Montpellier and its geothermal heating network

The challenge

The Hérault departmental council wanted to improve the energy and environmental performance of the departmental headquarters, the Domaine d'O, the Pierresvives archives and the Maison départementale des sports in Montpellier. The department invested €2.5 million for all the buildings.

The solution

To meet this challenge, we created a renewable heating and cooling network, fed by geothermal energy on a probe field. In other words, we chose to use the underground energy available on site (under an eight-year energy performance contract). The principle is simple: we placed 48 geothermal probes at a depth of 150 meters. They absorb the heat from the ground (where the temperature is 17°C all year round!), which is then used by a heat pump, whose reversible operation supplies the buildings with heat and cold depending on the season. In terms of control, our experts have connected the equipment to the Dalkia Energy Savings Center (Desc), which guarantees optimized management of consumption. The entire system is integrated into an energy contract that guarantees that the Departmental Council will achieve its results for eight years.

The benefits

70% of the buildings' thermal needs are covered by renewable and local energy.
The emission of 288 tons of CO₂ is avoided each year, the equivalent of 144 cars taken off the road.

Thanks to Dalkia, we have significantly reduced our carbon emissions and our energy bill. Connected systems allow us to measure occupant comfort on a daily basis and continuously improve our energy performance. As an added bonus, Dalkia's experts have also set up 580 square meters of photovoltaic shading, which supplies solar energy to our three electric vehicle charging stations and our buildings.