France advances underground energy heating with new geothermal boreholes

Geothermal drilling has commenced in the Paris suburbs of Plessis-Robinson and Châtenay-Malabry as part of district heating initiatives intended to supply low-carbon heat to local communities.

The project is being led by Énergies Positives 92, a public energy utility for the Hauts-de-Seine département. The goal is to develop shallow (a few hundred meters deep) geothermal systems that can replace fossil-fuel-based heating for residential buildings, schools, and public services in these municipalities.

In Plessis-Robinson, drilling began on two boreholes of approximately 450 m depth, targeting geothermal gradients and heat extraction capacity for district loops. Installation includes vertical heat exchangers coupled with a water-water heat pump system and insulated piping networks to distribute heat.

In Châtenay-Malabry, a similar program is underway with a pair of boreholes in the 500m range, anticipated to provide heating for communal buildings and possibly expand to residential neighborhoods depending on performance.

Taken together, the two towns envisage an initial combined capacity sufficient to serve a few thousand homes, cutting reliance on gas and reducing carbon emissions in line with France’s energy transition policies.

Geothermal systems in the Paris area face challenges including subsurface thermal conductivity, urban underground constraints, interference with existing infrastructure, and regulatory approvals. However, local officials view this phase as a proof of concept for broader geothermal expansion across Ile-de-France.

Project timelines foresee construction completion and system commissioning by 2026–2027. Once operational, the system is expected to offer stable heating costs and reduced greenhouse gas emissions relative to conventional heating.