Urban cooling networks: a solution that needs to be scaled to withstand extreme heatwaves

Faced with increasingly frequent heat waves, urban cooling networks are emerging as a collective solution for cooling buildings. These centralized infrastructures produce chilled water and then distribute it to buildings connected by a network of pipes.

Sharing these resources allows for the use of high-efficiency industrial equipment, better control of refrigerants, and, in some cases, the mobilization of natural resources or renewable and recovered energy. Ice storage also makes it possible to shift some electricity consumption to off-peak hours.

A target of 2 TWh of cooling delivered by 2030

As part of the multi-year energy programming project, the government wants to increase deliveries from cooling and recovery networks from 0,78 TWh in 2021 to 2 TWh in 2030, then between 2,5 and 3 TWh in 2035.

This technology is still not widely deployed in France. latest national survey published by Cerema lists 43 cooling networks supplying more than 1.600 buildings, mainly in major metropolitan areas.

The French groups Veolia and Engie have announced the launch of studies to implement these infrastructures in medium-sized cities, a market that is still largely undeveloped.

In its 2026 annual report, the High Council for the Climate (HCC) considers the development of district cooling networks and collective cooling systems necessary to avoid increasing dependence on less efficient individual equipment. This equipment releases heat outside buildings, can exacerbate urban heat islands, and increase strain on the electricity grid.

The heatwave of June 2026 pushed some networks to their limits

The heatwave that struck France from June 17 to 30, 2026, served as a full-scale test for these infrastructures. Described as historic by Météo-France, this event notably saw temperatures exceed 40°C in Paris on June 24 and 25.

At the height of the heatwave, some networks reached peak power demands. Several Parisian establishments experienced air conditioning outages, including the UGC cinema at Les Halles and a building belonging to the BPCE banking group.

"The problem is that in Paris you have cold production facilities designed for a maximum temperature of 35 degrees," explains Pascal Stabat, engineer and professor of energy at the École des Mines de Paris.

“When it’s very hot, there’s an imbalance between production and demand, so cooling production can be somewhat low,” he continued. From June 18 to 27, maximum temperatures exceeded 35°C every day in the capital.

In La Défense, subscribers are being asked to limit their air conditioning use.

The heatwave had also raised concerns about a "deteriorating" temperature in the cooling network of the La Défense business district, near Paris. The director of the site, operated by Idex La Défense, indicated that the cooling plant was no longer able to replenish its ice stocks overnight.

The company, which operates the second largest district cooling network in France, nevertheless maintains that it ensured "100% continuity of service." It attributes this result in particular to the "cooperation" of its subscribers, "who respected the air conditioning guidelines of around 26 degrees Celsius."

More power means additional investment

"In the future, we will need to ensure that we strengthen the robustness of the network," emphasizes Frank Lacroix, Deputy Chief Executive Officer of Engie.

For Pascal Stabat, adapting power grids to extreme temperatures is not an insurmountable technical difficulty. However, it does require increasing production capacity and therefore investment.

"There are cooling networks in Saudi Arabia, so adapting to higher temperatures is possible. But you have to invest to have more power. So it costs more." explains Pascal Stabat.

Reversible networks rely on the complementarity of uses.

Other configurations claim greater resilience to heatwaves. This is the case of the network operated by Veolia on the Saclay plateau, south of Paris, which is capable of distributing heat or cold according to the needs of the connected buildings.

The heating network's capacity, which is fully reversible for producing cooling, ensures sufficient heating during the summer. However, this operation relies on a "mix of uses" among the connected factories, laboratories, research centers, and sports facilities.

This organization is more difficult to reproduce in existing neighborhoods, "where the tertiary sector has long been located on one side, and housing on the other," observes Pascal Stabat.

Connecting homes to the district cooling network is therefore one of the next challenges for these networks, which are currently primarily intended for commercial buildings. Frank Lacroix specifically mentions the possibility of "bringing the cold air back to Paris via the courtyards" of buildings.