Ice water that cools the city

The appointment is given not far from the Jardin de la Nouvelle France, in the 8th arrondissement of Paris, just in front of the Pont des Invalides. At our feet, a retractable spiral staircase comes out of the sidewalk and under the surface, forty meters deep, one of the ten ice water production plants, named Canada, and inaugurated in 2008, is operating at full capacity. Water from the Seine is filtered and cooled to 4°C. Since 2013, this refrigeration network, 93 kilometers long, has been supplied with 100% renewable electricity.

In 1991, the City of Paris entrusted Climespace, a subsidiary of ENGIE, with the operation and development of its refrigeration network for twenty years. To their credit, ten refrigeration production sites and four energy storage sites with the aim of supplying refrigeration to more than 700 buildings, i.e. six million m2. “It is a gigantic air conditioning network, invisible on the surface, that runs in the Parisian basement” explains Catherine MacGregor, CEO of ENGIE. Since April, a new structure has been entrusted with the management of the network for two decades. Named Fraîeur de Paris, this company is 85% owned by ENGIE and 15% by RATP. Having become a dealer, it ensures the production, storage, transport and distribution of the city's refrigeration energy.

Freshness of Paris intends to contribute to the City's approach aiming for carbon neutrality by 2050. According to The new network is thus designed to be both more efficient and virtuous. It will be powered by 100% renewable electricity and produced in France, with nearly 70% of this production being provided by four new dedicated solar farms. At the same time, the use of the so-called free cooling technique — which consists in particular in capturing the refrigeration energy of the Seine water in winter to supply the network — will be preferred.

Centralized management of this infrastructure allows for resilient service, better efficiency — around 20% compared to a traditional individual air conditioning system — and much better water management. In addition, 5,000 m2 of urban areas will be planted, such as production sites and streets during major projects, to allow another form of refreshing Paris.

In winter, the system continues to operate, producing cold without electricity, the water in the network being directly cooled by being brought into contact with water from the Seine, which is naturally fresh at this season. In this configuration, the water used by the power plant to cool the network, heated to extract the cold, is released into the river. The few degrees of difference with the ambient temperature have no impact on the fauna and flora of the Seine.

By 2040, Fraîcheur de Paris wishes to develop “the largest global refrigeration network” by covering the entire surface of the capital, to initially cool Places of high traffic such as tourist sites, metro stations, hospitals and some Parisian schools. In addition to these public sites, the network will be open to private buildings wishing to join the network. The objective behind all this is to effectively remove air conditioners from the capital, in order to make Paris a fresher city, and therefore fatally more ecological.