District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of

insulated pipe Insulated pipes (called also preinsulated pipes or bonded pipe ) are widely used for district heating and hot water supply. They consist of a steel pipe called "service pipe", a thermal insulation layer and an outer casing. The main purpose of su ...

s for residential and commercial heating requirements such as

space heating Heating, ventilation, and air conditioning (HVAC) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. HV ...

and

water heating Water heating is a heat transfer process that uses an energy source to heat water above its initial temperature. Typical domestic uses of hot water include cooking, cleaning, bathing, and space heating. In industry, hot water and water heated t ...

. The heat is often obtained from a

cogeneration Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Cogeneration is a more efficient use of fuel or heat, because otherwise- wasted heat from elect ...

plant burning fossil fuels or

biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...

, but

heat-only boiler station A heating plant, also called a physical plant, or steam plant, generates thermal energy in the form of steam for use in district heating applications. Unlike combined heat and power installations which produce thermal energy as a by-product ...

geothermal heating Geothermal heating is the direct use of geothermal energy for some heating applications. Humans have taken advantage of geothermal heat this way since the Paleolithic era. Approximately seventy countries made direct use of a total of 270 PJ of ...

heat pump A heat pump is a device that can heat a building (or part of a building) by transferring thermal energy from the outside using a refrigeration cycle. Many heat pumps can also operate in the opposite direction, cooling the building by removing ...

s and

central solar heating Central solar heating is the provision of central heating and hot water from solar energy by a system in which the water is heated centrally by arrays of solar thermal collectors (central solar heating plants - CSHPs) and distributed through dis ...

are also used, as well as heat waste from factories and

nuclear power Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced b ...

electricity generation. District heating plants can provide higher efficiencies and better pollution control than localized boilers. According to some research, district heating with combined heat and power (CHPDH) is the cheapest method of cutting carbon emissions, and has one of the lowest carbon footprints of all fossil generation plants. Fifth-generation district heat networks do not use combustion on-site and have zero emissions of CO and NO on-site; they employ heat transfer using electricity, which may be generated from renewable energy or from remote fossil-fuelled power stations. A combination of CHP and centralized heat pumps is used in the Stockholm multi-energy system. This allows the production of heat through electricity when there is an abundance of intermittent power production, and cogeneration of electric power and district heating when the availability of intermittent power production is low. District heating is ranked number 27 in

Project Drawdown Climate drawdown refers to the future point in time when levels of greenhouse gas concentrations in the atmosphere stop climbing and start to steadily decline. Drawdown is a milestone in reversing climate change and eventually reducing global ave ...

's 100 solutions to

global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

History

District heating traces its roots to the hot water-heated baths and greenhouses of the ancient

Roman Empire The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediterr ...

. A hot water distribution system in

Chaudes-Aigues Chaudes-Aigues (; oc, Chaudas Aigas, ) is a commune in the Cantal department in south-central France. It is a spa town, famous for its hot spring waters. Geography The commune is situated in the Massif Central in Aubrac. Its inhabitants are ...

in France is generally regarded as the first real district heating system. It used geothermal energy to provide heat for about 30 houses and started operation in the 14th century. The U.S. Naval Academy in

Annapolis Annapolis ( ) is the capital city of the U.S. state of Maryland and the county seat of, and only incorporated city in, Anne Arundel County. Situated on the Chesapeake Bay at the mouth of the Severn River, south of Baltimore and about east o ...

began

steam Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization ...

district heating service in 1853. Although these and numerous other systems have operated over the centuries, the first commercially successful district heating system was launched in Lockport, New York, in 1877 by American hydraulic engineer

Birdsill Holly Birdsill Holly Jr. (November 8, 1820 – April 27, 1894) was an American mechanical engineer and inventor of water hydraulics devices. He is known for inventing mechanical devices that improved city water systems and patented an improved fire hy ...

, considered the founder of modern district heating.

Generations of district heating

Generally, all modern district heating system are demand driven, meaning that the heat supplier reacts to the demand from the consumers and ensures that there is sufficient temperature and water pressure to deliver the demanded heat to the users. The five generations have defining features that sets them apart from the prior generations. The feature of each generation can be used to give an indication of the development status of an existing district heating system.

First generation

The first generation was a steam-based system fueled by

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dea ...

and was first introduced in the US in the 1880s and became popular in some European countries, too. It was state of the art until the 1930s and used concrete ducts, operated with very high temperatures and was therefore not very efficient. There were also problems with reliability and safety due to the hot pressurized steam tubes. Nowadays, this generation is technologically outdated. However, some of these systems are still in use, for example in New York or Paris. Other systems originally built have subsequently been converted to later generations.

Second generation

The second generation was developed in the 1930s and was built until the 1970s. It burned coal and oil, and the energy was transmitted through pressurized hot water as the heat carrier. The systems usually had supply temperatures above 100 °C, and used water pipes in concrete ducts, mostly assembled on site, and heavy equipment. A main reason for these systems was the primary energy savings, which arose from using combined heat and power plants. While also used in other countries, typical systems of this generation were the Soviet-style district heating systems that were built after WW2 in several countries in Eastern Europe.

Third generation

In the 1970s the third generation was developed and was subsequently used in most of the following systems all over the world. This generation is also called the "Scandinavian district heating technology", because many of the district heating component manufacturers are based in Scandinavia. The third generation uses prefabricated, pre-insulated pipes, which are directly buried into the ground and operates with lower temperatures, usually below 100 °C. A primary motivation for building these systems was security of supply by improving the

energy efficiency Energy efficiency may refer to: * Energy efficiency (physics), the ratio between the useful output and input of an energy conversion process ** Electrical efficiency, useful power output per electrical power consumed ** Mechanical efficiency, a ra ...

after the two oil crises led to disruption of the oil supply. Therefore, those systems usually used coal, biomass and waste as energy sources, in preference to oil. In some systems, geothermal energy and

solar energy Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy (including solar water heating), and solar architecture. It is an essenti ...

are also used in the energy mix. For example, Paris has been using

from a 55–70 °C source 1–2 km below the surface since the 1970s for domestic heating.

Fourth generation

Currently, the fourth generation is being developed, with the transition to 4th generation already in process in

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Danish Realm, Kingdom of Denmark ...

. The fourth generation is designed to combat climate change and integrate high shares of variable renewable energy into the district heating by providing high flexibility to the electricity system. According to the review by Lund et al. those systems have to have the following abilities: * "1. Ability to supply low-temperature district heating for space heating and domestic hot water (DHW) to existing buildings, energy-renovated existing buildings and new low-energy buildings." * "2. Ability to distribute heat in networks with low grid losses." * "3. Ability to recycle heat from low-temperature sources and integrate renewable heat sources such as solar and geothermal heat." * "4. Ability to be an integrated part of smart energy systems (i.e. integrated smart electricity, gas, fluid and thermal grids) including being an integrated part of 4th Generation District Cooling systems." * "5. Ability to ensure suitable planning, cost and motivation structures in relation to the operation as well as to strategic investments related to the transformation into future sustainable energy systems". Compared to the previous generations the temperature levels have been reduced to increase the energy efficiency of the system, with supply side temperatures of 70 °C and lower. Potential heat sources are waste heat from industry, CHP plants burning waste, biomass power plants, geothermal and solar thermal energy (

), large scale

s, waste heat from cooling purposes and data centers and other sustainable energy sources. With those energy sources and large scale

thermal energy storage Thermal energy storage (TES) is achieved with widely different technologies. Depending on the specific technology, it allows excess thermal energy to be stored and used hours, days, months later, at scales ranging from the individual process, ...

, including

seasonal thermal energy storage Seasonal thermal energy storage (STES), also known as inter-seasonal thermal energy storage, is the storage of heat or cold for periods of up to several months. The thermal energy can be collected whenever it is available and be used whenever nee ...

, fourth generation district heating systems are expected to provide flexibility for balancing

wind Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hou ...

and

solar power Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV) or indirectly using concentrated solar power. Photovoltaic cells convert light into an electric current using the photovoltaic e ...

generation, for example by using heat pumps to integrate surplus electric power as heat when there is much wind energy or providing electricity from biomass plants when back-up power is needed. Therefore, large scale heat pumps are regarded as a key technology for smart energy systems with high shares of

renewable energy Renewable energy is energy that is collected from renewable resources that are naturally replenished on a human timescale. It includes sources such as sunlight, wind, the movement of water, and geothermal heat. Although most renewable energy ...

up to 100% and advanced fourth generation district heating systems.

Fifth generation/cold district heating

A fifth generation district heating and cooling network (5GDHC), also called ''cold district heating'', distributes heat at near ambient ground temperature: this in principle minimizes heat losses to the ground and reduces the need for extensive insulation. Each building on the network uses a heat pump in its own plant room to extract heat from the ambient circuit when it needs heat, and uses the same heat pump in reverse to reject heat when it needs cooling. In periods of simultaneous cooling and heating demands this allows waste heat from cooling to be used in heat pumps at those buildings which need heating. The overall temperature within the ambient circuit is preferably controlled by heat exchange with an aquifer or another low temperature water source to remain within a temperature range from 10 °C to 25 °C. While network piping for ambient ground temperature networks is less expensive to install per pipe diameter than in earlier generations, as it does not need the same degree of insulation for the piping circuits, it has to be kept in mind that the lower temperature difference of the pipe network leads to significantly larger pipe diameters than in prior generations. Due to the requirement of each connected building in the fifth generation district heating and cooling systems to have their own heat pump the system can be used both as a heat source or a heat sink for the heat pump, depending on if it is operated in a heating and cooling mode. As with prior generations the pipe network is an infrastructure that in principle provides an open access for various low temperature heat sources, such as ambient heat, ambient water from rivers, lakes, sea, or lagoons, and waste heat from industrial or commercial sources. Based on the above description it is clear that there is a fundamental difference between the 5GDHC and the prior generations of district heating, particularly in the individualization of the heat generation. This critical system has a significant impact when comparing the efficiencies between the different generations, as the individualization of the heat generation moves the comparison from being a simple distribution system efficiency comparison to a supply system efficiency comparison, where both the heat generation efficiency as well as the distribution system efficiency needs to be included. A modern building with a low-temperature internal heat distribution system can install an efficient heat pump delivering heat output at 45 °C. An older building with a higher-temperature internal distribution system e.g. using radiators will require a high-temperature heat pump to deliver heat output. A larger example of a fifth generation heating and cooling grid is Mijnwater in Heerlen, the Netherlands. In this case the distinguishing feature is a unique access to an abandoned water-filled coal mine within the city boundary that provides a stable heat source for the system. A fifth generation network ("Balanced Energy Network", BEN) was installed in 2016 at two large buildings of the London South Bank University as a research and development project.

Heat sources

District heating networks exploit various energy sources, sometimes indirectly through multipurpose infrastructure such as combined heat and power plants (CHP, also called co-generation).

Combustion of fossil or renewable fuels

The most used energy source for district heating is the burning of

hydrocarbons In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...

. As the supply of renewable fuels is insufficient, the fossil fuels

and

gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...

are massively used for district heating. This burning of fossil hydrocarbons usually contributes to

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

, as the use of systems to capture and store the CO₂ instead of releasing it into the atmosphere is rare. In the case of a cogeneration plant, the heat output is typically sized to meet half of the peak winter heat load, but over the year will provide 90% of the heat supplied. Much of the heat produced in summer will generally be wasted. The boiler capacity will be able to meet the entire heat demand unaided and can cover for breakdowns in the cogeneration plant. It is not economic to size the cogeneration plant alone to be able to meet the full heat load. In the

New York City steam system The New York City steam systems include Con Edison's Steam Operations, and other smaller systems that provide steam to New York University and Columbia University. Many individual buildings in New York have their own steam systems. Con Edi ...

, that is around 2.5 GW. Germany has the largest amount of CHP in Europe. A simple

thermal power station A thermal power station is a type of power station in which heat energy is converted to electrical energy. In a steam-generating cycle heat is used to boil water in a large pressure vessel to produce high-pressure steam, which drives a stea ...

can be 20–35% efficient, whereas a more advanced facility with the ability to recover waste heat can reach total energy efficiency of nearly 80%. Some may approach 100% based on the

lower heating value The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The ''calorific value'' is the total energy rele ...

by condensing the flue gas as well.

Nuclear fission

The heat produced by

nuclear chain reaction In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series of these reactions. The specific nu ...

s can be injected into district heating networks. This does not contaminate the district pipes with radioactive elements, as the heat is transferred to the network through

heat exchanger A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contac ...

s. It is not technically necessary for the nuclear reactor to be very close to the district heating network, as heat can be transported over significant distances (exceeding 200 km) with affordable losses, using

s. Since nuclear reactors do not significantly contribute to either

air pollution Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different types ...

, they can be an advantageous alternative to the combustion of fossil hydrocarbons. However, only a small minority of the nuclear reactors currently in operation around the world are connected to a district heating network. These reactors are in Bulgaria, China, Hungary, Romania, Russia, Slovakia, Slovenia, Switzerland and Ukraine. The Ågesta Nuclear Power Plant in Sweden was an early example of nuclear cogeneration, providing small quantities of both heat and electricity to a suburb of the country's capital between 1964 and 1974. The

Beznau Nuclear Power Plant The Beznau nuclear power plant (german: Kernkraftwerk Beznau KB is a nuclear power plant of the Swiss energy utility Axpo Holding, Axpo, located in the municipality Döttingen, Switzerland, Döttingen, Canton of Aargau, Switzerland, on an ar ...

in Switzerland has been generating electricity since 1969 and supplying district heating since 1984. The

Haiyang Nuclear Power Plant Haiyang Nuclear Power Plant is a nuclear power plant in Haiyang, Shandong province, China. It is the second site to house AP1000 units, after the Sanmen Nuclear Power Station. History Groundbreaking happened one month ahead of schedule on July ...

in China started operating in 2018 and started supplying small scale heat to the Haiyang city area in 2020. By November 2022, the plant used 345 MW-thermal effect to heat 200,000 homes, replacing 12 coal heating plants. Recent years have seen renewed interest in small modular reactors (SMRs) and their potential to supply district heating. Speaking on the

Energy Impact Center The Energy Impact Center is an American research institute based in Washington, D.C. It primarily advocates for the expansion of nuclear power as a clean energy solution to climate change. The organization's research into nuclear power has led it ...

's (EIC) podcast, '' Titans of Nuclear'', principal engineer at

GE Hitachi Nuclear Energy GE Hitachi Nuclear Energy (GEH) is a provider of advanced reactors and nuclear services. It is headquartered in Wilmington, North Carolina, United States. Established in June 2007, GEH is a nuclear alliance created by General Electric and Hitach ...

Christer Dahlgren noted that district heating could be the impetus for the construction of new nuclear power plants in the future. EIC's own open-source SMR blueprint design, OPEN100, could be incorporated into a district heating system.

Natural underground heat

History Geothermal district heating was used in

Pompeii Pompeii (, ) was an ancient city located in what is now the ''comune'' of Pompei near Naples in the Campania region of Italy. Pompeii, along with Herculaneum and many villas in the surrounding area (e.g. at Boscoreale, Stabiae), was buried ...

, and in

since the 14th Century. United States Direct use geothermal district heating systems, which tap geothermal reservoirs and distribute the hot water to multiple buildings for a variety of uses, are uncommon in the United States, but have existed in America for over a century. In 1890, the first wells were drilled to access a hot water resource outside of Boise, Idaho. In 1892, after routing the water to homes and businesses in the area via a wooden pipeline, the first geothermal district heating system was created. As of a 2007 study, there were 22 geothermal district heating systems (GDHS) in the United States. As of 2010, two of those systems have shut down. The table below describes the 20 GDHS currently operational in America.

Solar heat

Use of solar heat for district heating has been increasing in Denmark and Germany in recent years. The systems usually include inter

for a consistent heat output day to day and between summer and winter. Good examples are in

Vojens Vojens (german: Woyens) is a railway town in Denmark with a population of 7,475 (1 January 2022).Dronninglund Dronninglund is a town with a population of 3,487 (1 January 2022)Drake Landing Solar Community has achieved a world record 97% annual solar fraction for heating needs, using solar-thermal panels on the garage roofs and thermal storage in a borehole cluster.

Low temperature natural or waste heat

In Stockholm, the first heat pump was installed in 1977 to deliver district heating sourced from IBM servers. Today the installed capacity is about 660 MW heat, utilizing treated sewage water, sea water, district cooling, data centers and grocery stores as heat sources. Another example is the Drammen Fjernvarme District Heating project in Norway which produces 14 MW from water at just 8 °C, industrial heat pumps are demonstrated heat sources for district heating networks. Among the ways that industrial heat pumps can be utilized are: # As the primary base load source where water from a low grade source of heat, e.g. a river, fjord, data center, power station outfall, sewage treatment works outfall (all typically between 0 ˚C and 25 ˚C), is boosted up to the network temperature of typically 60 ˚C to 90 ˚C using

s. These devices, although consuming electricity, will transfer a heat output three to six times larger than the amount of electricity consumed. An example of a district system using a heat pump to source heat from raw sewage is in Oslo, Norway that has a heat output of 18 MW(thermal). # As a means of recovering heat from the cooling loop of a power plant to increase either the level of flue gas heat recovery (as the district heating plant return pipe is now cooled by the heat pump) or by cooling the closed steam loop and artificially lowering the condensing pressure and thereby increasing the electricity generation efficiency. # As a means of cooling flue gas scrubbing working fluid (typically water) from 60 ˚C post-injection to 20 ˚C pre-injection temperatures. Heat is recovered using a heat pump and can be sold and injected into the network side of the facility at a much higher temperature (e.g. about 80 ˚C). # Where the network has reached capacity, large individual load users can be decoupled from the hot feed pipe, say 80 ˚C and coupled to the return pipe, at e.g. 40 ˚C. By adding a heat pump locally to this user, the 40 ˚C pipe is cooled further (the heat being delivered into the heat pump evaporator). The output from the heat pump is then a dedicated loop for the user at 40 ˚C to 70 ˚C. Therefore, the overall network capacity has changed as the total temperature difference of the loop has varied from 80 to 40 ˚C to 80 ˚C–x (x being a value lower than 40 ˚C). Concerns have existed about the use of hydrofluorocarbons as the working fluid (refrigerant) for large heat pumps. Whilst leakage is not usually measured, it is generally reported to be relatively low, such as 1% (compared to 25% for supermarket cooling systems). A 30-megawatt heatpump could therefore leak (annually) around 75 kg of R134a or other working fluid. Given the high

global warming potential Global warming potential (GWP) is the heat absorbed by any greenhouse gas in the atmosphere, as a multiple of the heat that would be absorbed by the same mass of carbon dioxide (). GWP is 1 for . For other gases it depends on the gas and the time ...

of some HFCs, this could equate to over of car travel per year. However, recent technical advances allow the use of natural heat pump refrigerants that have very low global warming potential (GWP). CO₂ refrigerant (R744, GWP=1) or ammonia (R717, GWP=0) also have the benefit, depending on operating conditions, of resulting in higher heat pump efficiency than conventional refrigerants. An example is a 14 MW(thermal) district heating network in

Drammen Drammen () is a city and municipality in Viken, Norway. The port and river city of Drammen is centrally located in the south-eastern and most populated part of Norway. Drammen municipality also includes smaller towns and villages such as Konne ...

, Norway, which is supplied by seawater-source heatpumps that use R717 refrigerant, and has been operating since 2011. 90 °C water is delivered to the district loop (and returns at 65 °C). Heat is extracted from seawater (from depth) that is 8 to 9 °C all year round, giving an average

coefficient of performance The coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work (energy) required. Higher COPs equate to higher efficiency, lower energy ( ...

(COP) of about 3.15. In the process the seawater is chilled to 4 °C; however, this resource is not utilized. In a district system where the chilled water could be utilized for air conditioning, the effective COP would be considerably higher.Hoffman, & Pearson, D. 2011
Ammonia heat pumps for district heating in Norway 7 – a case study
. Presented at Institute of Refrigeration, 7 April, London. In the future, industrial

s will be further de-carbonised by using, on one side, excess renewable electrical energy (otherwise spilled due to meeting of grid demand) from wind, solar, etc. and, on the other side, by making more of renewable heat sources (lake and ocean heat, geothermal, etc.). Furthermore, higher efficiency can be expected through operation on the high voltage network.

Heat accumulators and storage

Increasingly large heat stores are being used with district heating networks to maximise efficiency and financial returns. This allows cogeneration units to be run at times of maximum electrical tariff, the electrical production having much higher rates of return than heat production, whilst storing the excess heat production. It also allows solar heat to be collected in summer and redistributed off season in very large but relatively low-cost in-ground insulated reservoirs or borehole systems. The expected heat loss at the 203,000m³ insulated pond in

Vojens Vojens (german: Woyens) is a railway town in Denmark with a population of 7,475 (1 January 2022).Power-to-X Power-to-X (also P2X and P2Y and P2Z) is a number of electricity energy transformation, conversion, energy storage, and reconversion pathways that use surplus electric power, typically during periods where fluctuating renewable energy generation ...

) is regarded as a key factor for energy systems with high shares of renewable energy.

Heat distribution

Pre-installation insulated underground pipes for district heating

After generation, the heat is distributed to the customer via a network of

s. District heating systems consist of feed and return lines. Usually the pipes are installed underground but there are also systems with overground pipes. Within the system heat storage units may be installed to even out peak load demands. The common medium used for heat distribution is water or

superheated water Superheated water is liquid water under pressure at temperatures between the usual boiling point, and the critical temperature, . It is also known as "subcritical water" or "pressurized hot water". Superheated water is stable because of overpres ...

, but

is also used. The advantage of steam is that in addition to heating purposes it can be used in

industrial processes Industrial processes are procedures involving chemical, physical, electrical or mechanical steps to aid in the manufacturing of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy ind ...

due to its higher temperature. The disadvantage of steam is a higher heat loss due to the high temperature. Also, the

thermal efficiency In thermodynamics, the thermal efficiency (\eta_) is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, steam turbine, steam engine, boiler, furnace, refrigerator, ACs etc. For a he ...

of cogeneration plants is significantly lower if the cooling medium is high-temperature steam, reducing

electric power Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billions o ...

generation. Heat transfer oils are generally not used for district heating, although they have higher heat capacities than water, as they are expensive and have environmental issues. At customer level the heat network is usually connected to the

central heating A central heating system provides warmth to a number of spaces within a building from one main source of heat. It is a component of heating, ventilation, and air conditioning (short: HVAC) systems, which can both cool and warm interior spaces. ...

system of the dwellings via

s ( heat substations): the working fluids of both networks (generally water or steam) do not mix. However, direct connection is used in the

Odense Odense ( , , ) is the third largest city in Denmark (behind Copenhagen and Aarhus) and the largest city on the island of Funen. As of 1 January 2022, the city proper had a population of 180,863 while Odense Municipality had a population of 20 ...

system. Typical annual loss of thermal energy through distribution is around 10%, as seen in Norway's district heating network.

Heat metering

The amount of heat provided to customers is often recorded with a

heat meter A heat meter attached to a heat exchanger in a District heating substation in a residential neighborhood. Right in white-blue: the calculator; in the center in bronze: the ultrasonic flow meter A heat meter or energy meter is a device which mea ...

to encourage conservation and maximize the number of customers which can be served, but such meters are expensive. Due to the expense of heat metering, an alternative approach is simply to meter the water – water meters are much cheaper than heat meters, and have the advantage of encouraging consumers to extract as much heat as possible, leading to a very low return temperature, which increases the efficiency of power generation. Many systems were installed under a

socialist Socialism is a left-wing economic philosophy and movement encompassing a range of economic systems characterized by the dominance of social ownership of the means of production as opposed to private ownership. As a term, it describes the e ...

economy (such as in the former

Eastern Bloc The Eastern Bloc, also known as the Communist Bloc and the Soviet Bloc, was the group of socialist states of Central and Eastern Europe, East Asia, Southeast Asia, Africa, and Latin America under the influence of the Soviet Union that existed du ...

) which lacked heat metering and means to adjust the heat delivery to each apartment. This led to great inefficiencies – users had to simply open windows when too hot – wasting energy and minimising the numbers of connectable customers.

Size of systems

District heating systems can vary in size. Some systems cover entire cities such as

Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...

Flensburg Flensburg (; Danish, Low Saxon: ''Flensborg''; North Frisian: ''Flansborj''; South Jutlandic: ''Flensborre'') is an independent town (''kreisfreie Stadt'') in the north of the German state of Schleswig-Holstein. Flensburg is the centre of the ...

, using a network of large 1000 mm diameter primary pipes linked to secondary pipes – e.g. 200 mm diameter, which in turn link to tertiary pipes that might be of 25 mm diameter which might connect to 10 to 50 houses. Some district heating schemes might only be sized to meet the needs of a small village or area of a city in which case only the secondary and tertiary pipes will be needed. Some schemes may be designed to serve only a limited number of dwellings, of about 20 to 50 houses, in which case only tertiary sized pipes are needed.

Pros and cons

District heating has various advantages compared to individual heating systems. Usually district heating is more energy efficient, due to simultaneous production of heat and electricity in combined heat and power generation plants. This has the added benefit of reducing

greenhouse gas emissions Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and lar ...

. The larger combustion units also have a more advanced

flue gas Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produc ...

cleaning than single boiler systems. In the case of surplus heat from industries, district heating systems do not use additional fuel because they recover heat which would otherwise be dispersed to the environment. District heating requires a long-term financial commitment that fits poorly with a focus on short-term returns on investment. Benefits to the community include avoided costs of energy through the use of surplus and wasted heat energy, and reduced investment in individual household or building heating equipment. District heating networks, heat-only boiler stations, and cogeneration plants require high initial capital expenditure and financing. Only if considered as long-term investments will these translate into profitable operations for the owners of district heating systems, or combined heat and power plant operators. District heating is less attractive for areas with low population densities, as the investment per household is considerably higher. Also it is less attractive in areas of many small buildings; e.g. detached houses than in areas with a fewer larger buildings; e.g. blocks of flats, because each connection to a single-family house is quite expensive. Individual heating systems can be completely shutdown intermittently according to local heating demand which is not the case with a district heating system.

Ownership, monopoly issues and charging structures

In many cases large combined heat and power district heating schemes are owned by a single entity. This was typically the case in the old Eastern bloc countries. However, for many schemes, the ownership of the cogeneration plant is separate from the heat using part. Examples are Warsaw which has such split ownership with PGNiG Termika owning the cogeneration unit, the Veolia owning 85% of the heat distribution, the rest of the heat distribution is owned by municipality and workers. Similarly all the large CHP/CH schemes in Denmark are of split ownership. Sweden provides an alternative example where the heating market is deregulated. In Sweden it is most common that the ownership of the district heating network is not separated from the ownership of the cogeneration plants, the district cooling network or the centralized heat pumps. There are also examples where the competition has spawned parallel networks and interconnected networks where multiple utilities cooperate. In the United Kingdom there have been complaints that district heating companies have too much of a monopoly and are insufficiently regulated, an issue the industry is aware of, and has taken steps to improve consumer experience through the use of customer charters as set out by the Heat Trust. Some customers are taking legal action against the supplier for Misrepresentation & Unfair Trading, claiming district Heating is not delivering the savings promised by many heat suppliers.

National variation

Since conditions from city to city differ, every district heating system is unique. In addition, nations have different access to primary energy carriers and so they have a different approach on how to address heating markets within their borders.

Europe

Since 1954, district heating has been promoted in Europe by Euroheat & Power. They have compiled an analysis of district heating and cooling markets in Europe within their Ecoheatcool project supported by the

European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body o ...

. A separate study, entitled Heat Roadmap Europe, has indicated that district heating can reduce the price of energy in the European Union between now and 2050. The legal framework in the member states of the

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...

is currently influenced by the EU's CHP Directive.

Cogeneration in Europe

The EU has actively incorporated cogeneration into its energy policy via the CHP Directive. In September 2008 at a hearing of the European Parliament's Urban Lodgment Intergroup, Energy Commissioner Andris Piebalgs is quoted as saying, "security of supply really starts with energy efficiency." Energy efficiency and cogeneration are recognized in the opening paragraphs of the European Union's Cogeneration Directive 2004/08/EC. This directive intends to support cogeneration and establish a method for calculating cogeneration abilities per country. The development of cogeneration has been very uneven over the years and has been dominated throughout the last decades by national circumstances. As a whole, the European Union currently generates 11% of its electricity using cogeneration, saving Europe an estimated 35 Mtoe per annum. However, there are large differences between the member states, with energy savings ranging from 2% to 60%. Europe has the three countries with the world's most intensive cogeneration economies: Denmark, the Netherlands and Finland. Other European countries are also making great efforts to increase their efficiency. Germany reports that over 50% of the country's total electricity demand could be provided through cogeneration. Germany set a target to double its electricity cogeneration from 12.5% of the country's electricity to 25% by 2020 and has passed supporting legislation accordingly in "Federal Ministry of Economics and Technology", (BMWi), Germany, August 2007. The UK is also actively supporting district heating. In the light of UK's goal to achieve an 80% reduction in carbon dioxide emissions by 2050, the government had set a target to source at least 15% of government electricity from CHP by 2010. Other UK measures to encourage CHP growth are financial incentives, grant support, a greater regulatory framework, and government leadership and partnership. According to the IEA 2008 modelling of cogeneration expansion for the G8 countries, expansion of cogeneration in France, Germany, Italy and the UK alone would effectively double the existing primary fuel savings by 2030. This would increase Europe's savings from today's 155 TWh to 465 TWh in 2030. It would also result in a 16% to 29% increase in each country's total cogenerated electricity by 2030. Governments are being assisted in their CHP endeavors by organizations like

COGEN Europe COGEN Europe is a European advocacy group based in Belgium that promotes the practice of cogeneration in energy production. The group acts as a liaison between its member companies and European Union The European Union (EU) is a supranat ...

who serve as an information hub for the most recent updates within Europe's energy policy. COGEN is Europe's umbrella organization representing the interests of the cogeneration industry, users of the technology and promoting its benefits in the EU and the wider Europe. The association is backed by the key players in the industry including gas and electricity companies, ESCOs, equipment suppliers, consultancies, national promotion organisations, financial and other service companies. A 2016 EU energy strategy suggests increased use of district heating.

Austria

The largest district heating system in Austria is in

Vienna en, Viennese , iso_code = AT-9 , registration_plate = W , postal_code_type = Postal code , postal_code = , timezone = CET , utc_offset = +1 , timezone_DST ...

(Fernwärme Wien) – with many smaller systems distributed over the whole country. District heating in Vienna is run by Wien Energie. In the business year of 2004/2005 a total of 5,163 GWh was sold, 1,602 GWh to 251,224 private apartments and houses and 3,561 GWh to 5211 major customers. The three large municipal waste

incinerators Incineration is a list of solid waste treatment technologies, waste treatment process that involves the combustion of substances contained in waste materials. Industrial plants for waste incineration are commonly referred to as waste-to-ene ...

provide 22% of the total in producing 116 GWh electric power and 1,220 GWh heat. Waste heat from municipal power plants and large industrial plants account for 72% of the total. The remaining 6% is produced by peak heating boilers from fossil fuel. A biomass-fired power plant has produced heat since 2006. In the rest of Austria the newer district heating plants are constructed as biomass plants or as CHP-biomass plants like the biomass district heating of Mödling or the biomass district heating of Baden. Most of the older fossil-fired district heating systems have a district heating accumulator, so that it is possible to produce the thermal district heating power only at that time where the electric power price is high.

Belgium

Belgium has district heating in multiple cities. The largest system is in the Flemish city

Ghent Ghent ( nl, Gent ; french: Gand ; traditional English: Gaunt) is a city and a municipality in the Flemish Region of Belgium. It is the capital and largest city of the East Flanders province, and the third largest in the country, exceeded in ...

, the piping network of this power plant is 22 km long. The system dates back to 1958.

Bulgaria

Bulgaria has district heating in around a dozen towns and cities. The largest system is in the capital

Sofia Sofia ( ; bg, София, Sofiya, ) is the capital and largest city of Bulgaria. It is situated in the Sofia Valley at the foot of the Vitosha mountain in the western parts of the country. The city is built west of the Iskar river, and ha ...

, where there are four power plants (two CHPs and two boiler stations) providing heat to the majority of the city. The system dates back to 1949.

Czech Republic

The largest district heating system in the

Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...

is in Prague owned and operated by Pražská teplárenská, serving 265,000 households and selling c. 13 PJ of heat annually. Most of the heat is actually produced as

waste heat Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility ...

in 30 km distant

Mělník Mělník (; german: Melnik) is a town in the Central Bohemian Region of the Czech Republic. It has about 19,000 inhabitants. The town centre is well preserved and is protected by law as an urban monument zone. Mělník lies in one of the most im ...

. There are many smaller central heating systems spread around the country including waste heat usage,

municipal solid waste Municipal solid waste (MSW), commonly known as trash or garbage in the United States and rubbish in Britain, is a waste type consisting of everyday items that are discarded by the public. "Garbage" can also refer specifically to food waste, ...

incineration Incineration is a waste treatment process that involves the combustion of substances contained in waste materials. Industrial plants for waste incineration are commonly referred to as waste-to-energy facilities. Incineration and other high ...

and .

Denmark

In Denmark district heating covers more than 64% of

and

. In 2007, 80.5% of this heat was produced by combined heat and power plants. Heat recovered from

waste incineration Incineration is a waste treatment process that involves the combustion of substances contained in waste materials. Industrial plants for waste incineration are commonly referred to as waste-to-energy facilities. Incineration and other high ...

accounted for 20.4% of the total Danish district heat production. In 2013, Denmark imported 158,000 ton waste for incineration. Most major cities in Denmark have big district heating networks, including transmission networks operating with up to 125 °C and 25 bar pressure and distribution networks operating with up to 95 °C and between 6 and 10 bar pressure. The largest district heating system in Denmark is in the

Copenhagen Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...

area operated by CTR I/S and VEKS I/S. In central Copenhagen, the CTR network serves 275,000 households (90–95% of the area's population) through a network of 54 km double district heating distribution pipes providing a peak capacity of 663 MW, some of which is combined with district cooling. The consumer price of heat from CTR is approximately €49 per MWh plus taxes (2009). Several towns have

with various types of

. The Danish island of

Samsø Samsø (Anglicized: "Samso" or "Samsoe") is a Danish island in the Kattegat off the Jutland Peninsula. Samsø is located in Samsø municipality. The community has 3,724 inhabitants (2017) (January 2010:4,010) called ''Samsings'' and is 114&n ...

has three straw-fueled plants producing district heating.

Finland

In Finland district heating accounts for about 50% of the total heating market, 80% of which is produced by combined heat and power plants. Over 90% of apartment blocks, more than half of all terraced houses, and the bulk of public buildings and business premises are connected to a district heating network.

Natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...

is mostly used in the south-east gas pipeline network, imported

is used in areas close to ports, and

peat Peat (), also known as turf (), is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. The peatland ecosystem covers and is the most efficien ...

is used in northern areas where peat is a local resource. Renewables, such as wood chips and other paper industry combustible by-products, are also used, as is the energy recovered by the

. Industrial units which generate heat as an industrial by-product may sell otherwise waste heat to the network rather than release it into the environment. Excess heat and power from pulp mill recovery boilers is a significant source in mill towns. In some towns waste incineration can contribute as much as 8% of the district heating heat requirement.

Availability In reliability engineering, the term availability has the following meanings: * The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at a ...

is 99.98% and disruptions, when they do occur, usually reduce temperatures by only a few degrees. In Helsinki, an underground

datacenter A data center (American English) or data centre (British English)See spelling differences. is a building, a dedicated space within a building, or a group of buildings used to house computer systems and associated components, such as telecommunic ...

next to the President's palace releases excess heat into neighboring homes, producing enough heat to heat approximately 500 large houses. A quarter of a million households around

Espoo Espoo (, ; sv, Esbo) is a city and municipality in the region of Uusimaa in the Republic of Finland. It is located on the northern shore of the Gulf of Finland, bordering the cities of Helsinki, Vantaa, Kirkkonummi, Vihti and Nurmijärvi ...

are scheduled to receive district heating from datacenters.

Germany

In Germany district heating has a market share of around 14% in the residential buildings sector. The connected heat load is around 52,729 MW. The heat comes mainly from cogeneration plants (83%). Heat-only boilers supply 16% and 1% is surplus heat from industry. The cogeneration plants use natural gas (42%), coal (39%), lignite (12%) and waste/others (7%) as fuel. The largest district heating network is located in Berlin whereas the highest diffusion of district heating occurs in

with around 90% market share. In

Munich Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the States of Germany, German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the List of cities in Germany by popu ...

about 70% of the electricity produced comes from district heating plants. District heating has rather little legal framework in Germany. There is no law on it as most elements of district heating are regulated in governmental or regional orders. There is no governmental support for district heating networks but a law to support cogeneration plants. As in the European Union the CHP Directive will come effective, this law probably needs some adjustment.

Greece

Greece has district heating mainly in the Province of

Western Macedonia Western Macedonia ( el, Δυτική Μακεδονία, translit=Ditikí Makedonía, ) is one of the thirteen regions of Greece, consisting of the western part of Macedonia. Located in north-western Greece, it is divided into the regional uni ...

, Central Macedonia and the Peloponnese Province. The largest system is the city of

Ptolemaida Ptolemaida ( el, Πτολεμαΐδα, Ptolemaïda, Katharevousa: Πτολεμαΐς, ''Ptolemaïs'') is a town and a former municipality in Kozani regional unit, Western Macedonia, Greece. Since the 2011 local government reform it is part of th ...

, where there are five power plants (

s or TPS in particular) providing heat to the majority of the largest towns and cities of the area and some villages. The first small installation took place in Ptolemaida in 1960, offering heating to Proastio village of

Eordaea Eordaea ( el, Ἐορδαία) was a geographical region of upper Macedonia and later an administrative region of the kingdom of Macedon. Eordaea was located south of Lynkestis, west of Emathia, north of Elimiotis and east of Orestis.Di ...

using the TPS of Ptolemaida. Today District heating installations are also available in

Kozani Kozani ( el, Κοζάνη, ) is a city in northern Greece, capital of Kozani regional unit and of Western Macedonia. It is located in the western part of Macedonia, in the northern part of the Aliakmonas river valley. The city lies above sea ...

, Ptolemaida, Amyntaio,

Philotas Philotas ( el, Φιλώτας; 365 BC – October 330 BC) was the eldest son of Parmenion, one of Alexander the Great's most experienced and talented generals. He rose to command the Companion Cavalry, but was accused of conspiring against Alex ...

, Serres and

Megalopolis A megalopolis () or a supercity, also called a megaregion, is a group of metropolitan areas which are perceived as a continuous urban area through common systems of transport, economy, resources, ecology, and so on. They are integrated enoug ...

using nearby power plants. In Serres the power plant is a Hi-Efficiency CHP Plant using natural gas, while coal is the primary fuel for all other district heating networks.

Hungary

According to the 2011 census there were 607,578 dwellings (15.5% of all) in Hungary with district heating, mostly panel flats in urban areas. The largest district heating system located in

Budapest Budapest (, ; ) is the capital and most populous city of Hungary. It is the ninth-largest city in the European Union by population within city limits and the second-largest city on the Danube river; the city has an estimated population ...

, the municipality-owned ''Főtáv Zrt.'' ("Metropolitan Teleheating Company") provides heat and piped hot water for 238,000 households and 7,000 companies.

Iceland

93% of all housing in Iceland enjoy district heating services – 89.6% from geothermal energy, Iceland is the country with the highest penetration of district heating. There are 117 local district heating systems supplying towns as well as rural areas with hot water – reaching almost all of the population. The average price is around US$0.027 per kWh of hot water. Southwest Iceland and Reykjavík's hot water supply for district heating comes from three geothermal power plants, producing over 800 MWth: * Svartsengi Combined heat and power plant (CHP) * Nesjavellir CHP plant * Hellisheiði CHP plant

Ireland

The Dublin Waste-to-Energy Facility will provide district heating for up to 50,000 homes in

Poolbeg Poolbeg () is an artificial peninsula extending from Ringsend, Dublin, into Dublin Bay. History The Poolbeg peninsula was built between the mid 18th century and the present day, starting with the Ballast Office Wall, the first section of the ...

and surrounding areas. Some existing residential developments in the North Docklands have been constructed for conversion to district heating – currently using on-site gas boilers – and pipes are in place in the

Liffey Service Tunnel The Liffey Service Tunnel is a service tunnel for various pipelines in Dublin, Ireland, owned by Dublin City Council. Project The tunnel was designed by British company Atkins and constructed by a joint venture of the German contractor Zübl ...

to connect these to the incinerator or other waste heat sources in the area. Tralee in Co Kerry has a 1 MW district heating system providing heat to an apartment complex, sheltered housing for the elderly, a library and over 100 individual houses. The system is fuelled by locally produced wood chip. In Glenstal Abbey in Co Limerick there exists a pond-based 150 kW heating system for a school. A scheme to use waste heat from an

Amazon Web Services Amazon Web Services, Inc. (AWS) is a subsidiary of Amazon that provides on-demand cloud computing platforms and APIs to individuals, companies, and governments, on a metered pay-as-you-go basis. These cloud computing web services provide d ...

datacentre in Tallaght is intended to heat 1200 units and municipal buildings

Italy

In Italy, district heating is used in some cities (

Bergamo Bergamo (; lmo, Bèrghem ; from the proto- Germanic elements *''berg +*heim'', the "mountain home") is a city in the alpine Lombardy region of northern Italy, approximately northeast of Milan, and about from Switzerland, the alpine lakes Como ...

Brescia Brescia (, locally ; lmo, link=no, label= Lombard, Brèsa ; lat, Brixia; vec, Bressa) is a city and ''comune'' in the region of Lombardy, Northern Italy. It is situated at the foot of the Alps, a few kilometers from the lakes Garda and Iseo. ...

Cremona Cremona (, also ; ; lmo, label= Cremunés, Cremùna; egl, Carmona) is a city and ''comune'' in northern Italy, situated in Lombardy, on the left bank of the Po river in the middle of the ''Pianura Padana'' ( Po Valley). It is the capital of th ...

Bolzano Bolzano ( or ; german: Bozen, (formerly ); bar, Bozn; lld, Balsan or ) is the capital city of the province of South Tyrol in northern Italy. With a population of 108,245, Bolzano is also by far the largest city in South Tyrol and the third la ...

Verona Verona ( , ; vec, Verona or ) is a city on the Adige River in Veneto, Northern Italy, Italy, with 258,031 inhabitants. It is one of the seven provincial capitals of the region. It is the largest city Comune, municipality in the region and the ...

Ferrara Ferrara (, ; egl, Fràra ) is a city and ''comune'' in Emilia-Romagna, northern Italy, capital of the Province of Ferrara. it had 132,009 inhabitants. It is situated northeast of Bologna, on the Po di Volano, a branch channel of the main stream ...

Imola Imola (; rgn, Jômla or ) is a city and ''comune'' in the Metropolitan City of Bologna, located on the river Santerno, in the Emilia-Romagna region of northern Italy. The city is traditionally considered the western entrance to the historical ...

Modena Modena (, , ; egl, label=Emilian language#Dialects, Modenese, Mòdna ; ett, Mutna; la, Mutina) is a city and ''comune'' (municipality) on the south side of the Po Valley, in the Province of Modena in the Emilia-Romagna region of northern I ...

Reggio Emilia Reggio nell'Emilia ( egl, Rèz; la, Regium Lepidi), usually referred to as Reggio Emilia, or simply Reggio by its inhabitants, and known until 1861 as Reggio di Lombardia, is a city in northern Italy, in the Emilia-Romagna region. It has abou ...

Terlan Terlan (; it, Terlano ) is a ''comune'' (municipality) in South Tyrol in northern Italy. Geography The municipal area is situated within the Adige Valley, about northwest of the city of Bolzano. Terlan is famous for its wine and asparagus produ ...

Turin Turin ( , Piedmontese language, Piedmontese: ; it, Torino ) is a city and an important business and cultural centre in Northern Italy. It is the capital city of Piedmont and of the Metropolitan City of Turin, and was the first Italian capital ...

Parma Parma (; egl, Pärma, ) is a city in the northern Italian region of Emilia-Romagna known for its architecture, Giuseppe Verdi, music, art, prosciutto (ham), Parmigiano-Reggiano, cheese and surrounding countryside. With a population of 198,292 ...

, Lodi, and now

Milan Milan ( , , Lombard: ; it, Milano ) is a city in northern Italy, capital of Lombardy, and the second-most populous city proper in Italy after Rome. The city proper has a population of about 1.4 million, while its metropolitan city h ...

). The district heating of Turin is the biggest of the country and it supplies 550.000 people (62% of the whole city population).

Latvia

In Latvia, district heating is used in major cities such as

Riga Riga (; lv, Rīga , liv, Rīgõ) is the capital and largest city of Latvia and is home to 605,802 inhabitants which is a third of Latvia's population. The city lies on the Gulf of Riga at the mouth of the Daugava river where it meets the Ba ...

, Daugavpils,

Liepāja Liepāja (; liv, Līepõ; see #Names and toponymy, other names) is a state city in western Latvia, located on the Baltic Sea. It is the largest-city in the Kurzeme Planning Region, Kurzeme Region and the third-largest city in the country after R ...

Jelgava Jelgava (; german: Mitau, ; see also other names) is a state city in central Latvia about southwest of Riga with 55,972 inhabitants (2019). It is the largest town in the region of Zemgale (Semigalia). Jelgava was the capital of the united Du ...

. The first district heating system was constructed in Riga in 1952. Each major city has a local company responsible for the generation, administration, and maintenance of the district heating system.

Netherlands

District heating is used in

Rotterdam Rotterdam ( , , , lit. ''The Dam on the River Rotte'') is the second largest city and municipality in the Netherlands. It is in the province of South Holland, part of the North Sea mouth of the Rhine–Meuse–Scheldt delta, via the ''"N ...

Amsterdam Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the Capital of the Netherlands, capital and Municipalities of the Netherlands, most populous city of the Netherlands, with The Hague being the seat of government. It has a population ...

Utrecht Utrecht ( , , ) is the List of cities in the Netherlands by province, fourth-largest city and a List of municipalities of the Netherlands, municipality of the Netherlands, capital and most populous city of the Provinces of the Netherlands, pro ...

, and

Almere Almere () is a planned city and municipality in the province of Flevoland, Netherlands, located about 20 km to the east of Amsterdam (as the crow flies) across the IJmeer. Bordering Lelystad and Zeewolde, the municipality of Almere comprise ...

with more expected as the government has mandated a transition away from natural gas for all homes in the country by 2050. The town of Heerlen has developed a grid using water in disused coalmines as a source and storage for heat and cold. This is a good example of a 5th generation heating and cooling grid

North Macedonia

District heating is only available in Skopje. Balkan Energy Group (BEG) operates three DH production plants, which cover majority of the network, and supply heat to around 60,000 households in Skopje, more than 80 buildings in the educational sector (schools and kindergartens) and more than 1,000 other consumers (mostly commercial). The three BEG production plants use natural gas as a fuel source. There is also one cogeneration plant TE-TO AD Skopje producing heat delivered to the Skopje district heating system. The share of cogeneration in DH production was 47% in 2017. The distribution and supply of district heating is carried out by companies owned by BEG.

Norway

In Norway district heating only constitutes approximately 2% of energy needs for heating. This is a very low number compared to similar countries. One of the main reasons district heating has a low penetration in Norway is access to cheap hydro-based electricity, and 80% of private electricity consumption goes to heat rooms and water. However, there is district heating in the major cities.

Poland

In 2009, 40% of Polish households used district heating, most of them in urban areas. Heat is provided primarily by combined heat and power plants, most of which burn hard coal. The largest district heating system is in Warsaw, owned and operated by Veolia Warszawa, distributing approx. 34 PJ annually.

Romania

The largest district heating system in

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...

is in

Bucharest Bucharest ( , ; ro, București ) is the capital and largest city of Romania, as well as its cultural, industrial, and financial centre. It is located in the southeast of the country, on the banks of the Dâmbovița River, less than north of ...

. Owned and operated by RADET, it distributes approximately 24 PJ annually, serving 570 000 households. This corresponds to 68% of Bucharest's total domestic heat requirements (RADET fulfills another 4% through single-building boiler systems, for a total of 72%).

Russia

In most Russian cities, district-level combined heat and power plants () produce more than 50% of the nation's electricity and simultaneously provide hot water for neighbouring city blocks. They mostly use

- and

-powered

steam turbine A steam turbine is a machine that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. Fabrication of a modern steam turbin ...

s for cogeneration of heat. Now,

combined cycle gas turbine A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turb ...

s designs are beginning to be widely used as well.

Serbia

Serbia Serbia (, ; Serbian language, Serbian: , , ), officially the Republic of Serbia (Serbian language, Serbian: , , ), is a landlocked country in Southeast Europe, Southeastern and Central Europe, situated at the crossroads of the Pannonian Bas ...

, district heating is used throughout the main cities, particularly in the capital,

Belgrade Belgrade ( , ;, ; Names of European cities in different languages: B, names in other languages) is the Capital city, capital and List of cities in Serbia, largest city in Serbia. It is located at the confluence of the Sava and Danube rivers a ...

. The first district heating plant was built in 1961 as a means to provide effective heating to the newly built suburbs of

Novi Beograd New Belgrade ( sr, / , ) is a municipality of the city of Belgrade. It is a planned city, built since 1948 in a previously uninhabited area on the left bank of the Sava river, opposite old Belgrade. In recent years, it has become the central bu ...

. Since then, numerous plants have been built to heat the ever-growing city. They use natural gas as fuel, because it has less of an effect on the environment. The district heating system of Belgrade possesses 112 heat sources of 2,454 MW capacity, over 500 km of pipeline, and 4,365 connection stations, providing district heating to 240,000 apartments and 7,500 office/commercial buildings of total floor area exceeding 17,000,000 square meters.

Slovakia

Slovakia's centralised heating system covers more than 54% of the overall demand for heat. In 2015 approximately 1.8 million citizens, 35% of the total population of Slovakia, were served by district heating. The infrastructure was built mainly during the 1960s and 1980s. In recent years large investments were made to increase the share of renewable energy sources and energy efficiency in district heating systems. The heat production comes mostly from natural gas and biomass sources, and 54% of the heat in district heating is generated through cogeneration. The distribution system consists of 2800 km of pipes. Warm and hot water are the most common heat carriers, but older high-pressure steam transport still accounts for around one-quarter of the primary distribution, which results in more losses in the system. In terms of the market structure, there were 338 heat suppliers licensed to produce and/or distribute heat in 2016, of which 87% were both producers and distributors. Most are small companies that operate in a single municipality, but some large companies such as Veolia are also present in the market. The state owns and operates large co-generation plants that produce district heat and electricity in six cities (Bratislava, Košice, Žilina, Trnava, Zvolen and Martin). Multiple companies can operate in one city, which is the case in larger cities. A large share of DH is produced by small natural gas heat boilers connected to blocks of buildings. In 2014, nearly 40% of the total DH generation was from natural gas boilers, other than co-generation.

Sweden

Sweden has a long tradition for using district heating (fjärrvärme) in urban areas. In 2015, about 60% of Sweden's houses (private and commercial) were heated by district heating, according to the Swedish association of district heating. The city of

Växjö Växjö ( ) is a city and the seat of Växjö Municipality, Kronoberg County, Sweden. It had 70,489 inhabitants (2019) out of a municipal population of 95,995 (2021). It is the administrative, cultural, and industrial centre of Kronoberg County ...

reduced its emissions from fossil fuels by 34% from 1993 to 2009. This was to achieved largely by way of biomass fired district heating. Another example is the plant of

Enköping Enköping is a locality and the seat of Enköping Municipality, Uppsala County, Sweden with 30,000 inhabitants in 2018. Geography Enköping is situated near Lake Mälaren, about 78 km west of Stockholm. A comparably large number of S ...

, combining the use of short rotation plantations both for fuel as well as for phytoremediation. 47% of the heat generated in Swedish district heating systems are produced with renewable

bioenergy Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms biom ...

sources, as well as 16% in

waste-to-energy Waste-to-energy (WtE) or energy-from-waste (EfW) is the process of generating energy in the form of electricity and/or heat from the primary treatment of waste, or the processing of waste into a fuel source. WtE is a form of energy recovery. Mo ...

plants, 7% is provided by

s, 10% by

flue-gas condensation Flue gas condensation is a process, where flue gas is cooled below its water dew point and the heat released by the resulting condensation of water is recovered as low temperature heat. Cooling of the flue gas can be performed either directl ...

and 6% by industrial

waste heat recovery A waste heat recovery unit (WHRU) is an energy recovery heat exchanger that transfers heat from process outputs at high temperature to another part of the process for some purpose, usually increased efficiency. The WHRU is a tool involved in cogen ...

. The remaining are mostly fossil fuels: oil (3%), natural gas (3%),

(2%), and coal (1%). Because of the law banning traditional

landfill A landfill site, also known as a tip, dump, rubbish dump, garbage dump, or dumping ground, is a site for the disposal of waste materials. Landfill is the oldest and most common form of waste disposal, although the systematic burial of the waste ...

s, waste is commonly used as a fuel.

Ukraine

United Kingdom

In the United Kingdom, district heating became popular after World War II, but on a restricted scale, to heat the large residential estates that replaced areas devastated by the

Blitz Blitz, German for "lightning", may refer to: Military uses *Blitzkrieg, blitz campaign, or blitz, a type of military campaign *The Blitz, the German aerial campaign against Britain in the Second World War *, an Imperial German Navy light cruiser b ...

. In 2013 there were 1,765 district heating schemes with 920 based in London alone. In total around 210,000 homes and 1,700 businesses are supplied by heat networks in the UK. The

Pimlico District Heating Undertaking The Pimlico District Heating Undertaking (PDHU) is a district heating system in the Pimlico area of London, United Kingdom. The first district heating system built in the United Kingdom, it is owned by Westminster City Council and operated by City ...

(PDHU) first became operational in 1950 and continues to expand to this day. The PDHU once relied on waste heat from the now-disused

Battersea Power Station Battersea Power Station is a decommissioned Grade II* listed coal-fired power station, located on the south bank of the River Thames, in Nine Elms, Battersea, in the London Borough of Wandsworth. It was built by the London Power Company (LPC) ...

on the South side of the

River Thames The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, se ...

. It is still in operation, the water now being heated locally by a new energy centre which incorporates 3.1 MWe / 4.0 MWth of gas fired CHP engines and 3 × 8 MW gas-fired boilers. One of the United Kingdom's largest district heating schemes is EnviroEnergy in

Nottingham Nottingham ( , East Midlands English, locally ) is a city status in the United Kingdom, city and Unitary authorities of England, unitary authority area in Nottinghamshire, East Midlands, England. It is located north-west of London, south-east ...

. The plant initially built by

Boots A boot is a type of footwear. Boot or Boots may also refer to: Businesses * Boot Inn, Chester, Cheshire, England * Boots (company), a high-street pharmacy chain and manufacturer of pharmaceuticals in the United Kingdom * The Boot, Cromer St ...

is now used to heat 4,600 homes, and a wide variety of business premises, including the Concert Hall, the

Nottingham Arena Motorpoint Arena (originally the Nottingham Arena) is a multi-use indoor arena joined with the National Ice Centre in the Lace Market district of Nottingham, England. The National Ice Centre and Nottingham Arena were opened by Olympic gold m ...

, the Victoria Baths, the

Broadmarsh Shopping Centre Broadmarsh is a historic area of Nottingham, England. The area was subjected to large scale slum clearance, creating large spaces used for regeneration. A shopping centre, car park, bus station and road complex created in the early 1970s cut-t ...

, the

Victoria Centre Victoria Centre is a shopping centre in Nottingham, England, constructed between 1967 and 1972. It contains fashion and high street chain stores as well as cafes, restaurants, a health and fitness centre, and the Nottingham Victoria bus station. ...

, and others. The heat source is a

incinerator. Scotland has several district heating systems with the first in the UK being installed at Aviemore and others following at Lochgilphead, Fort William and Forfar.

Sheffield Sheffield is a city status in the United Kingdom, city in South Yorkshire, England, whose name derives from the River Sheaf which runs through it. The city serves as the administrative centre of the City of Sheffield. It is Historic counties o ...

's district heating network was established in 1988 and is still expanding today. It saves an equivalent 21,000 plus tonnes of CO₂ each year when compared to conventional sources of energy – electricity from the national grid and heat generated by individual boilers. There are currently over 140 buildings connected to the district heating network. These include city landmarks such as the

Sheffield City Hall Sheffield City Hall is a Grade II* listed building in Sheffield, England in Barker's Pool, one of the city's central squares. It was built and is owned by Sheffield City Council but is now managed by the Sheffield City Trust, under a 99-year l ...

, the Lyceum Theatre, the

University of Sheffield , mottoeng = To discover the causes of things , established = – University of SheffieldPredecessor institutions: – Sheffield Medical School – Firth College – Sheffield Technical School – University College of Sheffield , type = Pu ...

Sheffield Hallam University Sheffield Hallam University (SHU) is a public research university in Sheffield, South Yorkshire, England. The university is based on two sites; the City Campus is located in the city centre near Sheffield railway station, while the Collegiate Cr ...

, hospitals, shops, offices and leisure facilities plus 2,800 homes. More than 44 km of underground pipes deliver energy which is generated at Sheffield Energy Recovery Facility. This converts 225,000 tonnes of waste into energy, producing up to 60 MWe of thermal energy and up to 19 MWe of electrical energy. The

Southampton District Energy Scheme The Southampton District Energy Scheme is a district heating and district cooling, cooling system in Southampton, United Kingdom. The system is owned and operated by ENGIE. History In the 1980s the Department of Energy (United Kingdom), Departmen ...

was originally built to use just geothermal energy, but now also uses the heat from a gas fired CHP generator. It supplies heating and district cooling to many large premises in the city, including the

Westquay Westquay (formerly WestQuay) is a shopping centre in Southampton, England. It has an area of of retail and leisure space and contains around 130 shops, including major retailers such as John Lewis and Partners, Marks and Spencer, Zara, Schuh ...

shopping centre, the De Vere Grand Harbour hotel, the

Royal South Hants Hospital The Royal South Hants Hospital, known locally as "The RSH", is a community hospital in Southampton. It is managed by NHS Property Services. History The hospital was founded as a voluntary hospital in 1835 and moved into its first premises in ...

, and several housing schemes. In the 1980s

Southampton Southampton () is a port city in the ceremonial county of Hampshire in southern England. It is located approximately south-west of London and west of Portsmouth. The city forms part of the South Hampshire built-up area, which also covers Po ...

began utilising combined heat and power district heating, taking advantage of geothermal heat "trapped" in the area. The geothermal heat provided by the well works in conjunction with the Combined Heat and Power scheme. Geothermal energy provides 15–20%,

fuel oil Fuel oil is any of various fractions obtained from the distillation of petroleum (crude oil). Such oils include distillates (the lighter fractions) and residues (the heavier fractions). Fuel oils include heavy fuel oil, marine fuel oil (MFO), bun ...

10%, and

natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...

70% of the total heat input for this scheme and the combined heat and power generators use conventional fuels to make electricity. "Waste heat" from this process is recovered for distribution through the 11 km mains network. Lerwick District Heating Scheme is of note because it is one of the few schemes where a completely new system was added to a previously existing small town. ADE has an online map of district heating installations in the UK. ADE estimates that 54 percent of energy used to produce electricity is being wasted via conventional power production, which relates to £9.5 billion ($US12.5 billion) per year.

Spain

North America

In North America, district heating systems fall into two general categories. Those that are owned by and serve the buildings of a single entity are considered institutional systems. All others fall into the commercial category.

Canada

District Heating is becoming a growing industry in Canadian cities, with many new systems being built in the last ten years. Some of the major systems in Canada include: * Calgary:

ENMAX Enmax Corporation (often styled as ENMAX) is a vertically integrated utility that generates and distributes electricity, natural gas, renewable energy, and value-added services to customers in Alberta, Canada. Overview Enmax, headquartered in C ...

currently operates the Calgary Downtown District Energy Centre which provides heating to up to of new and existing residential and commercial buildings. The District Energy Centre began operations in March 2010 providing heat to its first customer, the City of Calgary Municipal building. *

Edmonton Edmonton ( ) is the capital city of the Canadian province of Alberta. Edmonton is situated on the North Saskatchewan River and is the centre of the Edmonton Metropolitan Region, which is surrounded by Alberta's central region. The city ancho ...

: The community of Blatchford, which is currently being developed on the grounds of Edmonton's former City Centre Airport, is launching a District Energy Sharing System (DESS) in phases. A geo-exchange field went online in 2019, and Blatchford's energy utility is in the planning and design phase for a sewage heat exchange system. *

Hamilton Hamilton may refer to: People * Hamilton (name), a common British surname and occasional given name, usually of Scottish origin, including a list of persons with the surname ** The Duke of Hamilton, the premier peer of Scotland ** Lord Hamilt ...

, ON has a district heating and cooling system in the downtown core, operated by HCE Energy Inc. * Montreal has a district heating and cooling system in the downtown core. *

Toronto Toronto ( ; or ) is the capital city of the Canadian province of Ontario. With a recorded population of 2,794,356 in 2021, it is the most populous city in Canada and the fourth most populous city in North America. The city is the ancho ...

: **

Enwave Enwave Energy Corporation is a Canadian energy company headquartered in Toronto that provides sustainable district energy solutions including heating, cooling, hot water, combined heat and power, geoexchange, energy storage, sewer heat, waste- ...

provides district heating and cooling within the downtown core of

, including deep lake cooling technology, which circulates cold water from Lake Ontario through heat exchangers to provide cooling for many buildings in the city. ** Creative Energy is constructing a combined-heat-and-power district energy system for the

Mirvish Village Palmerston-Little Italy is a neighbourhood in central Toronto, Ontario, Canada. Its boundaries, according to the City of Toronto, are by Bathurst Street to the east, Bloor Street to the north, Dovercourt Road to the west and College Street to th ...

development. *

Surrey Surrey () is a ceremonial and non-metropolitan county in South East England, bordering Greater London to the south west. Surrey has a large rural area, and several significant urban areas which form part of the Greater London Built-up Area. ...

: Surrey City Energy owned by the city, provides district heating to the city's City Centre district. *

Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...

: ** Creative Energy's Beatty Street facility has operated since 1968 and provides a central heating plant for the city's downtown core of

. In addition to heating 180 buildings, the Central Heat Distribution network also drives a

steam clock A steam clock is a clock which is fully or partially powered by a steam engine. Only a few functioning steam clocks exist, most designed and built by Canadian horologist Raymond Saunders for display in urban public spaces. Steam clocks built ...

. Work is currently underway to move the facility from natural gas to electric equipment. ** A large scale district heating system known as the Neighbourhood Energy Utility in the South East False Creek area is in initial operations with natural gas boilers and serves the 2010 Olympic Village. The untreated sewage heat recovery system began operations in January 2010, supplying 70% of annual energy demands, with retrofit work underway to move the facility off its remaining natural gas use. * Windsor, Ontario has a district heating and cooling system in the downtown core. * Drake Landing Solar Community, AB, is small in size (52 homes) but notable for having the only

system in North America. * London, Ontario and Charlottetown, PEI have district heating co-generation systems owned and operated by

Veresen Veresen Inc. was a Calgary, Alberta-based energy infrastructure company with three main lines of business: pipelines, natural gas and power generation. It was a publicly-traded company on the Toronto Stock Exchange, and was known as Fort Chicago ...

. *

Sudbury, Ontario Sudbury, officially the City of Greater Sudbury is the largest city in Northern Ontario by population, with a population of 166,004 at the 2021 Canadian Census. By land area, it is the largest in Ontario and the fifth largest in Canada. It is a ...

has a district heating cogeneration system in its downtown core, as well as a standalone cogeneration plant for the

Sudbury Regional Hospital Health Sciences North is a teaching hospital in Greater Sudbury, Ontario, Canada. HSN offers a variety of programs and services, with regional programs in the areas of cardiac care, oncology, nephrology, trauma and rehabilitation. Patients visit ...

. In addition, Naneff Gardens, a new residential subdivision off Donnelly Drive in the city's Garson neighbourhood, features a geothermal district heating system using technology developed by a local company, Renewable Resource Recovery Corporation. * Ottawa, contains a significant district heating and cooling system serving the large number of federal government buildings in the city. The system loop contains nearly of chilled or heated water at any time. * Cornwall, Ontario operates a district heating system which serves a number of city buildings and schools. *

Markham, Ontario Markham () is a city in the Regional Municipality of York, Ontario, Canada. It is approximately northeast of Downtown Toronto. In the 2021 Census, Markham had a population of 338,503, which ranked it the largest in York Region, fourth largest ...

: Markham District Energy operates several district heating sites: ** Warden Energy Centre (c. 2000), Clegg Energy Centre and Birchmount Energy Centre serving customers in the Markham Centre area ** Bur Oak Energy Centre (c. 2012) serving customers in the Cornell Centre area Many Canadian universities operate central campus heating plants.

United States

The

Holly Steam Combination Company The Holly Steam Combination Company was an American company that was the first steam heating producer to commercially distribute district heating from a central steam heating system. The company was established in 1877 by engineer Birdsill Holly ...

was the first steam heating company to commercially distribute district heating from a central steam heating system. As of 2013, approximately 2,500 district heating and cooling systems existed in the United States, in one form or another, with the majority providing heat. * Consolidated Edison of New York (Con Ed) operates the

, the largest commercial district heating system in the United States. The system has operated continuously since March 3, 1882 and serves Manhattan Island from the Battery through 96th Street. In addition to providing space- and water-heating, steam from the system is used in numerous restaurants for food preparation, for process heat in laundries and dry cleaners, for steam sterilization, and to power absorption chillers for

air conditioning Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...

. On July 18, 2007, one person was killed and numerous others injured when a steam pipe exploded on 41st Street at Lexington. On August 19, 1989, three people were killed in an explosion in Gramercy Park. *

Milwaukee Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee is ...

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

has been using district heating for its

central business district A central business district (CBD) is the commercial and business centre of a city. It contains commercial space and offices, and in larger cities will often be described as a financial district. Geographically, it often coincides with the "city ...

since the Valley Power Plant commenced operations in 1968. The air quality in the immediate vicinity of the plant, has been measured with significantly reduced ozone levels. The 2012 conversion of the plant, which changed the fuel input from

, is expected to further improve air quality at both the local César Chavez sensor as well as

Antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other ...

sensors The Wisconsin power plants double as breeding grounds for peregrine falcons. * Denver's district steam system is the oldest continuously operated commercial district heating system in the world. It began service November 5, 1880 and continues to serve 135 customers. The system is partially powered by the

Xcel Energy Xcel Energy Inc. is an American utility holding company based in Minneapolis, Minnesota, serving more than 3.7 million electric customers and 2.1 million natural gas customers in Colorado, Texas, and New Mexico in 2019. It consists of four ope ...

Zuni

Cogeneration Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time. Cogeneration is a more efficient use of fuel or heat, because otherwise- wasted heat from elect ...

Station, which was originally built in 1900. *

NRG Energy NRG Energy, Inc. is an American energy company, headquartered in Houston, Texas. It was formerly the wholesale arm of Northern States Power Company (NSP), which became Xcel Energy, but became independent in 2000. NRG Energy is involved in ener ...

operates district systems in the cities of San Francisco,

Harrisburg Harrisburg is the capital city of the Pennsylvania, Commonwealth of Pennsylvania, United States, and the county seat of Dauphin County, Pennsylvania, Dauphin County. With a population of 50,135 as of the 2021 census, Harrisburg is the List of c ...

Minneapolis Minneapolis () is the largest city in Minnesota, United States, and the county seat of Hennepin County. The city is abundant in water, with thirteen lakes, wetlands, the Mississippi River, creeks and waterfalls. Minneapolis has its origins ...

, Omaha,

Pittsburgh Pittsburgh ( ) is a city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County, Pennsylvania, Allegheny County. It is the most populous city in both Allegheny County and Wester ...

, and

San Diego San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the List of United States cities by population, eigh ...

. * Seattle Steam Company, a district system operated by Enwave, in Seattle. Enwave also operates district heat system in

Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

Houston Houston (; ) is the most populous city in Texas, the most populous city in the Southern United States, the fourth-most populous city in the United States, and the sixth-most populous city in North America, with a population of 2,304,580 in ...

Las Vegas Las Vegas (; Spanish for "The Meadows"), often known simply as Vegas, is the 25th-most populous city in the United States, the most populous city in the state of Nevada, and the county seat of Clark County. The city anchors the Las Vegas ...

Los Angeles Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

New Orleans New Orleans ( , ,New Orleans
Merriam-Webster. ; french: La Nouvelle-Orléans , es, Nuev ...

, and

Portland Portland most commonly refers to: * Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States * Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...

along with additional Canadian cities. * Detroit Thermal operates a district system in

Detroit Detroit ( , ; , ) is the largest city in the U.S. state of Michigan. It is also the largest U.S. city on the United States–Canada border, and the seat of government of Wayne County. The City of Detroit had a population of 639,111 at th ...

that started operation at the

Willis Avenue Station The Willis Avenue station was an elevated rapid transit station of the Willis Avenue Spur that branched off of the IRT Third Avenue Line in the Bronx, New York City. It opened in 1886 and closed in 1924. History Willis Avenue station was opened ...

in 1903, originally operated by Detroit Edison. * Citizens Energy Group in

Indianapolis Indianapolis (), colloquially known as Indy, is the state capital and most populous city of the U.S. state of Indiana and the seat of Marion County. According to the U.S. Census Bureau, the consolidated population of Indianapolis and Marion ...

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...

, operates the Perry K. Generating Station, a gas-fired power plant that produces and distributes steam to about 160 downtown Indianapolis customers. *

Lansing Board of Water & Light The Lansing Board of Water & Light is a publicly owned, municipal utility that provides electricity and water to the residents of the cities of Lansing and East Lansing, Michigan, and the surrounding townships of Delta, Delhi, Meridian and DeWi ...

, a municipal utility system in

Lansing, Michigan Lansing () is the capital of the U.S. state of Michigan. It is mostly in Ingham County, although portions of the city extend west into Eaton County and north into Clinton County. The 2020 census placed the city's population at 112,644, making ...

operates a heated and chilled water system from their existing coal plant. They have announced their new natural gas cogeneration plant will continue to provide this service. * Cleveland Thermal operates a district steam (since 1894) from the Canal Road plant near The Flats and district cooling system (since 1993) from Hamilton Avenue plant on the bluffs east of downtown. *

operates district heating/co-generation plants in

Ripon, California Ripon is a city located in San Joaquin County, California. The population was 14,297 at the 2010 census. Ripon was originally known as Stanislaus City, but was renamed for Ripon, Wisconsin, in 1876. History Ripon, on the site previously known as ...

, and

San Gabriel, California San Gabriel (Spanish for " St. Gabriel") is a city located in the San Gabriel Valley of Los Angeles County, California. At the 2010 census, the population was 39,718. San Gabriel was founded by the Spanish in 1771, when Mission San Gabriel Arc ...

. * Veolia Energy, a successor of the 1887 Boston Heating Company, operates a district system in

Boston Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...

and

Cambridge, Massachusetts Cambridge ( ) is a city in Middlesex County, Massachusetts, United States. As part of the Boston metropolitan area, the cities population of the 2020 U.S. census was 118,403, making it the fourth most populous city in the state, behind Boston, ...

, and also operates systems in Philadelphia PA, Baltimore MD, Kansas City MO, Tulsa OK, Houston TX and other cities. * District Energy St. Paul operates the largest hot water district heating system in North America and generates the majority of its energy from an adjacent biomass-fueled combined heat and power plant. In March 2011, a 1 MWh thermal solar array was integrated into the system, consisting of 144 20' x 8' solar panels installed on the roof of a customer building, RiverCentre. * The California Department of General Services runs a central plant providing district heating to four million square feet in 23 state-owned buildings, including the State Capitol, using high-pressure steam boilers. Historically, district heating was primarily used in urban areas of the US, but by 1985, it was mainly used in institutions. A handful of smaller municipalities in

New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...

maintained municipal steam into the 21st century, in cities like Holyoke, Massachusetts and

Concord, New Hampshire Concord () is the capital city of the U.S. state of New Hampshire and the seat of Merrimack County. As of the 2020 census the population was 43,976, making it the third largest city in New Hampshire behind Manchester and Nashua. The village of ...

, however the former would end service in 2010 and the latter in 2017, attributing aging infrastructure and capital expenses to their closures. In 2019, Concord replaced a number of remaining pipes with more efficient ones for a smaller steam system heating only the State House and

State Library A national library is established by the government of a nation to serve as the pre-eminent repository of information for that country. Unlike public libraries, they rarely allow citizens to borrow books. Often, they include numerous rare, valuab ...

, mainly due to historic preservation reasons rather than a broader energy plan. BGSU Heating Plant Interior

District heating is also used on many college campuses, often in combination with district cooling and electricity generation. Colleges using district heating include the

University of Texas at Austin The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...

;

Rice University William Marsh Rice University (Rice University) is a Private university, private research university in Houston, Houston, Texas. It is on a 300-acre campus near the Houston Museum District and adjacent to the Texas Medical Center. Rice is ranke ...

;

Brigham Young University Brigham Young University (BYU, sometimes referred to colloquially as The Y) is a private research university in Provo, Utah. It was founded in 1875 by religious leader Brigham Young and is sponsored by the Church of Jesus Christ of Latter-day ...

;

Georgetown University Georgetown University is a private university, private research university in the Georgetown (Washington, D.C.), Georgetown neighborhood of Washington, D.C. Founded by Bishop John Carroll (archbishop of Baltimore), John Carroll in 1789 as Georg ...

;

Cornell University Cornell University is a private statutory land-grant research university based in Ithaca, New York. It is a member of the Ivy League. Founded in 1865 by Ezra Cornell and Andrew Dickson White, Cornell was founded with the intention to teach an ...

, which also employs

deep water source cooling Deep water source cooling (DWSC) or deep water air cooling is a form of air cooling for process and comfort space cooling which uses a large body of naturally cold water as a heat sink. It uses water at 4 to 10 degrees Celsius drawn from deep area ...

using the waters of nearby

Cayuga Lake Cayuga Lake (,,) is the longest of central New York's glacial Finger Lakes, and is the second largest in surface area (marginally smaller than Seneca Lake) and second largest in volume. It is just under long. Its average width is , and it is ...

;

Purdue University Purdue University is a public land-grant research university in West Lafayette, Indiana, and the flagship campus of the Purdue University system. The university was founded in 1869 after Lafayette businessman John Purdue donated land and money ...

;

University of Massachusetts Amherst The University of Massachusetts Amherst (UMass Amherst, UMass) is a public research university in Amherst, Massachusetts and the sole public land-grant university in Commonwealth of Massachusetts. Founded in 1863 as an agricultural college, ...

;

University of Maine at Farmington The University of Maine at Farmington (UMaine Farmington or UMF) is a public liberal arts college in Farmington, Maine. It is part of the University of Maine System and a founding member of the Council of Public Liberal Arts Colleges. Histo ...

;

University of Notre Dame The University of Notre Dame du Lac, known simply as Notre Dame ( ) or ND, is a private Catholic research university in Notre Dame, Indiana, outside the city of South Bend. French priest Edward Sorin founded the school in 1842. The main campu ...

;

Michigan State University Michigan State University (Michigan State, MSU) is a public university, public Land-grant university, land-grant research university in East Lansing, Michigan. It was founded in 1855 as the Agricultural College of the State of Michigan, the fi ...

;

Eastern Michigan University Eastern Michigan University (EMU, Eastern Michigan or simply Eastern), is a public research university in Ypsilanti, Michigan. Founded in 1849 as Michigan State Normal School, the school was the fourth normal school established in the United Sta ...

; Case Western Reserve University;

Iowa State University Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a public land-grant research university in Ames, Iowa. Founded in 1858 as the Iowa Agricultural College and Model Farm, Iowa State became one of the n ...

;

University of Delaware The University of Delaware (colloquially UD or Delaware) is a public land-grant research university located in Newark, Delaware. UD is the largest university in Delaware. It offers three associate's programs, 148 bachelor's programs, 121 mas ...

;

University of Maryland, College Park The University of Maryland, College Park (University of Maryland, UMD, or simply Maryland) is a public land-grant research university in College Park, Maryland. Founded in 1856, UMD is the flagship institution of the University System of Mary ...

University of Wisconsin–Madison A university () is an educational institution, institution of higher education, higher (or Tertiary education, tertiary) education and research which awards academic degrees in several Discipline (academia), academic disciplines. Universities ty ...

University of Georgia , mottoeng = "To teach, to serve, and to inquire into the nature of things.""To serve" was later added to the motto without changing the seal; the Latin motto directly translates as "To teach and to inquire into the nature of things." , establ ...

University of Cincinnati The University of Cincinnati (UC or Cincinnati) is a public research university in Cincinnati, Ohio. Founded in 1819 as Cincinnati College, it is the oldest institution of higher education in Cincinnati and has an annual enrollment of over 44,00 ...

North Carolina State University North Carolina State University (NC State) is a public land-grant research university in Raleigh, North Carolina. Founded in 1887 and part of the University of North Carolina system, it is the largest university in the Carolinas. The universit ...

, and several campuses of the

University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Francisco, ...

MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...

installed a cogeneration system in 1995 that provides electricity, heating and cooling to 80% of its campus buildings. The

University of New Hampshire The University of New Hampshire (UNH) is a public land-grant research university with its main campus in Durham, New Hampshire. It was founded and incorporated in 1866 as a land grant college in Hanover in connection with Dartmouth College, mo ...

has a cogeneration plant run on

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...

from an adjacent landfill, providing the university with 100% of its heat and power needs without burning oil or natural gas. North Dakota State University (NDSU) in Fargo, North Dakota has used district heating for over a century from their coal-fired heating plant.

Asia

Japan

87 district heating enterprises are operating in Japan, serving 148 districts. Many companies operate district cogeneration facilities that provide steam and/or hot water to many of the office buildings. Also, most operators in the

Greater Tokyo The Greater Tokyo Area is the most populous metropolitan area in the world, consisting of the Kantō region of Japan (including Tokyo Metropolis and the prefectures of Chiba, Gunma, Ibaraki, Kanagawa, Saitama, and Tochigi) as well as the pre ...

serve district cooling.

China

In southern

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

(south of the

Qinling–Huaihe Line The Qinling–Huaihe Line () is a reference line used by geographers to distinguish between northern and southern China, corresponding roughly to the 33rd parallel. Qinling refers to the Qin Mountains, and Huaihe refers to the Huai River. Runn ...

), there are nearly no district heating systems. In northern China, district heating systems are common. Most district heating system which are just for heating instead of CHP use

hard coal Anthracite, also known as hard coal, and black coal, is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the high ...

. Since

air pollution in China Pollution in China is one aspect of the broader topic of environmental issues in China. Various forms of pollution have increased as China has industrialised, which has caused widespread environmental health problems.Jared Diamond, '' Collapse: ...

has become quite serious, many cities gradually are now using

rather than coal in district heating system. There is also some amount of

and sea

systems. In February 2019, China's

State Power Investment Corporation State Power Investment Corporation Limited (abbreviation SPIC) is one of the five major electricity generation companies in China. It was the successor of China Power Investment Corporation after it was merged with the State Nuclear Power Tec ...

(SPIC) signed a cooperation agreement with the

Baishan Baishan (, ko, 백산시) is a prefecture-level city in southeastern Jilin province, in the Dongbei (northeastern) part of China. "" literally means "White Mountain", and is named after Changbai Mountain (, also known as Paektu Mountain (Kor ...

municipal government in

Jilin Jilin (; alternately romanized as Kirin or Chilin) is one of the three provinces of Northeast China. Its capital and largest city is Changchun. Jilin borders North Korea (Rasŏn, North Hamgyong, Ryanggang and Chagang) and Russia (Prim ...

province for the Baishan Nuclear Energy Heating Demonstration Project, which would use a

China National Nuclear Corporation The China National Nuclear Corporation (CNNC; ) is a state-owned enterprise founded in 1955 in Beijing. CNNC's president and vice-president are appointed by the Premier of the People's Republic of China. CNNC oversees all aspects of China's civ ...

DHR-400 (District Heating Reactor 400 MWt). Building cost is 1.5 billion yuan ($230 million), taking three years to build.

Turkey

Geothermal energy in Turkey provides some district heating, and residential district heating and cooling requirements have been mapped.

Market penetration

Penetration of district heating (DH) into the heat market varies by country. Penetration is influenced by different factors, including environmental conditions, availability of heat sources, economics, and economic and legal framework. The

aims to develop sustainable practices through implementation of district heating and cooling technology. In the year 2000 the percentage of houses supplied by district heat in some European countries was as follows: In Iceland the prevailing positive influence on DH is availability of easily captured

geothermal heat Geothermal heating is the direct use of geothermal energy for some heating applications. Humans have taken advantage of geothermal heat this way since the Paleolithic era. Approximately seventy countries made direct use of a total of 270 PJ o ...

. In most Eastern European countries, energy planning included development of

and district heating. Negative influence in the Netherlands and UK can be attributed partially to milder climate, along with competition from

. The tax on domestic gas prices in the UK is a third of that in France and a fifth of that in Germany.

Footnotes

External links

UK's Information Portal on Decentralised and District Energy

District Energy Library

Technical description of district heating and district cooling at Munich Airport, Germany

Geothermal District Heating, Iceland

* ttp://www.maxfordham.com/news/publications/a-case-against-the-widespread-use-of-district-heating-and-chp-in-the-uk Max Fordham argues against use of CHP District Heating
Energy Hub – EU funded FP7 Project – District heating, cooling and power aiming for 100% on-site renewable energy at Leuven, Belgium

* ttp://www.benuk.net A Balanced Energy Network integrates heat pumps, demand side response and distributed heat storage in a district heat sharing network.
Heat Interface UnitsThe Celsius Toolbox – Information on district energy solutions and energy transition.
{{DEFAULTSORT:District heating American inventions Energy conservation Residential heating

History

Generations of district heating

First generation

Second generation

Third generation

Fourth generation

Fifth generation/cold district heating

Heat sources

Combustion of fossil or renewable fuels

Nuclear fission

Natural underground heat

Solar heat

Low temperature natural or waste heat

Heat accumulators and storage

Heat distribution

Heat metering

Size of systems

Pros and cons

Ownership, monopoly issues and charging structures

National variation

Europe

Cogeneration in Europe

Austria

Belgium

Bulgaria

Czech Republic

Denmark

Finland

Germany

Greece

Hungary

Iceland

Ireland

Italy

Latvia

Netherlands

North Macedonia

Norway

Poland

Romania

Russia

Serbia

Slovakia

Sweden

Ukraine

United Kingdom

Spain

North America

Canada

United States

Asia

Japan

China

Turkey

Market penetration

See also

Footnotes

External links