rueil-Malmaison, an 11.5% shareholder.

For 28 years, GeoRueil will provide heat to the town's future network through a renewable, local and continuously available energy resource. The first phases of the geothermal system’s construction will begin in the spring of 2021, with commissioning in the summer of 2022.

The Rueil-Malmaison geothermal system will capture the resource at a depth of 1,500 metres deep with water at approximately 62°C. The use of geothermal energy will prevent the emission of 21,000 tonnes of CO2 into the atmosphere each year, which is equivalent to 11,600 vehicles on the move.

This ambitious project marks the continued development of low-energy geothermal systems in the west of Paris. ENGIE Solutions has invested more than €300 million in the sector in 10 years and has drilled 20 low-energy geothermal boreholes in the same period.


What is geothermal energy?

Geothermal energy is produced by recovering heat from groundwater, where the water temperature is between 50 and 95°C, and transforming it into energy. The collected heat is transferred to the urban network to supply heating or hot water to the buildings of a district. The water is then reincorporated into the groundwater.

This process is made possible by the so-called ‘two-well’ technique: an extraction well is used to recover calories from the geothermal water, and a re-injection well is used to restore the entire volume of extracted water into the groundwater table.

"The use of the geothermal resource in the Rueil-Malmaison territory and the creation of GéoRueil embody ENGIE Solutions' ambition to help communities find solutions that are adapted to their needs and to local available resources,” says Aurélie LEHERICY, Assistant Managing Director of ENGIE Solutions Villes & Collectivités. "We are proud to accompany the town of Rueil-Malmaison in the construction of this geothermal energy system. It is a fine example of our ability to adapt available technologies to the energy transition specific to each town, for the benefit of its inhabitants."

For Patrick OLLIER, Mayor of Rueil-Malmaison, former Minister, President of the Greater Paris Metropolitan Area: "In the face of the ecological emergency, local authorities must adapt and commit themselves immediately to the search for new balance and innovative solutions. That is why Rueil-Malmaison, which for a long time has played a part in accelerating the energy transition in its territory, naturally chose ENGIE Solutions to put a geothermal energy in place.  As the mayor of Rueil-Malmaison, but also as the President of the Greater Paris Metropolitan Area,it is my responsibility to boost this process in favour of clean energy, for the benefit of the environment and residents. 


Key figures on the geothermal energy

  • 11.3 MW: heating plant power
  • 1,500 metres: depth of the wells
  • 2,200 metres: total length of the wells
  • 62°C: temperature of the extracted water
  • 21,000 tonnes of CO2 prevented from entering the atmosphere, which is equivalent to 11,600 vehicles on the move