PARIS — Fraîcheur de Paris assumed control of the Paris district cooling network in 2022 under a €2.4 billion, 20-year concession contract with assistance from the city government. The city of Paris owns the network, which is operated by the transportation company RATP and Engie.

The system consists of 120 kilometers (75 miles) of underground pipes distributing chilled water to museums, offices, hospitals, schools, and public buildings, including the Louvre and the Grand Palais. The cooling system uses cold water from the Seine River, pumping it through one pipe that runs alongside a secondary pipe carrying warm water from city buildings. A heat exchanger with a thin metal wall facilitates the transfer of heat from the warm city water to the cold Seine water without the fluids mixing. The Seine water is then returned to the river after being slightly warmed.

Planning for this network began in the 1990s, with Engie conceptualizing and building the initial infrastructure. Paris plans to expand the cooling network to triple its current size by 2042. This expansion aims to serve more than 3,000 buildings, which will include hospitals, schools, day-care centers, and retirement homes.

Tim Guigon, a spokesperson for Fraîcheur de Paris, addressed the scope of the expansion. Guigon stated, "The figure of 3,000 … reflects a realistic development trajectory." He added, "The ambition is to move from a historic network focused on large tertiary buildings to a city-wide infrastructure." Guigon also noted, "Not all of [Paris's buildings] have the same cooling needs, nor are they all suited to be connected to the network."

Pauline Lavaud, the director of climate transition in the Paris city government, said, "Developing a district cooling network requires substantial investment." She added, "For the project to be economically viable and commercially attractive, a city must have sufficiently concentrated cooling demand … where a dense network can be justified." Thibauld Voïta, an energy and climate expert and adviser at the Jacques Delors Institute, described the cooling network as "a kind of miracle solution in the era of global warming."