Fed by a geothermal doublet using the Dogger limestone aquifer lying at a depth of about 2,000 metres and with a water temperature ranging from 55°C to 80°C, the heating network needed a new heat doublet (production and injection shafts) to replace the existing outdated system. Entrepose Drilling drilled the new doublet to a depth of 2,000 metres to tap the hot water layer in 2015.
In parallel with the commissioning of the new shaft, work was started in 2016 to permanently close the shafts sunk in 1983. The project was awarded to Entrepose Drilling. Its teams began work at the site in October 2016. The work, scheduled to take between three and four months to complete, will close off the facility in accordance with best practices applying to wells and shafts.
Tremblay en France opted to continue geothermal operations for a period of 30 years. The natural energy source, which is both cost-effective and sustainable, will generate space and hot water heating for some 4,300 housing units in the city centre and for several public facilities.