Three out of five public swimming pools are currently under construction in Bordeaux. A necessary project to reduce the energy bill of these dilapidated buildings.
Solar panels, geothermal energy, Nordic pool… In Bordeaux, three out of five public swimming pools are being renovated, a major project to modernize these dilapidated buildings, real energy sinkholes for communities. In “the top 10 most energy-intensive buildings in the city, three are swimming pools”explains Laurent Guillemin, deputy mayor of Bordeaux responsible for the economy of water resources.
A situation that is particularly visible in Bordeaux, but which is found almost everywhere in France. According to Guillaume Perrin, director of the ACTEE program, an energy saving certificate program supported by the National Federation of Granting and Governed Communities (FNCCR), swimming pools represent 10 to 25% of a municipality’s energy bill.
They are also the main sources of energy consumption in metropolises according to Ademe, the government agency dedicated to the ecological transition. At a time of rising energy costs, it is therefore urgent to renovate an aging pool – 60% of the 4,135 French municipal swimming pools are over 30 years old – especially those built from the 1950s to the 1980s. are the most poorly insulated.
Swimming pools heated by geothermal energy
“We had cheap energy, so we did not invest in sufficiently insulated buildings”notes Guillaume Perrin. “Heating the air consumes the most energy. We are talking about large volumes, with ceiling heights of 5, 6, 8 meters with a lot of humidity and air circulation.specifies Bordeaux elected official Laurent Guillemin.
It is therefore necessary to invest in “new virtuous air handling units which are responsible for cooling and dehumidifying, then heating the air”, adds the municipal councilor. An improvement taken into account in two swimming pools currently under construction in Bordeaux (Grand Parc and Judaaïque).
Another (Stéhelin) should be converted into a Nordic swimming pool, an outdoor pool open all year round, in order to eliminate expenses linked to air heating. As for gas, until now mainly used by French swimming pools, it is “a carbon-based energy to be abandoned in favor of renewable energies”explains Éric Aufaure, coordinator of the building division at Ademe Nouvelle-Aquitaine.
The Judaica swimming pool will therefore be heated using geothermal energy and that of the Grand Parc will be connected to the urban heating network, powered by both geothermal energy and wood. “If the swimming pool cannot be connected to the urban heat network, it can be heated by wooden boilers”, specifies Éric Aufaure. As is the case in Périgueux and Bergerac, in neighboring Dordogne. Photovoltaic solar power can power building lighting, while thermal solar power can heat shower water.
60 to 80% energy savings
Especially since “the swimming pools built during the Trente Glorieuses have flat roofs, where it is very easy to install solar”, affirms Guillaume Perrin. In New Aquitaine, 75 public swimming pools are already equipped with solar thermal, six are heated using geothermal energy and around twenty with wood or via connection to an urban heating network, according to Ademe.
“The overall renovation of a swimming pool can save 60 to 80% on a municipality’s energy bill”but “cheap and immediate work” are enough to achieve “30% energy savings”, says Guillaume Perrin. The ACTEE program recommends insulating the pipes and cleaning the air vents of the air handling unit.
After the invasion of Ukraine and the ensuing surge in energy costs, this program also recommended to the mayors of France to group together the times of use of the pools in order to lower the water temperature. of 1.5 degrees, excluding times dedicated to seniors and baby swimmers. In Bordeaux, this measure, implemented since winter 2022, saves 5 to 6% of the energy devoted to heating the pool.
Since 2017, the energy renovation effort has also been supported by Bordeaux Métropole, the intermunicipality bringing together 28 municipalities. The swimming pool plan for the Bordeaux metropolitan area, costed at 40 million euros, notably supports the renovation of 6 of the 24 municipal swimming pools spread across its territory and the construction of 7 new buildings.
