Alfortville's first geothermal network (1986)
France developed deep geothermal in response to 1970s oil shocks. Alfortville ran a feasibility study in 1983, drilled its first well in 1986, and started the network on October 1, 1986, pulling 73°C water from the Dogger aquifer at 275 m³/h.
The doublet heated buildings across south Alfortville for 40 years, with spent water reinjected to protect the corrosive aquifer.
The system became a model for renewable district heating in the Paris region, but by the 2020s the wells were at end of life and needed replacement.
This new triplet replaces that original facility — the renewal of a key piece of France's geothermal infrastructure.
