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District Heating and Cooling
in Copenhagen
Part of our Low Carbon Copenhagen project ... project index >
introduction  •  combined heat + power  •  Copenhagen's network  •  sources
key facts  •  urban planning timeline  •  pedestrianisation timeline  •  Denmark timeline
Copenhagen's network
Copenhagen's district heating network combines 160km of primary pipes and 1,500km of distribution pipes with 10 main combined heat and power (CHP) stations, three heat storage installations, pumping stations and peak load plants to form the largest such system in the world. It supplies 98% of the city's heat needs. In addition, Denmark's first district cooling network opened in central Copenhagen in 2010.
The heating network covers the city centre and 15 suburban districts. At the moment, cooling is only supplied to the city centre. Citizens own both systems, either directly through co-operatives or indirectly via municipal companies.
The Danish government is responsible for overall energy policy, legislation, tax regimes and subsidies, while the local municipalities are responsible for heat planning, project implementation and connections to the network, which are now compulsory (electric heating in buildings is not allowed).
District heating in Copenhagen
The district heating network
A plan of Copenhagen's integrated city-wide network —
see it larger and read its key. Diagram courtesy Rambøll.
District heating diagram courtesy Ramboll
There are two main district heating networks. One is run by Central Kommunernes Transmissionsselskab (CTR), otherwise known as the Metropolitan Copenhagen District Heating Company. The other is run by Vestegnens Kraftvarmeselskab (VEKS).
These, and the smaller Copenhagen Energy (steam) and Vestforbrænding (waste-to-energy) networks, are integrated into one system that is computer controlled from CTR's Frederiksberg operations centre. The distribution network is owned and operated by Copenhagen Energy (which is also a partner in CTR). The four companies sell heat to local district heating companies, who then re-sell it to consumers ..... more on network set-up >
District heating pipework
Denmark is a market leader in the design of pipes for district heating. The steel twin-bore pipes have plastic — or sometimes steel or concrete — casings and are packed with insulation and buried in drained soil. The 160km-long Copenhagen primary network carries hot water or steam to the city's distribution network through 250-800mm diameter pipes, which even run beneath Copenhagen Harbour in a purpose-built tunnel.
The 1,500km small-diameter distribution network combines 1,370km of hot water and 130km of steam twin-bore pipes. Hot water is delivered at 115 deg C to each building, where it is used to heat the building's own water-based central heating system via heat exchangers. Doing this cools the district heating water down (to 55 deg C) and it returns through the network for re-heating and re-circulation. It doesn't mix with the water flowing through building systems.
For Copenhageners, hot water 'on tap' is completely normal. There are heat (energy) meters at the point of heat supply to a building, and if there are multiple users, heat allocators can be attached to radiators to record how much heat each device uses. There are also water (flow) meters.
Citizens pay for heat in the same way they pay for other metered utilities like water or electricity. At the moment, Copenhagen Energy reads domestic meters every second year, with customers doing it in between. A three-tier tariff applies based on capacity (20-25%), heat consumption (75-80%) and cooling (for low return temperatures, not district cooling, which is separate). Prices are usually the same across the city, and a typical home costs around 11,350 Kroner (including taxes) to heat for a year — half of the cost of oil-fired heating.
Remote meter reading is being introduced, and a pilot project is underway. Data recorded includes energy consumption, flow and temperatures. It's hoped that this will be useful for implementing energy saving initiatives. Probably the best incentive is people being able to see how much energy (and water) they use and self-regulating accordingly. Danish heat and water taxes are high.
The steam network
Localised steam supply started in Frederiksberg, Copenhagen, in 1903 with a service supporting the city's hospitals, based on waste incineration. Buildings close to the hospitals were gradually connected to the early system — the start of Copenhagen's district heating is usually stated as 1925. Although hot water district heating now supplies most of the city, steam is still supplied to major city-centre customers and covers 25% of Copenhagen's heat demand.
Expansion of the steam network ceased in 1980 and work has begun to convert it to hot water. Conversion is planned to be completed by 2025. Driving this move is the better distribution efficiency of the hot water system, the higher efficiency of CHP plants producing hot water and the decrease in CO2 emissions achievable by making the change.
District cooling
Copenhagen's — and Denmark's — first district cooling plant opened on 10th June 2010 in Adelgade in the city centre near the Rosenborg Gardens. It supplies cold to major local customers in place of individual air conditioning installations. Another plant near City Hall should be operational by 2012-13.
The Adelgade plant is located inside the country's first electricity generating station, which dates from 1892 but has been idle since the 1970s. The plant uses two kinds of absorption chillers to convert waste heat or wind power to cold. It also makes good use of the power station's original cooling pipes, which connect to Copenhagen Harbour and bring seawater for additional cooling. The pipes are almost 1m in diameter and lie 6m underground.
back to introduction >
Top links
Central Kommunernes Transmissionsselskab (CTR)   www.ctr.dk
CTR operates the district heating in Copenhagen's city centre and eastern areas
Vestegnens Kraftvarmeselskab (VEKS)   www.veks.dk
VEKS operates the district heating in the city's western areas
Copenhagen Energy (Københavns Energi)   www.ke.dk
Non-profit public-shareholding energy company owned by the Municipality of Copenhagen
The Main District Heating Network in Copenhagen   www.ctr.dk/download.pdf
Pdf publication by the heating company CTR, one of the two big district heating supplliers
District Heating in Greater Copenhagen   www.ea-energianalyse.dk/download.pdf
Presentation given at COP15, December 2009
Copenhagen District Heating System   www.copenhagenenergysummit.org/download.pdf
Copenhagen Energy's award application document describes the system in detail
YouTube   www.youtube.com/watch?v=S3vNOIwCbHs
Part 1 of a 3-part video by Denmarks' Channel 6 on district heating
YouTube   www.youtube.com/watch?v=nqal_3DsHi8
Part 2 of the video looks at fuel types for CHP plants
Part 3 of Channel 6's video shows pipe manufacture and system components ...
introduction  •  combined heat + power  •  Copenhagen's network  •  sources
key facts  •  urban planning timeline  •  pedestrianisation timeline  •  Denmark timeline
images  courtesy Rambøll
sources and references  see sources
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"... they thought we were crazy."
Peter Bach, DEA regulator on reactions in the 1980s
"The ... concept is commonly accepted by the population, not least because it underpins the political tradition to create incentives that would benefit the society and pave the way for collective energy systems."
Application for 2009 Global District Energy Climate Award
Significant characteristics —
Danish district heating
— An integral part of national energy policy
— Strong support from central authorities using tax incentives, zoning, energy planning, building regulations, subsidies, etc.
— Strong support from municipalities
— Increasing heat-supply market share
— Consumer ownership
— Stable financing
— The variety of technical solutions and fuel types
— Support for design development and co-operation between developers
— Large-scale integrated systems with optimized load dispatch
— The use of heat accumulation tanks as part of system optimization
— Staightforward technical solutions
— Heat metering
see  www.dbdh.dk
District heating timeline
1925 ... Copenhagen's network founded
pre 1950 ... city centre steam heating
1970 ... network supplies 34% of city's heat demand
1973 ... worldwide oil crisis
1973 ... Denmark importing 80% of its oil supplies
1975 ... policy report calls for energy savings + CHP
1976 ... Danish Energy Plan '76 (January)
1976 ... CHP set as standard for power generation
1976 ... Danish Energy Authority established (April)
1977 ... state subsidy for using CHP surplus heat
1977 ... oil tax introduced
1979 ... Energy Report '79 (January)
1979 ... plan to use natural gas over oil for CHP
1979 ... second worldwide oil crisis
1979 ... Denmark passes Heat Supply Law
1980 ... state subsidy on residential energy savings
1981 ... Denmark-wide heat planning begins
1981 ... Energy Plan '81 (December)
1984 ... Heat Plan Denmark
1984 ... CTR and VEKS established
1984 ... North Sea natural gas production begins
mid 1980s ... tax incentives on power-plant fuel
mid 1980s ... big district heating expansion
1988 ... Denmark's first biomass/biogas plants open
1988 ... electric heating banned in new buildings
1988 ... and banned in district heating areas
1990 ... Energy 2000 - Action Plan (April)
1990 ... Denmark's second Heat Supply Law
1992 ... subsidies on a range of energy areas
1993 ... Danish government favours biomass
1993 ... district heating mandatory for all buildings
1996 ... Energy 21 action plan (April)
1998 ... Denmark self-sufficient in energy
1999 ... liberalisation of the electricity market
2000 ... Climate 2012 (March)
2000 ... Denmark's third Heat Supply Law
2008 ... 98% of city's heat demand met
2009 ... steam DH conversion to hot water begins
2010 ... city's first district cooling plant opens
2015 ... city expects 20% less overall CO2 emissions
2025 ... city's steam phase-out to be complete
see  www.ens.dk
see  www.ke.dk