In the 1960s, the Croix Blanche district was built to increase the housing stock available in Vigneux-sur-Seine. Energy supply was considered when the new 2,500-home neighbourhood was developed, as a central boiler powered by fuel oil was installed to supply the community.

In 1985, the town began to use geothermal power to connect public facilities while minimising the environmental footprint.

Since 1 January 2017, the public service delegation was associated with a renewable energy recovery programme and upgrades to the network. This made it possible to connect a certain number of public facilities previously powered by fossil fuels to the geothermal power network in anticipation of new build programmes being completed.

The equivalent of nearly 7,000 homes were identified within a 3-km radius around the geothermal power plant, thus doubling the number of people supplied by the network. The new geothermal doublet (October 2018) safeguarded and shored up the used of geothermal power for the next 30 years.

doublet geohermal

Three gas/fuel oil boilers (each 8 MW) and a fourth 6 MW pure gas boiler, providing total installed capacity of 30 MW, provide a back-up power source to the geothermal district heating.

The geothermal doublet 

The geothermal doublet technique serves to extract the heat in the ground produced by rock formations, transfer it to the distribution network via heat transfer fluid, before the cooled water is sent back underground. The cooled water is reinjected back into the ground far enough away from the wells to not affect the temperature of the extraction well.