Feature Report: Using Heat More Efficiently

4 items of content in this feature report



Heat: Uneven Use Around the World

The use of district heating systems varies significantly worldwide. Although the world’s first district heating systems were introduced in the United States in 1877, the country only uses them to meet 4% of its needs (See sidebar). Russia is the world leader (55%), but its systems are small and old. China is expanding its systems at a fast pace. The situation in Europe presents sharp contrasts. 

fr - Chaleur : une utilisation inégale dans le monde
The city of New York has one of the oldest and most extensive district heating systems. © AFP / D.EMMERT

Contrasting Use of District Heating Worldwide

District heating systems have been providing warmth to homes for decades around the world, although their development has been very uneven, according to data from 20171.

France had more than 750 district heating systems in 2017, mainly located in urban areas. 

In France, a district heating observatory has been set up by the French government and various organizations2. In 2017, more than 750 district heating systems had been listed, the majority of which were located in major urban centers. Three million people were connected to a district heating system in the residential sector and approximately three million more were covered in the tertiary sector, which includes education, offices/administration and healthcare facilities.

Some Examples of Systems

  • Dunkirk and Chevilly-Larue, France:

Begun in 1985, the Deux Synthes district heating system in Dunkirk is France’s biggest industrial waste heatLike waste energy, waste heat is heat whose release during a process or the manufacture of a product is unavoidable... recovery network, thanks to the ArcelorMittal steel plant. Two recovery units capture heat from the blast furnaces, which provide 55% to 60% of the network’s total heat. The remainder comes from cogeneration (combined heat and power) plants3. The heat is distributed to 180 buildings, 6,000 public housing units and private homes, a hospital complex, schools and other public buildings via 50 kilometers of pipes. Once installed, the system is carbon neutral and 90% of the industrial dust is recovered, improving air quality.

The district heating system for the Ile-de-France municipalities of Chevilly-Larue, L’Haÿ-les-Roses and Villejuif uses a different source of energy, namely a geothermal aquifer located more than 1,500 meters underground whose temperature varies between 57°C and 85°C. Created in 1985 and renovated in 2016, the system serves some 45,000 residents via 29 smaller networks, making it Europe’s largest geothermal district heating system4.

100 million: The number of European citizens, across 32 countries, benefiting from 4,500 district heating networks.


  • Gothenburg, Sweden:

Sixty percent of the residents of Gothenburg, Sweden’s second-largest city, are supplied with heat and hot water by a district heating system5. The heat is provided at 80% from the recovery process: 27% from waste incinerationTechnique used to convert waste into energy. The waste is burned, producing heat, power or both. , 30% from refineries, 19% from power plants, and 5% from wastewater. Renewable sources account for 15% of direct generation, with fossil fuels now representing just 5%. The most remarkable feature of the system is its steady expansion, thanks to the continuous backing of the authorities. The first building blocks were laid in 1953, with one, then two, fuelFuel is any solid, liquid or gaseous substance or material that can be combined with an oxidant... oil-fired power plants. In the 1970s, as oil prices soared, alternative solutions were pursued, with heat recovered from wastewater, waste incineration and two refineries. In 1990, a river-assisted cooling system was added. Wood-fired power plants were built in 2000.


  • Fredericia, Denmark:

In 1983, Fredericia, a considerable port city in Denmark, began installing a district heating system fueled by heat recovered from a fertilizer plant, a refinery and incineration plants6. Four other neighboring communities introduced similar systems, which have been tied into the original one, creating a vast integrated network that supplies 55,000 homes via 75 kilometers of pipes. Integration is the system’s defining characteristic: it is managed centrally from state-of-the-art control rooms, is highly efficient and heat losses are just 3%. The annual savings is estimated at 130 million liters of fossil fuels.


New York’s Steam SystemClouds of steam billowing from underground to wreathe skyscrapers form an iconic image of the New York cityscape.  This major North American city has the world’s biggest — and one of its oldest — district heating systems, created in 1882. Its 170 kilometers of pipes run under the streets of Manhattan to supply 1,800 buildings, from the Empire State Building to the United Nations. It has twice the capacity of the Paris system, which is not small. The steam that escapes from below ground is not leaking, but is created when groundwater comes in contact with hot pipes.



(1) See the website of the French Center of Research and Expertise on Risks, the Environment, Mobility and Development (CEREMA) (in French only)

(2) Observatory website (in French only)

(3) France 3 video (in French only)

(4) CEREMA feature report (in French only)

(5) City of Gothenburg

(6) City of Fredericia