Cooling cities differently: the role of district cooling networks

A high-performance, low-carbon solution

How does a district cooling network work?

Cooling is produced at a central facility and then distributed to multiple buildings through an underground piping network.

A district cooling network relies on three main components:

1. A central cooling plant: The plant produces chilled water using a range of energy sources and technologies, including: high-efficiency chillers, geothermal energy, seawater cooling (thalassothermal energy), river water cooling (aquathermal energy), or natural cooling sources such as outside air or surface water (free cooling)
2. An underground distribution network: chilled water circulates through insulated underground pipes in a closed-loop system to connected buildings.
3. Building substations: they transfer the cooling energy from the network to each building’s internal air conditioning system.

District cooling networks can also incorporate underground chilled water or ice storage systems, helping balance supply and demand while optimizing operating costs.

By replacing numerous individual cooling units with a shared infrastructure, district cooling networks provide a more efficient, lower-impact solution that integrates seamlessly into the urban landscape.

 Why choose a district cooling network?

By pooling cooling demand across multiple buildings, district cooling networks can achieve energy efficiency levels of up to 97% while significantly reducing electricity consumption compared with standalone cooling systems.

They also deliver substantial environmental benefits:

• Up to 50% lower electricity consumption
• Around 50% lower CO₂ emissions
• Up to 90% lower refrigerant emissions

At the city scale, district cooling networks also provide tangible urban benefits: fewer outdoor cooling units on building facades and rooftops, reduced visual and noise pollution, and less waste heat released into public spaces.

In France, district cooling networks already rely on a largely decarbonized energy mix, with around two-thirds of their energy coming from renewable sources (including geothermal energy, seawater, lake water and river water, as well as free cooling) and recovered heat, such as waste heat from waste-to-energy plants and, more recently, data centers via heat pump systems. The objective is to increase this share to 75% by 2030.

Source: FEDENE annual district heating and cooling survey 2025 (in French).

Cooling is becoming a major energy challenge

Across the globe, demand for cooling is rising due to rapid urbanization and increasingly frequent extreme heat events. Offices, hospitals, schools, retail facilities, and data centers are all requiring high-performance, reliable, and energy-efficient cooling solutions. District cooling networks are already expanding across many regions, from the Gulf countries to Europe’s largest metropolitan areas.

In France, the floor area served by district cooling networks grew by 12% in 2025, according to Fédération des Services Energie Environnement (FEDENE). Yet the growth potential remains significant: cooling demand is expected to reach 34 TWh by 2050, up from 20 TWh today, while district cooling networks currently supply only around 1 TWh. Their expansion is supported by an increasingly favorable regulatory framework, including recognition of “efficient” district cooling networks, the expansion of the Heat Fund (Fonds Chaleur), dedicated Energy Savings Certificate (CEE) schemes, a 5.5% reduced VAT rate, and formal recognition of their growing role in helping communities adapt to climate change under France’s 2026 Multiannual Energy Program (PPE3).

In the Middle East (including the United Arab Emirates, Saudi Arabia, Qatar, and Oman), district cooling networks have become essential infrastructure, supporting urban development while meeting exceptionally high cooling demand.

Urban cooling is expected to play an increasingly important role, with the potential to meet nearly one-third of total cooling demand by 2030.

What is the difference between district heating and district cooling networks?

District cooling networks operate on the same principle as district heating networks, but in reverse.

A district heating network distributes heat to warm buildings, while a district cooling network distributes chilled water to cool them. Both rely on centralized energy production and a shared distribution network, enabling the use of local and renewable energy resources while reducing CO₂ emissions.

ENGIE: the global leader in district cooling

Proven expertise across diverse environments

ENGIE is currently the world’s leading district cooling operator. It operates 116 district cooling networks, including Fraîcheur de Paris, Europe’s largest district cooling network, as well as Tabreed, the leading district cooling operator in the Middle East.

ENGIE develops and operates district cooling networks in 10 countries worldwide:

• In France, with 22 district cooling networks, including those serving Paris and Marseille, representing 56% of the national market;
• Across Europe, with two networks in Spain;
• Internationally, in major metropolitan areas such as Boston, Dubai, and Singapore.

With 6.4 GW of installed cooling capacity worldwide in 2026, ENGIE has built a strong and diversified international industrial footprint. Its projects are tailored to a wide range of local conditions, from the dense urban environment of Paris to seawater cooling solutions in the Mediterranean, as well as shallow geothermal systems deployed at the scale of eco-districts, such as those in Issy-les-Moulineaux and the Matabiau development district in Toulouse.

“As climate change accelerates, cooling buildings and public spaces is becoming a strategic priority for local authorities” – Benoît Brient, Director of Network Development at ENGIE

Innovating to decarbonize district cooling networks at scale

ENGIE invests in innovative technologies to reduce the environmental footprint of cooling. Through ENGIE New Ventures, we are supporting French startup Alpinov X, which has developed an innovative solution that uses water as a refrigerant, replacing polluting gases that are being phased out.

The partnership aims to accelerate the industrialization and deployment of this technology across district cooling networks and data centers, both in France and internationally. With energy efficiency gains of up to 30%, the technology represents a major step forward in reducing the environmental impact of air conditioning. Its first deployment is scheduled to take place soon on a district cooling network in the Paris region, with ENGIE’s support.

ENGIE’s flagship district cooling networks

Fraîcheur de Paris – Paris (France) :

The Paris district cooling network is operated by Fraîcheur de Paris, a company owned 85% by ENGIE and 15% by RATP, the world’s 3^rd largest urban transport operator. It produces, distributes, and stores cooling energy across the French capital.

With nearly 120 km (75 miles) of pipeline, it is one of the largest district cooling networks in Europe. It already serves more than 7 million m² (75 million sq. ft.) of buildings, including nearly 800 landmark sites, such as the Louvre Museum, Paris City Hall, the French National Assembly, major department stores, and leading hospitals.

The network runs on 100% renewable electricity and uses free cooling, drawing naturally cold water from the Seine River during winter. This approach reduces energy consumption by around 50% compared with standalone air conditioning systems.

By combining high energy performance, seamless urban integration, and the use of local energy resources, Fraîcheur de Paris helps cut CO₂ emissions associated with cooling buildings in Paris by nearly half.

Tabreed (National Central Cooling Company) – Gulf countries (Middle East)

ENGIE holds a 40% equity stake in Tabreed, the leading district cooling operator in the Middle East. This investment gives ENGIE a leading role in 94 district cooling networks operating across the Gulf countries, including the United Arab Emirates, Saudi Arabia, Qatar, and Oman. Tabreed stands out for its exceptional scale, distributing more than one million refrigeration tons of cooling capacity each year through its district cooling networks.

In 2025, Tabreed further strengthened its market position through two major milestones: securing the concession for the Palm Jebel Ali district cooling network in Dubai and acquiring PAL Cooling in Abu Dhabi, reinforcing ENGIE’s leadership in this strategic region.

Thassalia – Marseille (France) :

Thassalia is Europe’s first combined district heating and cooling network powered by seawater thermal energy (thalassothermal energy). The network supplies heating and cooling to the Euroméditerranée business district, currently serving 500,000 m² (5.4 million sq. ft.) of offices, retail space, and residential buildings from a plant located on the Mediterranean coast.

Its environmental performance is outstanding. By using seawater and heat pumps, the system can reduce CO₂ emissions by up to 80% for certain connected buildings, including the CMA CGM Tower (CMA CGM is a global player in sea, land, air and logistics solutions), while ensuring a highly reliable and continuous energy supply. By 2032, the network is expected to serve 20,000 residents in Marseille’s northern districts.

Similar projects are also emerging elsewhere. For example, in 2025, ENGIE launched a 100% renewable district heating and cooling network in Lyon, France, powered by wastewater heat recovery and solar energy, demonstrating the diversity of locally tailored solutions that we are deploying to support the energy transition.